PRE-SOWING TREATMENT OF KENTUCKY BLUEGRASS SEED TO ACCELERATE FIELD GERMINATION Thesis for flu Degree of M. S. MICHIGAN STATE UNEVERSITY Emmanuel Laiekan Ayokunnu Are 1960 11-15515 J LIBRARY 1. Michigan State ' University E 1111!.vll. HIIIIII“ 1. 1e... nuE.‘-Irc 9.1!"! PRE-SOWING TREATMENT OF KENTUCKY BLUEGRASS SEED TO ACCELERATE FIELD GERMINATION BY . Emmanuel Lalekan Ayokunnu Are AN ABSTRACT Submitted to the College of Agriculture of Michigan State University of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Farm Crops 1960 ’4'“ [I -‘, 1 p / / /‘ 74‘ i- /, - Approved ,x’: - ' /C)(. Lc, EMMANUEL LALEKAN AYOKUNNU ARE ABSTRACT This investigation was carried out to find out the effects of gibberellin and temperature alternations during the pre-sowing period on the rate of germination of Kentucky bluegrass seeds in the laboratory and in field seedings. Four lots of bluegrass seeds-—4026 (Kentucky Merion blue- grass), 4020 (Merion bluegrass), 4-5639 (Kentucky bluegrass) and 8Hl-2 (Kentucky bluegrass)--were used. Treatment involved temperature alternations for several days of seeds treated with tap water, gibberellin or KNO3 solutions, after which germination tests were conducted both in the laboratory and field. The effects on rate of germination and total germination as measured by germination percentages taken on different days was found to depend on the origin, variety and size of the seeds. Lots 4026 and 4-5639 were consistently faster in germination than lots 4020 and 8H1-2. Replicates agreed excellently only in germination tests with pure live seeds carried out in the laboratory. Both gibberellin and temperature alternations applied at the pre-sowing stage accelerated the speed of germination of seeds planted in the laboratory but did not help field seedings. It is suggested that for success in accelerating the rate of germination of Kentucky blue- grass in the field, very careful management practices may have to be combined with gibberellin and temperature alternations applied at the pre-sowing stage. PRE-SOWING TREATMENT OF KENTUCKY BLUEGRASS SEED TO ACCELERATE FIELD GERMINATION By Emmanuel Lalekan Ayokunnu Are A THESIS Submitted to the College of Agriculture of Michigan State University of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Farm Crops 1960 ii ACKNOWLEDGEMENT The author wishes to express his sincere thanks to Dr. S. T. Dexter for his guidance and assistance throughout the inves- tigation, and for his valuable help in preparing this thesis. The author is also greatly indebted to Mr. Hubert M. Brown for his help in the statistical analysis of the results and to Dr. G. P. Steinbauer of the Botany Department for the use of his mechanical device for obtaining the pure live seeds. Immense gratitude is extended to Tony Pinchinat, Paul Mezynski, Gerald Miller, F. Cardenas and Tony Adegbola of Rutgers University for the various assistance rendered; to Mrs. S. T. Dexter who helped to type part of the manuscript and to the Farm Bureau Services Inc. , Lansing, who furnished the seeds for the study. The author is also very grateful to the Western Nigeria Development Corporation, Ibadan, Nigeria for their generous scholarship which made the study possible, and to the Chairman-- Mr. Alfred O. Rewane--for his encouragement. Finally, the author is especially thankful to his wife and daughter, Bisi and Funke, for their inspiration and encouragement. iii TABLE OF CONTENTS Page LIST OF TABLES .......................................... iv LIST OF FIGURES ......................................... v INTRODUCTION ........................................... 1 REVIEW OF LITERATURE ................................. 3 MATERIALS AND METHODS ................................ 7 RESULTS ................................................. 12 I. Preliminary Experiments 12 II. Laboratory Trials with Farmers' Bluegrass Seeds 13 III. Field Trials with Farmers' Bluegrass Seeds 21 IV. Laboratory Germination Tests with Pure Live Seeds 29 DISCUSSION .............................................. 35 SUMMARY ................................................ 41 CONCLUSIONS ............................................ 42 LITERATURE CITED ...................................... 44 Table iv LIS T OF TAB LES Page Average percentage germination at 59oF - 86oF of Lot 4026 (Kentucky Merion bluegrass) treated with 30 ppm gibberellin solution, 0. 1% KNO3 solution or tap water during the 6 days alternation of temperature pre-sowing period .............................................. 14 Average germination percentage at 59oF - 86oF of Lot 4026 treated with 30 ppm gibberellin solution, 0. 1% KNO3 solution or tap water during the 8 days alternation of temperature pre-sowing period ........................ 14 Average germination percentage at 59°F - 86oF of four lots of seeds treated with 30 ppm gibberellin solution, 0, 1% KNO3 solution or tap water during the 6 days alter- nation of temperatures pre-sowing period ............. . 19 Average germination percentage at 59°F - 86oF of the pooled results of the 4 lots of seeds of Table 3 ........... 20 Average percentage germination at 59°F - 86oF of 3 lots of bluegrass seeds planted in plastic flats out of doors (May 13th to 29th) .................................... 21 Analysis of variance of Kentucky bluegrass germination test ................................................ 23 Average germination count of Lots 4026, 4020 and 4-5639 seeds planted in the field (June 25th to July 12th) ........ 27 Analysis of variance of germination of Kentucky bluegrass seeds ............................................... 28 Average percentage germination at 59oF - 86oF of pure live seeds of lots 4026 and 4020 under 5 different treat- ments ............................................... 30 LIST OF FIGURES Figure Page 1. A comparison of the effects of different treatments on rate of germination and total germination of Lot 4026 seeds (farmers' seeds) ............................... 16 2. The effects of different treatments on rate of germination, height and vigor of seedslings from Lot 4026 seeds ....... 17 3. The effects of different treatments on rate of germination. and total germination of Lot 4026 seeds (pure live seeds). . 31 4. The effects of different treatments on rate of germination and total germination of Lot 4020 seeds (pure live seeds). . 32 5A. The effects of different treatments on rate of germination, height and vigor of seedlings (from Lot 4020 seeds) ...... 33 5B. The effects of different treatments on rate of germination, height and vigor of seedlings (from Lot 4026 seeds) ...... 34 INTRODUCTION Kentucky bluegrass (Poa pratensis) is a cool-season per- ennial grass which, although native of Europe, has achieved high distinction in pasture, turf and lawns in mid-western United States (8, 17). Farmers and lawnmakers have generally observed slow emergence and thinner stands than desired from their seedings. Various factors may be responsible for this. To accelerate seed germination in seed testing, the official method adopted by the seed analysts is as follows: Seed samples are chilled for 5 days before planting. Pure live seeds of Kentucky blue- grass are placed in covered petri dishes with two layers of blotters and exposed to a daily temperature alternation of 150 C (590 F) for 16 hours and at 300 C (860 F) for approximately 8 hours in the presence of light daily for 28 days. The blotters are moistened with 0. 