THE E F F E C T OF SELECTED CHELATING AGENTS, GROWTH REGULA­ TORS, RESPIRATORY INHIBITORS AND ANTIBIOTICS ON THE LIFE OF CUT FLOWERS, WITH SPECIAL REFERENCE TO ANTIRRHINUM MAJUS By JAMES D. KELLEY AN ABSTRACT Subm itted to the School for Advanced Graduate Studies of M ichigan State U niversity of A griculture and Applied Science in p a rtia l fulfillm ent of the requirem ents for the degree of DOCTOR OF PHILOSOPHY D epartm ent of H orticulture 1957 Approved_ JAMES D. KELLEY ABSTRACT The effect of chelating agents, growth reg u lato rs, re s p ira to ry inhibi­ to rs, antibiotics, and cathode radiation on the keeping quality of cut flow ers, e s ­ p ecially A ntirrhinum m aju s, has been studied. Seven v a rie tie s of A ntirrhinum m ajus and two v a rie tie s of Rosa hybrida as well as Lilium speciosum rubrum and G erb era jam esonii w ere used in these experim ents. Of the 20 chelating agents tested, C upferron (Ammonium salt of Nnitroso-N -phenyl-hydroxylam ine) was the m ost effective. Cupferron in creased the cut life of A ntirrhinum m ajus four to nine days, and Rosa hybrida one and one-half days, but had no effect on the life of Lilium speciosum rubrum and G erb era jam eso n ii. A num ber of other chelating agents prolonged the life of A ntirrhinum m ajus two to four days. In tr ia ls using su cro se and Cupferron it was found that two percen t sucro se and 200 p a rts p e r m illion C upferron in d istilled w ater was as effective in extending cut life of A ntirrhinum m ajus as any com m ercial floral p r e s e r v a ­ tive tested, but when su cro se and C upferron w ere added to tap w ater, cut life was shortened. F o lia r applications of 1000 p a rts p e r m illion C upferron at pH 3. 0 and 7. 0, one and th re e days p r io r to harvest, and fo liar applications of 1000, 2000 and 4000 p a rts p e r m illion m aleic hydrazide one and th ree days before h arv est did not affect the cut life of A ntirrhinum m ajus, v ariety Snowman. M aleic h y d ra­ zide, when added to the keeping w ater at a concentration of 250 and 500 p a rts p e r m illion, in c re a se d the life of A ntirrhinum m ajus two and one-half to four days. A num ber of other growth reg u lato rs w ere tested, but m aleic hydrazide was the only one found to be effective in extending cut life of A ntirrhinum m ajus. R esp ira to ry inhibitors added to the keeping w ater proved to be in ­ effective in extending the cut life of flow ers. Two antibiotics, Actidione and Endomycin, at 100 p a rts p e r m illion extende^ cut life of Better T im es ro se s one and one-half to two and one-half days. Cathode radiation shortened the cut life of Better T im es ro se s at dos­ ages between ten and 1500 rep s. Radiation re su lte d in p rem atu re bluing and crinkling of p etals, and at higher concentration petal burn and leaf ab scissio n o ccurred. The effectiveness of C upferron and other chelating agents in extending cut flow er life is a ttrib u ted to a possible reduction in resp iratio n , an inhibition of auxin synthesis and a reduction of bacterial growth. The effect of m aleic hydrazide in prolonging cut life is believed due to a reduction in resp ira tio n and the acceleratio n of indoleacetic acid destruction within the plant. THE E F F E C T OF SELECTED CHELATING AGENTS, GROWTH REGULA­ TORS, RESPIRATORY INHIBITORS AND ANTIBIOTICS ON THE LIFE OF CUT FLOWERS, WITH SPECIAL REFERENCE TO ANTIRRHINUM MAJUS By JAMES D. KELLEY A THESIS Subm itted to the School for Advanced G raduate Studies of Michigan State U niversity of A griculture and Applied Science in p a rtia l fulfillm ent of the requirem ents for the degree of DOCTOR OF PHILOSOPHY D epartm ent of H orticulture 1957 ProQuest Number: 10008590 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. uest ProQuest 10008590 Published by ProQuest LLC (2016). Copyright of the Dissertation is held by the Author. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code Microform Edition © ProQuest LLC. ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106- 1346 Gr ACKNOWLEDGEMENTS The author w ishes to ex p ress his appreciation and sin ce re thanks to Dr. C h arles L. H am ner for his constant assistan c e and enthusiastic e n ­ couragem ent throughout the course of this investigation, and for his help in the p re p ara tio n of the m anuscript. A ppreciation is due Dr. R. S. Bandurski, P ro fesso r P. R. Krone, D r. R. F. Stinson, Dr. C. E. Wildon, and Dr. S. H. W ittwer for th e ir ad ­ vice and review ing of the m anuscript. The author e x p resses appreciation also to the M ichigan State F lo ris ts A ssociation, whose financial aid made this work possible. TABLE OF CONTENTS Page 1 INTRODUCTION.................................................................................. REVIEW OF L IT E R A T U R E .................................................... 3 G e n e r a l............................................................................ 3 Chelating A g e n ts ........................................................... 5 Growth R e g u la to r s ....................................................... 8 R esp ira to ry In h ib ito rs ................................................ 10 A ntibiotics and Cathode R a d ia tio n ........................ 13 MATERIALS AND M ETH O D S................................................. 16 EXPERIMENTAL R ESU LTS.................................................... 24 P relim in ary T r i a l s ...................................................... 24 Chelating A g e n ts ............................................................ 27 Growth R e g u la to r s ....................................................... 45 R esp ira to ry I n h i b i t o r s ............................................... 52 A ntibiotics and Cathode R a d ia tio n ......................... 62 DISCUSSION................................................................................. 70 CONCLUSIONS...................................................................................... 74 LITERATURE CITED ........................................................................ 78 INTRODUCTION M ore than 80 p ercen t of the re ta il flo rist business co n sists of the sale of cut flow ers. Although considerable em phasis in re s e a rc h work has been placed on im proving v a rie tie s, in creasin g production and reducing production cost, little em phasis has been placed on extending the life of the cut flower once it is in the hands of the consum er. Since much tim e and effort go into the production and m arketing of cut flow ers, it is only natural that the con­ su m er be allowed to gain the maximum amount of enjoyment and p leasu re from them , a s it is the cut life of the flower that determ ines its value. M ost studies for extending cut flower life have concerned environ­ m ental facto rs previous to cutting, stage of development at harvest, tim e of day fo r cutting, depth of holding w ater, inhibiting with chem icals, fungal and b a cte rial growth in w ater and daily cutting of stem s. It was decided that the m ost fruitful a re a of study of this problem would be in attem pting to find a chem ical or chem icals that would effect the m etabolic p ro c e ss within the flower a fte r cutting. The effect of chelating agents, re s p ira to ry inhibitors, growth regulators, antibiotics and cathode irrid a tio n of ro se s (Rosa hybrida), snapdragons (A ntirrhinum m ajus) and sev eral other flow ers was studied. The purpose of this investigation was to study the effectiveness of some of these new er and u n tried compounds in prolonging the life of cut flow ers at room tem p eratu re. Chelating agents w ere used, since it has been recognized that these substances effect growth (Heath and Clark, 1956; Beiler and M artin, 1954; W einstein et a l., 1956). A large num ber of re sp ira to ry inhibitors a re also known to effect plant m etabolism and thus a num ber w ere used in the work with A ntirrhinum m aju s. Growth reg u lato rs have played a m ajor p a rt in the development of ag ricu ltu re in the la st 20 y e ars. Compounds such as indole-3-acetic acid, 2, 4-dichlorophenoxyacetic acid, m aleic hydrazide, 2, 4, 5-trichlorophenoxyacetic acid and o th ers have found application in fruit setting, weed control, plant propagation and flow er induction. It is believed that this type of com ­ pound m ay also be effective in extending cut flow er life. A ntibiotics have been shown by Nickell and Finlay (1954) to effect plant growth. They found sev eral antibiotics that significantly reduced the growth of Lem m a m in o r. Also Ham ner (1957) has found the antibiotic Neomycin to affect plant development. Irrad iatio n also effects plant development. Skoog (1935) has rep o rted that X -ray s p a rtia lly inactivated the growth horm ones norm ally p resen t in p lants. 3 REVIEW OF LITERATURE G eneral In 1906 the f ir s t published work appeared concerning the prolonga­ tion of the life of cut flow ers by the use of chem icals being added to the w ater in which stem s of the flow ers w ere placed. F ourten and Ducoment (1906) r e ­ p o rte d that potassium hydroxide, calcium hydroxide, potassium chloride and su cro se w ere favorable in extending the life of some cut flow ers, such as p rim u la, a sp eru la and silene, to 9 days from a norm al life of 4 days. Knudson (1914), however, was unable to substantiate the favorable re su lts of Fourten and Ducoment. L au rie (1928) found that one-tenth of one p ercent boric acid in creased the keeping tim e of carnations 3 to 7 days, and obviated the need for cutting the stem s or daily changing of w ater. He also found that one-half of a tablet of a sp irin added to two q u arts of w ater prolonged the life of chrysanthem um s and dahlias. The life of a s te rs was doubled with the use of a one p ercen t sugar solution. L a te r w ork by L au rie (1936) indicated that copper w ire in g lass con­ ta in e rs affected the life of sev e ral cut flow ers, including a s te r, stocks, snap­ dragons and m arigold. T hese p lants lasted 1 to 2. 7 days longer than controls. Copper proved d etrim en tal to carnations. He also showed that of all cut flow ers tested, depth of w ater in the container was not a factor in determ ining cut life. Hitchcock and Z im m erm an (1929) using 50 chem icals, including aspirin, found that none w ere noticeably effective in prolonging the life of cut flow ers. Bossard and V e rd ier (1951) conducted te sts to determ ine the effect of a num ber of chem icals on the keeping quality of dahlias. They added to the w ater in which the cut flow ers w ere standing such m a te ria ls as sodium chloride, potassium perm anganate, silv e r n itrate, ortho-oxyquinoline sulfate, etc. A p ro p rie ta ry substance containing silv er n itrate was the m ost successful, p r o ­ longing the life of dahlias fo r 3 to 4 days. T incker (1942) states that no highly effective h arm le ss chem ical has yet been sa tisfa c to rily used to prolong the cut life of flow ers, and that the m ost ce rtain way to prolong life of flow ers is to low er the tem p eratu re of the room s which they decorate. Low tem p eratu re is very effective in prolonging the cut life of flow ers and is now a com m ercially accepted p ractice. It was rep o rted by P e rre t (1907) that a low tem p eratu re was a v ery effective m eans of p re se rv in g cut flow ers, and he co n sid ered rela tiv e humidity to be an im portant facto r also, with lim its of 60 to 90 p erc en t of satu ratio n being m ost favorable. Low tem p e ra tu re was beneficial in p ractically all case s on the m ore im portant com m ercial flow ers, according to Hitchcock and Z im m erm an (1929). 