. Agricultural botany, theoretical and practical. Botany, Economic; Botany. THE ROOT 143 piliferous layer, wither and shrivel. The older portions of a root after becoming covered by a protective periderm lose their absorptive function and henceforward act chiefly as con- ductors of the watery solutions absorbed by the younger parts still possessing root-hairs. For an account of the characteristic root-cap which covers the growing point of practically all roots see pp. 149 and 150. 1 2. Fig. 73.—Diagram illustrating secondary growth in thickness of the root of a dicotyledon, i. Transverse secti
. Agricultural botany, theoretical and practical. Botany, Economic; Botany. THE ROOT 143 piliferous layer, wither and shrivel. The older portions of a root after becoming covered by a protective periderm lose their absorptive function and henceforward act chiefly as con- ductors of the watery solutions absorbed by the younger parts still possessing root-hairs. For an account of the characteristic root-cap which covers the growing point of practically all roots see pp. 149 and 150. 1 2. Fig. 73.—Diagram illustrating secondary growth in thickness of the root of a dicotyledon, i. Transverse section of a very young root. 2. The same after the cambium {c) has formed a continuous band. 3. The same after secondary thickening has been in progress some time. / Piliferous layer; j primary cortex; e endodermis ; n pericycle ; b' primary bast; iv' primary wood ; c cambium ; b" secondary bast; w" secondary wood ; r secondary cortex m primary medullary ray. Ex. 69.—Soak some peas and barley grains in water for six or seven hours, and afterwards allow them to germinate on damp blotting paper or flannel as in Ex. 3. When the root-hairs are visible on the young roots examine them with a lens and make sketches noting especially their origin away from the extreme tip. Strip off with forceps a piece of the outer portion of a root, so as to. 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 Percival, John, 1863-1949. New York, H. Holt
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectbotany, bookyear1910
