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THE EFFECT OF FOUAGE SPRAYS
0N WATER LOSS OF PLANTS
Thesis for the Degree of M. 5.

Frank Baker Cross
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THE EFFECT OF FOLIAGE SPRAYS ON
WATER LOSS OF PLANTS

Thesis

Submitted to the Faculty of the Michigan State
College of Agriculture and Applied Science
in partial fulfillment of the require»
mente for.the degree of
master at Science

by , V‘
Frank Baker Cross
1927 ‘5'—

 

 

 

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‘1'

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Pablo of Contents.

Page
Introduction----~----------I --------------- 1
Review of Literature ----------------------- 1
Object of Investigation -------- - ------ ~---- 3
Methods and Materials ---------------------- 3
Experiment l-Jerusalem Cherry Plants ------- 6
Experiment ll-Oineraria Planta- ------------ 21
Experiment lll-Jerusalem Cherry Plants ----- 25
Experiment lV-Crabapple Trees -------------- 30
Experiment V-Seedling Apple Trees ---------- 34
Examination or Stomata- -------------------- 39
Summary----~-- ------ -- ------------------- --4l
Acknowledgement ----- -- ----------------- ----42
Citation of Literature--- ------------------ 43
Photomicrographs of Stomata- --------------- 45
Photographs of Jerusalem Cherry Trees ------ 49
Photographs of Apple Trees-e -------------- ~52

INTRODUCTION

Insects and diseases, some of which are very
persistent and destructive, are prevalent wherever
plants are grown for either ornamental or economic
reasons. The practice of spraying plants with various
materials for the control of injurious pests, though
of comparatively recent origin and development, is
now almost universal.

The kinds and amounts and the best time to make
spray applications have been studied by plant patholog-
ists, entomologists, and horticulturists. Little attenp
tion, however, has been paid‘to the effects of the spray
materials on the plants themselves, though it has been
observed that certain sprays applied under particular
conditions may lead to increased or decreased size and
color of leaves, extending or shortening the rest period,
'premature abscission of leaves, russeting of fruits,
and othertresponses. There may be still other less evident

effects which are of a physiological nature.

REVIEW OF LITERATURE
As early as 1893 Rumm (1) observed that abscissed
shoots of grapes sprayed with Bordeaux mixture remained
fresh longer than unsprayed. This he interpreted as
meaning that there is a falling off in the rate of water

loss from sprayed shoots as compared with the unsprayed

shoots. During the same year the theory that "lessened
transpiration" follows spraying was advanced by Miller--
Thurgau (2) and by Bayer (3).

Experimental work by Frank and Kruger (4), however,
led them to conclude that spraying with Bordeaux mixture
caused plants to use more water than is consumed by unv
sprayed plants. Later Zucker (5) confirmed their results.
Schander (6) reports less use of water as a result of
spraying with the same material, and Ewarts (7) work
seems to support the conclusions of Rumm and Schander.

In a carefully planned experiment Duggar and
Cooley (8) collected rather conclusive evidence which
tended to show that a surface film of Bordeaux mixture
increases the amount of water used by plants.

Martin (9), and later Shreve and Martin (10),
published data showing that spraying abscissed leaves
and also the foliage of potted plants with Bordeaux
mixture had the immediate effect of causing an increased
water loss. Duggar and Bonns (ll) confirmed these data.

wells (12) found that the use of Bordeaux mixture
as a spray on cherries increased the rate of water loss
from the leaves. He ascribed the reduction in size of
the fruit, which sometimes follows the use of Bordeaux
mixture as a spray on cherry trees, to this increased

‘water loss.

 

 

 

Numerous references may be found to the use of oil
sprays on plants, but all of them are concerned with
the concentration required for controlling insects with-
out inJuring the trees. Nothing is available on the

effect of oil sprays on rate of water loss from plants.
OBJECT OF INVESTIGATION

Though experimental data are available to show
that certain spray materials increase the rate of water
loss from the leaves of plants, there is no clear evidence
that any spray materials have the opposite effect.
Knowledge of how to reduce water loss by means of sprays
might conceivably be of considerable interest.

The purpose of this investigation was to determine
whether rate of water loss can be reduced by the applica-
tion of foliage sprays and, if so, what material or
class of materials has this effect. A preliminary investi-
gation started by Bayer (15), but never completed,
suggested that whole milk apparently decreases the rate
of water loss from the leaves of some plants. This find-
ing furnished the starting point for the present investi-
gation.

METHODS AND MATERIALS

The general plan of the investigation was to con-
duct a series of spraying tests with whole milk and

with its various component parts or groups of compounds

 

 

in such a way as to determine their influence on rate
of water loss. All told five tests were completed. Whole
milk was used first because a previous investigation
indicated that it decreased the rate of water loss. Sub-
sequent spray treatments were developed from the knowledge
gained by the use of this material and its component
parts. The first test was concerned with the use of
whole milk; later tests were then made useing fatty or
oily substances which were cheaper than butter fat. In
the later tests an emulsifying agent was required for
the proper mixing of oil with water to make the sprays
desired. For the most part soap was employed for this
purpose, although Bordeaux mixture also was used. Two
types of emulsion may be prepared; in one oil is the
dispersed phase and in the other water is the dispersed
phase. The former is the one utilized for this experi-
mental work.

The tests were all conducted inside a greenhouse.
None of the plants used were in an active growing cons
dition. Medium to large sized Jerusalem cherry plants
were used for the first and the third experiments.
Cineraria plants, from which the blossoms had been
removed, were used for the third. Well branched Hyslop
crabapple trees, averaging about three feet in height,
were used for the fourth experiment, and for the fifth,

one year old seedling apple trees.

The Hyslop crabapple trees were put in eight-inch
pots; all other plants were in six-inch pots. These had
been made impervious to water by painting the inside of
each with melted "parqwax" and the outside with two coats
of "Duco". The plants were transferred to these prepared
pots at the beginning of each experiment. The ball of
earth enclosing the roots of the plant was not broken
when the transfer was made.

To avoid loss of water from the soil, the top of
the pot was sealed with parawax. This was accomplished
by painting the top of the soil and the rim of the pot
with melted parowax and allowing it to harden. A small
circular piece of oil cloth over a slight mound of sand
around the base of each plant, or a strip of adhesive,
tape around its base, were used to prevent the hot
parawax from coming into direct contact with the Stems.