1% KNO3 solution. The first count is taken on the 10th day and the final count on the 28th day (23). In many cases, growth-promoting substances have been applied to seeds to increase their rate of germination. Gibberellin is one of the best known of these, and is one of a group of related chemical substances known to exert marked effects on plant behavior, particularly with respect to cell elongation, cell division, and the breaking of certain types of ”dormancies” (21, 24). Responses to gibberellin are often greatest at relatively low temperatures. Since rapid establishment of a good initial stand of blue- grass is difficult to obtain, it was thought desirable to investigate the effects of gibberellin and alternation of temperatures during a pre-sowing period on the rate of germination of Kentucky bluegrass seeds in the laboratory and in field seedings. Rapid emergence would reduce the hazards from drought and seedling diseases and help control the weed problem. REVIEW OF LITERATURE Edwards (25) in 1940 first suggested the promotion effect of gibberellin on seed germination when he observed that "seeds from the ears of corn infected with Gibberella fujikuroi grew more rapidly. ” Wittwer and Bukovac (25) reported that gibberellin had promise as a seed treatment and that a concentration of 500 to 1000 ppm was most effective for pea, bean and sweet corn seeds. They however observed a lower final percentage emergence in the field than they obtained in the greenhouse. Gibberellin is known to promote normal growth rates at sub-normal temperature (13, 24). Witwer and Bukovac also mentioned that treating seeds with gibberellin promotes faster and more uniform emergence and a better crop stand with cotton, pea, beans and sweet corn. It was mentioned that the promotive effects of gibberellin seed treatments on seedling emergence are most apparent in early spring when temperatures were otherwise too low for normal performance. . Gibberellin is reported to break dormancy in ”green potato” (24), it appears to show promise in breaking the dormancy of wild oat seeds (9, 10), the positional bud dormancy in asparagus (24) and epicotyl dormancy in tree peony.(24). It substitutes for light require- ment in the germination of Grand Rapid lettuce (15, 24), and Sudia (20) reported that gibberellin will replace vernalization requirement and also substitute for day length requirement. Brian (2) attributes the activity of gibberellin to the neutralization of a growth-inhibitory system which normally limits growth. This may well explain why it breaks the dormancy of some seeds. Koller (14) reported that gibberellin will substitute for the cold requirement of dwarf plants obtained by denying the embryoes of cold-requiring seeds the normal cold treatment. Gibberellin is also said to substitute for cold in rosette plants, and may cure here- ditary dwarfism in pea, corn, etc. In his experiment on the effect of gibberellic acids on laboratory germination of creeping red fescue Button (4) observed that gibberellic acids gave significantly higher germination rate over the control up to and including the 19th day of count; there was no significant difference between the two sources of gibberellic acid-- the potassium salt of the acid and a combination of two acid forms (CHO 19 24 6‘ and C19H2206)' but that there was no significant effect on total germination percentage. The most promising range of concen- tration of gibberellic acid was from 20 to 30 ppm (. 20 to . 30 mg per 100 seeds in 10 cc of water). Button observed that the seventh day count might place the germination percentage of gibberellic acid treated seeds well within the tolerance allowable for the labelled germination. Scherry (18) observed that a single climax point cannot be chosen to fairly evaluate all bluegrass seeds since they may vary from region to region, from lot to lot and in weight fractions. Each seed lot has its own personality. He also reported that under the prevailing cooler temperature at planting seasons, bluegrass will seldom sprout significantly before 15 days except when heavy seeds from southern sources are used. The causes of variability in the rate and total germination of seeds are attributed to differences in the sampling, the distribution of dead and live seeds and lack of proper balance of the prechilling (22). Toole and Toole also remarked that the germination requirement of a given seed may vary with conditions which existed during its development, on maturity and age of the seed, harvesting procedure, handling and storage conditions. Elliot and French (7) pointed out that root growth is dependent on temperature and not on light. Maximum root growth occurs between 25 and 30° c. In a later work, Scherry (19, 26) observed that soaking seeds before planting them appears to help slow1y germinating grasses, but that it showed no consistent advantage with Kentucky and Merion bluegrass. Porter and Rice (16) noticed in the laboratory that the germination of treated and untreated beet seeds planted in sand or in blotters showed no significant difference, whereas only approximately one-third as many sprouts per 100 seed balls was obtained in the field as in the laboratory. Crosier and Cullinan (5) reported that observations and statistical records from 169 lots of grass seeds indicate that KNO3 is of little value in securing an accurate germination from the average sample. KNO3 however improved the rate of germination of an occasional sample of Kentucky and Merion bluegrass seeds. The KNO3-soaked substrates unfortunately tend to increase the severity of blighting in the 28 day tests of Kentucky bluegrass. Only immature freshly harvested Kentucky bluegrass seeds require both light and O. 2% KNO (6). 3 It appears that both the degree of dormancy and the duration of dormancy in Kentucky bluegrass seeds vary from year to year and probably from field to field. The prevailing preharvest environmental conditions and plant population are possibly controlling factors. Also, the interval required before all the viable seeds will germinate varies from year to year and it may be affected by the stage of maturity and the germination method employed (6, 12). Bass (6) however stated that the stage of maturity when harvested influenced the germination of Kentucky bluegrass most. Andersen (1) applying gibberellin at a concentration of 50 mg per liter on Merion bluegrass seeds reported a slightly fungi- cidal effect of the chemical. MATERIALS AND METHOD Four lots of bluegrass seeds were used: a. Lot 4026--Kentucky Merion bluegrass, Washington grown. Germination percentage = 79%. b. Lot 4020--Merion bluegrass from Michigan. Germination percentage = 76%. c. Lot 8Hl-2--Kentucky bluegrass, grown in South Dakota. d. Lot 4-5639--Kentucky bluegrass from Ohio. Germination percentage = 75%. The overall method of procedure included: I. Laboratory trials for determining the best pre-sowing treatments. II. Field trials with cold nights. III. Field trials with warm nights. IV. Further laboratory trials using pure live seeds only. In brief, treatment involved temperature alternations for several days of seeds treated with water, gibberellin or KNO3 solutions. Approximately 5 cc bluegrass seeds from each lot was put in separate test tubes and later covered with a 30 ppm gibberellin solution, or a 0. 