5 They reaso n ed that since low tem p eratu re (3° to 10° C) will r e ta rd the m a tu r­ ing p ro c e ss e s in flow ers, attem pts w ere made to find a chem ical treatm en t which would produce sim ila r re s u lts at room tem p eratu re. H ardening of carnations for 24 hours at 40°F and no re frig e ra tio n a f­ te r cutting showed no significant differences in the keeping life of the flow ers, according to K nappenberger (1954). Tim e of cutting has been shown to also affect cut life. Howland (1945) found that greenhouse ro se s, v ariety Better Tim es, cut in the afternoon kept longer than those cut in the m orning. During the w inter and spring, those cut at 4:30 p. m. kept 7 p erce n t (7. 4 hours) longer than those cut at 8:00 a. m. But K nappenberger (1954) was unable to find significant differences in cut life of carnations, w hether cut during the m orning or afternoon. Chelating Agents Chelating agents have been shown to effect plant growth and naturally o ccu rrin g chelates in biological system s a re very common. Among the n a tu r­ ally o ccu rrin g chelates found in m ost plants a re the peroxidases, the cytochrom es, the p o rp h y rin s and catalase. T hese enzym es c a rry on vital functions in the o r ­ ganism , such as the cataly sis of oxidation-reduction reactions, o x y g en -carry ­ ing power, hydrolysis of pro tein s, decarboxylation, etc. 6 The addition of synthetic chelating agents has a profound effect on p lan ts and anim als. A chelating agent may p a rtia lly o r com pletely inhibit a m etal enzyme function if it is powerful enough to com pete with the enzyme fo r the m etal (M artell and Calvin, 1952). Z en tm y er (1943) suggested that the fungicidal action of oxines (d e ri­ v atives of 8-hydroxyquinoline) was due to the inactivation of essen tial m etal ions in the enzym e system s. Beiler and M artin (1954) have used chelating agents such as v ersen e (ethylenediam inetetra acetic acid), diphenylthiocarbazone and tetra eth y lth iu ran disulfide to inhibit the activity of 5-hydroxytryptophan decarboxylase. They concluded that enzyme activity depends on the p resen ce of a m etallic ion and that the inhibition obtained with chelating agents is due to the rem oval of this m etal from the enzyme com plex by these agents. E thylenediam inetetraacetate (EDTA) has been shown to cause injury to young tom ato shoots s im ila r to injury produced by lycom arasm in and fu saric acid (Gaumann and Naef-Roth, 1954). Again the injurious effect was believed to be due to the capacity of the chelating agent to fix m etal ions essen tial for the m etabolism of enzym es. Singh (1956) also noted the injurious effect of m etal chelating agents on growth of cucum ber seedlings. He obtained m arked inhibition of growth of cucum ber seedlings with a num ber of chelating agents. M etal chelating agents have been found to stim ulate as well as in­ hibit growth of higher plants. Heath and C lark (1956) have re p o rted that growth 7 of wheat coleoptiles was in c re ased by the use of ethylenediam inetetraacetate, 8-hydroxyquinoline, sodium diethyldithiocarbam ate (DIECA) and im inodiacetic acid. Root growth was inhibited by these chem icals. Weinstein_et al., (1956) obtained an in c re a se in height, fre sh weight and dry weight of soybeans by the use of disodium ethylenediam inetetraacetate (Na2 EDTA). H e rr et aL (1956) have found EDTA has a slight activating effect on aconitase activity, and W einstein et al. (1956) showed EDTA stim ulated polyphenol oxidase activity. Altm ann (1953) attrib u ted the activating effect of some che­ lating agents to th eir ability to rem ove heavy m etals from the reactin g system . Chelating agents can also inhibit enzyme activity. H e rr (1956) has r e ­ p o rted that ortho-phenanthroline, pyrophosphate, 8-hydroxyquinoline and alpha, alpha-dipyridyl inhibit aconitase activity. Increasing concentrations of Na£EDTA ' have been shown to d ecrease the activity of cytochrom e oxidase and asco rb ic acid oxidase (W einstein et a l . , 1956). They suggested that the d ecrease in cytochrom e oxidase activity may be due to successful competition by EDTA with porphyrin fo r iron, resu ltin g in d ecreased synthesis of the enzyme or d ire c t inhibition of p ro te in synthesis. In w orking with chelating agents it is often difficult to determ ine which m etal ion is being chelated. Ethylenediam ine tetra a c e ta te (EDTA) strongly chelates m ost of the m etals and has a high w ater solubility both as 8 s a lts and chelates (M artell and Calvin, 1952). A lbert and Gledhill (1947) have shown that few chelating reagents show tru e specificity for a m etal and that a v ery larg e num ber of reagents will chelate copper. They also found that a given chelate reagent will chelate the different m etal ions in various degrees. The chelates in th e ir study w ere divided into hydrophobic and hydrophilic ch elat­ ing agents. Hydrophobic ones being those that produce an insoluble p recip ita te in w ater and hydrophilic ones producing a w ater soluble compound. Growth R egulators M aleic hydrazide has been one of the m ore p rom ising growth reg u ­ la to rs in re g a rd to p ossible use in extending the life of cut flow ers (G riesel 1954; Lougheed 1954). O ther growth reg u lato rs have been used with some su c­ c e ss. M aleic hydrazide has been shown to be an antiauxin by Leopold and Klein (1951). It was shown that auxins have the capacity to overcom e m aleic hydrazide inhibition com pletely over a wide range of concentrations of the in ­ hibitor. Indoleacetic acid and naphthaleneacetic acid w ere the auxins capable of reliev in g m aleic hydrazide inhibition. Isenberg (1954) found that m aleic hydrazide was stim ulatory to r e s ­ p ira tio n of Sweet Spanish onions at lower concentrations and inhibitory at high 9 concentrations. He attrib u ted the d ecrease in resp iratio n of sto red onions tre a te d with m aleic hydrazide to an inhibition of succinic dehydrogenase. The aging p ro c e ss e s in the intact flower of Magnolia grandiflora w ere re ta rd e d by spraying at anthesis with m aleic hydrazide (G riesel, 1954). It was found that sta rc h re s e rv e s did not d ecrease as rapidly in the tre a te d as in the u n treated flow ers, and it was suggested that the retard atio n of starch digestion m ay account in p a rt for low ered resp iratio n , observed by other in ­ v estig ato rs, in m aleic hydrazide tre a te d plants. Lougheed (1954) has rep o rted that when cut ro se s w ere dipped in a 0. 3 p ercen t solution of m aleic hydrazide (MH-30) they could be kept for up to two weeks. Kalin (1955) has rep o rted that 0. 03 percent m aleic hydrazide was not effective in prolonging the life of cut daffodil flow ers held at room tem p eratu res. Growth reg u la to rs a re also effective in preventing bud and flower dropping. W arne (1947) found that by spraying inflorescences of lupines 4 or 5 hours after cutting with 400 to 800 p a rts p e r m illion alpha-naphthylacetic acid (NAA) or beta-indolylacetic acid (IAA) th ere was a great reduction in the amount and ra te of shedding buds and flow ers in the fir s t three days. ■Whiteman (1949) found that sodium alpha-naphthyl acetate, a growth substance used to prev en t fru it drop, prevented shattering of peony p etals when the cut flow ers w ere placed in a 50 p a rts p e r m illion solution. One year the 10 life of the cuf flow ers was extended from 4 to 8 days by this treatm ent, but in the subsequent two seasons, although sh atterin g was prevented, life was not prolonged. The keeping quality of lilies of the valley was considerably im ­ proved by 25 p a rts p e r m illion of the hormone in solution. T e sts with c a rn a ­ tions, gladoli, Iris re tic u la ta , G erm an iris , ro se s and perennial pea w ere ineffective. One of the f ir s t compounds found to act as an anti-auxin was gam m aphenylbutyric acid. O ther anti-auxin like substances which have been found to inhibit growth a re 2, 3, 5-triiodobenzoic acid and coum arin (Galston, 1947; Thim ann and Bonner, 1949). A ndreae and Andreae (1953) have shown the lactone, m ethyl um belliferone, to be effective in in creasin g the enzym atic destru ctio n of indoleacetic acid and that this excessive destruction of indoleacetic acid m ay inhibit growth. R esp irato ry Inhibitors The term plant re sp ira tio n has been defined as "all those m ateria l changes undergone by com plex ce llu lar substances" (James, 1953). R e s p ir­ ation is thus a com plex sequence of chem ically re v e rsib le and irre v e rs ib le reactio n s. The re sp ira tio n ra te of plants is m easu red by th e ir oxygen con­ sum ption o r carbon dioxide production, o r both. The ra te of re sp ira tio n of plant m a te ria l is dependent upon a num ­ b e r of environm ental facto rs, such as tem perature, carbon dioxide con cen tra­ tion, and light intensity, as well as age of the tissu e and genetic constitution of the plant. H ere we a re concerned p rim a rily with tem p eratu re as it effects re sp ira tio n . As e a rly a s 1874 it was shown that a r is e of tem p eratu re is likely to a c c e le ra te the re sp ira tio n ra te . At tem p eratu res n ear 0°C, r e s p ir ­ ation is usually m easu rab le, but very slow, but as tem p eratu re is in creased up to 40-50°C the re sp ira tio n ra te in creases. Numerous in v estig ato rs have shown that the Q^q for plant m ateria l is usually between 2 and 4, depending on the plant and the te m p era tu re range. Because of this effect of tem p eratu re on resp iratio n , plant products when harvested a re kept at reduced tem p e ra ­ tu re s until used. Cut flow ers a re no exception. Flow ers, a fte r cutting, a re kept under re frig e ra tio n to prevent rapid development and subsequent death. Through re frig e ra tio n enzym atic activity of the cells is reduced, and this, in turn, reduces the ra te of resp ira tio n . In apples, the relationship b e ­ tween re sp ira tio n ra te and duration of storage life has been dem onstrated by Kidd and W est (1930). They showed that approxim ately equal am ounts of carbon dioxide will have been lib erated at the tim e when