Before sealing with pardwax, a glass tube sevenp
eighths of an inch in diameter and eight inches in length
was inserted in the soil near the base of each plant.
This was for the purpose of renewing the water supply
from time to time. The upper end of the glass tube was
closed with a cork stopper. Thus from the unit consist-
ing of plant, soil and pot, water could escape only
through the leaves and the stems of the plant itself
and transpiration losses could be determined periodically

by weighing.

Care was taken to have as nearly as possible an
optimum soil moisture content at the time of sealing the
plant. As soon as the plant was sealed in, the unit was
weighed. Weights were taken once each day or once in two
days, depending on the rate of loss of water from the
plant. In most cases it was found best to weigh every
day.

After the plants had been sealed in the pots, a
period of two or three days was allowed for readjustment
before recording any weights. Records were then made of
the water losses from individual plants. At each weighing
sufficient water was added to bring the unit up to the
original weight.

EXPERIMENT l.
Transpiration Experiments with Jerusalem Cherry
Plants Sprayed with Whole Milk or with its Various
constituents.

Fifty-one Jerusalem cherry plants were sealed in
pots on January 12, 1926. Pots were numbered, from one
to fifty-one inclusive. Each unit (plant, pot and soil)
was then weighed daily between 8:00 and 10:00 A.M. and
the loss of weight replaced by the addition of water
through the glass tube.

Additions of water to each unit were recorded

January 24, 25, 26, 27, 28, 29. On the basis of the

total amount of water used for this period the plants
were divided into ten groups or series consisting of
five plants to each series. The selection of plants

for each group was made so that the total loss for

each group for the period was approximately the same,
thus securing an equal distribution of plants with high
and with low losses within each group. Table 1 shows
the transpiration records of these plants during this
preliminary test period.

TABLE 1

Individual plant losses of water on the basis of which
groups having lost the same amount of water were made
3 v '5 ‘Loss (IE grams)’ '3‘

 

 

 

 

 

 

 

Group Plant number 6 dailyéweighings Total
33 145
30 175
A 47 180
25 270
6 360 1130
16 145
35 175
B 37 218
13 245
3 350 1130
19 145
32 180
C 40 215
11 260
43 335 1135
48 150
34 170
D 31 220
8 265
20 330 1130
27 150
2 180
E l 215
50 260
14 325 1130
44 160
23 190
F 4 220
17 280
28 280 1130
41 165
18 240
G 38 215
10 250

51 260 1130

 

 

Table 1 con't
fl 1083 (In grams TV

 

 

 

Group Plant number 6 daily weighings Total
42 170
29 190
H 30 230
49 250

26 295 1135
46 180
22 200
I 15 205
24 245

‘ 12 305 1135
21 170
7 200
J 5 200
45 260

9 305 1135

'10

On January 31 the plants of each group in Table 1
were thoroughly sprayed with one of the materials shown
in Table 11. Both upper and lower surfaces of the leaves

were covered.
TABLE 11

Sprays Applied to Different Groups of Jerusalem Cherry
Plants in Experiment 1.

Group A.-Whole milk (3.4 per cent butter fat.)

Group B.-Milk from which butter fat has been removed.

Group 0.51 solution made by removing fat and casein
from whole milk.

Group D.-A solution made by removing fat, casein, and
albumen from whole milk.

Group E.-Cream testing 20 per cent butter fat.

Group F.-Cream testing 38 per cent butter fat.

Group G.-Check. '

Group H.-Calcium caseinate in solution and suspension.

Group I.-A solution made by diluting 38 per cent cream
with water to give a test of 3.5 per cent fat
(same butter fat content as whole milk used in A).

Group J.-A solution made by diluting 38 per cent cream
with solution used for spraying C.

11

After spraying with the materials listed in Table 11,
the plants were allowed to dry and then were brought up
to their original weights by the addition of water to
the soil. Regular daily weighings and additions of water
to make up for the loss of weight were made thereafter.
This record is shown in Table 111. During the whole
of the experiment the plants were subjected to uniform
light, temperature, and humidity conditions on a green-

house bench.

12

TABLE 111.
Daily losses of water from individual plants after spraying

Plant No. Original:Wt.Feb.l:Water added:Wt.Feb.2: Water
wt.grams:in gramszin grams :in grams: added

 

1 3460 3435 .25' 3444 16
2 3720 3692 28 3706 14
3 3525 3466 59 3484 41
4 3720 3705 15 3712 8
5 3520 3487 33 2503 17
6 3695 3644 51 3665 30
7 3625 3600 25 3614 11
8 3620 3574 46 3593 27
9 3370 3332 38 3348 22
10 3330 3288 42 3300 30
11 3495 3447 48 3465 30
12 3680 3650 30 3662 18
13 3630 3600 30 3610 20
14 3830 3795 35 3805 25
15 3395 3375 20 3377 18
16 3345 3323 22 3328 17
17 3630 3608 22 3615 14
18 3480 3550 30 3457 23
19 3450 3428 22 3434 16
20 3450 3397 53 3410 40
21 3540 3518 22 3525 15
22 3780 3756 24 3763 17
23 3380 3373 7 3371 9
24 3780 3756 24 3763 17
25 3600. 3566 34 3576 24
26 3680 3635 45 3648 32
27 3560 3550 10 3551 9
28 3650 3623 27 3635 15
29 3830 3802 28 3810 20
30 3815 3785 30 3792 23
31 3620 3590 30 3596 25
32 3380 3345 35 3360 20
33 3575 3555 20 3558 17
34 '3340 3312 28 3320 20
35 3100 3075 25 3082 18
36 3815
37 3470 3442 28 3440 30
38 3280 3250 30 3260 20
39 3340 3325 15 3325 15
40 3390 3352 38 3365 25
41 3395 3371 24 3376 19
42 3290 18 3275 15

3272

13

TABLE 111 con't

Plant: Original: Wt.Feb.1: Water added‘ Wt.feb.2 :Water
No. : Wt.grams: in grams: in grams : in grams :added

43 3540 3485 55 3603 37
44 3480 3467 13 3470 10
45 3665 3630 35 3643 22
46 3425 3400 25 3411 14
47 3540 3512 27 3520 20
48 3760 3747 13 3750 10
49 3310 3281 29 3290 20
50 3450 3433 17 3232 18
51 3335 3300 35 3309 27
52 3280