1% KNO3 solution or tap water. After a period of one hour, excess solution or water was drained off, a plug of cotton wool was then applied to the mouth of each test tube, and the test tubes were arranged in beakers placed in a refrigerator whose temperature reading was always about 400 F. After the desired length of time had expired, the test tubes containing the moist grass seeds were transferred into the germination chamber maintained at 860 F. The test tubes with their contents were returned to the refrigerator at the appropriate time depending on the particular hours of temperature alternations. Tap water was added to moisten any lot of seeds in the test tubes when they showed signs of drying up. The length of the pre-treatment varied from 6 to 9 days depending on the particular experiment. After the alternation of temperature pretreatment, the seeds were removed from the test tubes and exposed to air in thin layers on clear sheets of paper towels to dry a little in order to make counting of the seeds easier. One hundred seeds (not selected) were counted from each seed lot and arranged in rows on thoroughly soaked two- layered germination blotters in sterile plastic 3-inch diameter petri dishes. The substrate was usually gibberellin solution 30 ppm, 0. 1% KNO3 solution or just tap water. The covered petri dishes were then arranged in the germinators kept at 860 F (300 C) for 8 hours in the day in the presence of light, and at 590 F (150 C) for the next 16 hours in darkness. The corresponding replicates of each treatment were kept on the same shelf in the germinator to even out the environmental conditions at germination time. The seeds were watered adequately whenever they showed signs of drying up. The first germination count was taken after 2 1/ 2, 3 or 4 days depending on the experiment in question. Most of the experiments were stopped after the germination count had been recorded for the 15th day, although one was continued to the 28th day. The first attempt for a field planting was on May 13th, in the spring, before soil conditions were right for seedbed preparation. Small plastic flats filled with unsterilized soil were therefore used to substitute for true field planting. Three lots of bluegrass seeds-- 4026, 4020 and 4-5639—-were used and 6 treatments were applied. 1. Check; i. e. untreated seeds. 2. Soaking the seeds in 30 ppm gibberellin solution for 24 hours prior to planting. 3. Soaking the seeds in 0. 1% KNO solution for 24 hours prior to 3 planting. 4. Soaking the seeds in tap water for 24 hours prior to planting. 5. Soaking the seeds in 30 ppm gibberellin solution plus 6 days 48 hourly temperature alternations at 40 and 860 F. 6. Soaking the seeds in 0. 1% KNO solution plus 6 days 48 hourly 3 temperature alternations at 40 and 860 F. The pretreated seeds were all partially air dried to make counting easier before 200 seeds from each lot were counted at random and planted in the unsterilized soil in the small plastic flats which were placed out of doors. Fine soil from the Farm Crops laboratory was sprinkled on the seeds as coverage (1/8 inch deep) in 23 of the flats and fine sand used on the remaining 31 flats. Two big holes were 10 drilled into the bottom of each plastic flat so that excess water could easily drain out of the soil. The seeded plastic flats were later arranged in a split plot design. All the plastic flats were arranged on a band of coarse sand in order to ensure that the area surrounding the flats would be well drained. Watering was carried out with tap water as occasion demanded and all flats were watered on the same days. Germination counts were made on the 11th, 14th and 17th days. The minimum daily temperatures during the experimental period (May 13 to May 29) ranged between 38 and 590 F with an overall average of 48. 590 F. while the maximum daily temperature ranged between 50 and 790 F with an overall average of 68. 820 F. On June 25, seeds of lots 4020, 4026 and 4-5639 were planted in the field after being subjected to the same type of treatment. Each plot was 2 feet by 4 feet. Equal numbers of seeds were used but the weights of the seeds varied with the lots. Lot 4020 weighed 0. 6144 grams per plot; lot 4026 weighed 0. 544 grams per plot and lot 4-5639 weighed 0. 5088 grams per plot. The planting design was a split plot design. Unfortunately, there was only 0. 64 inches of rain throughout the duration of the experiment despite the rain forecasts by the Weather Bureau. Germination counts were made on the 12th, 14th and 17th days. The minimum temperatures recorded during the experimental period (June 25th to July 12th) were between 480 F and 660 F with an overall 11 average of 55. 30 F, while the maximum temperatures ranged between 73° F and 83° F with an overall average of 78.10 F. The last germination test was carried out in the laboratory with seeds from lots 4020 and 4026 which had previously been blown to remove inert matter, empty glumes and dead seeds thus leaving pure live seeds (as done by the official seed analysts) to work with. Five treatments were applied and there were 4 replicates to each treatment. Five hundred seeds of lots 4020 and 4026 were immersed in 2 cc of 30 ppm gibberellin or 0. 1% KNO3 solutions. They were soaked for one hour. Excess solution was drained off and 6 days temperature alternation was applied to each 500 seed lot starting with 48 hours at 40° F, followed by 860 F for 48 hours and finally at 40° F for another 48 hours. The other three treatments included 30 ppm gibberellin solution, 0. 1% KNO3 solution or tap water as substrates at planting time. There was neither temperature alternation nor pre-soaking treatment for these. One hundred seeds were used as germination sample for each of the 5 treatments and there were 4 replicates for each. 12 RESULTS 1. Preliminary Experiments Some preliminary experiments were conducted with seeds from lots 4026 (Kentucky Merion bluegrass) and 8H1-2 (Kentucky blue- grass) in order to find out whether alternation of temperatures in combination with gibberellin, KNO or tap water could be helpful in 3 speeding up the rate of germination of the various lots of Kentucky bluegrass seeds. The germination tests were carried out on blue blotters in covered plastic petri dishes placed in the germinator. The germination temperature was 860 F for 8 hours accompanied by light, and 590 F for 16 hours in darkness. Results from these investigations gave the following indications: Alternation of temperatures at the pre-sowing stage always increased early germination and was by far superior to prechilling alone. The germination rate of all seed lots was improved by alter- nation of temperatures in combination with gibberellin. Results with 0. 