apple tiss u e s collapse, re g a rd le ss of the tem p era tu re at which they have been stored. The sam e may be tru e for cut flow ers, that is, only a certain amount of re sp ira b le m ateria l m ay be in the cut flow er and once this m ateria l has been used the flow er p a rts s ta r t to decom pose. The length of tim e the resp ira b le m a te ria l will la st m ay thus be d ire ctly re la te d to the tem p eratu re of the plant. A ssum ing that the foregoing is true, the author has attem pted to prolong life of cut flow ers by not only placing m ore re sp ira b le m a te ria l at the p lan t’s disposal, but also by slowing down the inherent re sp ira tio n ra te of the plant. As stated previously, plant resp iratio n is a complex s e rie s of chem ­ ical reactio n s o ccu rrin g within the plant cell. As in all chem ical reactions, the ra te of the reactio n s is controlled by substances called cataly sts. organic cataly sts o ccu rrin g in plants a re known as enzym es. The Since r e s p ir ­ ation is the sum total of a num ber of complex chem ical reactions, we find that enzyme activity d eterm in es the ra te of resp iratio n . activity is dependent upon a num ber of fac to rs. In turn, enzyme The prin cip al facto rs which determ ine the activity of an enzym e a re tem perature, pH of the solution, concentration of the su b strate , and concentration of the enzyme. L au rie (1936) was one of the f ir s t to approach the problem of cut flow er life by attem pting to slow down plant resp iratio n . He ra n resp iratio n studies on se v e ra l types of cut flow ers, and concluded that low re sp ira to ry ra te was c o rre la te d with longevity of the cut flow er stem , while high r e s p ir ­ ato ry ra te was re la te d to a sh o rt life. T hree m a te ria ls w ere effective in cutting down the re s p ira to ry rate, according to L aurie (1936). They w ere "hydrozene sulphate, fluroglucinol and resin o l", but it is not stated if these chem icals prolonged cut life. Carbon dioxide output of ro se and gardenia flow ers has been studied by Siegelm an (1952). He found that long life and low re sp ira tio n ra te was in ­ duced by low te m p e ratu re s. Many re s e a rc h p ap ers have been w ritten dealing with chem icals that inhibit enzyme activity, but a specific inhibitor, acting upon a single enzyme is at p re se n t un realized (James, 1953). The prin cip al types of r e s ­ p ira to ry inhibitors used in this p re se n t work a re the weak organic acids and o th er compounds shown to effect resp iratio n . A ntibiotics and Cathode Radiation Using Lem na m inor as a te st plant Nickell and Finlay (1954) have r e ­ p o rte d that the use of such antibiotics as Actidione, A ureothricin, Catenulin, C hlortetracycline, Neomycin, Patulin, Polymyxin or Thiolutin re su lte d in a 90 to 98 p e rc e n t d ec re ase in weight over the control plants after th ree weeks of 14 growth at a concentration of 20 p a r ts p e r m illion. inhibition was not p resen ted . A possible m echanism for Bacitracin, Isonicotinic hydrazide and Peni­ cillin G all stim ulated growth. Cathrode .rays a re electro n beam s. When the negatively charged electro n from the cathode ray m achine p a sse s through or close to a m ole­ cule, the e lectro n lo ses a portion of its energy and leaves the m olecule in a state of disturbance. G am m a ra y s differ from cathode ray s in that they a re e le c tro ­ m agnetic rad iatio n s em itted by naturally o ccu rrin g and a rtific ia l rad io ­ active elem ents. Cathode ray dosage is m easu red in rep s (roentgen - equiv­ alent - physical). Irrad iatio n has been found to be very effective in inactivation of m ic ro -o rg a n ism s at dosages of he o rd e r of 2 X 10^ rep. (Hannan, 1956) and this has been the p rin c ip al a re a in which it has been applied. But radiation also has been found to kill in sects and to be effective in destroying certain enzym es. Because of its effect on enzym es it was thought that it may be effective in slowing down the re sp ira tio n rate of cut flow ers. Skoog (1935) has re p o rted that X -ray s p a rtia lly inactivate the growth horm one norm ally p re se n t in plants. He believes the m echanism involves the d estru ctio n and inhibition of form ation of the growth hormone with a c o r r e s ­ 15 ponding inhibition of internodal elongation and reduced form ation of new tissu es in the apex of the plant. Gam m a irrad iatio n has also been shown to be effective in inhibiting the activity of som e enzym es. R esp irato ry gas exchange in potato tubers was shown by Sussm an (1953) to be enhanced by dosages of gam m a ra d ia ­ tion as low as 1000 r . Carbon dioxide evolution was also in creased and the peak of this in crea se o ccu rred 24 hours a fte r that of the oxygen uptake. Cytochrom e oxidase and try o sin ase activ ities w ere not affected by dosages as high as 400, 000 r, but ty ro sin ase activity was reduced by 50 percen t at 3, 200, 000 r. MATERIALS AND METHODS Since the p rim a ry purpose of this work was to find chem icals that would influence the life of cut flow ers, it was decided to lim it the work p r i ­ m a rily to one kind of flow er. A ntirrhinum m ajus was chosen because it could be easily grown in a sho rt tim e, a larg e amount of uniform m ate ria l could be obtained at one tim e, it has a medium cut life and since it has an inflorescence and not a single flow er p e r stem , it was possible to study the effect of the chem icals on flo re ts that had fully developed and on ones which w ere co n sid er­ ably undeveloped. In all experim ents using snapdragons (A ntirrhinum m ajus) the fol­ lowing p ro ced u re was used unless otherw ise noted. The spikes w ere cut in late afternoon, when between 10 and 14 of the lower flo rets had fully opened. They w ere then placed in tap w ater in a 40° F re frig e ra to r for the next 24 hours to harden. A fter the 24 hours of hardening, the m ost uniform spikes w ere selected, cut to a length of about 30 inches, and placed in individual pint m ilk bottles containing the appro priate chem ical solution. All chem icals w ere in d istilled w ater and the stem s w ere not recu t o r rem oved from the solution at any tim e during the experim ent. A c r ite r ia for useful life was established. Since flo ret ab scissio n is v ery uncommon with the v a rie tie s used, it was thought that the best c r ite ria 17 for the length of tim e of useful o r cut life would be the num ber of days until the leaves had w ilted o r the num ber of days until the lower ten (the oldest) flo re ts had wilted. T his m ethod of m easuring cut life proved v ery useful for snapdragons. In o rd e r to te st a s many chem icals as possible, a flo ret te st was used also . F lo re ts between one and th re e days old w ere rem oved from the grow ­ ing spikes and hardened fo r about 12 hours at 40° F. They w ere then placed o ver the edge of a P etri dish containing the ap propriate solution. The pedicel was in the solution and the r e s t of the flo ret hung over the edge of the dish. Five to eight flo re ts w ere placed in each dish and the num ber of days until w ilting was m easu red . The flo rets w ere allowed to rem ain in the original solution fo r th e ir e n tire life span. R oses w ere not hardened but used im m ediately upon a rriv a l from the com m ission house. F o r ro se s, the c rite ria of life was the num ber of days until the p e ta ls had eith er fallen, wilted, or severely blued. In none of the ex perim ents was any attem pt made to control relative humidity. T e m p e ra tu re s fo r a ll experim ents ranged from 70 to 80° F, and in all experim ents adequate checks w ere run. F low ers used in these experim ents include A ntirrhinum m ajus, v a r ­ ie tie s B arbara, Jackpot. Navajo, Rockwood’s Sum m er Pink, Snowman, Spartan 18 Rose, and Spartan White; Rosa hybrida, v a rie tie s Better T im es and Red Delight; G erb era jam esonii and Lilium speciosum rubrum . The cathode ra y m achine was used as the source of radiation in the radiation studies. V arying concentrations of the chem icals w ere used depending upon the chem ical and re s u lts obtained from previous experim ents. The co m m er­ cial flo ral p re se rv a tiv e s used w ere F loralife, Bloomlife and Petalife*. Table 1 lis ts the chelating agents used in this study, Table 2 the growth reg u lato rs used, and Table 3 the re sp ira to ry inhibitors. used a re liste d in Table 4. A ntibiotics The antibiotics w ere obtained through the courtesy of the Upjohn Company, Kalamazoo, Michigan. All experim ents w ere a rran g ed in eith e r a random ized block o r splitplot design with gen erally from four to six rep lic a te s. The sta tistic a l treatm en t of the data is according to C ochran and Cox (1950). All the flow ers, except ro se s, used in these experim ents w ere grown at the Plant Science G reenhouse during 1955 and 1956. The ro se s used w ere grown at Mount Clem ens, Michigan. * F lo ralife (U. S. Patent No. 2,230, 931) is m anufactured by F lo ralife, Inc., 1435 South W abash Avenue, Chicago, Illinois, with a com position of 97. 6 p erce n t sugar, 2.1 p erce n t aluminum sulfate, and 0. 3 p ercen t hexam ethylene tetra m in e. Bloomlife is m anufactured by Flow er Foods, I n c ., Maywood, Illinois. Petalife is d istrib u ted by P ark -E litch Company, 1444 Wazee Street, Denver, Colorado. 