锶对苜蓿生长和抗氧化酶系统的影响

摘要

在1/2浓度Hoagland营养液中添加终浓度至0、1mmol/L、5mmol/L、10mmol/L、20mmol/L和40mmol/L的 SrCl2处理2叶1心期苜蓿,待其生长至3叶1心期分析6个处理对苜蓿生长、抗氧化酶(POD、SOD和 CAT)活性和同工酶谱的影响.结果表明:SrCl2处理在低浓度对苜蓿生长有一定促进作用,浓度超过5 mmol/L 后,苜蓿生长受到抑制.当 SrCl2处理浓度在0~40mmol/L范围内,苜蓿 POD、SOD和 CAT 活性表现为先升高后降低,其中POD和CAT在10mmol/L、SOD在20mmol/L 浓度时活性最高.SOD/POD、SOD/CAT和 SOD/(POD+CAT)比值先降低后升高,10mmol/L SrCl2处理比值最小,说明 POD和 CAT活性在锶胁迫时降低更快,限制了锶胁迫的缓解.锶处理导致POD同工酶谱带减少,20mmol/L SrCl2可诱导产生2条新的 SOD谱带,同时导致 SOD-3不表达, 10mmol/L SrCl2诱导1条新的CAT谱带;但随浓度增加,新产生的酶不表达,没有相应谱带.%The alfalfa in 2 leaves 1 heart were treated with different SrCl2concentration (0.00,1.00, 5.00,10.00,20.00 and 40.00 mmol/L)in 1/2-strength Hoagland nutrient solution,and grew to 3 leaves 1 heart.The effects of different treatment on growth traits,enzyme activities and isoenzymes of POD,SOD, CAT were analyzed.The results showed that growth of alfalfa was promoted by low concentration of SrCl2.The growth of alfalfa was inhibited when the SrCl2concentration was more than 5 mmol/L.The ac-tivities of antioxidant enzymes (POD,SOD and CAT)were increased first and then decreased when the concentration of SrCl2ranged from 0.00 to 40.00mmol/L,and the activities of POD and CAT were the highest at 10mmol/L SrCl2and SOD at 20mmol/L SrCl2.The ratio of SOD/POD,SOD/CAT and SOD/(POD+CAT)decreased first then increased,the ratio was minimal at 10mmol/L SrCl2treatment,it was a limiting factor of alleviation strontium stress,the activities of POD and CAT decreased faster in stress. POD isozyme bands were decreased along with strontium concentration increasing.The 2 new bands were induced and SOD-3 band vanished at 20mmol/L SrCl2treatment,There was 1 new CAT band in 10mmol/L SrCl2treatment.However,the new isoenzymes were not expressed and there was no corre-sponding band with the increase of concentration.These new isozymes may be the key pathway to resist the stress of strontium.