分蘖期干旱胁迫对水稻光合特性及产量的影响

Effects of drought stress at tillering stage on photosynthetic characteristics and yield of rice

采用测坑试验方式,设置3个水分梯度(相对田间持水量80%~85%、70%~75%、60%~65%),以相对田间持水量为90%~100%为对照,通过对滴灌水稻分蘖期进行干旱胁迫,测定不同处理叶绿素含量、光合特性、叶面积指数、分蘖动态、干物质积累量和产量等指标,分析不同干旱胁迫处理对滴灌水稻光合特性及产量的影响。结果表明:轻度和中度胁迫下水稻拔节期叶片总叶绿素含量分别较CK提高4.66%、17.62%,拔节期净光合速率分别较CK提高5.73%、10.98%,生育后期叶面积指数较CK分别提高21.41%、26.49%;轻度和中度干旱胁迫减少了拔节前干物质积累,提高了拔节后干物质积累量,优化干物质积累动态;轻度和中度干旱胁迫有利于控制水稻的分蘖数量,显著提高有效穗数,与CK相比提高了8.05%、23.29%;轻度和中度胁迫下水稻穗粒数和千粒重显著降低,各处理间结实率无显著差异,成穗率显著高于CK,与CK相比3种胁迫下成穗率分别提高了22.83%、32.50%、13.20%;轻度和中度胁迫下产量与CK相比分别增加2.73%、6.08%。滴灌水稻分蘖期水分调控时应考虑利用干旱胁迫的补偿效应,于分蘖期采用轻中度控水措施,有利于滴灌水稻光合作用和产量的提高。

Three water gradients(ralative field capacity 80%~85%,70%~75%,and 60%~65%)were set up by pit test method to regulate water content during the whole tillering period for 30 days.The effects of drought stress on photosynthetic characteristics and yield of drip-irrigated rice were analyzed by measuring chlorophyll content,photosynthetic characteristics,leaf area index,tillering dynamics,dry matter accumulation,and yield under different treatments.The results showed that under mild and moderate stress,the total chlorophyll content in leaves increased by 4.66%and 17.62%respectively at jointing stage.The net photosynthetic rate increased by 5.73%and 10.98%at jointing stage and the leaf area index increased by 21.41%and 26.49%at later growth stage.The dry matter accumulation before jointing was reduced and the dynamic of dry matter accumulation was optimized under mild and moderate drought stress,and the tillering number of rice was controlled and the number of effective panicles increased by 8.05%and 23.29%compared with that of CK under mild and moderate drought stress.The number of kernal number and 1000-grain weight under mild and moderate stress were decreased significantly,and the seed setting rate among treatments had no significant difference.The panicle forming rate under different drought stresses at tillering stage were significantly increased by 22.83%,32.50%and 13.20%,respectively,compared with CK.The yield under mild and moderate stresses increased by 2.73%and 6.08%over that of CK,respectively.The compensation effect of drought stress should be fully utilized in water regulation of drip irrigation rice at tillering stage,and the mild and moderate water control measures should be adopted at tillering stage,which is beneficial to the improvement of photosynthesis and yield of drip irrigation rice.