The characteristics of photosynthesis and dry matter production in Japonica rice cultivars with different type panicles

Chinese. 为了明确不同穗型粳稻产量形成的物质来源。以27个粳稻品种或品系为试材，对光合特性和干物质生产、分配及其与产量的关系进行了研究。齐穗期、灌浆期直立和半直立穗型品种的剑叶和倒2叶净光合速率高于弯穗型品种。齐穗期直立和半直立穗型品种的剑叶和倒2叶气孔导度大于弯穗型品种，但灌浆期各类品种气孔导度的差异变小。灌浆期细胞间隙CO2浓度比齐穗期有所增高，其中弯穗型品种增高幅度较大。齐穗期和成熟期细胞间隙CO2浓度与产量呈显著正相关。直立和半直立穗品种由于具有较强的光合效率和物质转运能力，干物质分配到穗部的比例较大，产量较高。

English. To clarify the material sources to form grain yield of different pamick types of rice cultivars the experiment was performed. Using 27 cultivars as materials, the photosynthetic characteristics and dry matter production and distribution of different types of rice were analyzed. The results indicated that the net photosynthesis in flag leaf and second leaf from above of erect and semi-erect panicle cultivars was higher than that of curved panicle cultivars at the full heading and ripening stages. The stomata conductance of erect and semi-erect panicle cultivars was bigger than that of curved panicle varieties at the full heading stage. But the difference of stomata conductance among three types of cultivars turned to be small. Compared with full heading stage, the intercellur CO2 concentration of the plants increased at the filling stage. In which the increase for curved panicle cultivars was significant. There was a significant positive correlation between the intercellur CO2 concentration at full heading and filling stages and grain yield. The erect and semi-erect panicle cultivars could translate higher ratio of the matter to panicle and produce more grain yield because of their high photosynthesis efficiency and great transportation ability.