1% KNO3 solution were erratic. Early germination was better with gibberellin than with KNO3 or water, which were in turn better than no treatment. The final germination count at the end of the test was however identical for all the treatments and no treatment. Six to 8 days of alternating temperatures appeared most promising; while 72 to 96 hours cold and at least 72 hours warmth appeared to give the 13 greatest promotive effects on the rapidity of germination of the seeds. Many difficulties were encountered during these preliminary experiments and they tended to affect the results. These were in connection with the seed samples, seed size, number of empty glumes, uniformity of treatments with chemicals and microclimatic conditions during germination tests . II. Laboratory Trials with Farmers' Bluegrass Seeds By "farmers' bluegrass seeds, ” is meant bluegrass seeds put out for sale, which were neither blown nor specially treated, in an attempt to obtain just the pure live seeds as used by the official seed analysts. A. Lot 4026 seeds (Kentucky Merion bluegrass) were soaked in various solutions--30 ppm gibberellin, O. 1% KNO tap water--and 3, subjected to 6 and 8 days alternation of temperature pre-sowing treatment respectively. The seeds were later germinated in plastic petri dishes in the laboratory. The results (see Tables 1 and 2) clearly showed that 6 days alternation of temperatures was much better than 8 days during the pre-sowing stage since the final germination count at the end of the 15th day was within tolerance in most cases. The 48 hourly and 12 hourly temperature alternations for 6 days at the pre-sowing stage were most effective in increasing the rate oflgermination of the seeds. The 48 hourly temperature alternation was however more consistent (see Table 1). TABLE 1. Average percentage germination at 59oF - 86oF of Lot 4026 (Kentucky Merion bluegrass) treated with 30 ppm gibberellin solution, 0. 1% KNO3 solution or tap water during the 6 days alternation of temperature pre-sowing period. 14 PRE-SOWING TREATMENTS ‘ Germination percentage in Ch , 1 Temperature alternation 4 6 7 15 emlca (cold=40O F, warm=86O F) days days days days 30 ppm gibberellin 48 hrs. colds-348 hrs. warm 37.0 59. 5 62.0 75. 5 0.1% KNO3 " " 18. 0 56. 0 65. 0 77. 5 Water “ " 11. 0 38. 0 45. 5 71. O 30 ppm gibberellin 36 hrs. cold:12 hrs. warm 28. 0 53. 0 60. O 70. 5 0.1% KNO3 " " 3. 0 15. 0 27. 0 39. 0 Water H H l. 0 3. 0 7. 0 39. 5 30 ppm gibberellin 12 hrs. cold—$12 hrs. warm 61. 5 69. 5 70. 0 73. 0 0.1% " ” 36. 0 44. 0 47. 0 55. 5 Water " H 41. 5 56. 5 58. 0 70. 0 None (Control) None 0. 5 2. 5 11. 0 74. 0 TABLE 2. Average germination percentage at 59° F - 86°F of Lot 4026 treated with 30 ppm gibberellin solution, 0. 1% KNO3 solution or tap water during the 8 days alternation of temperature pre-sowing period. PRE-SOWING TREATMENTS . Germination percentage in Ch , 1 Temperature alternation 4 6 7 15 em“ (eold=4o° F, warm=86° F) days days days days 30 ppm gibberellin 48 hrs. cold$48 hrs. warm 0.1% KNO3 “ " 8.3 21.0 31.5 40.8 Water " ” 6. 5 24. 5 40. 5 58. 0 30 ppm gibberellin 36 hrs. cold;512 hrs. warm 1. 5 ll. 5 24. 3 40. 8 0.1% KNO3 " II 0. 0 3. 5 13. 5 42. 5 Water " ” 0. 0 4. 8 10. 0 30. 8 30 ppm gibberellin 12 hrs. cold$12 hrs. warm 42. 5 56. 5 59. O 60. 8 0.1% " " 17. 5 47. 3 49. 8 58. 0 Water " " l5. 5 41. 8 44. 0 50. 0 None (Control) None 0. 0 0. 3 3. 8 54. 8 15 Alternation of temperatures always helped since the germination percentages of all the treated seeds were better than those of the control up to and including the germination count taken on the 7th day after the seeds were planted. By the 15th day however, the germination percentage of the control had caught up with those of the treated seeds (see Tables 1 and 2; Fig. 1). With the 6 days pre- sowing treatment. the germination counts on the 15th day in all the seeds subjected to the 48 hourly alternation of temperature at the pre- sowing stage were well within tolerance. Seedlings from gibberellin-treated seeds emerged more rapidly than any others. By the end of the experiment, the germination percentages of those with 6 days total alternation of temperatures were all within the tolerance limit irrespective of the different combinations of hours of cold and warmth at the pre-sowing stage. (See Fig. 1; Table 1.) In addition, the gibberellin treated seeds gave rise to the tallest and most vigorous seedlings (see Fig. 2). Some of the seedlings however looked wiry and slightly curved. The results from seeds treated with 0. 1% KNO3 or tap water were sometimes impressive. Root formation was not adversely affected in most of the seedlings although a few had inadequate root systems. .Ampoom .muocuummv mpoom omov Hod mo Coflumfiguow 133 paw cofimcfiEHom mo mama so monogamouu «Gouomfip mo muoowmo ofimo nomwndeou < A HGDOHM 6 l w>mQ a“ OFFH ma Ma HA mu m. m m A I“ u _ s . . . N o r\ . t S I ON 1 0m J Own 1 0m \..\r\ \\\\.O\\\ . I oo .1. \ .\H\\\\t\\\\\\\\Eth3 .mp5 wwl/ goo .mhn wv u compassofim oudumhomSoH I ow 4| \ 203.933? ougmuumaou + mOva .|.. I om cowumcumfiw magnuomgou + cflmononnwO a I 33:00 . co t 2: Germination Percentage FIGURE 2. II. III. IV. 17 .‘fl ‘ i T - 4d . ‘h ‘A . l’g I I “-p. i ‘ '4 . A \v s "“ I.‘. ; . ' g _ I. o. 5" e: ‘ fl . o " 1' -‘ ”‘2- 'L - ‘u N /£" M, '/ The effects of different treatments on rate of germination, height and vigor of seedlings from Lot 4026 seeds. 30 ppm gibberellin + 6 days 48 hourly temperature alternation Control (no treatment) 0. 1% KNO3 + 6 days 48 hourly temperature alternation Water + 6 days 48 hourly temperature alternation NB: Photo taken 13 days after seeds planted 18 B. The four lots of farmers' bluegrass seeds--4020 (Merion bluegrass), 4026 (Kentucky Merion bluegrass), 4-5639 (Kentucky blue- grass) and 8H1-2 (Kentucky bluegrass)--were treated as in IIA except that the 36 hours cold-12 hours warmth alternation of temperature treatment was omitted. The duration of the pre-sowing treatment was 6 days, and there were 4 replicates per treatment. The results in Table 3 showed that in all cases, seedlings from the gibberellin-treated seeds were superior as regards rapidity of germination to seedlings from all other treatments with the exception of those from the 12 hourly temperature alternation of Lot 4-5639. With 48 hourly temperature alternation applied at the pre- sowing stage, the germination counts of lots 4020 and 4026 were within tolerance by the 13th day of count. Lot 4020 appeared most helped by gibberellin. By the 28th day after the seeds were planted, the germination count of the control had caught up with those of the treated seeds except in Lot 4-5639. A fungal score was carried out on the last day of count, i. e. the 28th day. The system of scoring was as follows: 1 for no fungus 2 for slight fungal infection 3 for badly infected 4 for very badly infected The average fungal score for the treatments were: gibberellin treated seeds =1. 