【摘要】 采用测筒试验研究了水稻拔节孕穗期旱涝急转前后的光合特性和生理活性。结果表明,旱涝急转后各淹涝处理叶片的光合速率(Pn)、蒸腾速率(Tr)和气孔导度(Cs)均得以恢复;随淹涝历时的延长,轻度淹涝叶片的Pn、Tr和Cs呈上升趋势,逐渐高于对照;而重度淹涝在淹涝后期出现下降趋势,逐渐低于对照。旱后轻涝、旱后重涝处理的叶绿素(Chl)和类胡萝卜素(CAR)含量均出现降低趋势。旱涝急转后短期内(4 d)轻涝处理、重涝处理的丙二醛(MDA)浓度相对有所下降,且下降幅度与淹水深度呈正相关;而长历时淹涝(7 d)后重度淹涝的MDA浓度增加并高于对照。旱涝急转后轻涝处理有利于根系活力(TTC还原强度)的提高,表现出补偿和超补偿效应;重涝处理短期内(4 d)也有利于根系活力的恢复,但淹涝后期(7 d)根系活力低于对照,处理间差异不显著。更多还原

【Abstract】 The pot experiment was conducted to study the effects of drought stress and waterlogging stress on photosynthetic and physiological characteristics of rice in jointing-booting stage.In the experiment,Deep water was exposed immediately after designed down-limits of soil moisture had been reached to stimulate fast conversion from drought stress to waterlogging stress. It was found that the net photosynthetic rate(Pn),transpiration rate(Tr)and stomatal conductance(Cs) recovered gradually in both treatments.The Pn,Tr and Cs increased with time and overtaked those of CK under the treatment of drought stress followed by mild waterlogging stress(HQ),while under the treatment of severe waterlogging stress(HZ),Pn,Tr and Cs decreased and lower than those of CK at the end of waterlogging stress.Both under HQ and HZ,the contents of total chlorophyll and carotenoid all deteriorated gradually.The content of malondialdehyde(MDA) of HQ and HZ decreased relatively in a short time(4 d),and there was a positive correlation between the reduction extent of MDA and the depth of water.After a long period(7 d) of waterlogging stress,the content of MDA under HZ increased and higher than that of CK.The treatment of HQ obviously increased root activity,indicting that there was compensation and over-compensation effect,while under the treatment of HZ the root activity recovered in short-term(4 d),then reduced and lower than that of CK,but the difference was not significant betweem treatments.更多还原