 

‘v fivw' vfi vvvfi W V v~v W ‘r V‘—

Plant:Wt.in grams:Water added:Wt.Feb.4:Water:Wt.Feb.5:Water

 

 

Nb. :be.3 :in grams ':in grams:added:grams :added
: :' 3 :grams: :grams
1 3430 30 3430 30 3422 38
2 3690 30 3694 26 3682 38
3 3454 71 3469 56 3466 80
4 3698 22 3703 17 3695 25
5 3484 36 3494 26. 3480 40
6 3640 55 3650 45 3635 60
7 3600 25 3595 20 3595 30
8 3577 43 3583 35 3570 50
9 3330 40 3335 35 3325 45
10 3280 50 3300 30 3266 64
11 3460 45 3455 40 3445 50
12 3637 43 3648 32 3635 45
13 3691 39 3600 30 3588 42
14 3791 39 3800 30 3782 48
15 3355 40 3370 25 3351 44
16 3314 31 3325 20 3310 35
17 3607 23 3610 20 3599 31
18 3441 39 3455 25 3428 52
19 3424 26 3430 20 3415 35
20 3399 51 3400 50 3390 60
21 3514 26 3520 20 3500 32
22 3746 34 3655 25 3739 41
23 3363 17 3367 13 3359 21
24 3741 39 3753 27 ~ 3743 37
25 3553 47 3570 30 3554 46
26 3630 50 3640 40 3620 60
27 3542 18 3548 12 3541 19
28 3620 30 3625 25 3622 28
29 3798 32 3800 30 3794 36
30 3773 42 3782 33 3777 38

14

Table 111 con't
Plant: Wt.in Grams:Water added2Wt.Feb.4:Water:Wt.Feb.5:Water

 

 

 

No. : Feb.3 :in grams :in grams:added:in gramsxadded

: : : :grams: :grams
31 3585 35 3587 33 3585 35
32 3349 31 3357 23 3345 35
33 3550 25 3555 30 3547 28
34 3311 29 3316 24 3305 35
35 3063 37 3076 24 3065 35
36
37 3430 40 3436 34 3425 45
38 3230 40 3253 27 3240 40
39 3312 28 3324 96 3309 31
40 3354 36 3358 32 3351 39
41 3363 32 3370 25 3355 40
42 3260 30 3327 23 3257 33
43 3485 55 3498 42 3470 70
44 3460 20 3470 10 3458 27
45 3625 40 3530 29 3615 50
46 3390 35 3405 20 3388 37
47 3504 36 3509 31 3505 35
48 3728 32 3736 24 3732 28
49 3260 50 3282 28 3262 48
50 3421 29 3436 , 14 3418 32
51 3293 42 3299 36 3280 55
P1ant:Feb.7:Water:Feb.8:Water:Feb.9 :Water:Beb.10:later
No. :Wt. :added:Wt. :added:Wt. :added:Wt. :added

:;rams::rams:;rams:;rams:;rams :zrams:;rams :zrams

4 : o o . e o .o. e 'v

2 3490 30 3691 29 3690 30 3440 25
3 3430 95 3426 99 3470 55 3700 85
4 3695 25 3696 24 3695 25 3500 20
5 3483 37 3486 34 3490 30 3645 20
6 3633 62 3630 65 3650 45 3600 50
7 3600 25 3597 28 3600L 25 3575 25
8 3570 50 3570 50 3586 35 3335 45
9 3323 47 3320 50 3330 40 3280 35
10 3268 62‘ 3263 67 3290 40 3455 50
11 3445 50 3437 58 3460 35 3640 40
12 3640 40 3630 50 3650 30 3590‘ 40
13 3585 45 3085 45 3595 35 3790 40
14 3785 45 3787 43 3800 30 3360 40
15 3352 43 3362 43 3365 30 3315 35
16 3312 33 3310 35 3320 25 3605 30

15
TABLE 111 con't
Plant:Feb.7:Water:Feb.8:WaterzFeb.9.:Water:Feb.10:Water

 

No. :Wt. :added:Wt. :added:Wt. :added:Wt. :added
:grams:grams:gramsigrams:grams :grams:grams :grams

17 3598 32 3605 25 3605 25 3440 25
18 3435 43 3436 45 3450 30 3425 40
19 3420 30 3420 30 3425 25 3405 25
20 3380 70 3385 65 3400 50 3515 45
21 3510 30 3515 25 3510 30 3745 25
22 3740 40 3745 35 3750 30 3365 35
23 3360 20 3357 13 3365 ' 15 3750 15
24 3730 50 3547 33 3750 30 3565 30
25 3550 50 3545 55 3565 35 3630 35
26 3615 65 3632 58 3640 40 3550 50
27 3535 25 3550 10 3540 20 3620 10
28 3610 40 3620 -30 3625 25 3795 30
29 3784 46 3790 40 3800 30 3775 35
30 3765 50 3768 47 3785 30 3590 40
31 3576 44 3595 25 3585 35 3350 30
32 3345 35 3350 30 3355 25 3550 30
33 3542 33 3550 25 3660 25 3310 25
34 3305 35 3310 30 2215 25 3065 30
35 3055 45 3063 37 3070 30 3065 35
36

37 3415 55 3422 48 3435 35 3430 40
38 3232 48 2238 42 3255 25 3246 40
39 3305 35 3308 32 3320 20 3310 30
40 3343 47 3352 38 3325 25 3350 40
41 3355 40 3357 38 3375 20 3360 35
42 3257 33 3276 14 3255 35 3265 35
43 3475 56 3475 65 3505 35 3275 65
44 3455 25 3469 11 3470 10 3450 30
45 3616 49 3625 40 3640 25 3615 50
46 3385 40 3395 30 3405 20 3385 47
47 3495 47 3505 35 3520 20 3500 40
48 3725 35 3732 28 3740 20 3725 35
49 3260 50 3264 46 3285 25 3260 50
50 3412 38 3425 25 3430 20 3410 40
51 3275 60 3276 59 3305 30 3275 60

1.5.

