. Physiological botany; I. Outlines of the histology of phænogamous plants. II. Vegetable physiology. Plant physiology; Plant anatomy. 296 ASSIMILATION. The instructive similarity between the spectrum of the yellow coloring-matter of chlorophyll and that of the so-called etiolin, or yellow coloring-matter which can be extracted from blanched leaves, is shown in the two figures here given. BOP B 1 T .4011 \wi> SCO I iilililiilmillllllniilmiliiii'hl ^om B C ill D ll'lllllMl'lllll [illliiiiliiiiliiii'iiiii|iiiim. 300 \liM SO' iulll 789. An alcoholic solution of chlorophyll undergoes very littl
. Physiological botany; I. Outlines of the histology of phænogamous plants. II. Vegetable physiology. Plant physiology; Plant anatomy. 296 ASSIMILATION. The instructive similarity between the spectrum of the yellow coloring-matter of chlorophyll and that of the so-called etiolin, or yellow coloring-matter which can be extracted from blanched leaves, is shown in the two figures here given. BOP B 1 T .4011 \wi> SCO I iilililiilmillllllniilmiliiii'hl ^om B C ill D ll'lllllMl'lllll [illliiiiliiiiliiii'iiiii|iiiim. 300 \liM SO' iulll 789. An alcoholic solution of chlorophyll undergoes very little if any change when kept in the dark ; but even a short exposure to strong light destroys its green color, and leaves the liquid pale brown, or nearly colorless. When, however, strong sun- light passes through a solution of chlorophyll before it reaches a second receptacle filled with the same liquid, the first solution protects the second for a considerable time ; and only after the first has lost a portion of its green color can the second be also acted upon. 790. Sachs ^ has pointed out the interesting fact that green leaves, especially those of delicate texture, become paler when exposed to a very bright light, and resume their deep green color when again subjected to a less intense light. If one leaf is partially' shaded by another, the shaded leaf preserves its nor- mal deep green color, while the leaf exposed to the light grows distinctly paler. This effect, due probably to a change of posi- tion of the chlorophyll grains, can be shown experimentally in the following manner: Fasten closelj- to a green leaf, still ^ Ber. iiber die Verhandlungen (Math. Phys. Classe) der Siichsischen Ge- sellsch. xi., 1859, 226 ; and also in Experimcntal-physiologie, 1865. Fig. 151. The upper spectrum is that of the yellow constituent of chlorophyll ftom Deutzia scabra; the lower, that of the coloring-matter of etiolated barley, in dilute solution. (Kraiis). Please note that these images
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectplantanatomy, bookyea
