Title: Development and activities of roots of crop plants; a study in crop ecology
Identifier: developmentactiv00weav (find matches)
Year: 1922 (1920s)
Authors: Weaver, John E. (John Ernest), 1884-1966; Jean, Frank Covert, 1880- joint author; Crist, John W. , joint author
Subjects: Roots (Botany); Plant ecology; Crops and climate
Publisher: Washington, Carnegie Institution of Washington
Contributing Library: The Library of Congress
Digitizing Sponsor: The Library of Congress

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14 Development and Activities of Roots of Crop Plants. The root systems of the wheat plants examined agreed with the statement of Rotmistrov, for not only at this period did these primary roots penetrate deepest, but they lived and continued to grow and function until the plant matured, at which time they had reached greater depths than any of the roots that formed later (fig. 3 c). Of these primary roots a few grew almost ver- tically downward, but by far the greater number passed off obliquely to a distance of 0.5 to 1.3 feet and then, turning downward, pursued a zigzag but generally vertical course to a depth of 3.9 to 4.2 feet. The maximum depth
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Fiq. 3.—A. Marquis wheat 20 days old; B. 70 days old. C. Durum wheat 60 days old. of penetration was 4.5 feet. These main roots were yellowish in color and quite tough. Throughout their course, excepting the last 8 to 12 inches, they were quite abundantly branched, the branches varying from a few milli- meters to 2 or more inches in length. These branches were themselves often rebranched. Just below the surface of the soil another set of roots arose from a node on the main stalk. These passed out almost horizontally in all directions to a distance of 6 to 8 inches. Some of these, however, were

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