. A textbook of botany for colleges and universities ... Botany. 53^ ECOLOGY. Fig. 772. — A longitudiaal section through a portion of the stem of .5o/«:orttMi, showing oblique palisades (^), and also a "storage" tracheid (t); the arrow is directed toward the stem apex; jf, stoma; considerably magnified. to the leaf surface, regardless of the position of the leaf in relation to light. The position of the palisade layers seems relatively fixed in most cases (not in Lactuca and in Eucalyptus), a rudimentary palisade region often being discernible in the bud; in sub- sequent development
. A textbook of botany for colleges and universities ... Botany. 53^ ECOLOGY. Fig. 772. — A longitudiaal section through a portion of the stem of .5o/«:orttMi, showing oblique palisades (^), and also a "storage" tracheid (t); the arrow is directed toward the stem apex; jf, stoma; considerably magnified. to the leaf surface, regardless of the position of the leaf in relation to light. The position of the palisade layers seems relatively fixed in most cases (not in Lactuca and in Eucalyptus), a rudimentary palisade region often being discernible in the bud; in sub- sequent development the thickness of the layer, but not its position, may vary as external conditions vary. Thus light appears to affect chiefly the cell length, the region of develop- ment and the orientation of the pali- sade cells being due to other and mostly unknown causes. The influence of light upon cell elongation might be conceived of as direct or indirect. In many but not in all albescent leaves the palisades stop sharply at the edge of the green tissue (fig. 773), although the green and colorless spots are ex- posed equally to the light; thus palisade de- velopment appears to be correlated with the formation or with the activity of chlorophyll rather than with light directly. Again, the palisade length in- creases and decreases with the amount of car- bon dioxid, seeming to indicate that palisade size is associated with synthetic activity. Palisades and trans- piration.—Not all cases of palisade development can be referred to light,. 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 Coulter, John Merle, 1851-1928; Barnes, Charles Reid, 1858-1910, joint author; Cowles, Henry Chandler, 1869- joint author. New York, Cincinnati [etc] American book company
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectbotany, bookyear1910
