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This is to certify that the

thesis entitled
Influence of Tangerature on Flowering of
.1

Greenhouse Carnations (Di-3n mus gagg-

PMS.) presented by
‘.‘."i llial‘l G 0 Ha 111d ay

has been accepted towards fulfillment
of the requirements for

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Major professor
8., 2? M 1452.
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0-169

 

. V- fi ‘fi‘ 4--fi A

INFLUENCE OF TEMPERATURE ON FLOWERING
OF GREENHOUSE CARNATIONS

BY

William Gilmore Halliday Jr.

W

A THESIS

Submitted to the School of Graduate Studies of Michigan
State College of Agriculture and Applied Science
in partial fulfillment of the requirements

for the degree of
MASTER OF SCIENCE

Department of Horticulture
Year 1952

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v.

TABLE OF CONTENTS

INTRODUCTION 0 O O O O O O O O O O O 0

DISCUSSION OF PREVIOUS CONTRIBUTIONS .
PROCEDURE. . . . . . . . . . . . . . .
RESULTS FOR FIRST EXPERIMENT . . . . .
RESULTS FOR SECOND EXPERIMENT. . . . .
ANATOMICAL RESULTS . . . . . . . . . .
CONCLUSIONS. . . . . . . . . . . . . .
BIBLIOGRAPHY . . . . . . . . . . . . .

11
16
26
32
3h

Figure
I._
II.
III.
IV.
V.
VI.
VII.
VIII.
IX.
X.

LIST OF FIGURES

CSW Grade Chart .

Planting Diagram - 19’49‘1950. o o c o
Planting Diagram - 1950-1951. . . . .

Average Number of Flowers Per Plot. .

Average % Split Per Plot. . . . .

Quality of Crap -
Quality of CrOp -
Quality of Crap -
Quality of CrOp -

Petal Count of a "Split" and a "Hon-Split”

Flawero o I O O

60' F. N. T.. .
50° F. N. T.. .
50ox F. N. T. .
60° F. N. T.. .

A. Transverse Section of Calyx Tube Through

Origin of Split

B. Transverse Section Through Split in

Calyx Tube

C. Transverse Section of Petal.

Page

10
18

BEEP-S

29

30

LIST OF TABLES
Table Page
1 Influence of Temperature on Flower
Production and Percent of Calyx Splitting
of Carnation . . . . . . . . . . . . . . . . . 12

2 Sample Record Sheet - 19h9-1950. o o o o o o o 0 1h

3 Influence of Temperature on Flower

Production and Percent of Calyx Splitting

Of Carnation e e o o o o o o o o o c o o o o o 17
h Quality Price. a c . o o o o o o o . o o . . o c 20
5 Sample Record Sheet - 1950-1951. . . . . . . . . 23
6 Average Petal Count. 0 o o o o c o o o o o . o o 27
7 Average Number of Petals from.Flowers Brown

at Four Different Temperatures . . . . . . . . 27

ACKNOWLEDGEMENTS

The author wishes to OXpress his appreciation to
Dr. Donald P.‘Watson for all of his time devoted to this
experiment, for his guidance, patience, and encouragement.
He also wishes to thank Prof. Paul Krone and Dr. Walter
J. Haney for their advice and help in planning and
recording this experiment; and.Martha Gruber Davidson for
her help in the laboratory on the anatomical studies and
her assistance in the greenhouse when time was short.

The author would also like to thank the following
growers who supplied the plants to make this experiment
possible: Gaertner Greenhouses, Saginaw; Smoke Bros.,

Mt. Clemens; and'Yoder Bros., Ashtabula, Ohio.

INTRODUCTION

The size and quality of peduncle, calyx and petal as
well as the yield of flowers are important to the commercial
grower of carnations, Dianthus cagyoghyllus. A great
varietal difference in growth habits of this plant is
recognized (Beach, 1939). Commercial growers believe that
the frequency of occurrence of splitting or tearing of the
calyx tube is not uniform throughout the growing season.
Szendel (1937) has shown that light intensity, temperature,
humidity, soil nutrient level and balance, source of
nutrients, and water relations either directly or indirectly
influence the quality of the flowers and the frequency of
splitting.

In the present investigation the influence of temper-
ature on flowering was studied, attempting to maintain
the other environmental influences as constant as is

feasible under normal greenhouse growing conditions.

