花期和鼓粒期低温胁迫对大豆叶片生理特性及产量的影响OA北大核心CSTPCD

To study the effects of low temperature stress on the physiological characteristics and yield of soybean leaves at flowering and bulging periods,and to explore the physiological response mechanism and recovery effect of soybean under low temperature stress at different periods,we used Hefeng 50 as the material and set up the natural ambient temperature treatment at flowering stage(T1),low temperature stress treatment at flowering stage(T2),ambient temperature treatment at seed filling stage(T3)and low temperature stress treatment at seed filling stage(T4).The duration of low temperature stress was 4 d,and 4 d rewarming treatment was conducted after the stress ended.We analyzed the effects of low temperature stress(15 ℃)on membrane lipid peroxidation,antioxidant enzymes,osmoregulatory substances and yield of soybean leaves at different periods.The results showed that the low temperature stress treatment significantly reduced the yield of soybean at both flowering and grain bulge stages,with 15.96％and 36.64％yield reduction at flowering stage and 24.06％and 50.56％yield reduction at grain bulge stage after 1 d and 4 d of low temperature stress,respectively.Low temperature stress at anthesis significantly reduced the number of pods and grains per plant in soybean,and low temperatureg stress at the bulge stage significantly reduced the 100-seed weight of soybean.During the low temperature stress treatment,malondialdehyde(MDA),hydrogen peroxide(H2O2),osmoregulatory substance content,superoxide anion(O2-)production rate,superoxide dismutase(SOD)and peroxidase(POD)activities of soybean leaves showed an increasing trend and catalase(CAT)activity showed a decreasing trend with the duration of low temperature stress,which was alleviated during the recovery period.However,they did not reach the control level.It is evident that low temperature stress exacerbates cellular membrane lipid peroxidation in soybean leaves and that soybean plants can withstand low temperature stress to some extent by increasing the content of osmoregulatory substances and regulating the activities of antioxidant enzymes.Low temperature stress at anthesis significantly reduced soybean yield mainly by reducing the number of pods and grains per plant,while chilling stress at bulge stage mainly inhibited the process of soybean grain filling and fruit set,resulting in lower yield.