水稻光合作用“午睡”现象的初探

PRELIMINARY STUDIES ON AFTERNOON-NAP IN RICE PHOTOSYNTHESIS

水稻的光合作用表现出明显的午睡现象,即13时左右(北京夏令时)光合作用出现低谷。叶面喷水可以减缓午睡的程度,但不能消除午睡现象。恒温、恒光照处理,光合速率的日变化仍与对照植株相似。延迟见光时间,植株从黑暗中取出即可测出光合作用。说明已具备进行光合作用的生理条件。自然温光加夜间人工光照,夜间的光合作用均为负值。这说明水稻的光合作用需要预先的生理准备过程。光合作用的日变化与内部生理状态的周期性变化有关。

The photosynthesis of rice have a afternoon-nap, which is characterized hy the lowest synthetic rate of the day at 13 O'clock ( Beijing Summer time). Spraying water to the leaf could decrease the degree of the nap. When treated with constant temperature and light, the plants still showed the same daily changes in photosynthetic rate as that of control plants. Delaying the exposure time of the plants to light, there was measurable photosynthesis immediately after the plants were transtered from dark to light. This means that the plants were prepared physiologically for photosynthesis even in the dark. Under conditions of natural temperature and light combining with artificial light at night, negative photosynthetic rate was observed in the night. These results indicate that the photosynthesis of rice needs a physiological preparation. The daily changes of photosynthetic rate is associated with the cyclic alterations of internal physiological periods.