. Elements of biology; a practical text-book correlating botany, zoology, and human physiology. Biology. ROOTS AND THEIR WORK 95 it rate 5 x. plants mentioned are found little swellings or tubercles; in the tubercles exist millions of tiny plants called bacteria, which take out nitrogen from the at- mosphere and fix it so that it can be used by the plant; that is, they form nitrates for the plants to use. These bacteria, alone of all the living plants, have the power to take the free nitrogen from the air and make it over into a form that can be used by the roots. This fact is made use of by c
. Elements of biology; a practical text-book correlating botany, zoology, and human physiology. Biology. ROOTS AND THEIR WORK 95 it rate 5 x. plants mentioned are found little swellings or tubercles; in the tubercles exist millions of tiny plants called bacteria, which take out nitrogen from the at- mosphere and fix it so that it can be used by the plant; that is, they form nitrates for the plants to use. These bacteria, alone of all the living plants, have the power to take the free nitrogen from the air and make it over into a form that can be used by the roots. This fact is made use of by careful farmers who wish to make as much as possible from a given area of ground in a given time. Such plants as are hosts for the nitrogen-fixing bacteria are planted early in the season. Later these plants are plowed in and a second crop is planted. The latter grows quickly and lux- uriantly because of the nitrates left in the soil by the bacteria which lived with the first crop. For this reason, clover is often grown on land in which it is pro- posed to plant corn, the nitrogen left in the soil thus giving nour- ishment to the young corn plants. The annual yield of the average farm may be greatly increased by this means. Forms of Roots and their Relation to the Life of the Plant. — Roots assume various forms. The form or position of the root is usually dependent on the needs of the plant, the roots acting to help it succeed in certain localities. Food Storage. — The use to the plant of the food stored in the taproot may be understood if we think of the life history^ of the parsnip. Such a plant produces no seed until near the end of the second year of its existence. After forming seeds it dies. The. Tubercles on clover Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Hunter, George William, 1873
Size: 1167px × 2140px
Photo credit: © Paul Fearn / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., boo, bookpublishernewyorkamericanbookcompany, booksubjectbiology