DISCUSSION OF PREVIOUS CONTRIBUTIONS

General factors influencing»the_production of flowers:
There has been little scientific work reported on the
effect of temperature on growth of carnations and splitting
of the calyx. Szendel in 1937 and 1938 made a comprehen-
sive report on calyx Splitting. He compiled the early
references to splitting as far back as 1869. These early
reports related splitting to light (Allwood, 1926), humid-
ity (Weston, 1908), fertilizer and soil (Bauer, 1935)
rather than to the influence of temperature.

Connors (1917) maintained that heat, light, and moisture
had a marked effect upon the character of plant growth.

According to Laurie (l9h8) splitting can be attributed
to nutritional irregularities such as an excess or deficiency
of nitrogen’or phosphorous as well as a deficiency of lime.
Underdevelopment of the calyx caused by weakening of the
plant as a result of thrip or red spider injury, uneven
temperature, insufficient light, or frequent light watering

at low temperature is also suggested.

The influence of temperature on flowergpreduction:,
One of the earliest references to temperature effects was
made by Wheeler (1908). He states, "It appears probable

that the character of the manure, as well as the degree of

forcing tends to affect the splitting of the calyx."

By "degree of forcing“ Wheeler probably referred to changes
brought about by the temperature used in growing the crep.
It is felt that Wheeler's hypothesis is not substantiated
by sufficient data to be certain of this conclusion.

Connors (1917) failed to make much comment on the
role of temperature but found increased splitting at the
lower light intensities where it was likely that the
temperature was lower also. The percentage of "splits”
was high in December, January, and February when light
intensity was low. These are the months when temperature
is most likely to fluctuate and Connors made no mention
of his control of temperature.

Szendel (1938) found an indirect relation between
temperature and splitting. Using three temperature
ranges, ho to 50, 50 to 60, and 60 to 70° F. for his
carnations, he showed that the higher temperatures reduced
the number of split calyces. After nine weeks using the
variety Sephelia he found that the calyces on 78, 23, and
11 percent of the flowers had split in the low, medimm,
and high temperatures respectively. In this same experi-
ment there was an average of 71.5 petals on plants grown
at the too compared to 68.8 petals on plants grown at the
60°F. night temperature. This experiment was conducted
for nine weeks with ten plants per treatment. Szendel
subjected carnation plants to 35° F. for periods of from

1h days to 75 days. An increase in the length of this

h
treatment increased both the percentage of split calyces
and the average number of petals per flower. This experi-
ment was conducted over a longer period than the previous
one but there were only four plants per treatment. Szendel
also showed that a period of high temperature decreased
the number of split calyces and that reducing the tempera-
ture from 50 to h0° F. twice a month would produce more
splitting than would a constant h0° F. temperature.

Bauer (19h?) suggested that splitting of the calyx
might be traced to either irregular temperature or to
excess quantities of fertilizer. Allwood (1931) stated
that the chief causes of this fault are sudden changes of
temperature and reduced light intensity.

Post (19h2) showed that temperature above 50° F.
hastened deve10pment of buds on carnation plants. Szendel
(1938) found over 60 percent increase in production by

raising the temperature from 50 to 60° F.

The influence of petal number and flower number on

 

flower quality: Connors (1917) postulated that conditions

 

causing slow deveIOpment of the flowers tended to increase
the nmmber of petals in the flowers of plants that are
unstable in the number of floral parts. There is little
doubt that the double carnation has large fluctuations in
the number of petals per flower. The presence of more
petals per flower would be likely to cause more mechanical

pressure on the calyx. Connors merely suggested this as

a reason for an increase in the percentage of splitting
during periods of low light intensity or cold temperature.
Bailey (l9hl) states that with "higher than normal"
temperatures, the growth of carnations becomes weak, the
flowers are fewer and of poor quality. The weak growth
and poor quality are in agreement with Post (l9h2) and
Szendel (1938) but they did not find a reduced number of

flowers.