TABLE 111 con't

 

Plant No. :Feb. 11 2 Water :Feb. 12 : Water
:wt. in grams: added :wt. in grams: added
: : grams : grams
“‘ 31‘ ‘7‘ ‘3425 " 35 33455* ‘25”‘
2 3690 30 3700 20
3 3435 90 3670 55
4 3700 20 3700 20
5 3485 35 3500 20
6 3645 55 3665 30
7 3605 20 3600 25
8 3575 45 3600 20
9 3330 40 3340 20
10 3280 50 3290 40
11 3450 45 3465 30
12 3650 40 3650 30
13 3590 40 3600 30
14 3490 36 3800 30
15 3360 36 3375 20
16 3320 25 3330 15
17 3610 20 3605 25
18 3440 40 3455 25
19 3425 25 3430 20
20 3400 50 3405 45
21 3515 20 3515 25
22 3746 35 3750 30
23 3365 15 3365 15
24 3740 40 3460 20
25 3555 46 3570 30
26 3630 50 3636 45
27 3540 20 3550. 10
28 3620 30 3630 20
29 3795 36 3805 25
30 3775 40 3790 25
31 3595 25 3595 25
32 3345 35 3370 10
33 3660 25 3555 20
34 3310 .30 3320 20
35 3070 30 3075 25
36
37 3425 45 3445 25
38 3240 40 3250 20
39 3305 35 3340 20
40 3360 30 3365 25
41 3360 35 3375 20
42 3260 30 3275 15
43 3485 55 3500 40
44 3460 20 3470 10
45 3625 40 3640 25
46 3400 25 3405 20
47 3500 40 3520 20
48 3735 25 3740 20
49 3275 35 3285 25
50 3420 30 3430 20

17

The total loss of water for each plant and for each
group during a period of twelve days after spraying is
shown in Table 17.

Table 17.

individual and group ldsses after spraying

 

 

 

 

 

 

Group Plant No. Loss of water Total 038 of
(grams) water grams)
twelve days for each group

33 263
39 277
A 47 351
25 347

6 548 1786
16 228
35 341
B 37 425
13 396

3 786 2236
19 274
32 309
C 40 375
11 471

43 584 2013
48 270
34 306
D 31 342
8 456

20 597 1953
27 163
2 280
E 1 344
50 283

14 400 1470

 

18

Table 17 con't

Loss of water Total loss of

 

 

 

 

 

Group Plant No. (grams) water (grams)
twelve days for each group

44 186
23 160
F » 4 206
17 263

28 300 1115
41 328
18 394
G 38 372
10 525

51 489 2108
42 271
29 357
H 30 398
49 406

26 535 1967
46 306
22 346
I 15 353
24 347

12 398 1750
21 270
7 259
J 5 328
45 405

9 422 1684

 

fivfiv—v—

4 comparison of the total loss of water from each
group shows that there was a wide variation after sprays
were applied. Since, after a preliminary; transpiration
test, these plants were grouped in series, each one of

which had lost approximately the same amount of water

19

( only five grams difference in six days), we may conclude

that in:

Group A.

Group B.

Group

Group

Group

Group

Group

Group

Group

C.

D.

E.

I.

J.

Whole milk reduced transpiration 5.2 per cent.

Milk, with fat removed, increased transpiration

6 per cent.

The solution made by removing fat and casein from
milk reduced transpiration 4 per cent.

The solution made by removing fat, casein, and
albumen from milk reduced transpiration 7.3 per cent.
Twenty per cent cream reduced transpiration 30.1

per cent.

Thirty-eight per cent cream reduced transpiration
42.3 per cent.

Solution and suspension of casein (calcium caseinate)
reduced transpiration 6.6 per cent.

Cream diluted with distilled water to test 3.5

per cent butter fat reduced transpiration 16.9

per cent.

Cream diluted with a solution derived from milk

(milk less fat less casein) reduced transpiration

20.1 per cent.

Hewever, gains or loss up to five or ten per cent may

have been due to variability of plants, slight errors in

weighing, and other causes. Thus probably no significance

is to be attached to the relatively slight differences found

20

in comparing Groups B, C, D, and H with the check group.
On the other hand, where variations run as high as 15 per
cent and higher, the spray treatment must have had some
real influence. A difference as high as 42 per cent must
be regarded as bearing special significance. Reductions in
the rate of water loss amounting to 15 per cent and over
resulted whenever butterfat was a constituent of the spray
material applied. Thus Groups A, E, F, I, and J show
significant differences. They also show a certain relation-
ship between the concentration of the butterfat causing
greater reductions.

Ten days after the application of sprays the leaves
of Groups E and F (20 per cent cream and 38 per cent cream)
began to turn yellow; during the next six days many leaves
dropped from the plants. Plants of the other groups showed
some loss of color and foliage later. This was more pre-
valent among the groups to which butterfat sprays were
applied. 03.March 1 (one month after the application of
sprays) a careful.estimate of leaf loss was made.

Results were as follows:

Per cent of leaf loss

Group A 20
Group B 10
Group C 10
Group D 10

Group E 95

21

Per cent of leaf loss

Group F 99
Group G 10
Group H 10
Group I 30
Group J 20

Photographs of representative plants six weeks
after spraying are shown in Figures 9, 10, ll, 12, 13,

14, pages 49, 50, and 51.

Having secured such a strong indication that the
butterfat or "oily" properties of the foregoing sprays
were responsible for the reduction of water losses,
further experiments were planned to secure additional data
and to test different concentrations of vegetable and

mineral oils.
EXPERIMENTle

Transpiration Experiments with Cineraria Plants
Sprayed with Whole Milk. "Wesson" Oil Emulsion, and
'Suncco".

Cineraria plants from which the blossoms had been
removed were used in the second experiment. The method
of procedure previously outlined was followed. The plants

were divided into four groups, to which treatments were

applied as shown in Table V.

22

Table V.
Sprays used on Cinerariaplants ‘fi v“ -
Group A. Check (foliage sprayed with distilled water).
Group B. Foliage sprayed with whole milk (3.5 per cent
butterfat).
Group C. Foliage sprayed with an emulsion of "Wesson"
oil (vegetable oil) 3.5 per cent.
Group D. Foliage sprayed with "Sunoco" (mineral oil)
diluted to make 3.5 per cent oil.

Each group consisted of six plants. Sprays were
applied April 25, and units (plants, pots, etc.) brought
up to the original weights by additions of the required
amount of water the same day. Weights were then taken
and water added April 26, 28, 30; may 3, 5, 7, The amount
of water required to bring a unit up to its original
weight was recorded at each weighing. After the completion
of the spraying test the leaf area of each plant was secured
with a planimeter.

