374 
EARL S. JOHNSTON 
Beach and Allen^ state that maturity bears an important relation to 
hardiness and that the amount of moisture present in tissues is an important 
factor relating to maturity. These writers found that the moisture content 
is slightly lower in twigs of the more hardy apple varieties than in tender 
ones. Shutt^ gives a series of determinations of moisture content of apple 
twigs which compares very favorably with a series arranged according to 
hardiness, the more tender containing the greater percentage of water. 
Thayer^ notes the general rule that buds on young trees are more apt to be 
injured than those on more matured trees. This is no doubt closely related 
to the water content of the tissues. Daily variation in water content of 
leaves and twigs has been observed in several cases, ^ and in all probability 
a change in water content of plant tissues and organs is a most important 
factor influencing the response of the plant to its environment. 
An experiment was carried out in the winter of 1918-1919 with the object 
of determining the moisture content of fruit buds taken from two varieties 
of peach, one of which is commonly considered relatively more hardy than 
the other. The two varieties selected for this study were the Elberta and 
Greensboro. Fifteen trees of each variety chosen for this work formed 
part of a nine-acre peach orchard. Four trees of each variety were situated 
on high ground, three on low ground, and seven trees were growing under 
various fertilizer treatments. Beginning with November 8, 1918, and there- 
after at monthly intervals, except for the last period which was three weeks 
in length, buds were collected from these trees. The samples were taken 
from the same marked branches of the selected trees on clear days that were 
preceded by at least one clear day. This precaution was taken in order to 
avoid getting the buds when they were in an excessive moist condition fol- 
lowing a rain or fog. Likewise, the afternoon was selected as the time of day 
for collecting the samples. The samples were immediately placed in small 
medicine vials with screw caps and weighed the following day in the labor- 
atory. Each sample consisted of ten fruit buds. After determining the 
green weights, the buds were placed in a vacuum electric oven and dried to 
constant weight at a temperature of approximately 82° C. and a partial 
vacuum of 40 to 65 cm. of mercury. The drying usually required from 14 
to 18 hours. The dry weights were then determined. 
^ Beach, S. A., and Alien, F. W., Jr. Hardiness in the apple as correlated with struc- 
ture and composition. Iowa Agr. Exp. Sta. Res. Bull. 21. 1915. 
^ Shutt, F. T. On the relation of moisture-content to hardiness in apple twigs. Proc. 
& Trans. Roy. Soc. Canada, II. 9: sec. 4: 149-153. 1903. 
^ Thayer, P. Winter killing of peach buds. Ohio Agr. Exp.Sta. Mo. Bull. 1:311-312. 
1916. 
^ Livingston, B. E., and Brown, W. H. Relation of the daily march of transpiration 
to variations in water content of foliage leaves. Bot. Gaz. 53: 309-330. 1912. Lloyd, 
F. E. The relation of transpiration and stomatal movements to the water content of leaves 
in Fouquieria splendens. PI. World 15: 1-14. 1912. Shreve, Edith B. The daily march 
of transpiration in a desert perennial. Carnegie Inst. Wash. Publ. 194. 1914- 
