Difference in Single Leaf Photosynthesis between Old and New Rice Varieties : III. Physiological bases of varietal difference in single-leaf photosynthesis between varieties viewed from nitrogen content and the nitrogen-photosynthesis relationship

[摘要] Using many rice varieties differing in the year of registration, the bases of the higher single-leaf photosynthesis (CER) in new varieties than that in old ones at the ripening stage were investigated in terms of nitrogen content and the nitrogen-CER relationship in leaves. In new varieties, the total nitrogen content of leaves was higher than that in old varieties at the ripening stage. Further, it was found that there was a fairly close positive correlation between total nitrogen content of leaves and CER. From this, it was concluded that one of the bases of the higher CER in new varieties was the higher leaf nitrogen. However, CER of new varieties was higher than that of old varieties even if they were compared under the same level of leaf nitrogen content and this was thought to be another basis for higher CER in new varieties. This kind of superiority of new varieties was found to be attributable to their gs which was larger than that of old varieties even under the same level of leaf nitrogen.

[学科分类] 农业科学（综合）

[关键词] Nitrogen content;気孔伝導度;Rice plants;個葉光合成;Single-leaf photosynthesis;水稲;Stomatal conductance;窒素含量;Varietal difference;品種間差異