Table 71 gives individual plant losses, leaf areas,
and average daily loss per square centimeter of the plants
used in this experiment.

Table 711 repeats the average daily loss per square
centimeter and gives the mean daily loss for each group

of plants to which different sprays were applied.

23

Table 71.

Average daily loss of water from Cineraria plants after
*7 spraying
Grams of water lost Leaf area in
Plant No. in twelve days sq.centimeters

A7 odaily
loss in grams
per sq.cm.

 

fl _r

2 195 310.96 .05225

5 197 365.80 .04487

6 357 380.67 .08019

9 107 103.87 .08584
10 269 503.22 .04454
11 301 444.51 .05643
12 410 552.90 .06199
15 185 263.22 .05857
17 345 312.90 .09187
18 387 309.03 .07739
20 276 296.12 .07767
24. 694 654.19 .08840
28 195 310.96 .06494
29 235 326.45 .06998
31 367 625.16 .04892
33 322 524.51 .05115
35 249 569.67 .03642
40 392 483.22 .06760
41 299 282.58 .08817
42 519 503.86 .08583
43 248 405.16 .05101
45 266 380.64 .05823
49 232 549.99 .03333
52 403 455.48 .07372

24

Table 711

 

 

 

 

 

Total and mean daily group losses from Cineraria plants
after spraying
Plant Av.daily loss Total daily Mean daily
No. (grams)per sq. loss per loss per
centimeter .ETQEQ plant
17 .09187
20 .07767
Group A 18 .07739
40 .06760
52 .07327
42 .08583 .47363 .07893-.0025
2 .05225
49 .03333
11 .05642
Group B 12 .06179
31 .04892
6 .08019
.33290 .05548-.0039
5 .04487
10 .04454
15 105857
Group C 28 .04494
41 .08817
24 .08840
.36949 .06158-.0054
; Average daily loss
(grams) cu.cm.
9 .08584
43 .05101
29 .05998
Group D 33 .05115
35 .03642
45 .95834

 

fiwv‘ v

v ‘ fififiw‘fiv—V wivfi-‘fifi W

In this experiment three sprays reduced the rate of

water loss. "Wesson" oil emulsion reduced it 22 per cent.

"Sunoco" 27.6 per cent, and whole milk 29.7 per cent.

Foliage injury was not serious. A slight loss of color

was observed in leaves of plants in Groups B, B, and D.

25

EXPERIMENT 111

Transpiration Experiments with Jerusalem Cherry Plants
Sprayed with Linseed, Cottonseed, Corn, and Mineral Oils,
Bordeaux Mixture, and Soap.

Having found in Experiment 11 that fatty or oily
compounds other than butter fat caused a reduction in
the rate of water loss when applied as sprays to the foliage
of plants, a rather extensive test of different materials
was made in Experiment 111 to determine their efficiency
in this respect. Jerusalem cherry plants were prepared
and divided into groups as in the previous experiments.
Emulsions, with linseed, cottonseed, caster, corn, or
mineral oil supplying the oil content and with soap as
the emulsifying agent, were sprayed at a concentration of
two per cent on the foliage of these plants. An additional
,two per cent mineral oil spray made by substituting

W

Bordeaux mixture for squéused on another group of plants.
Three checks on the above materials were used; one group
was sprayed with soap of the same concentration as found
in the oil emulsions, a second group was sprayed with
Bordeaux mixture of the same formula as used in making
the mineral oil spray, and a third was sprayed with dis-
tilled water. These sprays are shown in Table 7111.

Table 7111.§Spray§wapplied toiJerusalem chergy plants

'fiw w—YVfiV W *“

 

Group A. Linseed oil emulsion spray.
Group B. Cottonseed oil emulsion spray.
Group 0. Bordeaux mixture 4-4-50.

Group D. Castor oil emulsion spray.

Group E. Corn oil emulsion spray.

26
Table 7111 con't

Group F. Mineral oil emulsion spray.
Group G. Soap (same dilution as used in emulsion).
Group H. Bordeaux mixture mineral oil.emulsion spray.
Group I. Check. (Sprayed with distilled water).

The plants were sprayed June 5, and brought up
to standard (original) weight June 6, and June 7.
Water losses were recorded June 8, 9, 10, 12, 14, 15,
16, 17, 18, 19. Individual plant losses and group

losses for this period are shown in Table IX.

Table IX 0"

water loss of Jerusalem cherrygplants»after_sprayiggvv

v ‘v vv wfivvwv—fivvv vww WY

 

 

 

 

 

 

Plant no. Individual Group loss Mean loss
plant losses (grams) (grams)
grams
11 692
36 738
38 592 ,
Group E 23 607
15 563 3292 658-18.9
4 552
49 608
41 543
Group F. 3 560
19 452 2715 543-15.3
6 877
37 872
Group I 8 661
50 648
2 545 3603 72l~39.8
61 765
18 751
Group A 14 645
34 459

39 763 3383 676-34.1

 

fivvv—ffi V w‘v V~ fi “ fi~~ h

27

Table IX con't

 

 

 

 

 

Plant No. Individual Group loss mean less
plant losses (grams) (grams)

(grams)
7 - 360
17 754
Group B 42 782
52 680

32 626 3193 638-45.3
33 836
31 306
Group C 44 633
40 571

10 721 3567 713.30.2
43 897
12 718
Group D 26 637
30 604

29 639 3395 679-38.8
9 652
24 875
Group G 25 641
13 627

45 804 3599 720-30.5
I 648
28 874
Group H 48 713
47 606

35 529 3370 654-35.7

 

w—vv‘~ V

28

The reductionsin the amount of water used after

the application of emulsion sprays are shown in Table X.