84 KNO3 treated seeds = 3. 22 water treated seeds = 2. 72 TABLE 3. Average germination percentage at 59oF — 86oF of four lots of seeds treated with 30 ppm gibberellin solution, 0. 1% KNO3 solution or tap PRE-SOWING TREATMENTS \ LOT 4026 LOT 8Hl—2 water during the 6 days alternation of temperatures pre—sowing period. LOT 4—56 39 LOT 4020 Temperature alternations Germination percentage in Germination percentage in Germination percentage in Germination percentage in Chemical 4 7 13 28 4 7 13 28 4 7 13 28 4 13 28 Cold24OOF Warm286OF days days days days days days days days days days days days days days days days 30ppm gib. 12 hrs. coldgf12 hrs. warmth 32. 55. 8 63. 3 65.0 25. 8 46. 3 59.8 62. 5 33. 5 42.3 48. 0 52. 20. 3 43. 5 59. 8 65. 5 0-1070 KNO3 " H 1° 11.0 53.3 58.0 0.0 3.0 15.8 40. 3 1.8 7.3 33.5 37. 4.3 8.0 27.0 42.5 Water H H 29. 42.0 52.3 54.3 8. 8 16.0 34. 5 46.8 25.8 36. 0 51. 0 55. 0.5 2.0 20.0 44.8 30ppm gib. 48 hrs. coldg‘l48 hrs. warmth 59. 70. 8 72.0 72.5 18.3 47. 8 54. 5 56.5 39.8 59.3 63.8 65. 21. 8 56.3 70. 3 73.8 0-1070 KNO3 H H 3. 14.8 41.0 41.8 0.8 3. 3 26.8 42.0 12. O 14.8 23.5 25. 8. 3 12.5 42. 5 52.8 Water H H 27. 42.0 52.3 54.5 6.0 13.0 27.8 44.3 21.3 29. 0 39. 8 43. O. 3 O. 8 13. 8 54.0 None (COntrol) None 8. 45. O 71.5 76. 0 5. 3 19. 5 39.8 47. 3 1. 8 6. 8 l5. 8 17. 0.5 5.0 32.0 46. 3 \— 20 Gibberellin was therefore slightly fungicidal (1). The pooled result of the four lots of seeds shown in Table 4 revealed that the promotive effect of gibberellin in accelerating the rate of germination of the blue- grass seeds was by far superior to those of all the other treatments and the control. The final count on the 28th day was almost identical for the KNO3 and water-treated seeds and the control. TABLE 4. Average germination percentage at 59oF - 86oF of the pooled results of the 4 lots of seeds of Table 3. PRE-SOWING TREATMENTS Germination percentage in Temperature alternation 4 7 13 28 Ch ' l emlca (cold=40°F, warm=86°F) days days days days 30 ppm gibberellin 12 hrs. cold‘Z‘12 hrs. warm 27. 9 46. 9 57. 7 61. 3 0.1% KNO3 " " 1. 9 7. 3 32. 4 44. 5 Water " " l6. 0 24. 0 39. 5 50. 4 30 ppm gibberellin 48 hrs. cold:48 hrs. warm 34. 8 58. 6 65. 2 66. 9 0.1% KNO3 " " 6.1 11. 3 33. 5 40. 5 Water " " l3. 8 21. 2 33. 4 48. 9 None (Control) None 3. 9 19. 1 39. 8 46. 8 Gibberellin-treated seeds with 48 hourly temperature alter- nation at the pre-sowing stage were somewhat better than those subjected to 12 hourly temperature alternation in speed of germination. The most striking thing however, was that the different lots of seeds varied greatly in speed of germination. (See Table 3. ) III. Field Trials with Farmers' Bluegrass Seeds 21 A. Three lots variously treated seeds-—4020 (Merion bluegrass), 4026 (Kentucky Merion bluegrass) and 4-5639 (Kentucky bluegrass)--were planted in small plastic flats exposed to cold nights and warm days. TABLE 5. Average percentage germination at 59oF - 86oF of 3 lots of blue- grass seeds planted in plastic flats out of doors (May 13th to 29th). PRE-SOWING TREATMENTS * Germination percentage Days Chemical Temperature alternations Lot Lot Lot (eold=400F warm=86°F) 4020 4026 4-5639 None (control) None 11th 4. 5 15. 2 20. 5 14th 14. 2 30. 0 33. 7 17th 17. 7 35. 7 38. 0 0.1%KNO3 48 hrs.cold.-\_—“48 hrs.warm 11th 3.9 25. 0 21.2 14th 13. 7 36. 7 29. 5 17th 19. 7 42.9 33.4 30 ppm gib. 48 hrs. cold$48 hrs. warm 11th 11. 0 24. 0 26. 4 14th 27. 2 38. 2 35. 5 17th 37. 0 42. 0 35. 9 24 hours soaking before planting 0.1% KNO3 " 11th 6. 4 26. 0 14th 14. 9 48. 4 17th 19. 4 54. 4 30 ppm gib. " 11th 6. 5 10. 2 14th 16. 7 26. 0 17th 22. 9 34. 4 Water " 11th 6. 9 12. 4 14th 17. 0 29. 4 17th 22. Z 34. Z 30. 46. 45. 18. 36. 39. 21. 34. 36. CO Kl OU'I Days when germination counts were made. 22 The results as shown in Table 5 indicated that: The rate of germination of the control, seeds treated with either water or 30 ppm gibberellin solution 24 hours prior to planting, and seeds treated with O. 1% KNO3 solution for 6 days at a 48 hourly temperature alternation during the presowing period, appeared about equally good. Soaking seeds in 0. 1% KNO3 solution, 24 hours before planting or in 30 ppm gibberellin solution with 6 days 48 hourly temperature alternation during the pre-sowing period were effective in speeding up the rate of germination. It was observed that the germination percentage at any level was considerably lower than the corresponding laboratory germination percentage. One reason, may be weather conditions. The temperatures during the experimental period were far from optimum. Moreover, the 16 hours to 8 hours ratio of cold to warm periods which the seeds enjoy during laboratory germination tests were denied them. The results were statistically analyzed. The following are the tables of the analysis of variance: 23 TABLE 6. Analysis of variance of Kentucky bluegrass germination test 11th day result Source 68 df M. Sq F Main plots Replicates 2489. 9 2 1244. 9 — Lots 10570. 3 2 5285. 2 60. 8** Replicates x lots = errora 347. 8 4 86. 95 Subplots Treatments 2463. 7 5 492. 7 4. 75** Lot x treatments 1757. 7 10 175. 8 1. 69 Errorb 3110. 3 30 103. 7 Totals 20739. 7 53 ** = significant at the 1% level (highly significant) * = significant at the 5% level Mean germination percentage for treatments Mean Pre-sowing treatments germination percentage Control 27.1 RE.6 5% = 11. 05 Gibberellin + 24 hours soaking 23. 7 1% = 14. 69 Water + 24 hours soaking 27. 0 L. S. D. 5%= 9. 83 KNO3 + 48 hourly temp. alternation for 6 days 33. 2 1%: 13. 26 Gibberellin + 48 hourly temp. alternation,. 6 days 39. 8 KNO3 + 24 hours soaking 41. 7 Mean germination percentage for lots RE3 5% = 8. 82 hr- 1% = 14. 96 Mean germination percentage L. S. 5% = 8. 65 l = 14. 32 4020 13. o % 4026 37. 1 4—5639 46. 2 RE or RE refer to the total number of means compared in the respective table s . 24 Any difference less than the corresponding L. S. D. value should not be considered significant at that level. Any difference greater than the corresponding RE value may be considered significant at that level. All differences between the corresponding L. S. D. and RE values may be considered questionable as to their significance. TABLE 6B. Analysis of variance of Kentucky bluegrass germination test. 14th day results Source 55 df M. Sq F Mainplots Replicates 1830. 5 2 915. 3 Lots 15940. 7 2 7970. 4 24. 95** Replicates x lots = errora 1277. 4 4 319. 4 Subplots Treatments 3730. 9 5 746. 2 3. 269* Lot x treatments 3824. 4 10 382. 4 . 1. 675 Errorb 6845. 4 30 228. 2 Totals 33449. 3 53 Mean germination percentage for treatments RE6 5%=16. 38 Mean 1%=21. 77 Pre-sowmg treatments germination L.S.D. 5%:14. 57 percentage 1 =1 . 61 Check 51. 9 % 9 Gibberellin + 24 hours soaking 52. 