重穗型杂交稻的产量及一些生理生化特性研究

以18个不同穗重型籼稻品种为材料，研究了重穗型杂交稻的产量及一些主要的生理生化特性。结果表明，重穗型杂交稻具有更高产量潜力，其高产主要依赖于大“库”、籽粒的正常充实使单穗重大幅度提高。后期LAI的适当降低、高效叶面积率的增加、根、叶不早衰和净光合速率的提高是其“源”足的主要因素。齐穗后重穗型杂交稻剑叶的净光合速率明显高于中、轻穗型品种的机理是剑叶Rubisco活性的提高及叶绿素含量的增加；具有在高、低光强、高温和低CO2浓度下对C02有较强的同化能力的优势，光合“午休”现象较轻，能保持较高的净光合速率，显示其对环境有较强的适应性；气孔性状优良、气孔开度积（单位面积上的气孔密度乘以其气孔开度）大也是重穗型杂交稻净光合速率高的重要气孔因素。重穗型杂交稻抽穗后物质积累优势明显，且茎鞘物质向穗部的转运量、转运率和转化率也均远高于中、轻穗型品种。

Studies on the Grain Yield and some Characteristics of Physiology and Biochemistry in Heavy Panicle Type of Hybrid Rice

Using 18 indica rice varieties with different panicle weight, the grain yield and some characteristics of physiology and biochemistry in heavy panicle type of hybrid rice (HPT) were studied. The results showed that the HPT hybrid rice had higher grain yield than medium panicle type (MPT) and light panicle type (LPT) rice. High grain yields in HPT hybrid rice were mainly due to large weight of single panicle, which was mainly determined by the large number of spikelets per panicle and their good grain-filling. The rich source to fill the large sink of HPT hybrid rice came from the proper low LAI, high rate of highly effective leaf area, the slow senescence of leaf and root and the high -level photosynthetic capacity in late growing period. The reason for the high net photosynthetic rate of the flag leaf in HPT hybrid rice as compared with MPT and LPT rice was the increase of Rubisco activities and chlorophyll content, and keeping high assimilate ability to CO2 under high and low light intensity, high temperature and low CO, content, and light midday depression and wide adaptability to environmental conditions. The high net photosynthetic rate of HPT hybrid rice might be also the results of its excellent stomatal characteristics and higher total quantity of stomatal opening degrees (stomatal density x stomatal opening degrees). There was a large amount of dry matter production after heading and obvious high assimilate's transformation to panicle in HPT hybrid rice.