. A textbook of botany for colleges and universities ... Botany. 522 ECOLOGY. In Anthoceros and Selaginella the chloroplasts in some cells are many and small, while in other cells they are few and large (fig. 754). Sun plants commonly have smaller chloroplasts than do shade and water plants. The so-called chromoplasts of carrot roots, nasturtium flowers, etc., often are irregular in shape (fig. 755). The pigments. â Chlorophyll is not a simple green pigment, but it contains, in addition to the green pigment or chlorophyllin, a yellow pigment known as xanthophyll and an orange pigment known as
. A textbook of botany for colleges and universities ... Botany. 522 ECOLOGY. In Anthoceros and Selaginella the chloroplasts in some cells are many and small, while in other cells they are few and large (fig. 754). Sun plants commonly have smaller chloroplasts than do shade and water plants. The so-called chromoplasts of carrot roots, nasturtium flowers, etc., often are irregular in shape (fig. 755). The pigments. â Chlorophyll is not a simple green pigment, but it contains, in addition to the green pigment or chlorophyllin, a yellow pigment known as xanthophyll and an orange pigment known as carotin. Closely related to xanthophyll and carotin are most yellow, orange, and brown pigments associated with color-bearing bodies (chromatophores or plastids), including those of yellow flowers, diatoms, and plants exposed to darkness ( etiolated plants, whose pigment often is called etiolin). Phaeophyll, the brown pigment of the Phaeophyceae, is closely related to chloro- phyll. Chlorophyll differs widely in tint. The leaves of succulent plants, salt plants, and epiphytes have a pale green color that is in strong contrast to the dark green color of beech leaves and of shade leaves generally. The deep green tints of shade leaves may be due in part to the greater concentration of the chlorophyllin, in part to the paucity of xantho- phyll, and in part to the number and size of the plastids. Miscellaneous features. ââ Chloroplasts contain various inclusions, notably starch grains (fig. 756; ); the pyrenoids of algae and of Anthoceros are protein inclusions, and oil is common, especially in dying plastids. Plastids arise by division from preexisting plastids (fig. 753), and perhaps at times de novo in the cell cytoplasm, though careful search usually reveals them, even where their absence might be expected ( in embryos). Although chlorophyll usually occurs only in chloroplasts, spectroscopic tests show its presence in the blue- FlG. 755. â Cells from a per
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