4 H20 + 24 hours soaking 53. 6 KNO3 + 48 hourly temp. alternation for 6 days 54. 3 Gib. + 48 hourly temp. alternation for 6 days 67. 2 KNO3 + 24 hours soaking 73. 2 Mean germination percentage for lots R. E3 5% = 16. 88 Lots Mean germination percentage 1% = 28. 63 4020 L.S.D. 5% = 16. 55 4026 1% = 27. 41 4—5639 25 TABLE 6C. Analysis of variance of Kentucky bluegrass germination test. 17th day results Source 55 df M. Sq F Mainplots Replicates 1410. 0 2 705. 0 Lots 12803. 5 2 6401 8 43.11** Replicates x lots = errora 593. 9 4 148. 5 Subplots Treatments 2887. 9 5 577. 6 2. 59* Lots X treatments 4725. 4 10 472. 5 2. 12 Error 6677. 4 30 222. 6 Totals 29098. 1 53 Mean germination percentage for treatments R. E6 5%=16. 15 Mean 1%=21. 47 Pre-sowing treatments germination L.S.D.5%=14. 36 percentage 1%:19. 33 Check 60. 9 Gibberellin + 24 hours soaking 64. 6 H20 + 24 hours soaking 61. 7 KNO3 + 48 hourly temp. alternation for 6 days 63. 9 Gib. + 48 hourly temp. alternation for 6 days 76. 5 KNO3 + 24 hours soaking 79. 3 Mean germination percentage for lots R. E3 5% = 11. 50 Lots Mean germination percentage 1% = 19. 51 L.S.D. 5% = 11. 28 4020 46. 2 1% = 18. 68 4026 81. 1 4-5639 76. 2 26 In brief, the statistical analysis shows that: Seed lots varied significantly in rapidity of germination and in total germination. There was no significant difference between adjacent treatment means for any day. There was a highly significant difference between the best and the three poorest treatments. B. Farmers' bluegrass seeds from lots 4020 (Merion bluegrass), 4026 (Kentucky Merion bluegrass) and 4-5639 (Kentucky bluegrass) were differently treated as in IIIA and later planted in 2 feet by 4 feet plots on the Farm Crops farm on June 25th. Results in Table 7 failed to show any actual difference in promotive effect among the different treatments. Dry weather during most of the experimental period affected the results adversely as artificial irrigation was carried out only three times throughout the experimental period of 17 days as the Weather Bureau forecase rain which failed to fall. The drought affected the final count most severely as very many of the seedlings died. The dead seedlings were not counted. A statistical analysis of the results (see Table 8) was carried out and it found that there was no significant difference among treatments, lots or replicates. This may be a pointer to the fact that very good care of bluegrass seedlings would be necessary before the effects of the treatments could show properly. 27 TABLE 7. Average germination count of Lots 4026, 4020 and 4-5639 seeds planted in the field. (June 25th to July 12th. ) PRE -SOWING TREATMENTS Ge rmination c ount Chemical Temperature alternations Da 5** Lot Lot Lot (cold:40°F warm=860 F) Y 4020 4026 4-5639 None (control) None 12th 83. 3 87. 7 64. 3 14th 137. 0 180. 3 149. 3 17th 160. 3 160. 3* 130. 7* 0.1% KNO3 48 hrs. cold 48 hrs. warm 12th 46. 7 85. 7 91. 7 14th 98. 0 173. 3 206. 3 17th 97. 3* 188. 3 213. 3 30ppm. gib. 48 hrs.cold 48 hrs.warm 12th 44.8 108. 7 188.3 14th 90. 3 178. 0 328. 3 17th 69. 3* 155. 3* 261. 3* 24 hours soaking before planting 30 ppm gib. ” 12th 80. 0 83. 0 64. 7 14th 168.0 148.3 161.3 17th 224. 3 176. 3 180. 0 0.1% KNO3 " 12th 41. 0 102. 7 96. 0 14th 62. 0 211. 3 209. 0 17th 95.0 241.7 210.0 Water " 12th 87. 0 72. 7 168. 0 14th 151. 3 124. 3 268. 0 17th 137. 3* 91. 0* 234. 0* **Days when germination counts were made. *Germination count adversely affected by drought, hence the drop. TABLE 8. Analysis of variance of germination of Kentucky bluegrass seeds 12th day re sults 28 Source 55 df M. Sq F Mainplots Replicates 19, 158. 1 2 9576.1 Lots 20, 877. 5 2 10438. 8 1. 49 Replicates x lots 2 errora 28,040. 8 4 7010. 2 Subplots Treatments 14, 650. 1 5 2930. 0 0. 798 Lots x treatments 37, 332. 3 10 3733. 2 1. 018 Errorb 110, 058. 8 30 3668. 6 Totals 230, 317. 9 53 14th day results Mainplots Replicates 151. 175.1 2 70587. 6 Lots 94, 659.1 2 47329. 6 1. 52 Replicates x lots = errora 124, 230. 5 4 31057. 6 Subplots Treatments 13, 363. 7 5 2672. 7 0. 39 Lots x treatments 93,197. 4 10 9319. 7 1. 36 Errorb 204, 931. 5 30 6831.1 Totals 681, 557. 3 53 17th day results Mainplots Replicates 47. 452. 1 2 23726. 0 Lots 213, 758. 8 2 106879. 4.. 4. 31 Replicates x lots = errora 99.106. 8 4 24776. 7 Subplots Treatments 11, 579. 8 5 2315. 9 O. 41 Lots x treatments 104, 921. 4 10 10492.1 1. 88 Errorb 167, 579.1 30 5585. 6 Totals 644, 398. 0 53 No significant difference. 29 IV. Laboratory Germination Tests with Pure Live Seeds The farmers' bluegrass seeds of lots 4026 (Kentucky Merion bluegrass) and 4020 (Merion bluegrass) were blown with a machine to remove all the inert matter, dead seeds and empty glumes. The pure live seeds obtained were planted in covered petri dishes containing two blotters each. Five treatments were applied in four replicates each. The results are contained in Table 9. Results shown in Table 9 indicate that: 1. Treatment with gibberellin appears slightly better than KNO3 or water in accelerating germination. 2. Presoaking seeds for 6 days accompanied by alternation of temperatures before placing the seeds in the germinator gave more rapid germination than when dry untreated seeds were placed on germination blotters. 3. The 6 days of damp alternation of temperature storage in the test tubes were approximately equivalent to an equal number of days on the germination blotters. 4. There was a much greater difference in the rapidity of germination than in total percentage germination in the two lots of seeds (see Figs. 3 and 4). Gibberellin treated seeds gave rise to the tallest and most vigorous seedlings. Those treated with 0. 1% KNO3 were next best while the untreated seeds, i. e. control gave rise to the smallest and shortest seedlings. (See Figs. 5A and 5B.) ~30 w .8 m .o... o .N o .o m .2 m on m .2 o .o 29:88 Hood? 952 282 .m m . o.$ m .3 an m .o m.$ m .8 m .2 co 05:18 282 282 e o .3 o o... o :2 m .o o .3 m .3 m .2. m .2 .flm Sam cm 282 282 .m m .3 m .2. o .2 o .e o .3 m .E o .E o om mozm es; .o .. ._ .. m0sz e: .o .N m .3 m .3 o om o o m .3 m .3 m .2. m .3 .flm Eon em o .93 menu/3 .ess wemwo .uss we .sam Boa o... .2 a a a a a a u m on 30.36 93% m on m mu m an m on m on boom hog... “:00 HdowEoAO ma om N. m ma A: N. m oumnumndm cowumapofim magmuoafimh. a“ ommueoouom cowumcflsuoo cm owmuCoonom Goflmfisuomu :oflmcflhhomu omov .HOiH omov .HOA mBZ§Hfi 0.“di mvmmm omov ”—04 mo Goflmawfinom H33 93 cofldggumm mo 3m." :0 mucoaummb ”25.3836 Ho 303mm 9.5. m>mQ Gun 2GB”. 28:... M02% 283 522395 Gofimcuofim mudumuomaou + mOZvH l £338.3qu mndumuvmeg + cfiamuono’ww 33:00 .m HMDOHLH H OM OM 0m 3» cm 00 on ow emu on: Germination Perc entage 32 .Amvmmm 3,: 0.3:: mvmmm omow Hod mo nofidFflEHmm 133 cam coflwfifinom mo 3m.“ Go madmeummuu ”2.5.3.“me mo 303mm ova. .w HmDOHh Tana GM $8.3. 2“on MOZUH .II I ll macaw “3:on“;an | a. II Goflmdumfim whadnomeg + mOZM I ll Goflmnumfid magmaomEou + Gfiaouonnmu loll .. HOEGOU III ow ca ooH Germination Perc entage 33 FIGURE 5A. The effects of different treatments on rate of germination, height and vigor of seedlings (from Lot 4020 seeds). 