19 TABLE 1. L is t of Chelating Agents and the M etals they Chelate Used in V arious E xperim ents. Chelating Agent M etals M ost Commonly C helated Benzotriazole C upferron (Ammonium salt of N -nitroso-N -phenyl hy droxylam ine) Cu - Fe, Cu D iethyldithiocarbam ic acid (Na salt) Cu 2, 4-Dihydroxyacetophenone Fe 2, 3-Dihydroxyquinoxaline Ca Dim ethylglyoxime 2, 4 -D in itro so reso rcin o l None Co, Cu Diphenylamine Fe Diphenyl glyoxim e Ni Diphenylthiocarbazone Co, Cu, Pb, Zn E th ylenediam inetetraacetic acid Fe H exam ethylenetetram ine Fe 2, 2’, 4, 4 \ 6, 6T-H exanitrodiphenylam ine 8-Hydroxyquinoline K Cd, Cu, Co, Mn, Pb, Zn 1- N itro so - 2 - naphthol Co, Cu, Pb l-N itro so -2 -n ap h th o l-3 , 6-disulfonic acid (di sodium salt) Co, Cu, Fe Phenolphthalein Co delta -Phenyl - gam ma - thiohydantoic acid Cu Q uinalizarin (tetrahydroxyanthraquinone) R esorcinol B, Co, Fe, Mn, Pb Co, Cu, Ni 20 TABLE 2. Growth R egulators and Growth R egulator-like C hem icals used in the V arious E xperim ents. para-A m inobenzoic acid Biuret 5 -C h lo ro -salic y lic acid Coum arin 2, 4 Dimethoxybenzoic acid E sculin F u ril dioxine beta-H ydroxyethylhydrazine 2 -H ydroxy-3-m ethylbenzoic acid l-H ydroxy-2-naphthoic acid 3 -H ydroxy-2 -naphthoic acid Indole-3-acetic acid (IAA) M aleic hydrazide beta-M ethyl um belliferone 1 -Naphthoic acid 2-Naphthoic acid Picolinic acid Quinaldic acid 6 - Quinoline carboxylic acid Salcicylic acid 2, 3, 5 Triiodobenzoic acid (TIBA) 2 -T h io b arb itu ric acid TABLE 3. R esp ira to ry Inhibitors used in E xperim ents. Benzoin- alpha- oxime Hydroxy lam ine hydrochloride Iodoacetic acid M aleic acid D -L M aleic acid M alonic acid M esaconic acid para-N itrophenol ortho - Phenanthroline Q uinoline-8-carboxylic acid Salicylaldoxim e S em icarbazide hydrochloride Sodium azide TABLE 4. A ntibiotics used in T hese E xperim ents. Actidione A m icetin A ntibiotic b acitracin Antibiotic D-45, free acid A ntibiotic D-45, sodium salt Antibiotic fum agillin A ntibiotic U-5956 C elesticetin o r Antibiotic D-52 (free base) Endomycin Neomycin sulfate Penicillin G P enicillin O Salicylate D-52 S treptothricin sulfate T etracy clin e hydrochloride The re s u lts a r e divided into five sections; p relim in a ry tria ls , chelating agents, grow th reg u lato rs, and growth reg u lato r-lik e substances, re s p ira to ry inhib ito rs and antibiotics and cathode radiation but it is of im portance to note that the tab les in any of these sections do not indicate that this table contains exclusively chem icals of this type. C helating agents w ere u sed as a com parison in many of the ex­ p e rim e n ts which w ere predom inantly growth reg u lato rs o r re s p ira to ry in ­ h ib ito rs. R eference to T ables 1, 2, 3 and 4 indicates the type m aterial of any specific chem ical. 24 EXPERIMENTAL RESULTS P relim in ary T ria ls It is well known that cutting a flow er definitely shortens its life but nowhere in the lite ra tu re was inform ation found as to how much life is actually shortened. An experim ent using th ree v a rie tie s of A ntirrhinum m ajus was designed to determ ine how much life is shortened by cutting. P a irs of A ntirrhinum m ajus of equal m aturity w ere selected, one spike was cut and one allowed to rem ain on the plant. The cut one was handled in the re g u la r co m m ercial m anner and then placed in a bottle of distilled w ater d irectly beside the spike with which it had been paired. The re su lts in Table 5 indicate that cutting definitely shortened the life of the low er ten flo rets. On spikes that w ere cut the lower ten flo rets la sted 8. 2, 10. 6 and 12. 2 days fo r the v a rie tie s Barbara, Navajo and Spartan Rose resp ectiv ely . The low er ten flo rets on uncut v a rie tie s lasted as many as 35 days. Several fa c to rs contribute to this shortening of flow er life after cu t­ ting. One p rin c ip al facto r is the lack of carbohydrates. Photosynthesis in the cut stem is probably reduced but lack of carbohydrates can be com pen­ sated for in p a rt by the addition of sucrose o r other sugars to the w ater. 25 Cut flow ers often w ilt even in d istilled w ater and this is due to w ater being lo st fa s te r from the leaves and stem than can be absorbed through the xylem of the stem . The xylem v ery often becom es blocked by growth of fungal and b a cterial o rg an ism s at the cut surface and also within the xylem v essels. Lack of m in eral elem ents com ing from the soil is also believed to be a factor contributing to an upset m etabolism . TABLE 5. Effect of Cutting on the Life of the Lower Ten F lo re ts of A ntirrhinum m ajus, V arieties Barbara, Navajo and Spartan Rose. T reatm en t A verage Number of Days before W ilting of Ten Lower F lo rets under G reenhouse Con­ ditions* Barbara Spikes cut Spikes not cut Navajo Spartan Rose 8.2 10.6 12.2 25.8 35.8 30.5 L .S . D. at 5% level 3. 1 5.0 7 .0 L. S. D. at 1% level 4 .9 7. 9 11.0 *Each v a riety is an av erag e of six rep lic a te s and one spike p e r plot. Since flo re ts on the uncut spike lasted about th re e tim es as long as those on cut ones, it can be seen that the goal in extending the life of cut A n tir­ r hinum m ajus is yet to be achieved. In o rd e r to study the effect of the p resen ce of unopened flo rets on ones that had alread y opened and the p resen ce of opened flo re ts on ones about 26 to open the experim ent sum m arized in Table 6 was conducted. The four tr e a t­ m ents w ere, no flo re ts rem oved from spike, all opened and unopened flo rets rem oved except ten low er ones, rach is rem oved above tenth floret, and a con­ tro l in d istilled w ater. The re su lts indicate that by rem oving all the opened and unopened flo re ts above the tenth one, the lower ten lasted one to two days longer and that by rem oving the ra c h is above the tenth floret, the rem aining lower ten flo rets la ste d two to th re e days longer. The re su lts w ere significant at the 1 p ercen t level fo r the v a rie tie s B arbara and Jackpot, and at the 5 percen t level for the v ariety Spartan Rose. TABLE 6. Effect of Removing F lo re ts on the Life of the Low er Ten F lo re ts of A ntirrhinum m ajus, V arieties Barbara, Jackpot, and Spartan Rose. T reatm en t Days from T reatm ent until Low er Ten F lo re ts Wilted*______________ Jackpot B arbara Spartan Rose D istilled w ater (control); no flo re ts rem oved 4 .0 4 .6 6.3 2 % F lo ralife; no flo re ts rem oved 4. 7 6. 4 7.8 6.1 8 .4 8.2 6.8 9.3 10.2 L. S. D. at 5% level 1.2 1.4 2 .3 L .S .D . at 1 % level 1.6 1.8 N.S. 2 % F lo ralife; all opened and un­ opened flo re ts rem oved except ten low er ones 2 % F lo ralife; ra c h is above tenth flo re t rem oved *Each v a rie ty is an average of six rep lic a te s and one spike p e r plot. 27 Chelating Agents The effect of a num ber of chelating agents on the life of th re e v a r ie ­ tie s of A ntirrhinum m ajus is shown in Table 7. These p a rtic u la r chelating agents a re capable of chelating one o r m ore such m etals as boron, calcium, cobalt, copper, iro n and nickel. The re su lts indicate significant differences in the keeping qualities of v arietie s, but in m ost instances the chelating agents at the concentrations used w ere of little o r no benefit in prolonging cut life. Chelating agents significantly in creased the length of cut life of the v ariety Rockwood’s Sum m er Pink (Table 8). The re su lts show that Cupferron, a f e rric iro n chelating agent, was especially effective in extending the cut life of this v ariety two to th re e tim es that of the check. Diphenylthiocarbazone and delta-phenyl-gam m a-thiohydrantoic acid, both copper chelates, and 2, 2 ’, 4, 4’, 6, 6*-hexanitrodiphenylam ine, a potassium chelate, doubled the cut life of this v ariety . The rem aining chelating agents had little o r no effect in extending cut life. Since it was found that Cupferron, an iron chelating agent, im proved the keeping of Rockwood’s Sum m er Pink as well as other v a rie tie s of snapdragons, it was decided to try the effect of other iron chelating agents on the life of snap­ dragons. As is shown in Table 9, diphenylamine and 2, 4-dihydroxyacetophenone, both iro n chelating agents w ere effective in prolonging life. 28 TABLE 7. Effect of Chelating Agents on the Life of T hree V arieties of A ntirrhinum m ajus. i reaumenz Average Life in Days* Spartan Rose B arbara Navajo D istilled w ater (control) 5.8 3. 0 6.0 2 % F lo ralife 6.5 5. 6 6. 2 100 ppm l-n itro so -2 -n ap h th o l 8.1 4.8 3.8 100 ppm diethyldithiocarbam ic acid (sodium salt) 7.7 7.8 6 .2 100 ppm 2, 3-dihydroxyquinoxaline 7 .0 6 .0 6.2 100 ppm benzotriazole 7. 1 5. 3 7. 0 100 ppm re so rc in o l 7.1 5.6 6. 8 100 ppm 2, 4 -d in itro so reso rcin o l 6. 1 5. 5 6. 4 100 ppm quinalizarin 7.7 5.6 5.8 L .S . D. at 5 % level N.S. 0.9 1.9 L. S. D. at 1% level N.S. 1. 1 N.S. *Average of six rep lic a te s and one spike p e r plot. Life was co n sid ered ended when eith e r leaves o r the low er ten florets wilted. 29 TABLE 8. Effect of Chelating Agents on Life of A ntirrhinum m ajus, v ariety Rockwood’s Sum m er Pink. T reatm en t Average Life in Days* D istilled w ater (control) 4 .7 2 % F lo ralife 3. 3 200 ppm hexam ethylenetetram ine 3. 5 200 ppm phenolphthalein 4.8 200 ppm dim ethylglyoxim e 4.8 200 ppm diphenylthiocarbazone 5. 8 200 ppm delta-phenyl-gam m a-thiohydantoic acid 6 .0 200 ppm 2 , 2 \ 4, 4’, 6, 6’-hexanitrodiphenylam ine 6.2 200 ppm C upferron 10.0 L. S.D . at 5% level 1.2 L. S. D. at 1 % level 1.7 *A verage of th re e re p lic a te s and two spikes p e r plot. 30 TABLE 9. Effect of C helating Agents on Life of A ntirrhinum m ajus, v ariety Jackpot. T reatm en t Average Life in Days* D istilled w ater (control) 5.2 2 % F lo ralife 6. 8 100 ppm diphenylglyoxime 7.4 100 ppm 2, 4-dihydroxyacetophenone 7.8 100 ppm diphenylam ine 9.6 100 ppm C upferron 10. 4 L. S. D. at 5% level 1.2 L. S. D. at 1% level 1.7 Average of five rep lic a te s and one spike p e r plot. 31 Table 10 also shows the effect of iron chelating agents on the life of two v a rie tie s of snapdragon, B arbara and Jackpot. In this experim ent 200 p a rts p e r m illion hexam ethylenetetram ine, l-n itro so -2 -n ap h th o l-3 , 6-disulfonic acid o r Cupferron in 2 p erce n t F lo ralife significantly in creased the life of these two v a rie tie s and the in c re a se d tim e was two to th ree tim es that of the control. Since sev eral iron chelating agents w ere found effective in extending life, it was decided to try a com bination of the m ore prom ising chelates. The re su lts of using hexam ethylenetetram ine, l-n itro so -2 -n ap h th o l-3 , 6-disulfonic acid and Cupferron singly and in combination are shown in Table 11. With the variety, Rockwood’s Sum m er Pink, hexam ethylenetetram ine and 1-nitroso2-naphthol-3, 6-disulfonic acid w ere not effective alone, o r in combination with C upferron in prolonging cut life. The th ree chelating agents at 70 p a rts p e r m illion (in d istilled w ater) did double cut life, as com pared to the control. Table 12 shows the re su lts of th re e com m ercial flo ral p rese rv a tiv e s with and without Cupferron on cut life of two v arie tie s of snapdragon, Spartan Rose and Spartan White. Petalife alone was fa r superior to the two p r e s e r ­ vatives, F lo ralife and Bloomlife, but when 200 p a rts p e r m illion C upferron was added to the flo ral p re se rv a tiv e s a considerable im provem ent was shown in cut flow er life, except with Petalife. When Cupferron was added to Bloom­ life, the life of Spartan White was in creased from an average of 3. 4 days to TABLE 10. Effect of Iron Chelating Agents on the Life of A ntirrhinum m ajus, V arie ties B arbara and Jackpot. Average Life in Days* Trpfl 1~m Barbara D istilled w ater (control) _ Jackpot 3.2 3.8 6.7 6.8 200 ppm hexam ethylenetetram ine 6. 8 8.7 200 ppm l-n itro so -2 -n a p h th o l-3 , 6 -d i­ sulfonic acid 8.5 10.3 11.0 9.8 L. S. D. at 5 % level 1.3 2.8 L. S.D . at 1% level 1.7 3.8 2 % F lo ralife 200 ppm C upferron *A verage of six rep lic ates and one spike p e r plot. 33 TABLE 11. Effect of Chelating Agents on the Life of A ntirrhinum m ajus, V ariety Rockwood’s Sum m er Pink. T reatm en t Average Life in Days* D istilled w ater (control) 3.3 2 % F lo ralife 5.2 210 ppm hexam ethylenetetram ine (A) 3.8 210 ppm l-n itro so -2 -n ap h th o l-3 , 6 -d isu l­ fonic acid (di sodium salt) (B) 5.2 210 ppm C upferron (C) 8.2 105 ppm A and 105 ppm C 5. 