高产杂交籼稻Ⅱ优129光合碳同化特性的研究

从光能利用率差异的角度探讨了高产杂交籼稻Ⅱ优129和对照汕优63的光合碳同化特性。结果表明：a)Ⅱ优129的光能利用率和产量显著高于汕优63，但其叶面积指数、消光系数及生育期无显著差异，说明光合效率及光合功能期是导致两组合光能利用率差异的主要原因；b)Ⅱ优129剑叶的CO2日同化量、叶源量及单茎CO2同化量均极显著高于汕优63，说明前者的碳同化能力较后者强；c) 提高一个耐光抑制等级即可减少约3％的CO2日同化量的损失，提高品种的耐光抑制等级可进一步提高光能利用率；d)用光合速率高值指数作为衡量叶片一生中光合机构高效运行状态的一个生理指标，有助于揭示光合功能衰退对产量影响的生理机制，提高光合速率高值指数是提高光合效率的一个重要途径。

Photosynthetic Carbon Assimilating Properties in High-yield Hybrid Rice

Photosynthetic carbon assimilating properties were studied in high-yield hybrid rices Ⅱ You 129 and Shanyou 63 (as the check) from the point of view of the difference of their solar energy use efficiency . The results showed that solar energy use efficiency and yield for Ⅱ You 129 were remarkably higher than those of Shanyou 63,but their leaf area index, foliar absorption coefficient and growth duration had not much difference, which suggests that photosynthetic efficiency and time are the important reasons resulting in the difference of their solar energy use efficiency. Daily CO2 assimilation capacity(DCAC), leaf source capacity(LSC) in flag leaf and CO2 assimilation capacity of a stem(CACS) of Ⅱ You 129 were more than those of Shanyou 63, which indicates that the carbon assimilation capacity of the former is better than that of the latter. The improvement of one grade of photoinhibition might reduce 3% loss of DCAC, and solar energy use efficiency could be improved by increasing photoinhibition grade for rice varieties. Active photosynthesis index(API) was used as a physiological index for weighing the active state of photosynthesis organ in leaf life span, which facilitates elucidating the influence of photosynthesis function degeneration on rice yield. To improve API would be an important approach to increasing photosynthetic efficiency.