Table X

Reduction in water losses by leaves of the Jerusalem
9.118131 after 54:43:14

 

fl VW fiw Viwfi fifi *

Percentage reduction
compared to check

Group A. Linseed oil emulsion spray 6.24
Group B. Cotton oil emulsion spray 11.51
Group C. Bordeaux mixture 4-4-50 1.10
Group D. Castor oil emulsion spray - 45.82
Group E. Corn oil emulsion spray 8.74
Group F. Mineral oil emulsion spray 24.69

Group G, Soap (same dilution as used in
emulsion) 0.00

Group H. Bordeaux mixture mineral oil
emulsion spray 9.29

The figures in Table I show material reduction
in water losses as a result of covering the foliage of
the plants with oil sprays. They also show that a low
concentration of oil is effective, and that five
different oils will produce the same general result.
A spray consisting of mineral oil emulsified with soap was
much more effective than any of the others. The other
sprays ontaining oil caused reduction in water losses,
the specific reduction for each differing to some extent.
The checks did not differ materially in rate of water
losses. Computations for Table X wmmade by comparing

the average rate of water loss from each group to the

29

the average rate of loss from the group sprayed with
distilled water. The plants used in this experiment
were kept under observation for a month after the
completion of the test and at no time did they show
any evidence of foliage injury except a slight loss

of green color after the application of oil sprays.

EXPERIMENT IV
Transpiration experiments with Hyslop crabapple
trees sprayed with corn, cottonseed, and mineral
oils.

A group of Hyslop Crabapple trees, such as are
illustrated in Figures 15 and 16,were used in this
experiment. They were growing in eight-inch pots that
had been waterproofed as previously described and had
already formed their terminal buds for the season.
Consequently there was little if any change in the
leaf area of any individual plant during the course
of the experiment. The experiment was begun June 20-22.
After a preliminary transpiration test of about two
weeks the plants were grouped according to water
losses and on July 4 the different groups were treated
to spray applications as listed in Table II. The con-

centration of oil for each emulsion spray was one per

081150

30

Table XI
Sprays applied tofiHyslop Crabapple trees

 

 

Group A. Bordeaux mixture mineral oil emulsion.spray.
Group B. Corn 011 emulsion spray.

Group C. Mineral oil emulsion spray.

Group D. Check. (Distilled water spray).

Group E. Cottonseed oil emulsion spray.

 

Records of transpiration losses were made July
6, 7, 8, 8, 10, 12, l3, 14, 15 and 16.

After all data had been collected, alternate
leaves from tip to base of each shoot were removed
from the trees, and their surface area measured by
use of a planimeter. All leaves (those left on trees
and those removed) were then measured at points of
greatest width and greatest length of leaf blade, to
obtain a factor with the aid of which the area of leaves
not removed from the tree could be accurately calculated.
The total leaf area of each tree was obtained by adding
the calculated area of the leavesileft on the tree to
the measured area of the leaves removed. Data on trans-

piration losses are presented in Table XII.

31

Table 111

Leaf area and water losses from Hyslop Crabapple trees
sprayed with one per cent oil emulsion

j

 

 

 

 

 

Plant Grams lost Total grams Mean daily
No. per sq.cm. lost dailynby loss of
per day each group each plant
19 .09572
25 .07374
Group A 14 .14448
5 .10069
26 .09897
.51360 .iozvzzooea
4 .08335
10 .08609
Group B 3 .09422
1 .12509
6 .12137
.51012 .10202t.0053
21 .07232
9 .07288
Group C 8 .07891
12 .08311
13 .08745
.39467 .ovegzt.0017
11 .12363
20 .11791
Group D 7 .11758
24 .08443
2 .14826 <
.59181 .118363.0061
22 .05764
23 .06536
Group E 15 .08263
16 .07023
17 .06094

.36379 .oevset.qoze

 

32

Comparing each of these different sprays to the
check shows that a Bordeaux mixture-mineral oil emulsion
spray reduced the transpiration loss 13 per cent; a corn
oil emulsion spray reduced the transpiration loss 14
per cent; a mineral oil emulsion spray reduced it 33 per
cent; and a cottonseed emulsion spray reduced it 43 per
cent. Thus a rather marked reduction of water loss was
secured by the application of oil sprays. The specific
reduction for each oil used was variable, cottonseed
being the most effective. A mineral oil emulsion with
soap was more effective than the same 011 emulsified
with Bordeaux mixture.

The leaves of some of the trees developed typical
"spray burn" injury a few days after they had been sprayed.
However, this injury appeared just after the greenhouse
had been fumigated with a proprietary nicotine compound.
The fact that most of the injured foliage was on plants
adjacent to the source of the gas indicated that the gas
was the cause of the injury. A slight amount of injury,
evidenced by a drying out of the margins of leaves, develop-
ed at a later date on the groups sprayed with mineral oil
(E) and with cottonseed oil (C). The appearance of this
injury was preceded by two days of hot weather. A slight
loss of green color was also observed in the leaves of

.the plants in these two groups.’

33
Experiment 7.

Transpiration Experiments with Seedling Apple Trees Sprayed
with Mineral Oil, Bordeaux Mixture, and"7010k".

Seedling apple trees one year of age were started
in six-inch pots during the winter. They were forced
into rapid growth by copious watering during the spring
and early summer, then watered sparingly until terminal
buds were formed; after this, with adhering ball of earth
undisturbed, they were transferred to waterproofed pots
and sealed in as previously described. Sealing in was
completed July 18. Sixty prepared plants were divided
into five groups, and sprays , as indicated in Table XIII,
were applied July 27. Each emulsion was diluted with
. water to give an oil concentration of eight-tenths of
one per cent.

Table XIII.-Sprays applied to apple seedlings.

 

Group A. Bordeaux mixture-mineral oil emulsion.
Group B. Bordeaux mixture 5-5-50.
Group C. Check (distilled water spray).
Group D. "Volck" oil emulsion.
Group E. Mineral oil emulsion.

Records were taken July 29, 30, 31; August 1, 2,
3, 4, 5, 6, 7, 8. The leaves were then stripped from
the trees, and leaf areas determined by using a
planimeter. Table XIV gives detailed data for each
plant used in this experiment.

Group losses are shown in Table X7.

 

iii."

34

Table X17
Leaf areas and rates of water 10Sses of seedling apple trees

Plant Leaf area Loss of water in Gms.1oss per sq.