7 105 ppm A and 105 ppm B 4.5 105 ppm C and 105 ppm B 7. 7 70 ppm A, 70 ppm B, 70 ppm C 70 ppm A, 70 ppm B, 70 ppm C in distilled w ater 5. 8 6. 3 L. S. D. at 5% level 1.2 L. S. D. at 1 % level 1.6 *A verage of six re p lic a te s and one spike p e r plot. 34 TABLE 12. C om parison of Several C om m ercial F lo ral P reserv ativ es with and without Cupferron on the Life of A ntirrhinum m ajus, V arieties Spartan Rose and Spartan White. T reatm en t Average Life in Days* -------------------------------------------------Spartan Rose Spartan White D istilled w ater (control) 5.8 3.6 2 % F lo ralife 5.6 6.4 2 % Bloomlife 4. 4 3.4 2 % Petalife 8.8 11.8 2 % F lo ralife and 200 ppm C upferron 7.6 8.4 2 % Bloomlife and 200ppm Cupferron 8.2 13.6 2 % Petalife and 200 ppm Cupferron 8.8 12.4 2 % Sucrose 2 .0 3.4 t- 10.0 13.2 2 .2 2. 6 7.4 8.2 L. S. D. at 5% level 1. 6 1. 9 L. S. D. at 1 % level 2.1 2. 5 2 % Sucrose and 200 ppm Cupferron 2 % Sucrose and 350 ppm Aluminum Sulfate 2 % Sucrose and 350 ppm Aluminum Sulfate and 200 ppm Cupferron *A verage of five re p lic a te s and one spike p e r plot. an average of 13. 6 days. C upferron was effective in im proving the quality of both F lo ralife and Bloomlife, but not Petalife. Two p erc e n t su cro se shortened the life of both v arietie s, but when 200 p a rts p e r m illion Cupferron was added to the sucrose solution, life was extended four to five tim es. The addition of 350 p a rts p e r m illion aluminum sulfate to the C u p ferro n -su cro se solution shortened the cut life of both v a rie ­ ties. The life of the snapdragon variety, Barbara, was also shortened by the addition of 2 p ercen t su cro se to the w ater (Table 13). This experim ent indicated that a 2 p e rc en t F lo ralife and Cupferron m ixture when used in tap w ater was as effective in prolonging life as when used in distilled w ater (Table 10). Since Cupferron was so effective in extending cut life, it was de­ cided to determ ine when this chelating agent was m ost effective. Snapdragons, v ariety Rockwood’s Sum m er Pink, w ere placed in a F loralife-C upferron solu­ tion fo r various lengths of tim e, for en tire life, firs t th ree days afte r cutting, and fir s t six days a fte r cutting. The re s u lts (Table 14) indicate that the C upferron was n e c e ssa ry the f ir s t few days only, and after this tim e its p re sen ce o r absence was n eith er beneficial o r harm ful to the cut life of this variety . 36 TABLE 13. Effect of C upferron with Sucrose and F loralife on the Life of A ntirrhinum m ajus, V ariety Barbara. T reatm en t Average Life in Days* Tap w ater (control) 5.1 2 % Sucrose 2.8 2 % S ucrose and 125 ppm Cupferron 2.6 2 % F lo ralife 5.6 125 ppm C upferron 5.6 2 % F lo ralife and 125 ppm Cupferron 1 0 .0 L. S. D. at 5% level 2 .3 L. S. D. at \% level 3.1 *Average of five rep lic a te s and one spike p e r plot. 37 TABLE 14. Effect of Cupferron for V arious Lengths of Tim e on Life of A ntirrhinum m ajus. V ariety Rockwood’s Summer Pink. T reatm en t Average Life in Days* Continuous in Solution** (Control) 8.2 Solution for f ir s t 3 days 7 .4 Solution fo r f ir s t 6 days 8.2 *No significant d ifferences. Average of five rep licates. **Solution was 2 % F lo ra life plus 200 ppm Cupferron after 3 and 6 days the spikes w ere placed in solution m inus the Cupferron. TABLE 15. Effect of V arious C oncentrations of C upferron on Life of A ntirrhinum m ajus, V arieties Jackpot and Navajo. T reatm en t Average Life in Days* --------------------------------------------Jackpot Navajo 5.6 6.2 50 ppm C upferron 8.6 6.8 100 ppm C upferron 9.6 6.2 500 ppm C upferron 12.6 10.0 1000 ppm C upferron 9 .4 -- L. S. D. at 5 % level 2 .9 N.S. L. S. D. at 1% level 3 .9 N.S. 2 % F lo ralife *A verage of five re p lic ates and one spike p e r plot. 38 In o rd e r to a s c e rta in what level of Cupferron was best for snapdragons the experim ent shown in Table 15 was designed. The re su lts indicate that be­ tween 100 and 500 p a r ts p e r m illion Cupferron were the m ost desirable range fo r the v a rie ty Jackpot. F o r the v ariety Navajo the differences w ere not sig ­ nificant. Since Cupferron was found to prevent the wilting of leaves and to delay the w ilting of flo rets, it was decided to study the effect of various levels of C upferron on snapdragon flo rets. in Table 16. R esults of this experim ent a re shown C upferron was effective in prolonging life when used at a m in­ imum of 100 p a rts p e r m illion. C oncentrations of 400 p a rts p e r m illion were not harm ful and prolonged life about one day. When 1 p ercent F loralife was added, the life of the flo rets was reduced by one o r two days (Table 16). R esults indicate that low am ounts of Cupferron, less than 50 p a rts p e r million, m ay shorten the life of Snowman snapdragon flo rets. The data shown in Table 17 a re re s u lts of an experim ent designed to study the in teractio n between various levels of m aleic hydrazide and Cup­ ferro n . M aleic hydrazide at a concentration of 250 or 500 p a rts p e r m illion was v ery effective in prolonging cut life of the snapdragon, v ariety Spartan Rose, while high concentrations (3000 and 4000 p a rts p e r m illion) of m aleic hydrazide shortened cut life appreciably. C upferron was not significantly effective in extending life even at 500 p a rts p e r m illion but a concentration TABLE 16. Effect of C upferron on the Life of A ntirrhinum m ajus F lo rets, V ariety Snowman. T reatm en t Average Life in Days* Tap w ater 6.3 1% F lo ralife 5.3 1% F lo ralife and 50 ppm Cupferron 6. 5 50 ppm Cupferron 6.0 D istilled w ater 7.4 1% F lo ralife 5.2 1% F lo ralife and 50 ppm C upferron 5. 7 12. 5 ppm Cupferron 6.7 25 ppm Cupferron 6 .9 50 ppm C upferron 7. 3 100 ppm Cupferron 8. 5 200 ppm C upferron 8.2 400 ppm C upferron 8.7 L. S. D. at 5% level 1.0 L. S. D. at 1 % level 1. 3 *A verage of four re p lic a te s and six florets p er plot. 40 TABLE 17. Effect of V arious Concentrations of M aleic Hydrazide and C upferron Singly and in Combination on the Life of A ntirrhinum m ajus, V ariety Spartan Rose.* Average Life inlDays** M aleic H ydrazide (ppm) Cupferron (ppm) M-H mean (days) 0 100 0 7. 0 8.0 8.0 7.7 250 9.5 10. 5 8 .3 9.4 500 1 1 .3 9.8 9.7 10. 3 1000 7.8 7. 2 12. 7 9.2 2000 4 .2 3. 7 4. 3 4. 1 4000 2 .0 2.2 3. 3 2.5 7 .0 6.9 7. 7 Cupferron m ean (days) 500 Cupferron: No significant differences between m eans. M aleic Hydrazide: D ifference req u ired for significance at 5 % level, 1. 2 days; at 1% level, 1. 6 days. Two m aleic hydrazide m eans for a given level of cupferron: D ifference r e ­ quired for significance at 5% level, 2. 0 days; at 1% level, 2. 7 days. Two C upferron m eans for a given level of m aleic hydrazide: D ifference r e ­ q uired for significance at 5% level, 2.1 days; at 1 % level, 2. 8 days. *A11 tre atm e n ts contained 2 p ercen t F loralife. **A verage of six re p lic ates and one spike p e r plot. 41 of 500 p a r ts p e r m illion m aleic hydrazide in creased cut life alm ost 6 days over the control. C oncentrations of Cupferron as high as 500 p a rts p e r m illion w ere not harm ful, however. R esults indicated that m oderate levels of (between 250 and 500 p a rts p e r million) m aleic hydrazide with o r without Cupferron w ere m ost effective in prolonging life of this variety. Since both C upferron and m aleic hydrazide proved effective when added to the keeping w ater, it was decided to te st the effect of these two chem icals in addition to 8-hydroxyquinoline, when used as a foliage spray one and th re e days before h arv est. R esults (Table 18) showed no signifi­ cant differences am ong tre atm e n ts. C upferron as high as 1000 p a rts p e r m illion and m aleic hydrazide up to 4000 p a rts p e r m illion neither lengthened nor shortened the cut life of Snowman snapdragon. Since the ro se is a flow er having a ra th e r short cut life, it was thought that C upferron m ight extend the life of cut ro ses. Table 19 shows that 200 p a rts p e r m illion C upferron plus 2 percen t F loralife extended the life of Better T im es ro s e s two and one-half days, while 200 p a rts p e r m illion C upferron extended life one day over F loralife. Lilium speciosum rubrum was not effected by Cupferron (Table 20) nor was F lo ralife of any benefit in extending cut life. Table 21 shows the effect of th ree iron chelates on G erbera jam esonii. The chem icals had no effect on the cut life of this flower and F lo ralife was of no value. 42 TABLE 18. Effect of P re -h a rv e st Foliage Sprays on the Life of A ntirrhinum m ajus, V ariety Snowman. Average Life in Days T reatm en t Sprayed 1 day before harvest* Sprayed 3 days before harvest** Control 7.5 6.9 200 ppm C upferron pH 3. 0 7. 5 7.3 200 ppm C upferron pH 7. 0 7. 2 6.9 1000 ppm C upferron pH 3. 0 7. 1 7.0 1000 ppm C upferron pH 7. 0 7. 7 6. 9 1000 ppm m aleic hydrazide 7. 3 7.0 2000 ppm m aleic hydrazide 7. 0 7.0 4000 ppm m aleic hydrazide 7. 2 7.0 100 ppm 8-hydroxyquinoline 7. 7 7 .0 200 ppm 8-hydroxyquinoline 7. 4 7 .0 ^Significant at 1% level. L .S .D , at 5% level, 0.4 days; a t 1 % level, 0. 6 days. **No significant differences. 43 TABLE 19. Effect of C upferron on Life of Rosa hybrida, V ariety B etter T im es. T reatm en t Average Life in Days* D istilled w ater (control) 4 .0 2 % F lo ralife 5.5 2 % F lo ra life and 200 ppm Cupferron 6. 6 L. S. D. at 5% level 0 .9 L .S .D . at 1 % level 1.4 *A verage of four re p lic a te s and two flow ers p e r plot. TABLE 20. Effect of C upferron and F lo ralife on Life of Lilium speciosum rubrum . Tap w ater 5. 3 D istilled w ater (control) 5 .0 2 % F lo ralife 4. 3 2 % F lo ralife and 200 ppm Cupferron 5.0 2 % Sucrose and 200 ppm C upferron 5.0 No significant differences. *A verage of th re e rep lic a te s and one flow er p e r plot. 44 TABLE 21. Effect of Chelating Agents on Cut Life of G erbera jam esonii. T reatm en t Average Life in Days* D istilled w ater (control) 5.2 2 % F lo ralife 5. 5 100 ppm 2, 4 -d in itro re so rcin o l 4. 7 100 ppm diphenylam ine 5.3 100 ppm C upferron 5.2 No significant d ifferences. *A verage of four re p lic a te s and four flow ers p e r plot. When browning of the lily p etals started, cut life was considered ended. G erb era cut life was com pleted when the heads wilted. Both of th ese flow ers w ere hardened 24 hours before placing in the various solu­ tions. 