粳稻品种Dongjin在干旱胁迫下苗期生理反应

为了明确苗期水稻对干旱胁迫的生理反应,笔者从光合作用、水分生理、植株体内的氧化逆境、渗透调节物质代谢以及细胞膜的完整性等几个方面分析了粳稻品种Dongjin(OryzasativaL.subsp.japonica)在干旱胁迫处理下的生理变化。结果表明:干旱胁迫过程中,叶片的净光合速率与植株地上部相对含水量在处理5d内均已显著降低,5d后大幅度下降;植株地上部丙二醛含量的显著增加以及相对电导率的快速上升发生在处理5d以后,并且二者的变化趋势相类似;脯氨酸含量在处理6d时有所增加,处理6d后快速上升;叶片的活性氧含量在处理6d时略微下降,6d后逐渐上升,处理8d时显著升高。光合速率与相对含水量最先响应旱胁迫信号,与活性氧、丙二醛、脯氨酸含量和相对电导率一起可用作综合评价水稻苗期耐旱性的指标。

Physiological Responses to Drought Stress in Seedlings of Rice Cultivar Dongjin

In order to find out the physiological responses of rice plants to drought stress, several aspects, including plant water status, oxidative stress, osmoprotectant metabolism and integrity of cell membrane, were analyzed of the seedlings of cultivar Dongjin (Oryza sativa L. subsp. japonica) under drought conditions. The results showed that both the net photosynthesis rate and the relative water content decreased significantly within 5 days of drought treatment and declined rapidly thereafter. The rapid increase of the content of malondialdehyde and the electrolyte leakage rate happened after 5-day drought treatment and both responses had a similar trend. The proline content increased dramatically after treatment for 6 days. The level of reactive oxygen species first dropped slightly at day 6 of treatment, then increased gradually, and elevataed to a significant level at 8th day. The net photosynthesis rate and the relative water content are among the quick responses to drought stress, and combined with the electrolyte leakage rate and the contents of ROS, malondialdehyde and praline. These physiological responses can be used in comprehensive evaluation of rice seedlings for drought tolerance.