Histochemical Studies of Protein Accumulating Process in Rice Grain

Abstract

Protein is contained in the rice grain in the largest quantity next to starch, and supposed to be concerned with the transparency process of rice grain. In this report, we studied protein distribution in rice grain, protein accumulating process, and protein amount related to nitrogen fertilizer, rice quality which is classified by white portion in grain and varieties. The result are summarized as follows; 1. Protein was observed by ninhydrin reaction, and section was pre-treated with perchloric acid as solvent of starch grain. 2. Protein is distributed in outer layer of endosperm except for aleuron layer, richer on ventral side, and less on dorsal side and in central part of endosperm. 3. We did not notice any protein coloration by ninhydrin solution in pericarp, seed coat and aleuron layer. 4. Protein accumulates from outer layer of endosperm to inner layer, while starch accumulates from center line of grain to outer layer of endosperm. 5. Grains of heavily nitrogen applied plot were richer in protein than normally fertillized plot. 6. White ventral part grain and white core grain were richer in protein than fully ripe grain. The development of grain was rapid. White basal part grain was less in protein. It is because of poor ripening. 7. Early varieties were richer in protein than late varieties except for Koshisakae having germinated seed caused by lodging.