 

No. sq; cm. eleven days (gms) cm. in one day
1 229.03 403 .15996
2 280.64 745 .24133
3 361.28 558 .19414
4 574.83 119 .17728
5 286.54 520 .16503
6 358.06 751 .19067
7 472.25 1074 .20675
8 329.67 663 .18625
9 413.54 492 .17410

10 341.93 673 .17893

11 281.28 522 .15996

12 370.32 770 .24133

13 314.83 632 .19414

14' 516.12 059 .17728

15 463.22 780‘ .16503

16 290.32 495 .15500

17 331.61 739 .20259

18 414.83 864 .18934

19 542.57 432 .12264

20 292.90 578 .17939

21 330.96 694 .19063

22 452.90 978 .19631

‘23 230.96 461 .18109

24 502.57 837 .18901

25 434.83 740 .15471

26 417.41 792 317231

27 439.32 1032 .21802

28 410.32 863 .19120

29 481.29 854 .16131

30 663.86 1003 .13644

31 456.06 910 .18060

32 370.32 794 .19491

33 409.67 853 .18929

34 363.22 766 .19172

35 266.45 535 .13227

36 651.61 1249 .17425

37 387.74 928 .21758

38 425.16 968 .20698

39 269.67 606 .20427

40 288.40 367 .11062

41 531.61 1141 .19512

42 250.96 593 .21481

Table XIV con't

 

Plant Leaf area Loss of water in Gms.loss per sq.
No. sq: cm. eleven days (gms) cm.in one day
43 369.03 939 .23132
44 575.48 396 .14786
45 610.32 834 .12423
46 407.09 394 .19964
47 591.61 1211 .18690
48 296.77 653 .20003
49 448.38 900 .18247
50 542.57 899 .15063
51 452.90 836 .16781
52 335.48 854 .23142
53 254.83 738 .26327
54 532.90 020 .17400
55 420.64 702 .15710
56 398.70 738 .16824
57 369.67 698 .17165
58 392.90 892 .20639
59 310.96 699 .20435
60 249.67 413 115938
61 189.03 470 .22603

62 422.57 884 .19018

36

Table X7

Individual daily water losses and mean daily losses from

fl

apple seedlings

Plant Grams of water Total loss for Mean daily

 

 

 

No. lost per sq. group (grams) loss of each
cm. per day pplant (grams)
1 .15996
6 .19067
11 .16871
16 .15500
21 .19063
Group A 26 .17231
31 .18060 -
36 .17425
41 .19512
46 .19964
51 .16781
55 .16827 ’
2.12297 .17691-.002
2 .24133
7 .20675
12 .18902
17 .20259
22 .19631
Group B 27 .21802
32 .19491
37 .21758
42 .21481
47 .18609
52 .23142
57 .17165 +
2.47048 .20587-.004
3 .19414
8 .18265
13 .17989
18 .18934
23 .18109
Group C 28 .19120
33 .18929
38 .20698
43 .23132
48 .20003
53 .26327
58 .20639 +
2041559 02013-0004

 

V fifi

VVv

37

Table X7 con't

Plant Grams of water Total loss for Mean daily

 

 

No. lost per sq. group (grams) loss of each
cm. per day plant (grams)

4 .16593
9 .17893

14 .15327

19 .17939

24 .15471

29 .13644

Group D 34 .13272

39 .11062

44 .12423

49 .15062

54 .17400

59 .20435 +

2.11554 .17629-.004

5 .16503

10 .17893

15 .15327

20 .17939

25 .15471

30 .13644

Group E 35 .13272

40 .11062

45 .12423

50 .15062

55 .15171

60 .15038 +

1.78805 .149-.003

 

vi‘v' "v—

fi

38

Substantial reductions in losses of water followed
the application of oil sprays. A mineral oil spray
emulsified with Bordeaux mixture reduced the transpira-
tion rate 11 per cent, and the same oil emulsified with
soap reduced it 26 per cent; "Volck" reduced it 12 per
cent. The plants in Group B, to which Bordeaux mixture
was applied, showed a slight increase in amount of water
used as compared with the check. No foliage injury or
["loss of color developed.

Reviewing the data for the five experiments we find
that in general, regardless of the kind of plant, organic
and mineral oil sprays have a tendency to lessen water
loss. There is much difference between the various oils
used; sprays made up from mineral oil and from cottonseed
oil give the greatest reductions. Their influence is more
or less proportional to the concentration of the sprays,
a concentration of approximately one per cent causing

the greatest reduction without injuring the foliage.
Examination of Stomata

The data that have been offered show that there
is a reduction in water losses from plants following
the use of oil sprays. They do not furnish any informa-
tion as to how such reductions in water loss are brought

about. With this object in mind a brief study was made

39

of the daily periodic opening and closing of the stomata

of the leaves of the apple seedlings used in Experiment 7.
Following Lloyd's (16) procedure samples of epidermis were
taken from the under sides of leaves from sprayed and

from unsprayed trees. These samples were secured by
stripping off with tweezers a portion of the epidermis,
which was immediately plunged into absolute alcohol. By
this procedure it is possible to preserve epidermAl
sections without any change in the opening of the stomata.
These sections were stained, mounted and photographed.

A study of many stained sections indicated that an oil spray
caused a delay in the opening and also in the closing

of the stomata of the leaves. This may have had some

effect on the amount of water lost because evaporation
would be less during the evening when the stomata in leaves
of unsprayed plants were partly open, than it would be
during the pro-noon period when those in leaves of sprayed
plants were fully cpen. Further studies are necessary

to verify this point. Figures 1, 2, 3, 4, 5, 6, 7, and

8 give some indication of the nature of the evidence

on which these statements are based.

1.

2.

4.

40

UMMARY
Oil sprays applied to the foliage of apple,
cineraria, and Jerusalem Cherry plants caused
a reduction in the rate of water loss. Sprays
containing high concentrations of oil caused
greater reductions in rate of water loss than
sprays containing low concentrations of oil.
Some oils gave greater reductions than others.
Sprays made up from mineral oils and from cotton-
seed oil gave the greatest reductions.
Injury to foliage was not apparent when sprays
of low oil concentration were used; it was serious
when sprays of high oil concentration were used.
Injury was evidenced by the drying and browning
of the margins of leaves. Another form of possible
injury was evidenced by a lighter color of the
leaves on sprayed plants. This was apparent in
Experiments 1, 2, 3, and 4, but did not develop
in Experiment 5.
Oil sprays containing one per cent or less of oil
caused marked reductions in the rate of water loss
and at the same time produced no visible evidences

of injury to the foliage.

Acknowledgement.

The work described herein was started at
the suggestion of Professor 7.R.Gardner, of
the Department of Horticulture, Michigan
State College. The writer wishes to express
to him, and to Doctor John W.Crist and
Professor W.C.Dutton of the same Department,
his thanks for the helpful suggestions and
kindly criticism offered during this in-

vestigation.