34 FIGURE 5B. The effects of diffefent treatments on rate of germination, II. III . IV. height and vigor of seedlings (from Lot 4026 seeds). 30 ppm gibberellin + 6 days 48 hourly temperature alternation O. 1% KNO3 30 ppm gibberellin 0. 1% KNO3 Control (no tr eatment) NB: Photo taken 9 days after seeds were planted. 35 DISCUSSION The object of the experiment was to attempt to improve the rate of germination of Kentucky bluegrass seeds. It was felt this could probably be achieved by treating the seeds with gibberellin in combination with alternation of temperature at the pre-sowing stage. Temperature alternation from 40017‘ to 860F was tried since the natural temperature alternation between the days and nights in early spring when bluegrass seeds are usually planted approximates to that. In the experiments, temperature alternation at the pre-sowing stage did actually help speed up the rate of germination of the seeds. This might be attributed to the fact that at higher temperatures, the bluegrass seeds probably respired faster; and since oxygen concentration in plant tissues rapidly diminishes with increasing temperature above 25°C (77°F) (James, 1953; 11, 3), (an effect attributed to the high temperature coefficient of respiration and the reduced solubility of oxygen at higher temperatures) the lowering of the temperature from 86°F to 40°F probably pushed the seeds to faster germination as more oxygen could then diffuse through the compact cells of the bluegrass seeds in order to satisfy the oxygen requirement of the already rapidly respiring embryo. This suggests that the slow rate of germination in Kentucky bluegrass seeds may perhaps be due to the low oxygen concentration within its compact seeds. Earlier work by Delouche (6) on germination of Kentucky bluegrass seeds revealed that seeds whose lemma and 36 palea were removed germinated faster and achieved maximum germination percentage regardless of the stage of maturity at which the seeds were har- vested. This might indicate that the lemma and palea may be responsible for limiting oxygen entry into the seeds and gaseous exchange as well. Forty-eight hourly temperature alternation was the most consistent in speeding up the rate of germination of the seeds. This may have resulted because the initial 48 continuous hours at low tem- perature provided a high concentration of oxygen within the seeds. This in turn might enable a high rate of respiration to become established during the subsequent 48 hours at 86°F. Similarly, during a second 48 hour period at low temperature, oxygen could be supplied in amounts adequate for high respiration continuing throughout the next warm period. Emphasis may be placed on the relative and absolute lengths of time at the different temperatures-~4OO and 86°F. The 12 hours cold?’ 12 hours warm alternation may not have permitted as vigorous a respiration to become established due to the shorter warm periods. In the 36 hours coldil’lz hours warm alternations, relative durations of cold and warmth may have been in poor balance for establishing rapid respiration. In the 48 hours coldF‘-48 hours warm and 12 hours cold-(:1 12 hours warm alternations, the much greater total period of low tem- perature than in 36 hours cold(—_’12 hours warm alternations may have accentuated‘the beneficial low temperature effects of gibberellin (13, 24). In the experiments with pure live seeds, both the 0. 1% KNO 3 and 30 ppm gibberellin solutions in combinations with temperature 37 alternation at the pre-sowing stage performed about equally well. (See Table 9 and Figs. 3 and 4. ) Without the temperature alternation however, gibberellin-treated seeds got off to a faster start. This may suggest that gibberellin is probably more efficient than KNO3 in speeding up the germination of bluegrass seeds under a condition of lower oxygen tension. [The seeds were set in the germinator at 86oF (300C).] Moreover, it was possible that gibberellin probably took advantage of the 16 hours at 59°F which existed throughout the ger- mination period. Despite the generally good response of the seeds to the treatments-~especia11y to gibberellin and temperature alternation at the pre-sowing stage--the various seed lots were observed to have shown differences in their response to the treatments (Table 9 and Figs. 3 and 4). This was not surprising as Scherry (12, 18) had earlier observed that "a single climax cannot be chosen to fairly evaluate all bluegrass seeds since they may vary from region to region, from lot to lot and in weight fractions. Each seed lot has its own personality.” The lots of seeds used came from Washington (4026), Michigan (4020), South Dakota (8H1-2) and Ohio (4—5639). They also varied in weights. In addition, the variations observed in the rapidity of germination between lots and in even the best seed sample could be attributed to several factors such as: 1. the varying maturity levels at which the different seeds in each lot were harvested and the time interval after 38 harvesting the seeds (6, 22); 2. the difficulty in giving uniform treatment with the chemicals at the pre-sowing stage (22); 3. the size of seeds-~which varied with the lots (18); 4. the number of empty glumes and dead seeds in each lot and in each seed sample drawn for the germination test. [This does not apply in the experiment with pure live seeds (22).] 5. the difficulty in providing adequately identical experimental conditions; a. in the germinator, owing to microclimatic differences in the various shelves of the germinator, and b. in the soil, owing to the differences in soil texture, structure, fertility gradient etc. 6. the differences in the condensation of water on the plastic petri dish covers and the differences in the drying rate of the structures. The lower total germination percentage obtained both in the field and in the small plastic flats was most probably due to the far from optimum conditions which prevailed at the time of the experi- ments. The evaporation rate of water from the soil was certainly higher than it was in the laboratory. This high loss of water must have created dry environments in the neighborhood of the seeds. The bad effect was more felt in field planting where little water must have 39 been available to the seeds due to lack of adequate rainfall during the experimental period. (Only 0. 64 inches of rain fell throughout the 17 days of the experiment. ) Also, the. temperature alternation in both cases during the germination period was from an average of 55. 30F to 78.10F for field planting and an average of 48. 59°F to 68. 