小麦叶片经受30分钟高温胁迫后,其电解质伤害性渗漏量(IL)随胁迫温度而增加,两者关系符合指数曲线性质,但超过某一临界温度时,曲线突然变陡,(IL)的温度系数(Q_(10))比临界温度之前增加数十倍至数百倍。该临界温度大致相当于或略高于致...小麦叶片经受30分钟高温胁迫后,其电解质伤害性渗漏量(IL)随胁迫温度而增加,两者关系符合指数曲线性质,但超过某一临界温度时,曲线突然变陡,(IL)的温度系数(Q_(10))比临界温度之前增加数十倍至数百倍。该临界温度大致相当于或略高于致死温度。麦株经适当高温锻炼后,致死温度及 IL 达50％时的温度(IT50)均显著增高,但恢复常温后,锻炼效果逐渐解除。展开更多
Possible mediatory roles of heat acclimation and salicylic acid in protecting the sporophyte of marine macroalga Laminaria japonica(Phaeophyceae) from heat stress were studied.Heat stress resulted in oxidative injury ...Possible mediatory roles of heat acclimation and salicylic acid in protecting the sporophyte of marine macroalga Laminaria japonica(Phaeophyceae) from heat stress were studied.Heat stress resulted in oxidative injury in the kelp blades.Under heat stress significant accumulation of hydrogen peroxide(H_2O_2) and malonaldehyde(MDA),a membrane lipid peroxidation product,and a drastic decrease in chlorophyll a content were recorded.Activity of the enzymatic antioxidant system was drastically affected by heat stress.The activity of superoxide dismutase(SOD) was significantly increased while peroxidase(POD),catalase(CAT) and glutathione peroxidase(GPX) were greatly inhibited and,simultaneously,phenylalanine ammonia-lyase was activated while polyphenol oxidase(PPO) was inhibited.Both heat acclimation pretreatment and exogenous application of salicylic acid alleviated oxidative damage in kelp blades.Blades receiving heat acclimation pretreatment and exogenous salicylic acid prior to heat stress exhibited a reduced increase in H_2O_2 and MDA content,and a lower reduction in chlorophyll a content.Pretreatment with heat acclimation and salicylic acid elevated activities of SOD,POD,CAT,GPX and PPO.Considering these results collectively,we speculate that the inhibition of antioxidant enzymes is a possible cause of the heat-stress-induced oxidative stress in L.japonica,and enhanced thermotolerance may be associated,at least in part,with the elevated activity of the enzymatic antioxidant system.展开更多
文摘小麦叶片经受30分钟高温胁迫后,其电解质伤害性渗漏量(IL)随胁迫温度而增加,两者关系符合指数曲线性质,但超过某一临界温度时,曲线突然变陡,(IL)的温度系数(Q_(10))比临界温度之前增加数十倍至数百倍。该临界温度大致相当于或略高于致死温度。麦株经适当高温锻炼后,致死温度及 IL 达50％时的温度(IT50)均显著增高,但恢复常温后,锻炼效果逐渐解除。
基金Supported by the Open Funds of the Key Oceanic Science and Engineering Laboratory of National Bureau of Oceanography(MESE-2008-01)the Specialized Research Program for Marine Public Welfare Industry,SOA(No.200805066)
文摘Possible mediatory roles of heat acclimation and salicylic acid in protecting the sporophyte of marine macroalga Laminaria japonica(Phaeophyceae) from heat stress were studied.Heat stress resulted in oxidative injury in the kelp blades.Under heat stress significant accumulation of hydrogen peroxide(H_2O_2) and malonaldehyde(MDA),a membrane lipid peroxidation product,and a drastic decrease in chlorophyll a content were recorded.Activity of the enzymatic antioxidant system was drastically affected by heat stress.The activity of superoxide dismutase(SOD) was significantly increased while peroxidase(POD),catalase(CAT) and glutathione peroxidase(GPX) were greatly inhibited and,simultaneously,phenylalanine ammonia-lyase was activated while polyphenol oxidase(PPO) was inhibited.Both heat acclimation pretreatment and exogenous application of salicylic acid alleviated oxidative damage in kelp blades.Blades receiving heat acclimation pretreatment and exogenous salicylic acid prior to heat stress exhibited a reduced increase in H_2O_2 and MDA content,and a lower reduction in chlorophyll a content.Pretreatment with heat acclimation and salicylic acid elevated activities of SOD,POD,CAT,GPX and PPO.Considering these results collectively,we speculate that the inhibition of antioxidant enzymes is a possible cause of the heat-stress-induced oxidative stress in L.japonica,and enhanced thermotolerance may be associated,at least in part,with the elevated activity of the enzymatic antioxidant system.
