. Plant life, considered with special references to form and function. Plant physiology. VEGETATIVE REPRODUCTION. 215 309. Food.âIn almost all cases there is a suppl)- of reserve food within the spore. This reserve food varies in amount with the conditions under which the spores are formed. It is ordinarily greater in resting spores than in those intended for immediate growth. Spores may contain chlorophyll, but generally do not ; even the spores of green plants are mostly without it. Its presence seems to indicate an active condition of the protoplasm, and the vitality of such spores is usual
. Plant life, considered with special references to form and function. Plant physiology. VEGETATIVE REPRODUCTION. 215 309. Food.âIn almost all cases there is a suppl)- of reserve food within the spore. This reserve food varies in amount with the conditions under which the spores are formed. It is ordinarily greater in resting spores than in those intended for immediate growth. Spores may contain chlorophyll, but generally do not ; even the spores of green plants are mostly without it. Its presence seems to indicate an active condition of the protoplasm, and the vitality of such spores is usually of short duration. It is of course absent from the spores of colorless plants, such as the Fig. 210.âPart of a vertical section of a leaf of a u-illow, attacked by a fungus {Melamfi- sora salicina). eo, epidermis of upper side lifted by the young teleuto spores; t, de- veloping from the spore-bed abo\'e the ends of the palisade parenchyma,/;;?-,â t-w, epidermis of the under side, broken through spore-bed from which spring uredo- spores, St. and paraphyses, /, eo will also finally be ruptured to set free /. Magni- fied 260 diam.â.After Pranll. 310. Growth.âSpores germinate by absorbing water, thus bursting the more rigid layer or layers of the cell-wall. The inner layer then grows in area to accommodate the increas- ing protoplasm, which so controls the regions of growth and the mode of cell division as to produce a plant of definite. 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 Barnes, Charles Reid, 1858-1910. New York, H. Holt & company
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