PROCEDURE

This work was begun on September 15, 19h9. Four
hundred and fifty large field plants of Dianthus Eggyg-

h llus, varieties Victory Red, Ida, White Briry, and ‘
Puritan were divided equally and planted in three houses
as illustrated in Figure II. One house was maintained at
each of the following temperatures at night: to, 50 and
60° F. The soil in each house was maintained at as close
to the same nutrient level as was possible by soil tests
(Spurway every h to 6 weeks), and the water content held
within similar ranges. The flowers were out and graded
twice a week using the C. S. W. (Cornell Standard‘Weight)
grading system (Figure I). In additionto the grade re-
quirement, stem strength was considered. If the peduncle
was not strong enough to support the flower in a vertical
position when it was held at its proximal tip, the flower
was designated as one grade lower than the C. S. W. system
would require. Records were made of the grade and number
of split calyces produced by each variety in each of the
three plots (Figure II) in the no, 50 and 60° F. green-.
houses. The last cutting of flowers was made on June 19,
1950, no weeks after the experiment was begun.

The plants were removed from.the benches the week

following the last cutting and peat and.manure were

 

CARNATIONS
CSW grade Weight Minimum
designation per flower stem length
(ounces) (inches)
Special 1 and over 2h
Fancy 3/Li - 1 24
Extra 1/2 - B/h 18
First 1/Li - 1/2 12
Second Less than l/h 12

 

Flowers should be bunched with like colors together.
Stems should be reasonably strai t, calyx not split, stems
disbudded and suckered. Lower 1 3 of the foliage removed.
Split calyces or those mended could be graded as normal
but labled No. l and so forth.

19h9 Project Sponsored by Society of American Florists
and New York State Flower Growers

Figure I. CSW Grade Chart

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>4 >4 N N N Victory Red

 

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N N N N N N N N N
N N N N N N N N N
N N N N N N N N N
N N N N N N N N N

incorporated in the soil which was then sterilized at
1800 F. for two hours. On June 25, 1950.the benches were
replanted with plants from three-inch plant-bands. The
varieties Wm. Sims, Northland, and Millers"Yellow were
arranged as shown in Figure III. Records for the second
year were taken similarly to the previous year except that
individual plant records were made instead of a total for
all of the plants of one variety in each plot. Yield records
between November 19, 1950, and.March 13, 1951, are
presented here.

Microtome sections were made of split and normal
calyces of the variety Millers' Yellow. Severa1.ca1yces
were torn by hand and sectioned for contrasting observations.
The tissue was killed in Carnoy's fluid #2 for one and
one-half hours, washed in two changes of 95 Percent ethyl
alcohol, embedded in paraffin, sectioned twelve microns
in thickness, stained with Haematoxylin and Safranin, and

permanent slides mounted in Canada balsam.

10

Hmoauomoa . sapwood monogram

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RESULTS FOR FIRST EXPERIMENT
19u9-1950

The data for the first year's eXperiment are pre-
sented in Table 1. The controlled temperatures used were
not sufficiently accurate to produce dependable results.
This work was preliminary and the results were used merely
as a guide for the second experiment.

The total number of flowers cut was greater from the
plants grown at 60° F. than from those grown at 50° F.

N. T. (night temperature), but it was greatest from plants
grown at h0° F. N. T. The large production in the h0° F.
N. T. house may have occurred because the plants were in
excellent condition in the Spring when the temperature
began to rise and the favorable temperature brought on
heavy production. The temperature controls were only in
effect for a short time before the warm weather started.

Using the 50° F. N. T. as normal (that temperature
commonly used by growers in this area) the increase in
production was 8.6 percent at 60° F. and 18.u percent at
Roi F. N. T. At a 60° F. N. T. growth was more rapid but
it was Spindly and weak.

The flower heads were not measured but they appeared

to be smaller on plants grown at 60° F. N. T. than those

12
TABLE 1

INFLUENCE OF TEMPERATURE ON FLOWER PRODUCTION AND
PERCENT OF CALYX SPLITTING OF CARNATIONS

 

 

 

Varities Average
60° 50° 1+0"
Victory Red Cut h2.6 h1.3 h9.3
(5 plants}
% Split 9.6 6.6 9.0
Ida Cut 37.0 30.6 N7.0
(5 plants)
% Split 0.6 0.0 0.3
White Briry Cut 95.3 88.0 111.0
(9 plants)
% Split 2.3 2.0 1.0
(30 plants) '
% Split 36.6 3703 5303
Total flowers cut 1393.0 ' 1283.0 1519.0

Average percent Split 10.0 10.8 12.5

 

13
grown at.50o F. N. T. The peduncles were noticeably thinner
and were the main cause of low quality grades of flowers
produced at the higher temperatures. With the variety
Victory Red during the period from.February 6 to April 17,

73 percent of the flowers cut from plants grown at 60° F. N. T.
were grades 1 and 2 while for those grown at 50° F. N. T.
only 50 percent were in these two grades.

