两系杂交稻PA64S/E32生育后期的光抑制和光合产物分配

以两系杂交稻PA64S/E32和汕优63为材料，在自然条件下测定叶绿素荧光参数和同化产物分配等关键指标。在中午（高光高温）和叶衰老过程中，PA64S/E32的叶绿素、蛋白质含量、PSⅡ原初光化学效率（Fv/Fm）、量子产量（φPSⅡ）和光化学猝灭系数（qP）的降低较少；非光化学猝灭系数（qN）增加较少。表明在自然条件下，两系杂交稻PA64S/E32吸收的光能能较多的转化为化学能，通过热耗散的能量较少，表现耐光抑制。通过用同位素14C对光合同化产物运转分配进行研究，发现两系杂交稻PA64S/E32光合同化产物向穗部的运转速率和分配比率均较高，表明其具有较好的源库协调性。上述有关光合和同化产物的分配特点可能是两系超级稻高产的生理基础。

Photoinhibition and Assimilate Distribution in Two-line hybrid Rice (Oryza sativa L.) PA64S/E32 at Late Development Stage

Using hybrid rice PA64S/E32 and Shanyou63 as materials, chlorophyll fluorescence parameters , assimilate distribution and other key indexes were assayed under natural condition. Compared with that of Shanyou63, the decrement of contents of chlorophyll and protein, PSⅡprimary photochemical efficiency（Fv/Fm）, photon yield (φPSⅡ) and photochemical quenching coefficient (qP) were less; increment of non-photochemical quenching coefficient（qN）and Fo were less in two-line hybrid rice PA64S/E32 at noon (high light intensity and temperature) and during leaf senescence. Transport rate and distribution ratio of photosynthetic assimilate to ear were all-higher, which indicated that PA64S/E32 has better coordination of source-sink in terms of the studies on photosynthetic assimilate using isotope. The above photosynthetic characteristics and assimilate distribution is possibly the physiological basis of high yield in two-line hybrid rice PA64S/E32.