On the Structure and the Development of Starch Grains II

Abstract

1. The reserve starch formation in the amyloplasts in the cells of the endosperm as well as of the embryo in Oryza sativa, Zea Mays, Pisum sativum, Vicia Faba, Dolichos lablab, Phaseolus vulgaris, Ph. radiatus var. typicus, and in the cells of potato tuber and of the bulbils of Dioscorea batatas.2. The amylum is formed in a chamber, the amylum vacuole, which appears in the amyloplast. It is considered that the amylum vacuole may be a grana in the amyloplast.3. Oryza sativa has the most primitive starch grains in its endosperm cells. This kind starch grain is called primary or true compound starch grain.4. The starch granule in the starch grain in the cotyledonary cells of starchy seed of Pisum sativum is the kind of the most complicated starch granule. Indeed it takes place the most complicated developmental process in all others which were investigated by this writer. The starch granule in the potato tuber cells is the kind of the next complicated granule. The starch grain having such starch granule is called as the derivative starch grain.5. The endosperm cells of the sugar corn as well as the starch, the dent, the flint, and the pop corn have the starch grains belonging to the same category in their composition. The starch grains are called as the secondary compound starch grains.6. All starch grains as far as this work concerned have passed through the the primary compound stage in their developmental process.7. The aggregated starch granule, semi-aggregated starch granule, derivative starch grain, secondary compound starch grain and the plastid plasma-center or plasma-center are explained and defined respectively (cf. p. 63, 65 and 66.)8. The detailed general discussion on the composition of the starch grains and on the zonation (the amylum crystal layer formation) in the granules will give in the next paper.Here the writer's hearty thanks are due to Em. Prof. K. Fujii for his kind advice and encouragement during this work.