This information.merely served as a guide for the

second experiment.

Discussion of Table 2
Sample Record Sheet - 1949-1950

The sheet is divided into four main columns, one for
each variety grown. These are further divided into N
(number of flowers) and G (grade) for the normal and split
flowers. On each date there is one entry for each grade
cut. Other separate records were kept for each plot in
each temperature. In addition to the grades listed in
the CSW system is the grade 0 to represent flowers below
grade #2, because ef either stem strength or stem length.

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RESULTS FOR SECOND EXPERIMENT
1950-1951

During the second experiment the temperature was
controlled much more accurately; other environmental
conditions were similar to those in commercial green-
house Operation.

Table 3 and Figure IV illustrate that the total pro-
duction of flowers was increased with the increase in
temperature. Table 3 and Figure V illustrate that the
percentage of Split calyces decreased on plants grown at
the higher temperature. Plants grown at 500 F. N. T. pro-
duced almost twice the number of flowers that were produced
on plants grown in the "fluctuating" 50° F. N. T.

All three varieties reacted similarly to the temper-
ature treatments in both production and in percentage of
”Splits". The production of Millers' Yellow was greatly
decreased by the low temperature, more so than the other
two varieties and the percentage of "splits" in.Millers'
“Yellow was considerably greater than in the other two
varieties when grown at ho. F. N. T.

These results are in agreement with Connors (1917),
Szendel (1938), and Post (19h2), but seem to disagree with
Bailey (19h1) where he states that "flowers are fewer with

higher than normal temperatures". Bailey may infer tempera

17?

TABLE 3

INFLUENCE OF TEMPERATURE ON FLOWER PRODUCTION AND
PERCENT OF CALYX SPLITTING OF CARNATIONS

 

 

Night temperatures oF. ,

 

 

Varieties Average *

60° 50° 50° uo°

Wm. Sims Cut 107.3 76.0 h8.3 22.3
(20 plants)

% Split 1.99 2.05 n.21 13.6

Northland Cut 6h.3 32.3 26.3 10.0
(15 plants)

% Split Oeué 1.0u 2.h9 130a

M111OI'S' Yellow CUt 50.7 36e0 Ill-e6 3e6
(15 plants)

% Split 2.us 3.97 7.u 53.9

Total flowers cut 657.0 uu3.o 266.0 108.0

Average percent
split 1.65 2.u8 h-1 15.7

 

*Temperature was lowered to 35° F. on December 9 and
January 9, and to h0° F. on February IN to study the effect
of fluctuating temperature.

atures above the 60° F. N. T. used in the present investi-
gation.

Szendel (1938) found a 60 percent increase in pro-
duction of the variety Sophelia by raising the temperature
from.50 to 60° F. N. T. In the present investigation,'
however, the increase in production for the variety North-
land is slightly under 50 percent and less for the other
two varieties and tends to show that there is varietal

18

AVERAGE NUMBER OF FLOWERS PER PLOT

:00
so
so
.0

20

“RAGE NUMER W FLOWERS CUT PER PLOT

 

 

 

60’ 50° FLmTUATING 40' 60’ 50° FLUCTUATING 40‘ 60‘ 50° FLUCTUATING 40°

WILLIAM S“ . NORTHLANO MILLERS YELLOW

l-DUS E TEMPERATURE

Figure IV.

difference in response to temperature.

Beth Bauer (19h?) and Allweod (1931) link splitting
with.changos in temperature. The larger (approximately
no percent) increase in incidence of splitting in the
50‘ F. fluctuating night temperature ever that in the
50° F. constant night temperature house substantiates those
statements. No attempt was made to determine the effect
of an occasional high night temperature. Because splitting
was less with the higher night temperature, it is not
believed.that an occasional high night temperature would

increase the percentage of "splits”. It is probable that

19

AVERAGE % SPLIT PER PLOT

50—————-—-——————1h——~————-— —— —-—-—1

% SPLIT PER PLOT

AVERAGE

 

 

   

60' 50' FLUCTUATING 40' 60' 50' FLUCTUATING 40’ 80‘ 50' FLUCTUATING 40°
WILLIAM SIMS NORTHLAND MLLERS YELLOW

HOUSE TEMPERATURE

Figure V.

a fluctuating temperature will increase the percentage of
"splits“ only if the fluctuation is lower than the
normal temperature.

