拔节孕穗期水分胁迫对水稻生理特性的影响

采用盆栽试验研究了水稻拔节孕穗期水分胁迫复水后的光合特性和生理活性。结果表明,胁迫后复水叶片净光合速率日变化为双峰曲线,有明显的光合午休,对照则为单峰曲线。轻度5 d胁迫处理的叶片在复水后其净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Cs)均高于对照;轻度10 d和重度5 d处理在午前较低而在午后高于对照,但重度10 d处理则低于对照。轻度胁迫处理复水后叶片叶绿素a、叶绿素b、类胡萝卜素(CAR)含量和叶绿素(a b)总量均可超过对照,表现出超补偿效应,而重度水分胁迫处理则低于对照。复水短期内胁迫处理丙二醛(M DA)浓度均低于对照,后期则高于对照。长历时水分胁迫降低了水稻的产量和干物质累积量,而短历时胁迫处理与对照接近。

Effects of water stress on photosynthetic and physiological characteristics of rice in jointing-booting stage

The pot experiment was conducted to study the effects of water stress on photosynthetic and physiological characteristics of rice in early jointing-booting stage.It was found that the diurnal variation of net photosynthetic rate showed double-peak curve in the treatment of water stress followed by rewatering,while it was single-peak curve in CK.Under the treatment of 5-days mild stress,net photosynthetic rate(P_n),transpiration rate(T_r) and stomatal conductance(C_s) of the second leaf from the top were higher than those of CK; under the treatment of 10-days mild stress or 5-days severe stress,the values of these parameters were lower before midday depression of photosynthesis(MDP) but higher after MDP than those of CK;but under 10-days severe stress,they were always lower than those of CK.Under the treatment of mild stress,the contents of total chlorophyll(a b),chlorophyll a,chlorophyll b and carotenoid were all higher than those of CK,indicting that there was an over-compensation effect;but under the treatment of severe stress,they were lower than those of CK.In the early stage of rewatering after stress,the content of malondialdehyde (MDA) was less than that of CK,but in the later stage it was larger than that of CK,suggesting that rewatering accelerated the senescence of rice leaves.The yield and accumulation of dry matter were close to those of CK under 5-days stress,but were lower than those of CK under 10-days stress.