. Plant anatomy from the standpoint of the development and functions of the tissues, and handbook of micro-technic. Plant anatomy. PROCESS OF STORAGE I85 Sometimes it happens that the starch begins to be deposited at more than one point in the leucoplast, so that two or more rela- tively small grains become closely associated, and adhering with more or less tenacity they constitute a compound grain (Fig. loi). In storage tissues, where simple grains are the rule, com- pound grains may*also occur; and in some instances, as in oats and rice, compound grains are the rule. In some cases small unit
. Plant anatomy from the standpoint of the development and functions of the tissues, and handbook of micro-technic. Plant anatomy. PROCESS OF STORAGE I85 Sometimes it happens that the starch begins to be deposited at more than one point in the leucoplast, so that two or more rela- tively small grains become closely associated, and adhering with more or less tenacity they constitute a compound grain (Fig. loi). In storage tissues, where simple grains are the rule, com- pound grains may*also occur; and in some instances, as in oats and rice, compound grains are the rule. In some cases small units of starch may begin to form a compound grain and then all become encased in a common starch sheath deposited by the exterior part of the leucoplast. These grains are called half-compound. f«5- ioi.—showing con- r •! J £: 1 centric and excentric stria- The storage of oils and fats takes tions of starch grains, e, place in the vacuoles and throughout p°*^'° ^f'"'^ excentdcaiiy ^ ^ striated; /, compound starch the meshes of the cytoplasm, and it grain from potato; «, bean 1 , r lii^.i ,1 1 starch concentrically striated. may be mferred that the cytoplasm has more to do with their construction and storage than have the other cell organs; but the mere fact that reserve food occurs in a certain cell organ is not to be taken as evidence that other cell organs have not cooperated in its manufacture. In following the ripening of oily seeds it is found that sugars and starch are present in the immature seeds, but little or no oil. As ripening proceeds, however, oil appears and gradually increases in amount, while the sugars and starch disappear, having unquestionably contributed the elements for the con- struction of the oil. In the leaves of Vanilla and other Monocotyledons have been found rounded bodies containing oil in their meshes, and these bodies have been supposed to be oil formers and have been named elaioplasts {Gr. elaion, oil, and plassein, to form). Reserve s
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