The large increase in production in the 60' F. house
naturally must be sufficient to offset the lower quality
and higher costs of production if it is to be of practical
value to comorcial growers of flowers. 'rable h. was com-
piled to demonstrate this comparison. The following plan
was adopted in the construction of this table: the umber
of flowers of each grade was multiplied by a figure that.
was an approximation of the average price for each grade.

These prices were: Seconds 1 $0.05, Firsts 1 $0.07,

20

TABLE u
QUALITY PRICE

(per square foot)

 

 

 

 

Variety Nighi Fimperaturfl o F.
60° 50° 50°* “0°
‘Wm. Sims $2.99 $2.21 $1.u1 $0.6u
Northland 2.09 1.3h 1.05 0.35
Millers' Yellow 1.50 1.h9 0.53 0.09

 

*See Table 3

Extras 1 $0.09, Fancys 1 $0.12, and Specials x $0.15.

The figures of A. Washburn and Sons, Bloomington,
Illinois, for costs of greenhouse production for 1950
were used to determine the differences in cost for each
of the three temperatures used. Using the no. F. N. T.
as a standard, it costs 10} more per square foot to
produce flowers in the 50’ F. N. T. and 30A more in the
60° F. N. T.

Growing these plants until March 15 (as in the
present investigation) the profit from plants in the
60° F. N. T. would be considerably greater for‘Wm. Sims
and Northland than from plants grown in the 50° F. N. T.
even with the 20¢ increase in cost per square foot. The
decrease in quality of Millers' Yellow was so great with
the higher temperature that a greater profit was indicated
on plants grown in the 50° F. N. T.

The increase in gross income by an increase in temper-
ature from no to 50° F. N. T. was great enough with all
three varieties to more than offset the added costs of the
higher temperature. It can easily be seen that unless the
production from.March 15 to June 15 increased phenomenally,
there would be no profit from carnations grown at h0° F. N. T.

The constant temperature increased gross income over
the fluctuating temperature enough to warrant automatic
devices or added labor to control temperature. With the
fluctuating temperature a.profit would be realized on the
plots with'Wm. Sims, it would be doubtful for Northland, and
practically impossible for Millers' Yellow with only $0.53
gross income from plants grown through March 15.

These data would indicate that a greater profit is
obtained by growing carnations at 60 than at 50° F. N. T.
in spite of the lower grade of the product produced at
the higher temperature.

Table A also suggests that there is probably an

Optimum temperature for each variety of carnations.

Discussion of Tablegé

 

Sample Record Sheet - 1950-1951

At the t0p of the sheet "Rows 1 to h" and letters
"A,B,C,D,E" correspond to the_p1ants' locations in the
planting diagram (Figure III). The numbers 1 to h,
representing the vertical rows in the planting diagram,
are for the four horizontal spaces divided by the double

22

lines; the letters, in like manner, representing the
horizontal rows. 0n the left-hand edge the "2,1,E,F,S"
represent the five grades of the CSW grading system. The
numbers entered on the sheet each represent one flower cut;
the nwmber itself being a code for the date the flower was
out. For example: 1 = Nov. 28, 2 = Nov. 30, 3 = Dec. 6, etc.
A parenthesis around the number indicates that the flower
had a split calyx. The space, therefore, between two double
horizontal lines under one of the letters A, B, C, D, or E

shows the record of one single plant.

23

TABLE 5

SAMPLE RECORD SHEET - 1950-1951
M

 

 

 

 

 

 

House #1 60° F. N. T. Rows 1 to h. 'Wm. sums
Grade A. B C D E

2 3 9 8,8,8

1 #91291” ”97s1hs1h 18 991” h.8.9

E 1,6,6 5,5,6 6 l

P

S

2 13 n.13 1h A _ 11+

1 5.9 1 3.h.10 h.9.9

E 16 6 (S) 12 5,10

F 6

S

2 1,L|.,10 ‘ 8,9313

1 12913913 9:12 (u).(h).9 (u) 8

E 10 6 3 (5)s596

F

S .
W

2 3.9 , . it

1 10’12’17 339912313 “3999,12, 9 17

p _ 1 .11
E 1§6,6,9’ ' 395,16 S 2,16,16

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Figure VIII. Figure Ix.
Figures VI - Ix. Quality of Crop

