EXTENT AND LONGEVITY OF THE SEMINAL ROOTS OF CERTAIN GRASSES

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Abstract
Ten spp. of perennial grasses native to midwestern prairie and 4 spp. of introduced grasses of great economic importance were grown in loam soil in boxes 10 X 10 in. in diam. and 24 in. deep (some 48 in.) with a removable side. Two boxes were used for each species. When the seedlings were 21 days old the seminal roots of some plants were first examined; on most plants they were marked by a tin band and examined at the approx. ages of 41, 70, and 119 days. Seminal roots were 6-10 in. deep when 21 days old, and 7.5-27 in. deep, as were also many nodal roots, when the plants were 8-10 in. tall and well tillered. At 90-123 days after planting, when the grasses were 9-19 in. tall and 2 spp. had blossomed, the seminal roots, despite 6-60 nodal roots, extended deeply and frequently to 24 in. Microscopic examination indicated that on most spp. 1/2-2/3 of the seminal root surface appeared normal with cortex and root hairs intact. In deeper boxes depths of 24-36 in. were ascertained in certain spp. Normally developed plants of several spp. grew in 3.5 months to heights of 8.5-14 in. on the seminal roots alone, and plants of 3 spp. from which all nodal roots were continuously excised tillered freely and remained alive 4 months. Spp. used were Agropyron cristatum, A. intermedium, A. smithii, Andropogon furcatus, A. scoparius, Bouteloua curtipendula, Bromus inermis, Buchloe dactyloides, Elymus canadensis, E. junceus, Panicum virgatum, Sorghastrum nutans, Stipa comata, and S. spartea.