ABSORPTION OF WATER 49 
45. Importance of Root-hairs. In Chapter II attention 
was called to the root-hairs. Their chief function is the 
absorption of water and dissolved substances from the 
soil. This may be demonstrated by a very simple 
experiment. If a young seedling of bean, corn, or any 
other plant growing in soil, is pulled up, care being taken 
not to loosen the dirt from the roots, then properly 
transplanted in another place, and well watered, it 
will continue to grow, having suffered no apparent injury. 
If another seedling, of about the same size and vigor is 
pulled up, and the soil removed from the roots by means 
of the fingers, some of the very delicate root-hairs will 
be torn off with the soil, and many others will dry up owing 
to too prolonged exposure to the air. If this seedling 
is then transplanted, it will recover with difficulty, or 
it will wilt and die, even though well watered, showing in 
a very clear manner the inability of a plant to take in 
water when deprived of its root-hairs. 
46. Location of Root-hairs. Root-hairs for study may 
be easily secured by germinating seeds in a moist chamber, 
formed by inverting a flower pot over a saucer of water. 
Small seeds, such as flax or white mustard, will readily 
adhere to the moistened inner surface of the inverted 
flower pot. Within 24 to 36 hours the roots will have 
developed to a length of several millimeters, and the 
root-hairs will appear as a delicate white "fuzz," near 
the end of the root, but not extending clear to the tip 
(Fig. 36). On older roots it may be seen that the root- 
hairs are confined to a relatively short zone, only a 
few millimeters long. The hairs nearer the root-tip are 
shorter than those further back, indicating that they are 
younger. 
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