Figures VI through IX represent typical yield of
flowers from the four temperature treatments on February
18, 1951. There is a large quantity of low quality flowers
from.the 60' F. N. T. planting (Fig. VI). This was the
only planting from which any No. 2 grade carnations were
cut. The flower heads were small, the stems weak, and the
leaves thin and undorsise. The 50' F. N. T. produced the
largest number of flowers with the grade of Extra (Fig. VII).
These flowers have strong, fairly straight stems, heavy

leaves, and good sized flower heads. There was much lower

25

production in the fluctuating 50° temperature (500x) than
in the 50° F. N. T. where the temperature was constant
(Fig. VIII). There is no noticeable difference in the
size of flower heads from these two temperature treatments.
The stems and leaves appear slightly thinner when grown
under’the fluctuating temperature. The poor production

at no“ F. N. T. is very evident from Figure 1):. The flower

heads are poorly formed, and a split calyx is present.

ANATOMICAL RESULTS

A count was made of the petals in all flowers where
the calyx was split and of a typical flower of the same
variety taken at random in the same plot for comparison.
Petal count is presented in Table 6. There is a 16-18
percent increase in the average number of petals in the
”splits" over the normal flowers. In all of the pairs
counted there was only one pair in which the petals in
the normal flower exceeded the petals in the flower with
the split calyx. If more splitting of calyces is found
at low temperatures and more petals in the split flowers,
it is possible that there may be some relationship between
temperature at which the plants are grown and the number
of petals. Table 7 shows the relationship between number
of petals and temperature. The number of petals per
flower is greater at a higher temperature. For each
variety the highest number of petals was found in flowers
grown at the 60° F. N. T. This is not in agreement with
Szendel's (1939) work. He found a decrease in the number
of petals per flower from flowers grown at a higher temper-
ature. Szendel's average petal count per flower varied
from 71.5 petals at ho. to 68.6 petals at 60° F. No definite
conclusions may be made from these results since they were

secondary findings.

TABLE 6
AVERAGE FETAL COUNT
(45 Flowers)

27

 

ET *—

 

Variety Split Normal
Wm. Sims 63.2 52.9
Northland 67o3 579°
Millers' Yellow 68.0 55.h

TABLE 7

AVERAGE NUMBER OF PETALS FROM FLOWERS
GROWN AT FOUR DIFFERENT TEMPERATURES

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Fe No To I

Variety ‘365—-———365‘ —300 “0
Normal 57.6 E7.7 5h.6 52.0
Northland Split 0 70.3 0 63.5
Normal 0 57o5 0 511.0
Millers' Yellow Split 85.5 71.3 58.0 6h.6

Normal 55.0 51.0 h9.0

h9.6

28

In about one-half of the "split" Millers' Yellow
flowers there were from two to eight growing points which
greatly increased the number of petals. These extra
growing points were also found in a few “split”'Wm. Sims.
Figure X shows the petals from two‘Wm. Sims flowers cut
on February 18, 1951. The flower with the "Split“ calyx:
has 66 petals compared to the "non-split" of EB. In the
"non-split" flower most of the petals are uniform, the
lower part of each petal is straight and narrow. The petals
from.the "split" flower are often immature, malformed, and
some petals are fused to others from the proximal tip for
half the length of the petal. In almost all ”split" flowers
examined, there were some abnormal petals.

Many microscOpic preparations were made of the naturally
split area in calyx cups of those split by hand and of
normal calyces from the variety Millers' Yellow. No
difference in structure was observed between the naturally
and the artificially split calyces. The area of splitting
was similar in all flowers examined and is illustrated by
drawings A and B of Figure XI. Drawing A is a typical trans-
verse section at the origin of the split. The splitting
begins on the inner surface of the sepal at the tip and
proceeds down a line of parenchyma between two vascular
bundles. The rupture did not cross through the vascular
bundle in any of the split calyces examined.

Drawing B (Fig. XI) is of a transverse section of a

calyx, approximately one-eighth inch above the origin of

29

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Figure I. Petal Count of a "Split" and a ”Non-split" Flower
(Wm. Sims Variety) _

the split. These two cross sections are similar except

for the dehydration and browning of the exposed cells and

distortion of the epidermal layer.