45 Growth R egulators Growth re g u lato rs as well as chelating agents w ere used in attem pt­ ing to prolong cut life of flow ers. The effect of sev eral growth regulators on two v a rie tie s of snapdragon is shown in Table 22. These chem icals when used at 100 p a rts p e r m illion in a 2 p ercen t F loralife solution had no effect on cut life. D ifferences in ex trem es w ere one and one-half days for Jackpot and one day for Spartan Rose. Since the chem icals listed in Table 22 had no ap p ar­ ent physiological effect on snapdragons, it was decided to try some chem icals known to e x e rt considerable physiological effect, such as indole-3-acetic acid, 2, 3, 5-triiodobenzoic acid, and beta-m ethyl um belliferone. The effect of a num ber of these chem icals is sum m arized in Table 23. Indole-3 -acetic acid at 175 p a rts p e r m illion reduced the life of this v a rie ty by one-half, as did 600 p a rts p e r m illion beta-hydroxyethylhydrazine and 200 p a rts p e r m illion 2, 3, 5-triiodobenzoic acid. 2 -th io b arb itu ric acid had no effect on cut life. Coumarin, esculin or No treatm ent was as good as the d istilled w ater control. The re su lts of four organic acids on four v arietie s of snapdragon a re shown in Table 24. Salcicylic acid, 2-hydroxy-3-m ethylbenzoic acid, 3-h y d ro x y -2-naphthoic acid and 1-hydroxy-2-naphtoic acid all shortened the life of th ese four v a rie tie s when used at 100 p a rts p e r m illion in a 2 p ercent 46 TABLE 22. Effect of S everal Growth R egulators on the Cut Life of A ntirrhinum m ajus, V a rie ties Jackpot and Spartan Rose. _ Average Life in Days T reatm en t-------------------------------------- ;---------------------------------------Jackpot* Spartan Rose** D istilled w ater (control) 5.4 5.0 2 % F lo ra life 5.0 5.8 100 ppm 1-naphthoic acid 5.7 5. 5 100 ppm 2-naphthoic acid 6 .0 6 .0 100 ppm 6-quinoline carboxylic acid 6. 5 5.8 100 ppm quinaldic acid 6 .0 5. 3 100 ppm 5-chloro salicy lic acid 5.6 5. 0 100 ppm picolinic acid 5.6 5.8 No significant differences. *Average of seven rep lic ates. ** A verage of four rep lic a te s. TABLE 23. Effect of Several Growth R egulators on the Life of A ntirrhinum m ajus, V ariety Rockwood’s Summer Pink. T reatm en t Average Life in Days* D istilled w ater (control) 6. 3 2 1/2% F lo ralife 5. 5 200 ppm beta-hydroxyethylhydrazine 6.0 600 ppm beta-hydroxyethylhydrazine 3. 7 17. 5 ppm indole- 3 - acetic acid 5. 2 175. 0 ppm in d o le-3 -acetic acid 3.2 14. 6 ppm coum arin 5. 8 146. 0 ppm coum arin 5. 3 35 ppm esculin 6.2 200 ppm beta-m ethyl um belliferone 5.5 200 ppm 2, 3, 5-triiodobenzoic acid 4.0 400 ppm 2 -th io b arb itu ric acid 6.2 L. S. D. at 5% level 1.4 L. S. D. at 1% level 1.9 *A verage of th re e rep lic a tes and two spikes p e r plot. 48 TABLE 24. E ffect of Growth R egulator-like Substances on the Life of A ntirrhinum m aju s, V arieties Barbara, Jackpot, Navajo, and S partan Rose. A verage Life in Days* T reatm en t Barbara Jackpot D istilled w ater (control) 3.3 4.7 6. 3 6.8 2 % F lo ra life 5. 8 7.0 6.2 5. 7 100 ppm salcicy lic acid 3 .3 4. 0 3.5 4.5 100 ppm 2 -h y d ro x y -3-m ethylbenzoic acid 3.6 4 .7 4.2 5.7 100 ppm 3-hydroxy-2-naphthoic acid 3.3 4. 7 4 .0 6. 0 100 ppm 1 -hydroxy-2-naphthoic acid 3.3 5.0 4 .0 6.3 L. S. D. at 5 % level 0 .7 1.6 0 .9 1. 1 L. S. D. at \% level 1. 0 N. S. 1.3 N.S. *A verage of six rep lic a te s and one spike p e r plot. Navajo Spartan Rose F lo ra life solution. It is of in te re st to note that F loralife in creased the life of two v a rie tie s about two and one-half days and had no effect on the life of the o th er two v a rie tie s. O ther grow th reg u lato rs w ere tested using flo rets of the variety B arbara (Table 25). In general, all growth regulators used in this ex p eri­ m ent shortened the life of flo re ts. Cupferron, a m etal chelating agent, in ­ c re a se d the life span of flo re ts approxim ately th ree days over the control. The tre n d was that the higher the concentration of the growth regulator, the sh o rte r the life span. M aleic hydrazide was m ost effective in extending cut life of snap­ dragons. Table 26 shows the effect of th re e concentrations of this chem ical on cut life of v a rie tie s Jackpot and Navajo snapdragon. M aleic hydrazide at 2000 p a rts p e r m illion was m ost effective in prolonging life, but another experim ent (Table 11) indicated that th is concentration was too high. The re d variety, Navajo, showed no significant differences in cut life when tre ated with m aleic hydrazide. 50 TABLE 25. Effect of V arious Chem icals on the Life of Antirrhinum m ajus F lo re ts, V ariety Barbara. T reatm en t A verage Life in Days D istilled w ater (control) 5.2 2. 5 ppm indole- 3 -a ce tic acid 4 .9 50 ppm in d o le-3 -acetic acid 3.5 2. 5 ppm sodium azide 5.0 2. 5 ppm m alonic acid 4 .9 10 ppm b iu re t 5.7 5 ppm 2, 3, 5-triiodobenzoic acid 4.4 50 ppm fu ril dioxine 5. 1 100 ppm fu ril dioxine 5.0 5 ppm beta hydroxyethylhydrazine 5.3 25 ppm beta hydroxyethylhydrazine 5. 7 50 ppm 2, 4 -dim ethoxy benzoic acid 4.5 50 ppm p -am inobenzoic acid 3. 7 100 ppm C upferron 8. 1 L. S. D. at 5 % level 0. 6 L. S. D. at 1 % level 0.8 *A verage of th re e rep lic a te s and five flo rets p e r plot. TABLE 26. Effect of M aleic H ydrazide on the Life of A ntirrhinum m ajus, V a rie tie s Jackpot and Navajo. T reatm en t Average Life in Days Jackpot Navajo D istilled w ater (control) 4 .0 5.4 2% F lo ralife 6 .4 4 .4 1000 ppm m aleic hydrazide 8.6 6. 6 2000 ppm m aleic hydrazide 10.2 7. 2 4000 ppm m aleic hydrazide 9.4 5.0 L. S. D. at 5% level 1.3 N.S. L. S. D. at 1% level 1.8 N. S. * A verage of five re p lic ates and one spike p e r plot. 52 R esp irato ry Inhibitors D uring the la tte r p a rt of the experim ental work a num ber of r e s p ir ­ ato ry in h ib ito rs w ere selected in o rd e r to study th eir effect on the length of life of cut snapdragons. Table 27 shows the effect of sodium azide and malonic acid on the v a rie ty Rockwood’s Sum m er Pink. the life of th is v ariety in all cases. These two chem icals shortened The re su lts indicated that the concentra­ tions used w ere considerably higher than optimum. TABLE 27. Effect of R esp irato ry Inhibitors on the Life of A ntirrhinum m ajus, V ariety Rockwood's Sum m er Pink. T reatm en t Average Life in Days* D istilled w ater (control) 3 .9 2% F lo ralife 5.6 130 ppm sodium azide 1. 1 65 ppm sodium azide 2 .0 200 ppm m alonic acid 3.1 104 ppm m alonic acid 4.1 52 ppm m alonic acid 5.5 L. S. D. a t 5% level 0 .9 L. S. D. at 1% level 1.2 *A verage of four re p lic a te s and one spike p e r plot. When snapdragons w ere dipped for one minute in . 05M malonic acid o r . 05M sodium azide, th e ir cut life was shortened (Table 28). Snapdragons, v a rie ty B arbara, dipped in 20, 000 p a rts p e r m illion m aleic hydrazide lasted approxim ately one day longer than undipped spikes. The v ariety Spartan Rose la ste d two days longer when dipped for one minute in 20, 000 p a rts p e r million m aleic hydrazide (Table 29), but spikes dipped in solutions of . 05M malonic acid o r . 05M sodium azide had a sh o rter life than the checks. F loralife in­ c re a se d the life of v a rie tie s B arbara and Spartan Rose about one and one-half days (T ables 28 and 29). In Table 30 the effect of sev eral re sp ira to ry inhibitors and che­ latin g agents on the flo re ts of the snapdragon Spartan White a re given. Hydroxylam ine hydrochloride and quinoline-8 -carboxylie acid both re sp ira to ry inhibitors ap p ear to have no effect on flo ret life, but quinoline-8-carboxylic acid at 25 p a rts p e r m illion did extend the life of flo rets one day. The th re e chelating agents, eth ylenediam inetetraacetic acid, l-n itro so -2 -n ap h thol-3, 6-disulfonic acid and diphenylamine had little effect on cut life. At in creasin g concentrations of EDTA cut life was shortened. The experim ent (Table 31) using a num ber of re sp ira to ry inhibitors indicates that 10 p a r ts p e r m illion was not harm ful to flo rets. But 50 p a rts p e r m illion of the chem icals, except iodoacetic acid, decidedly shortened the 54 TABLE 28. Effect of R esp ira to ry Inhibitors on the Life of A ntirrhinum m ajus, V ariety B arbara. R e sp ira to ry Inhibitors (dipped fo r 1 minute) No F loralife Floralife Resp. Inhib. Mean* (days) D istilled w ater 3.7 5.5 4.6 20, 000 ppm m aleic hydrazide 4.8 6.3 5. 6 . 05M m alonic acid 3.7 4. 7 4.2 . 05M sodium azide 3.3 3.8 3.6 3.9 5.1 F lo ralife mean* (days) F lo ralife: D ifferences re q u ired for significance at 5% level - 0. 4 days; at 1% level - 0. 7 days. R esp ira to ry inhibitors: D ifferences req u ired for *A verage of six re p lic a te s and one spike p e r plot. significance at 5% level - 1 . 0 days at 1% level - 1 . 3 days 55 TABLE 29. Effect of R esp irato ry Inhibitors on the Life of Antirrhinum m ajus, V ariety Spartan Rose. R esp ira to ry Inhibitors (dipped fo r 1 minute) No F loralife Floralife Resp. Inhib. n Mean (days) D istilled w ater 5. 5 7. 3 6.4 20, 000 ppm m aleic hydrazide 7. 5 9.0 8. 3 . 05M m alonic acid 5.3 6.3 5.8 . 05M sodium azide 5.3 5.0 5.2 5 .9 6.9 F lo ralife mean* (days) F lo ralife: No significant differences between m eans. R esp ira to ry inhibitors: D ifferences req u ired for significance at 5% level - 1. 4 days at 1% level - 1 . 9 days *A verage of six re p lic a te s and one spike p e r plot. 56 TABLE 30. Effect of Several Chem icals on the Life of Antirrhinum m ajus F lo re ts , V ariety Spartan White. T reatm en t Average Life of F lo re t in Days* D istilled w ate r (control) 7.0 25 ppm hydroxylam ine hydrochloride 6.9 50 ppm hydroxylam ine hydrochloride 6.9 100 ppm hydroxylam ine hydrochloride 7. 1 25 ppm quinoline-8-carboxylie acid 8.1 50 ppm quinoline-8 -carboxylic acid 7. 5 100 ppm quinoline-8-carboxylic acid 7.0 25 ppm ethylen ed iam in etetraacetic acid (EDTA) 6 .0 50 ppm eth y lenediam inetetraacetic acid (EDTA) 5.5 100 ppm ethylenediam inetetraacetic acid (EDTA) 4. 9 25 ppm l-n itro so -2 -n ap h th o l-3 , 6-disulfonic acid 6.8 50 ppm l-n itro so -2 -n a p h th o l-3 , 6-disulfonic acid 7.1 100 ppm l-n itro so -2 -n a p h th o l-3 , 6-disulfonic acid 6. 3 25 ppm diphenylam ine 7. 3 50 ppm diphenylam ine 7.5 100 ppm diphenylam ine 7.2 L. S. D. at 5% level 0. 9 L. S.D . at 1% level 1.2 * A verage of four re p lic a te s and six flo rets p e r plot. 57 TABLE 31. Effect of R esp irato ry Inhibitors on Life of F lo rets of Antirrhinum m ajus, V arie ties Spartan Rose and Spartan White. T reatm en t Average Life in Days* Spartan Rose* Spartan White** D istilled w ater (control) 5.2 6.8 10 ppm m alonic acid 5. 3 6.5 50 ppm m alonic acid 3. 7 3.8 10 ppm m esaconic acid 4.7 6 .0 50 ppm m esaconic acid 3.8 3.9 10 ppm p-nitrophenol 5. 9 6. 5 50 ppm p-nitrophenol 5. 9 4.4 10 ppm sem icarb azid e hydrochloride 6.0 6. 9 50 ppm sem icarb azid e hydrochloride 4. 3 5.4 10 ppm salicylaldoxim e 6.3 7. 4 50 ppm salicylaldoxim e 4. 8 5. 7 10 ppm m aleic acid 5. 3 6. 1 50 ppm m aleic acid 3. 9 4 .0 10 ppm iodoacetic acid 4 .7 4. 