RESERVE FOOD MATERIALS IN VEGETATIVE TISSUES 
GWYNETHE M. TUTTLE 
In view of the importance of the distribution of starch and fats 
as food reserve substances in vegetable tissues, and its connection 
with investigations regarding the effect of low temperatures on 
cells, it was thought desirable to investigate the conditions prevail- 
ing in some trees and shrubs of northern Alberta. Observations by 
several investigators have been made from other regions in the 
north temperate belt, such as those of Liprorss (3), MIvAKE (4), 
and Srnnott (5) from Sweden, Japan, and eastern United States 
respectively. All of these districts lie between the winter iso- 
therms of 30° and 40° F., whereas northern Alberta lies between 
those of 10° and 20°F. (1). Furthermore, vegetation in this 
region is frequently subjected to short periods of very low tempera- 
tures during the winter months, reaching —50° F., which makes 
the problem of resistance to cold a very important one. 
Liprorss found that all “winter green” leaves are free from 
starch, but contain sugar and sometimes oil in winter. The 
starch is replaced by sugar during November, while the reverse 
change takes place in April. These results were largely confirmed 
for this region. Much of the material examined by SINNOTT 
retained starch as a food reserve throughout the winter, although 
many of the species were characterized by an oily reserve. He 
found that starch was most common in regions remote from the 
conducting channels, and fat most abundant in and near the 
phloem, close to the vessels. His ‘‘starch”’ trees were character- 
ized by thick, squarish medullary ray cells with strongly lignified 
and small pitted walls; while the “fat’’ trees showed medullary ray 
cells with thin or unlignified walls and large pits. This he inter- 
preted as indicating that ‘‘the character of the food reserve in any 
cell depends primarily upon the ease with which water, or sub- 
stances carried by water, have access to the cell. Where the 
movement is appareritly slow and difficult, the reserve persists as 
Botanical Gazette, vol. 71] [146 