82°F for the small plastic flat plantings. This did not compare quite favorably with the 400F to 860F range used for laboratory germination tests. Moreover, the temperature alternations in field and small plastic flats experiments did probably not follow the regular 16 hours cold at 40°F and 8 hours warm at 86°F which obtained during the laboratory germination tests. The results however seem to be in line with the findings of Porter and Rice (16) who found that, approximately one-third as many sprouts per hundred seed balls of sugar beets was obtained in the field as against the laboratory performance. The results for the germination tests in the small plastic flats were not unexpected since it was assumed that the natural tem— perature alternation in early spring might be a help to those treatments which hadn't any alternation of temperatures. The fact that the seeds soaked in 0. 1% KNO3 24 hours prior to planting gave the best result (See Tables Sand 6 ) was not surprising. Other factors such as: the number of empty glumes and dead seeds in each sample, and the difficulty of giving a uniform treatment with the chemicals at the pre- sowing stage were probably responsible for this. 40 Soaking the seeds 24 hours before planting them was expected to help in speeding up the rate of germination of the seeds if water uptake alone was the limiting factor in slowing down the rate of ger- mination. This treatment was effective only once, and that was with the 0. 1% KNO3 on seeds planted in the small plastic flats. The promotive effect was probably due partly to the natural temperature alternation of the early spring when the experiment was conducted. Replicates agreed excellently in the germination tests with pure live seeds as compared with those in which farmers' bluegrass seeds were used. This could be explained by the fact that true samples could not be obtained from farmers' bluegrass seeds since no attempt was made to sort out the pure live seeds. 41 SUMMARY Four lots of Kentucky bluegrass seeds--2 of certified Merion and 2 of common Kentucky bluegrass--were used. The various seed lots were pre-soaked in 30 ppm gibberellin solution, 0. 1% KNO3 solution or tap water with or without alternation of temperatures in different combinations of days and hours. Germination tests were carried out: a. in the laboratory on blotters in covered plastic petri dishes at an alternating temperature of 59°F and 86°F; b. in soil placed in small plastic flats exposed to cold nights and fairly warm days during spring; and c. a special germination test was also carried out in the laboratory in covered plastic petri dishes using only pure live seeds. The rate of germination and total germination percentage were recorded. 42 CONCLUSIONS From this study, the following conclusions could be drawn: 1. The different lots of bluegrass seeds differed considerably in their response to treatments. 2. Alternation of temperatures applied at pre-sowing stage was always helpful in speeding up the rate of germination of the blue- grass seeds in the laboratory. The 48 hourly alternation from 4OOF to 86oF for 6 days had the most consistent promotive effects. 3. Gibberellin was the most helpful treatment in accelerating germination of the bluegrass seeds in the laboratory. In addition, gibberellin was somewhat fungicidal. 4. There was no noticeable difference in the promotive effects of O. 1% KNO3 and 30 ppm gibberellin solutions on pure live seeds if preceeded by 6 days 48 hourly alternation'of temperatures at 40°F and 86°F. 5. Acceleration of field germination of bluegrass seeds was not significant in these trials, either in May or late June plantings. Something else-~probably some extra care aside from the gibberellin and alternation of temperature treatment--may be necessary for success in the field. 6. Gibberellin plus temperature alternations at the pre-sowing stage may soon replace the present method used by the official seed analysists for bluegrass laboratory germination tests in order to cut 43 down testing time. It should be remembered that time now involved to complete laboratory testing of Kentucky bluegrass seeds is a vital factor to the seed industry and seed users. 10. 11. 44 LITERATURE CITED Andersen, A. M. The effect of certain fungi and gibberellin on the germination of Merion Kentucky bluegrass seed. USDA Bettsville, Maryland. Assn. of Official Seed Analysts of N. America. Proceedings, 1957. Brian, P. W. Role of gibberellin-like hormones in regulation of plant growth and flowering. Nature 181 (4616):1122-23. 1958. Burton, W. G. 1950. Studies on the dormancy and sprouting of potatoes. The oxygen content of the potato tuber. New Phyt. 49: 121-34. Button, E. F. Effect of gibberellic acids on laboratory ger- mination of Creeping Red Fescue. Agron. Jour. 51: 60-61. 1959. Crosier, W. 8: Cullinan, B. Some observations in the germination of grass seeds. Proceedings of the Assn. of Official Seed Analysts, p. 69. 1941. Delouche, J. C. Germination of Kentucky bluegrass harvested at different stages of maturity. Proceedings of the Assn. of Official Seed Analysts. 1958. Elliot, R. F. and French, C. S. Germination of light sensitive seed in crossed gradients of temperature and light. Plant Physiol. 34:454-6. 1959. Fergus, E. N. A second look at bluegrass. Crops and Soils, p. 15. Aug-Sept., 1956. Helgeson, E. A. and Green, J. G. Gibberellic acid vs. wild oats. North Dakota Farm Research Bimonthly Bul. Vol. 20, No. 7, Sept-Oct., 1958, pp. 7-8. 1957. New weapon against wild oats. North Dakota Agr. Expt. Sta. Bimonthly Bul. 19:121-122. Hussey, C. An analysis of the factors controlling the germination of the seeds of the Oil Palm--Elaeis guineensis (Jacq). Annals of Bot. 1958. pp. 259-284. 12. 13. 14. 15. 16. 17. 18. 119-. 20. 21. 22. 23. 24. 25. 26. 45 Jensen, L. More dormant seed found in new crops. Crops and Soils, p. 31, Jan., 1960. Kline, J. W. Growth responses of gibberellin-treated celery plants. Bot. Gaz. 120, No. 2:122-124. 1958. Koller, Dov. Germination. Scientific American, April, 1959. Leben, C. and Barton, L. V. Effect of gibberellic acid on growth of Kentucky bluegrass. Sci. 125:494-5. 1957. Porter, R. H. and Rice, W. N. Laboratory and field germination of treated and untreated beet seed. Proceedings of the Assn. of Official Seed Analysts. 1939. Scherry, R. W. The story of bluegrass. Hort. 37:530-31. 1959. . Bluegrass sprouting under stress. The Lawn Institute, Route 4, Kimberdale, Marysville, Ohio. . Lawn seeding. Crops and Soils, pp. 13-14. April, 1959. Sudia, T. W. Influence of temperature on the response of germinating barley grains to potassium gibberellate. Plant Physiol. 34:473-5. 1959. Toole, E. H. Hendricks, S. B., Borthwick, H. A. and Toole, V. K. Physiology of seed germination. Annual Rev. of Plant Physiol. Vol. 7:299-319. 1956. Toole, E. H. and Toole, V. K. Variability in germination as affected by physiological condition of seeds and germination microclimate. Proceedings of the Assn. of Official Seed Analysts. 1955. USDA. Manual for Testing Agricultural and Vegetable Seeds. Wittwer, S. H. and Bukovac, M. J. The effects of gibberellin on economic crops. Econ. Bot. Vol. 12, No. 3, July- Sept., 1958. pp. 213-55. Gibberellin and higher plants. Seed treatments for beans, peas and sweet corn. Mich. Agr. Exp. Sta. Quart. Bull. 40:215-224. 1957-58. Wolff, W. H. For better results, try pre-germination. Hort. 37:14. 1959.