. How crops grow. A treatise on the chemical composition, structure and life of the plant, for students of agriculture ... Agricultural chemistry; Growth (Plants). 266 HOW CROPS GBOW. the plant, as carefully lifted from the sand in which it grew, and B the same plant, freed from adhering soil by agitating in water. The entire root, save the tip, is thickly beset with hairs. In Fig. 39 a minute portion of a barley-root is shown highly magnified. The hairs are seen to be slender tubes that proceed from, and form part of, the outer cells of the root. The older roots lose their hairs, and suffer a
. How crops grow. A treatise on the chemical composition, structure and life of the plant, for students of agriculture ... Agricultural chemistry; Growth (Plants). 266 HOW CROPS GBOW. the plant, as carefully lifted from the sand in which it grew, and B the same plant, freed from adhering soil by agitating in water. The entire root, save the tip, is thickly beset with hairs. In Fig. 39 a minute portion of a barley-root is shown highly magnified. The hairs are seen to be slender tubes that proceed from, and form part of, the outer cells of the root. The older roots lose their hairs, and suffer a thicken- ing of the outermost layer of cells. These dense-walled and nearly impervious cells cohere together and consti- tute a rind, which is not found in the young and active roots. As to the development of the root-hairs, they are niore abund- ant in poor than in good soils, and appear to be most numer- ously produced from roots which have otherwise a dense and un- absorbent surface. The roots of those plants which are destitute of hairs are commonly of consid- erable thickness and remain white and of delicate texture, preserving their absorbent power ^'^' ^®' throughout the whole time that the plant feeds from the soil, as is the case with the onion. Tlie Silver Fir [Abies Picea) has no root-hairs, but its rootlets are covered with a very delicate cuticle highly favorable to absorption. The want of root-hairs is fur- ther compensated by the great number of rootlets which are formed, and which, perishing mostly before theybe- come superficially indurated, are continually replaced by new ones during the growing season. (Schacht, i>«r Baum, p. 165.) Contact of Roots with the Soil.—The root-hairs, as they extend into the soil, are naturally brought into close. 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
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectagriculturalchemistr
