Differential Responses to Heat Stress in Activities and Isozymes of Four Antioxidant Enzymes for Two Cultivars of Kentucky Bluegrass Contrasting in Heat Tolerance
Differential Responses to Heat Stress in Activities and Isozymes of Four Antioxidant Enzymes for Two Cultivars of Kentucky Bluegrass Contrasting in Heat Tolerance
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DOI：
10.21273/jashs.135.2.116
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发表时间：
2010-03-01
影响因子：
1.9
通讯作者：
Huang, Bingru
中科院分区：
文献类型：
--
作者：
He, Yali;Huang, Bingru
了解热胁迫下植物的抗氧化机制对于提高冷季型植物的耐热性具有重要意义。通过比较两个耐热性不同的草地早熟禾品种的抗氧化酶活性和同工酶的热响应，确定与品种耐热性差异相关的抗氧化酶。将耐热的“Spilleton”和热敏感的“Brilliant”的植物在生长室中暴露于20摄氏度（对照）或40摄氏度（热胁迫）28天。叶绿素（Chl a）含量在“白灵顿”中保持不变，而Chl B含量增加，而在“辉煌”中两者均下降，到28 d时，“白灵顿”的Chl a和Chl B含量显著高于“辉煌”。高温胁迫28 d时，‘蓝宝石’的超氧化物歧化酶（SOD）活性显著高于‘辉煌’。同工酶SOD 2诱导早期在热胁迫期间在'Alberleton'，而同工酶SOD 3降解，在较小程度上在'Alberleton'比'辉煌'。高温胁迫下，‘光辉’的过氧化氢酶（CAT）活性显著升高，而‘白灵顿’的CAT活性基本不变，且‘光辉’的CAT活性和同工酶CAT 1显著高于‘白灵顿’。抗坏血酸过氧化物酶（APX）的活性显着增加发生在热胁迫下，在更大程度上在“立顿”，而同工酶没有表现出品种之间的差异。愈创木酚过氧化物酶（POD）活性下降，在两个品种的热胁迫。高温胁迫7 d后，‘光辉’POD同工酶的活性基本保持不变，而‘白灵顿’POD 1活性则出现短暂的升高。结果表明，高温胁迫下，肯塔基州早熟禾的抗氧化防御机制主要与超氧化物歧化酶（SOD）清除超氧阴离子（O-2）和抗坏血酸过氧化物酶（APX）清除过氧化氢（H2 O2）的活性和同工酶的变化有关。
Understanding antioxidant mechanisms for heat stress is important for improving heat tolerance in cool-season plant species. The objective of this study was to identify antioxidant enzymes associated with cultivar variations in heat tolerance in kentucky bluegrass (Poa pratensis) by comparing heat responses of activity and isoforms of antioxidant enzymes in two cultivars contrasting in heat tolerance. Plants of heat-tolerant 'Eagleton' and heat-sensitive 'Brilliant' were exposed to 20 degrees C (control) or 40 degrees C (heat stress) for 28 days in growth chambers. Chlorophyll (Chl) a content remained unchanged and Chl b content increased in 'Eagleton', while both of them decreased in 'Brilliant', and by 28 days, 'Eagleton' had significantly higher Chl a and b content than 'Brilliant'. The activities of superoxide dismutase (SOD) were significantly higher in 'Eagleton' than in 'Brilliant' by 28 days of heat stress. An isozyme SOD2 was induced early during heat stress in 'Eagleton', while isozyme SOD3 degraded, to a lesser extent in 'Eagleton' than in 'Brilliant'. Catalase (CAT) activity significantly increased in 'Brilliant' but remained constant in 'Eagleton', and 'Brilliant' had a significantly higher CAT activity and isozyme CAT 1 than 'Eagleton' during heat stress. Significant increases in ascorbate peroxidase (APX) activities occurred under heat stress, to a greater extent in 'Eagleton', whereas isozymes did not exhibit difference between cultivars. Guaiacol-peroxidase (POD) activity declined during heat stress in both cultivars. The intensity of POD isozymes in 'Brilliant' remained constant, while 'Eagleton' showed a transient increases in POD1 at 7 days of heat stress. Our results indicated that antioxidant defense mechanisms for heat tolerance in kentucky bluegrass could be mainly associated with changes in activity and forms of isozymes of SOD for O-2 scavenging and APX activity for H2O2 scavenging under heat stress.