Salicylic acid and heat acclimation pretreatment protects Laminaria japonica sporophyte(Phaeophyceae) from heat stress  

作　　者：周斌 唐学玺 王悠 

机构地区：[1]Laboratory of Ecology,College of Marine Life Sciences,Ocean University of China

出　　处：《Chinese Journal of Oceanology and Limnology》2010年第4期924-932,共9页中国海洋湖沼学报（英文版）

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)

摘　　要：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.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（H2O2） 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 H2O2 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.

关 键 词：Laminaria japonica salicylic acid heat acclimation THERMOTOLERANCE oxidative stress antioxidant system 

分 类 号：Q945[生物学—植物学]