MOISTURE REQUIREMENT 91 
perature is lowered as it often is by heavy rains which fill the soil 
with water or by days of cool cloudy weather, germination is 
either very slow or prevented as is well known to every farmer 
and gardener. 
Moisture Requirement. — The amount of moisture required 
for germination is, in general, that which will completely saturate 
and soften the seeds. The water absorbed saturates the cell 
walls and starch grains, and fills the living cells of the embryo 
and all empty spaces that exist in theseed. Although the amount 
of water required to saturate different seeds varies, it is always a 
large per cent, sometimes more than 100 per cent of the dry 
weight of the seed, as shown in the table below. Reckoning in 
pounds from the percentages given in the table, 100 Ibs. of Corn 
after being soaked for germination may weigh 144 lbs. and 100 
lbs. of White Clover seeds after soaking may weigh 226.7 lbs. 
WATER ABSORBED BY GERMINATING SEEDS 
Per cent of water 
Seeds. absorbed in 
germination. 
Tndian; COTrtiinnc:causnebaarecaeieen dpacGeeasnse chs 44 
WG a ence 5 agile, haber acawerechars SQA AE« obacensh ecads a hanes 45.5 
BUChwhe artes icy icnscse fcc.» ani uievssaryubate 1 shoe een eels 46.9 
IRV Etc eetnd, cea ean ass sulted, tad). | liddya esas assueiedas 57.7 
QaGS ics Rie cs cae dee Pai oer an te, Wieder AIA eleichtakebai a 59.8 
White Beans............. ale’ Tagtetes 92.1 
Peas ........ 106.8 
Red Clover... 117.5 
Sugar Beet............... ; 120.5 
White Clover 126.7 
Most seeds, though not all, swell as water is absorbed, some- 
times more than doubling their dry size. In fact, the per cent 
of increase in volume is often greater than the per cent of water 
absorbed, as in case of the Pea which may increase in volume 
167 per cent while absorbing only enough water to increase its 
weight about 100 per cent. 
If seeds are confined in a space which they fill when dry, their 
swelling may exert a force of several hundred pounds and often 
sufficient to break strong containers. This force is sometimes 
used in opening skulls in anatomical laboratories, in which case 
the skulls are filled with dry Peas, which after being moistened 
swell and force the bones apart. 
