Archive image from page 63 of The cytoplasm of the plant. The cytoplasm of the plant cell cytoplasmofplant00guil Year: 1941 Guilliermond - Atkinson — 48 Cytoplasm with eccentric hilum, on the contrary, arises at a point near the periphery of the plastid and, in this case, by enlarging, soon pro- jects beyond the plastid, which no longer covers it except at one of its poles where it takes the form of a cap. The hilum surrounded by the earliest formed layers is then found at the extremity of the grain opposite the plastidial cap. The grain, no longer coming under the influence of the plastid in
Archive image from page 63 of The cytoplasm of the plant. The cytoplasm of the plant cell cytoplasmofplant00guil Year: 1941 Guilliermond - Atkinson — 48 Cytoplasm with eccentric hilum, on the contrary, arises at a point near the periphery of the plastid and, in this case, by enlarging, soon pro- jects beyond the plastid, which no longer covers it except at one of its poles where it takes the form of a cap. The hilum surrounded by the earliest formed layers is then found at the extremity of the grain opposite the plastidial cap. The grain, no longer coming under the influence of the plastid in that region, ceases to grow and enlargement no longer takes place except at the point of con- tact with the plastid, , at the pole opposite the hilum. There the concentric layers become increasingly numerous and thick. The compound grain arises by a plastid forming several starch grains inside itself, instead of only one. These are in contact with one another and remain small. They are semi-compound grains if they become surrounded by common concentric layers. On the basis of all his investi- gations, as well as those of SCHMITZ on the algae, Schimper was led to consider the plastids as component parts of the cell, incapable of arising de novo, be- ing transmitted by division from cell to cell beginning with the egg, so that plastids of higher plants, according to him, are com- parable to the chloroplasts which are encountered permanently in many algae, but with this differ- ence : in the algae the plastids al- ways keep their chlorophyll and remain as green plastids, while in higher plants they appear first as leucoplasts and do not become chloroplasts except in stem and leaf tissue. Arthur Meyer (1883) working at the same time, confirmed the theory of Schimper which was verified also as far as the chromoplasts are concerned by Courchet (1888). It is fitting to call attention to the observation that the plas- tids, at the same time that they are elaborating starch and p
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