0 50 ppm iodoacetic acid 5.6 6.8 L. S. D. at 5% level 1.6 1.6 L. S. D. at 1% level 2.1 2.1 *A verage of four re p lic a te s and th re e flo rets p e r plot. ^ A v e r a g e of four re p lic a te s and four flo re ts p e r plot. life of flo re ts of both Spartan Rose and Spartan White. In general, none of the re s p ira to ry in hibitors (Tables 31 and 32) significantly in creased length of life of e ith e r flo re ts o r the whole spike. The experim ents sum m arized in T ables 33 and 34 show the effect of a num ber of re s p ira to ry inhibitors on life of two v arie tie s of snapdragon, Spartan Rose and Spartan White. The basic solution in these two ex p eri­ m ents was 2 p e rc en t su cro se and 200 p a rts p e r m illion Cupferron in d is­ tille d w ater. The basic solution was v ery effective in extending cut life, but the addition of 10 and 50 p a rts p e r m illion of a re sp ira to ry inhibitor gave no im provem ent. P ara-nitrophenol and ortho-phenanthroline at 50 p a rts p e r m illion shortened the life of flo rets of both v arie tie s. 59 TABLE 32. Effect of R esp irato ry Inhibitors on the Life of Antirrhinum m a ju s, V a rie ties Spartan Rose and Spartan White] T reatm en t Average Life in Days* Spartan Rose Spartan White D istilled w ater (control) 7. 3 7.8 Tap w ater 7.8 8 .0 2% F lo ralife 7.8 7.8 10 ppm m alonic acid 8. 5 7.5 50 ppm m alonic acid 8. 8 7. 5 100 ppm m alonic acid 8 .0 5. 5 10 ppm m esaconic acid 8 .3 8. 3 50 ppm m esaconic acid 7.0 7 .0 100 ppm m esaconic acid 7.5 7.0 10 ppm p-nitrophenol 7. 3 6 .3 50 ppm p-nitrophenol 6.8 5.8 100 ppm p-nitrophenol 4. 5 3.0 10 ppm m aleic acid 8.0 7.3 50 ppm m aleic acid 6. 3 6. 5 100 ppm m aleic acid 5.8 6 .0 200 ppm C upferron 9.5 10. 3 L. S. D. at 5% level 1 .9 2. 1 L. S. D. a t 1% level 2 .5 2.8 *A verage of four re p lic a te s and one spike p e r plot. 60 TABLE 33. Effect of Several R esp irato ry Inhibitors on the Life of A n tirrhinum m ajus. V arie ties Spartan Rose and Spartan White. T reatm en t Average Life in Days* Spartan Rose Spartan White D istilled w ater (control) 5.3 7.8 Basic solutions** 14.0 10. 3 10 ppm ortho-phenanthroline 10.3 8.8 50 ppm ortho-phenanthroline 7.3 5. 3 10 ppm hydroxylam ine hydrochloride 15.3 15.0 50 ppm hydroxylam ine hydrochloride 11.3 12. 3 10 ppm D -L m aleic acid 10.3 12.8 50 ppm D -L m aleic acid 12. 7 10.0 10 ppm quinoline-8 -carboxylic acid 14.3 11. 0 50 ppm quinoline-8-carboxylic acid 14.0 14.0 L. S. D. at 5% level 3. 9 4 .0 L. S. D. at 1% level 5.6 5.5 * A verage of four re p lic a te s and one spike p e r plot. **Basic solution of 2% su cro se and 200 ppm Cupferron used in all treatm ents except control. 61 TABLE 34. Effect of R esp ira to ry Inhibitors on the Life of Antirrhinum m a ju s, V arieties Spartan Rose and Spartan White] T reatm en t D istilled w ater (control) Average Life in Days* Spartan Rose Spartan White 6.8 7.0 10.5 12.5 10 ppm benzoin oxime 11.8 13.0 50 ppm benzoin oxime 13.5 11. 3 10 ppm m alonic acid 10.8 11.8 50 ppm m alonic acid 10.3 7.8 10 ppm p ara-n itro p h en o l 12.3 12.5 50 ppm p ara-n itro p h en o l 7.0 5.8 L. S.D . at 5% level 2.2 2.8 L. S. D. at 1% level 3.0 3. 7 Basic solution** *A verage of four rep lic a te s and one spike p e r plot. **A11 tre atm e n ts except control w ere in a "Basic Solution" containing 2% su cro se and 200 ppm C upferron. 62 A ntibiotics and Cathode Radiation F lo re ts of the snapdragon Spartan Rose w ere placed in W hite’s solution (White, 1943) containing five antibiotics at two concentrations. Re­ su lts (Table 35) indicated that W hite’s solution alone shortened the life of these flo re ts. The antibiotics used had little or no effect on length of life of th is variety , but 10 p a rts p e r m illion Endomycin appeared to counteract the d etrim en tal effect of W hite’s solution. In Table 36 the re su lts of a num ber of antibiotics on the florets of the v ariety B arbara a re p resen ted. These antibiotics in the p resence of W hite’s solution had no significant effect on the life of the florets. w ater was significantly b e tte r than tap w ater in p reserv in g cut life. D istilled A 1 p er­ cent solution of F lo ra life shortened the life of flo rets about two and one-half days. Spikes of the v ariety Spartan Rose w ere not significantly affected by concentrations of 10 and 100 p a rts p e r m illion D-52 Salicylate, Neomycin sulfate o r actidione (Table 37). A ntibiotics had no significant effect on length of cut life of Red Delight ro s e s (Table 38). A solution of 2 p ercen t F loralife did in crease life about two days over the control (distilled w ater). TABLE 35. E ffect of A ntibiotics in W hite’s Solution on the Life of A n tirr­ hinum m a ju s, V ariety Spartan Rose, F lo rets. T reatm en t Average Life in Days* D istilled w a ter (control) 4 .6 Tap w ater 3.2 W hite’s solution 2 .5 10 ppm Endomycin 3.5 50 ppm Endomycin 2.5 10 ppm Penicillin 0 2 .4 50 ppm Penicillin 0 2 .4 10 ppm A ntibiotic D-52 2 .0 50 ppm A ntibiotic D-52 2 .6 10 ppm S trep to th ricin sulfate 2 .5 50 ppm S trep to th ricin sulfate 2. 9 10 ppm A ntibiotic D-45, sodium salt 2.7 50 ppm A ntibiotic D-45, sodium salt 2.8 L. S. D. at 5% level 0 .6 L. S.D . at 1% level 0 .9 *A verage of four re p lic a te s and five flo rets p e r plot. TABLE 36. E ffect of A ntibiotics in W hite’s Solution on the Life of F lo rets of A ntirrhinum m ajus, V ariety Barbara. T reatm en t Average Life in Days* D istilled w ater (control) 7.5 Tap w ater 3.8 D istilled w ater and 1% F lo ralife 4 .9 D istilled w ater and 1% F lo ralife and 25 ppm C upferron 8.5 W hite’s solution 4 .5 10 ppm A ntibiotic b acitracin 3.7 50 ppm A ntibiotic b acitracin 4 .6 10 ppm A m icetin 5.0 50 ppm A m icetin 4 .3 10 ppm T etracy clin e hydrochloride 4. 5 50 ppm T e tracy clin e hydrochloride 3. 8 10 ppm Penicillin G 4 .0 50 ppm P enicillin G 4 .8 10 ppm A ntibiotic D-45, free acid 4 .5 50 ppm A ntibiotic D-45, free acid 3.6 L. S. D. at 5% level 0 .9 L. S. D. at 1% level 1.2 *A verage of four re p lic a te s and five flo re ts p e r plot. TABLE 37. Effect of A ntibiotics on the Life of Antirrhinum m ajus, V ariety S partan Rose. Treatm ent* 2% F lo ra life (control) Average Life in Days** 7.4 10 ppm D-52 Salicylate 6. 6 100 ppm D-52 Salicylate 6. 2 10 ppm Neomycin sulfate 6.4 100 ppm Neomycin sulfate 6. 4 10 ppm Actidione 6.2 100 ppm Actidione 6.2 No significant differences. *Each tre atm e n t contained 2% F loralife. **A verage of five rep lic a te s and one spike p e r plot. 66 TABLE 38. Effect of A ntibiotics on the Life of Rosa hybrida, V ariety Red Delight. T reatm en t Average Life in Days* D istilled w ater (control) 2 .0 Tap w ater 3.2 2% F lo ralife 4.4 Basic solution** 3.2 10 ppm Endomycin 3.8 100 ppm Endomycin 3.6 10 ppm P enicillin 0 3.2 100 ppm Penicillin O 3.4 10 ppm A ntibiotic D-52 4 .0 100 ppm A ntibiotic D-52 3.6 10 ppm S trep to th ricin sulfate 2 .6 100 ppm S treptothricin sulfate 3.0 10 ppm Antibiotic D-45, sodium salt 3. 0 100 ppm A ntibiotic D-45, sodium salt 4.2 10 ppm Antibiotic b acitracin 4 .0 100 ppm A ntibiotic b acitracin 2 .4 10 ppm Neomycin sulfate 4.2 100 ppm Neomycin sulfate 3.8 10 ppm A m icetin 3.4 100 ppm A m icetin 3.4 No significant differences. * A v e r a g e of five re p lic a te s and one ro se p e r plot. **All antibiotics w ere in a "Basic solution" of 1% sucrose in distilled w ater adju sted to pH 4 with c itric acid. 67 Two antibiotics (Table 39) were effective in prolonging the life of B etter T im es ro s e s . Endomycin at 100 p a rts p e r m illion and Actidione at 10 o r 100 p a r ts p e r m illion w ere both effective in extending the life of this v a rie ty from one and one-half to two days. The thirteen other antibiotics had no effect on cut life. The effect of cathode ray s on ro ses, variety Better Tim es, is shown in T able 40. Dosages of less than 75 reps had little effect on ro ses but dosages of g re a te r than 100 rep s caused anatom ical differences in petals and flow er opening. O uter p etals of buds receiving g re a te r than 100 reps developed crin k ly a re a s . Crinkling developed the firs t day after treatm ent w ith 150 re p s o r g re a te r. M ore than 150 rep s also kept flower buds tight through the fourth day, and dosages between 500 and 1500 rep s caused ab­ sc issio n of leaves within fifteen m inutes a fte r treatm ent. Peduncles broke at the end of the f ir s t day at concentrations of 1500 reps. 68 TABLE 39. Effect of A ntibiotics on the Life of Rosa hybrida, V ariety B etter T im es. T reatm en t Tap w ater D istilled w ater acid ified to pH 4. 5 and 2% sucrose 10 ppm Endomycin 100 ppm Endomycin 10 ppm P enicillin 0 100 ppm Penicillin O 10 ppm D-52 Salicylate 100 ppm D-52 Salicylate 10 ppm S trep to th ricin sulfate 100 ppm S trep to th ricin sulfate 10 ppm A ntibiotic D-45, sodium salt 100 ppm A ntibiotic D-45, sodium salt 10 ppm A ntibiotic b acitracin 100 ppm A ntibiotic b acitracin 10 ppm Neomycin Sulfate 100 ppm Neomycin Sulfate 10 ppm A m icetin 100 ppm A m icetin 10 ppm T etracy clin e hydrochloride 100 ppm T etracy clin e hydrochloride 10 ppm P enicillin G 100 ppm Penicillin G 10 ppm A ntibiotic D-45, free acid 100 ppm A ntibiotic D-45, free acid 10 ppm A ntibiotic U-5956 100 ppm A ntibiotic U-5956 10 ppm C elesticetin 100 ppm C elesticetin 10 ppm A ntibiotic fum agillin 100 ppm A ntibiotic fum agillin 10 ppm A ctidione 100 ppm Actidione L. S.D . at 5% level L. S. D. at 1% level *A verage of five re p lic a te s and one flow er p e r plot. Average Life in Days* 4 .4 4 .4 4. 6 6.0 5.0 5.2 5.2 5.0 4. 4 4 .2 4.6 4.4 4.2 4.2 5.0 4.8 5. 0 5.0 4.4 4 .4 4. 6 4.2 4. 4 4 .4 5. 2 5. 4 5. 0 4.8 4. 6 4. 6 6. 6 6. 8 0.8 1.1 69 TABLE 40. E ffect of 1000-KVP Cathode Rays on the Life of Rosa hybrida, V ariety Better T im es. T reatm en t in Reps. 0 O bservations N orm al developm ent. W ilting of petals on 5th day. 10 Slight bluing of p etals on 4th day. 20 Slight bluing of p etals on 3rd day. 30 Slight bluing of p etals on 3rd day. 40 M argins of o u ter petals crinkly at end of 1st day and m oderate bluing on 3rd day. 50 Buds on "tight" side on 2nd day and bluing by 3rd day. 60 Buds on "tight" side and outer petals a little crinkly by 2nd day. Bluing of p etals by 3rd day. 75 O uter p etals a little crinkly at end of 1st day and buds on "tight" side on 2nd day. By 4th day buds had good form, still tight, but definite bluing. On 5th day still buds had good form . 100 Buds rem ained somewhat "tight" through 4th day but bluing of p e ta ls began to appear on 3rd day. 150 O uter p e ta ls a re crinkly and appearance not good at end of 1st day. Buds rem ained "tight" through 4th day. Bluing of petals evident on 2nd day. 200 O uter p etals crinkly on 1st day. Buds rem ained very "tight" through 4th day and petal burning appeared by 5th day. 250 Same as fo r 200 r e p s . , except buds rem ained very "tight" through 5th day and leaves dried out on 5th day, with wilted buds. 500 Some a b scissio n of leaves about 15 m inutes after treating, with a burning of side of buds exposed to radiation on 1st day. Buds nev­ e r opened and p etals burned. Dead by 5th day. 1000 Bluing of p etals within 15 m inutes of treating. Side of bud exposed to radiation showed severe burn on 1st day. N early 100% leaf ab ­ sc issio n within 15 m inutes of treating. Buds never opened p ro p e r­ ly and had broken necks by 3rd day. 1500 L eaves fell im m ediately upon treating. Very close to 100% leaf ab scissio n . Stem broke at peduncle by end of 1st day. Bluing of p e tals evident within 15 m inutes of treating. Buds never opened. 