. The cytoplasm of the plant cell. Plant cells and tissues; Protoplasm. Chapter XV -171 Origin of Vacuoles tion take on the appearance of solid, spherical, very refractive bodies. These bodies can, by crushing, be expelled from the cell and then will not take up neutral red unless they have been im- mersed in water for a long time. The vacuoles are thus transformed into bodies of protein nature whose dimensions are variable. They are very small in some cells and very large in others. They are aleurone grains and are formed by the solidification of the protein contained in solution in the vacuo
. The cytoplasm of the plant cell. Plant cells and tissues; Protoplasm. Chapter XV -171 Origin of Vacuoles tion take on the appearance of solid, spherical, very refractive bodies. These bodies can, by crushing, be expelled from the cell and then will not take up neutral red unless they have been im- mersed in water for a long time. The vacuoles are thus transformed into bodies of protein nature whose dimensions are variable. They are very small in some cells and very large in others. They are aleurone grains and are formed by the solidification of the protein contained in solution in the vacuole. As a result of losing water, a grain of protein has there- fore been substituted for a vacuole. It is not astonishing, then, to. Fig. 118. — Ricinus. Endosperm. 1, young cell, starch (A) forms in chondriconts. 2, just before maturation; starch is absorbed, the large vacuole is fragmented into small vacuoles con- taining protein crystals (C) and protein precipitates (P). 3, oil globules (H) blackened by osmic acid, protein crystals (P). 4, detail of (3). 5, dormant seed; A, aleurone grain, G, globoid. 6, during germination of the seed; aleurone grains (P) beginning to dissolve. M, chondriosomes. 1, 2, 5, 6, Regaud's method. 3, 4, Meves* method. find along with the protein in these vacuoles, inclusions of phytin and crystals of calcium oxalate, products encountered in many vacuoles. Some aleurone grains may even contain oxyflavanol pig- ments or anthocyanin. Investigations of Speiss and Chaze have shown that aleurone grains of some varieties of maize contain an anthocyanin pigment which gives them their characteristic black coloration. At first red, this pigment appears in the vacuoles which will later be transformed into aleurone grains, then remains ab- sorbed by the protein of which the aleurone grain is composed. At germination, when the aleurone grains are again transformed into vacuoles, the anthocyanin pigment changes to red. Furthermore Chaze has found oxyflavanol p
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