Varietal Difference in the Rate of Photosynthesis of Rice Plant and Its Relation to Dry-matter-production

Abstract

The varietal differences of photosynthetic activity among rice varieties and their relationship to dry-matter-production were studied with twelve varieties at seedling and maximum tillering stages, the results being as follows: (1) Relatively stable varietal difference was found with varieties tested through young and adult plants grown under different cultivating conditions. It was also observed that early maturing varieties tended to have higher activities than late maturing ones. (2) Photosynthetic activities of varieties at the former growth stage were determined by protein-nitrogen content on unit leaf area. (3) When leaf area was not too big or solar radiation was abundant, relative growth rates of varieties were determined by photosynthetic rate on unit leaf area through net assimilation rate.