70 DISCUSSION It was found that some chelating agents w ere effective in increasing cut flow er life. Cupferron, diphenylamine, hexam ethylenetetram ine and 1-nitro- 2-naphthol-3, 6-disulfonic acid, all rep o rted to chelate iron and in some cases copper, w ere effective in prolonging the cut life of snapdragons. There are s e v e ra l p o ssib le reaso n s why these chelating agents w ere effective in prolong­ ing cut flow er life. They could have reduced bacterial growth at the base of the cut stem , in c re a se d the m obility of m inor elem ents in the plant, reduced re sp ira tio n o r acted as an anti-auxin. Chelating agents have been shown to act as bactericides and fungi­ cides (Zentm yer, 1943). Since the plugging of the xylem v essels by m ic ro ­ o rg an ism s is known to contribute to a shortened cut flower life, it is possible that the chelating agents inhibited the growth of these organism s in the xylem and thus w ere in d irec tly beneficial in prolonging cut flower life. The m obility of the m inor elem ents may also have been increased and thus the m etabolic p ro c e ss e s m ay have continued at a m ore norm al rate. Reduced re sp ira tio n could have been a factor in the prolonged life of flow ers tre a te d with chelating agents. C helating agents can inhibit p a rtia lly or completely, the m etal enzym e function if it is pow erful enough to compete with the enzyme for the m etal. Since a la rg e num ber of co-enzym e a re either m etal-containing or m etal-activ a te d , such as iron in catalase, peroxidase and cytochrom es; cop­ p e r in polyphenoloxidase, asco rb ic acid oxidase and tyrosinase; zinc in carbonic anhydrase and some p eptidases and molybdenum in nitrate reductase, it is p o ssib le that enzym e activity was reduced and thus produced a subsequent r e ­ duction in plant re sp ira tio n . This is in p a rtia l agreem ent with the work of W einstein et al. (1956) who found that cytochrom e oxidase and ascorbic acid oxidase activity was r e ­ duced by the p re se n c e of the chelating agent EDTA. found polyphenol oxidase activity increased. But at the sam e tim e they Total oxygen uptake rem ained constant. It is of in te re st to note that developing leaves on snapdragon spikes becam e ch lo ro tic a fte r six to eight days in a Cupferron solution. This chloro­ s is of new foliage would indicate an im m obility of eith er iron or magnesium or both by the chelating agent. The chelating agents also may be acting as an ti­ auxins in that they m ay stim ulate the activity of indoleacetic acid oxidase and thus low er the concentration of indoleacetic acid in the plant. W einstein et ah (1956) have shown that EDTA will stim ulate activity of some enzym es. The re s u lts with m aleic hydrazide suggest that the destruction of indoleacetic acid m ay account for prolonged life when the flow ers w ere placed in a m aleic hydrazide solution. This chem ical, when used at le ss than 1000 72 p a r ts p e r m illion, was effective in prolonging cut life. This ag rees with the w ork of A ndreae and A ndreae (1953) who suggest that m aleic hydrazide stim u­ la te s the oxidation of indoleacetic acid and thus inhibited growth by this ex ­ cessiv e d estru ctio n of auxin. Leopold and Klein (1951) a re also of the opinion that m aleic hydrazide is an anti-auxin. contributed to a low er re sp ira tio n ra te . M aleic hydrazide may also have Stored onions, treated with m aleic hydrazide, have been found to have lower resp iratio n ra te s (Isenberg, 1954). Although cut flow er life was prolonged in a 0.1 percent solution of m aleic hydrazide, a 0. 4 p ercen t foliage spray one and three days p rio r to cutting, did not affect cut life. It was possible that the foliage application was m ade too n e ar h arv est, and although high concentrations w ere used, there was not sufficient tim e for a physiological effect. E xperim ents with re sp ira to ry inhibitors showed that in general th ese compounds shortened, o r did not affect length of cut life. Sodium azide and m alonic acid a t concentrations above 100 p a rts p e r m illion shortened cut life of snapdragons. leaves. Sodium azide induced p rem atu re wilting of snapdragon Since sodium azide is a potent re sp ira to ry inhibitor, resp iratio n m ay have been stopped p re m a tu re ly and the n e cessary energy needed for w ater uptake was not available. The sam e could be tru e when higher concentrations of m alonic acid w ere used. M alonic acid is an inhibitor of succinic dehydro­ genase and thus can stop dehydrogenation of succinic acid. 73 The action of m aleic hydrazide on plant resp iratio n has been a t t r i ­ buted also to the inhibition of the enzyme succinic dehydrogenase (Isenberg, 1954). spikes. Indoleacetic acid also shortened cut life of snapdragon flo rets and T his is p o ssibly due to the in crease in growth and m etabolism due to ex cess indoleacetic acid. Two antibiotics w ere found to prolong the life of Rosa hybrida. Actidione and Endomycin prolonged the length of life of Better Tim es ro ses one and one-half to two and one-half days. These antibiotics were probably effective in inhibiting the growth of m icroorganism s in the w ater solution and in the xylem of the stem . The antibiotics m ay also have acted as a chelate of some of the m inor elem ents in plants, thereby reducing the m etabolic p ro cesses. Nickell and Finlay (1954) dem onstrated that Actidione and other antibiotics inhibited grow th of Lem na m inor, but gave no explanation for the decrease in growth. Cathode rad iatio n was found not to prolong cut life of Rosa hybrida. T re a te d flow ers developed bluing of petals sooner than usual and at higher con­ cen tratio n s produced p etal burn and leaf wilt. Although it has been re p o rted that irrad iatio n will inactivate m ic ro ­ o rg an ism s (Hannan, 1956) and that X -ray s p artia lly inactivate the growth h o r­ mone of p lan ts (Skoog, 1935), the harm ful effects of irrid atio n w ere g re a te r than the beneficial effects. High concentrations m ust be n ecessary to p artia lly d es­ tro y auxins. It is possib le that if only the stem s w ere exposed to radiation, blu­ ing of p eta ls would have been prevented. Some type of p retreatm en t also may have been useful before exposure to cathode radiation. CONCLUSIONS 1. The effect of chelating agents, growth regulators, resp irato ry inh ib ito rs, antibiotics and cathode radiation on the keeping quality of cut flow ers, esp ecially A ntirrhinum m ajus, has been studied. 2. Seven v a rie tie s of A ntirrhinum m ajus and two v a rietie s of Rosa hybrida as well a s Lilium speciosura rubrum and G erbera jam esonii were u sed in th ese experim ents. 3. Several chelating agents, Cupferron, dephenylamine, hexam ethylenetetram ine and l-n itro -2 -n ap h th o l-3 , 6-disulfonic acid were effective in prolonging the cut life of sev eral v arie tie s of A ntirrhinum m ajus. Cupferron, especially, was v ery effective and in creased cut life of some v a rietie s of A ntirrhinum m ajus as much as six days. 4. When 200 p a rts p e r m illion Cupferron was added to a two p e r ­ cent solution of the co m m ercial floral p re se rv a tiv e s Bloomlife or Floralife, the cut life of A ntirrhinum m ajus, v ariety Spartan Rose and Spartan White, was in c re a se d four to ten days over the control (two percent Bloomlife or two p e rc e n t F lo ralife). 5. The effectiveness of the com m ercial floral p reserv ativ e Petalife was not in c re a se d by the addition of C upferron. Bloomlife and F lo ralife. Petalife was su p erio r to both 75 6. Two hundred p a rts p e r million Cupferron and two percen t sucrose in d istille d w ater in cre a se d cut life of Antirrhinum m ajus four to nine days, but when C upferron and su cro se w ere added to tap w ater, cut life was sh o rt­ ened. 7. Two p ercen t su cro se and 200 p a rts p e r m illion Cupferron in d istille d w ater was as good o r b etter in extending cut life of Antirrhinum m ajus than any com m ercial flo ral p reserv ativ e tested. 8. The level of C upferron for extending cut life of Antirrhinum m ajus was not c ritic a l, but at levels le ss than 100 p a rts p e r million, little resp o n se was noted and above 500 p a rts p e r m illion some injury was evident. 9. C upferron at 200 p a rts p e r m illion extended cut life of Better T im es ro s e s one day. The life of Lilium speciosum rubrum and G erbera jam esonii was not affected by Cupferron. 10. A foliage application of 1000 p a rts p e r m illion Cupferron at pH 3. 0 and 7. 0, one and th ree days p rio r to h arv est did not affect cut life of A ntirrhinum m ajus v a rie ty Snowman. 11. The effectiveness of Cupferron in prolonging cut life is be­ lieved to be p a rtia lly due to a reduction in the resp iratio n ra te of the cut flow er. 12. Of a num ber of growth reg u lato rs used, only m aleic hydrazide a t 250 and 500 p a r ts p e r m illion added to a two percen t F lo ralife solution, 76 in c re a se d cut life of A ntirrhinum m ajus, variety Spartan Rose, two and onehalf to four days over the control. 13. A foliage application of 1000, 2000 and 4000 p a rts p e r million m aleic hydrazide, one and th re e days before harvest, did not affect cut life of A ntirrhinum m aju s, variety Snowman. 14. A ntirrhinum m ajus, variety Spartan Rose, dipped for one m inute in 20, 000 p a rts p e r m illion m aleic hydrazide in creased cut life two days. 15. R esp ira to ry inhibitors such as sodium azide, malonic acid, m aleic acid, p-nitrophenol and o thers did not extend cut life of Antirrhinum m a ju s. 16. Two of the fifteen antibiotics tested im proved cut life. A cti­ dione and Endom ycin at 100 p a rts p e r m illion extended cut life of Better T im es ro se s one and one-half to two and one-half days, but had no effect on cut life of A ntirrhinum m aju s. 17. Cathode rad iatio n of dosages between 10 and 1500 rep s sh o rt­ ened the cut life of B etter T im es ro se s. At all dosages bluing of petals was h astened and at dosages of 50 re p s and higher, crinkling developed in the p etals, while at dosages above 100 rep s, opening of buds was delayed, and between 500 and 1500 rep s, leaf ab scissio n o ccu rred within 15 m inutes af­ te r tre atm e n t. 18. Wide v a rie ta l differences w ere noted in the cut life of A ntirrhinum m aju s, with some v arie tie s having a cut life of three and onehalf days, while o th ers had double this cut life. 19. The low er ten flo rets of uncut spikes of three v arietie s of A ntirrhinum m aju s, Barbara, Navajo and Spartan Rose lasted three tim es as long as the low er ten flo rets on cut spikes. 20. 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