Since the rupture is apparently of a mechanical nature
it is possible that mechanical pressure from the inside is
the main cause of the rupture.

The corolla constitutes the greatest bulk of the flower.
It is the most logical part of the flower to cause most of
the pressure on the calyx. An examination was made of the
structure of the lower part of the petal. Drawing 0 (Fig.
II) is a transverse section through the narrow basal

portion of a petal from the variety Millers' Yellow. At

 

A. TRANSVERSE SECTION OF OALYX
TIDE THROUGH 'ORISIN 0F SPLIT

XI”

8. TRANSVERSE SECTION

SPLIT
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30

C. TRANSVERSE

PETAL

31

this stage of deveIOpment, the only well organized tissue
in the petal is vascular. The epidermis is evident but
the intervening tissue is loosely connected, disorganized
and parenchymatSus in nature. With this type of tissue
constituting the bulk of the petal it is possible that
growing conditions might greatly influence both the size
and number of cells in this tissue. This in turn might

regulate pressure on the calyx cup.

l.

2.

3.

h.

5.

6.

7.

8.

CONCLUSIONS

Temperature has a considerable effect upon growth and
splitting of the calyx of carnation flowers.

A night temperature of 60° F. resulted in greater
production and less splitting of calyces but poorer
quality than the 50' F. night temperature.

At h0° F. night temperature production was greatly
decreased but calyx splitting was increased.

There is a marked difference in varietal reSponse to
temperature.

It is possible that with some varieties the increased
production from the 600 F. night temperature would be
enough to offset the increased operating expenses and
lower quality flowers.

If once a month the temperature is lowered 10 to 15° F.
below the night temperature usually used, production
will greatly decrease and splitting increase.

The number of petals in a flower with a ”split" calyx
is usually greater than in a normal flower of the same
variety from the same plot.

Splitting of the calyx cup appears to be caused by A
mechanical pressure inside the calyx. It may be because
of an increased number of petals, an increase in the

size of the basal portion of the petal, reduced growth

33

of the calyx itself, or failure of elongation of petals

as the flower develOps.

BIBLIOGRAPHY

Allwood, M. C., l9hl. "Carnations for Everyone", Count
Life Limited, London, p. kl.

Bailey, L. H. and Bailey, E. 2., 19M. Hortus Secund,
The Macmillan Co., New'York.

Bauer, A. F. J., l9h7. "Carnation", The Standard Cyclo-

pedia g£_Horticulture, L. g, Baile , The Macmillan Co.,
New'York, Vol. I:671.

Beach, G. A., 1939. "Carnation Yield and Quality as Affected
by Watering and Phosphate", American Society for Horti-

 

cultural Science Proceedings, 37:1022-1026.

Connors, C. H., 1913. ‘N23 Jersey Agricultural Experiment
Station Annual Re ort, pp. 135-1h2.

, 1917. ”Factors Causing the Splitting of
Carnation Calyces", New Jersgy Agricultural Experiment
Station Annual Re ort, 1916:83-89.

Post, Kenneth, l9h2. "Effects of Daylength and Temperature
on Growth and Flowering of Some Florist Cr0ps", Cornell

University Agricultural Experiment Station Bulletin,
787:28.

 

Szendel, A. J., 1937. "Calyx Splitting of Carnation Flower:
Preliminary Reports on Nutritional Experiments",

American Society for Horticultural Science Proceedings,
35:781-787.

 

35

, 1937. "Sex Abnormalities in Carnation

 

Flowers", American Society for Horticultural Science

Proceedingé. 35:7h8-75ho
, 1938. "The Effect of Temperature on

 

Splitting of Carnations”, American Society for Horti-
cultural Science Proceedings, 36:760-762.

, 1939. "Temperature and Nutritional Studies

 

in Splitting of the Calyces of Carnation Flowers",
Ph.D. Thesis. ‘

U.S.D.A., 1909. Farmers Bulletin.§ég, pp. 7-8.

wheeler, H. J. and Adams, G. E., 1908. ”A Further Study of
Soil Treatment in Greenhouse Culture", 52292 Island

Experiment Station Bulletin, 128:183-19u.

m 1300M use ONLY

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MICHIGAN STATE UNIV

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