4i

1.

2.

4.

5.

6.

7.

8.

9.

42

Citation of Literature

Rumm, 0. Ueber die Wirkung der Kupferpraparate
bei Bekampfung der sogenannten Blattfallkrankheit
der Weinrebe. Ber. d.deut. bot. Ges.ll: 79-93. 1893.

Miller-Thurgau, H.Jahresb. der schweizischen
Versuchsstation und Schule f. Obst-, Wein-und
Gartenbau in Wadensweil. 1892-93: 58-59.

Bayer, L. Beitrag sur pflanzenphysiologischen Bedeutung
des Kupfers in der Bordeauzbruhe. Inaug-Dissert.

' Kenigsberg, 1902.

Frank, A.B., and Kruger, Fr. Ueber den direkten
Einfluss der Kupfervitriolkalkbruhe auf die Kartofel-
pflanze. Arb. d. deut. landw. Ges. 1894; 1-46.

Zucker, A. Beitrag zur direkten Beeinflussung der
Pflanzen durch die Kupfervitriol-Kalketruhe. Inaug-
Dissert. Stuttgart. 1896.

Schnader, R. Ueber die physiologische Wirkung der
thfervitriOlkalkbruhe. Landw. Jahrb. 33: 517-584. 1904.

Ewert, R. Der wechselseitige Einfluss des Lichtes
und der Kupferkalkbruhen auf den Stoffwechsel der
pjlanzen. Landw. Jahrb. 34: 233-311. 1905.

Duggar, B.M., and Cooley, J.S. Effect of Surface
Films and Dusts on the Rate of Transpiration. Ann.
Me. Bot.Gard.l: 1-22: 351-356. 1914.

Martin, W.H. Influence of Bordeaux Mixture on the

. Rate of Transpiration from Abscissed Leaved and from

Potted Plants. Jour. Agr. Res. VII 529-584. 1916.

10. Shive, J.W£, and Martin, W.H. The Effect of Surface

11.

Films of Bordeaux on the Foliage Transpiring Power
in Tomato Plants. Plant World 20: 67-97. 1917.

Duggar, B.M., and Bonns, W.W. The Effect of Bordeaux
Mixture on the Rate of Transpiration. Ann. Mo. Bot.
Gard. 5: 153-176. 1918.

12. Wells, H.M. Unpublished Thesis in Michigan State

College Library.

13. Smith, J.B., N.J. Agr. Exp. Sta. Rpt. 1904, page 646.

43

14. Ackerman, A.J° Preliminary Report on Control
of San Jose Scale with Lubricating Oil Emulsion.
UeSeDeA. Circular 263, 19230

15. Boyer,.C.A. Data collected while registered as
Graduate Student at Michigan State College.
Unpublished. '

16. Lloyd, Francis E. The Physiology of Stomata.
Corn. Inst. Pub. No.82, 1908.

45

 

Figure I.‘ Section of Epidermis From the Lower Side of an
Apple Leaf Sprayed Two Weeks Previously with
en .8 Per Cent Oil Emulsion, Showing Opening of
Stomata at 6 A.M. Compare with Figure II.

C
..
\
t.
o
\

We: 9'“
, | p 4. / '"I .:
”2,\3‘!§5’[:‘ 1’757‘2, (...,

Figure II. Section of Epidermie from the Lower Side of en
Apple Leaf Which Had not Bee

n s ,
Opening of Stomata at e A. 14. £33.91. 3111221113
Figure I. '

I

“4763.; , ‘3,

 

46

"I’

. \ . , .
‘ " ‘fl‘l‘ ...
'7. p 4 I." “ ~ 91%

t~4§“i’ '?~‘ ‘K IF

 

Figure III. Section of Epidermie From the Lower Side of an
Apple Leaf Sprayed Two Weeks Previously with en
.8 Per Cent Oil huleion. Showing Opening of
Stomata at 12 M. Compare with Figure IV.
A . e .. -
? 5' ' x ' ‘0':
4 9 ‘ '2 4:45"- ,
g2. .y“... {g .y‘ -
as . ‘. - , ‘
' "S 3‘6 7.

 

Figure 17. Section of spidermis Iran the Lower Side of an
Apple Leaf Ihich Bad Not seen Sprayed. Showing

Opening of Stomata at 12 M. Compare with Figure
III.

47

 

Figure 7. Section of Bpidermis From the Lower Side of an
‘ Apple Leaf Sprayed Two Weeks Previously with an
.8 Per Cent 011.3mulsion. Showing Opening of
Stomata at 2 P.M. Compare with Figure VI.

 

Figure VI. Section of Epidermis From the Lower Side of an
Apple Leaf Which Bad Not Been Sprayed, Showing
Opening of Stomata at 2 Pen. Compare with
Figure V.

48'

 

Figure VII. Section of Bpidermis From the Lower Side of an
' - Apple Leaf Sprayed Two Weeks Previously with an

.8 Per Cent Oil hinulsion, Showing Opening of

Stomata at 8 P.M. Compare with Figure VIII.

 

Figure VIII. Section of Bpidermis From the Lower Side of an

(Apple Leaf Which Bad Not Been Sprayed. Showing
Opening of Stomata at 8 P.u. Compare with
Figure VII.

 

Figure [1. Jerusalem Cherry Plant One Month After Applying °
a 80% Cream Spray. -

 

Figure 1. Jerusalem Cherry Plant One Month After Applying
a 38% Cream Spray.

 

,-

Figure XI. Jerusalem Cherry Plant One Month After Apply-
ing a 3.5% Butter Fat Spray Made by Di‘luting
38% Cream withfleter.‘ _ ‘ ' -

 

Figure XII. Jerusalem Cherry Plant One Month After Apply-
ing Whole Milk Spray (3.5% Butter Fat).

' 51

 

 

 

 

Figure XIII. Jerusalem Cherry Plant One Month After Applying -
a Spray Consisting of'a Solution made by Extract-
ing Fat and Casein From Whole Milk.

._ H w .

 

 

 

 

Figure_XI!. Check. No Spray Applied.

 

Figure IV. Apple Tree Used in Experiment 17.

 

52'

 

rim. “to

Apple Tree Used in Experiment IV.

as

e~ .
e \
a ' .
‘ .

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