温光对水稻抽穗后剑叶衰老和籽粒灌浆的影响

EFFECT OF TEMPERATURE AND LIGHT ON SENESCENCE OF FLAG LEAF AND GRAIN-FILLING AFTER RICE HEADING

对不同温光组合下水稻衰老和籽粒灌浆过程进行研究.结果表明,在水稻灌浆期间高温促使水稻剑叶的衰老加快;同时籽粒灌浆加速,有效灌浆期缩短,籽粒充实度降低.实验还表明,同一穗中弱势粒受到的温光影响比强势粒要显著.遮荫能减缓过氧化物酶(POD)活性的下降速度,延缓叶的衰老,但遮荫同时会造成光合作用减弱,籽粒充实度不够.籽粒灌浆速度主要受温度调控,但前提条件是需有充足的光照.

Under different temperature and light condition, the senescence of rice and the grain-filling were studied. The results showed that high temperature and light could accelerate the senescence of the flag leaf of rice. Under the high temperature condition, the chlorophyll decomposes more quickly and its content is lower than what under the condition of proper temperature. The high temperature can also increase the MDA content in the flag leaf of rice, accelerate the rate of the filling-milk in grain, shorten the period of the filling-milk and decrease the degree of grain-filling. The study also showed that the effect of high temperature on the weak grain was greater than what on the strong grain. Shading (50% natural light) after heading caused the extending of the growth duration of the flag leaf, and and which showed the decreases in decomposing rate of chlorophyll and MDA content. However, the shading can restrain the photosynthesis of the flag leaf, and it caused that the degree of the grain-filling was lower than what under the strong light. The study also suggested that the grain-filling rate of rice was mainly adapted by temperature under the condition of enough light.