摘要
在铝和酸胁迫下,比较分析了天蓝苜蓿和紫花苜蓿根瘤菌的生长及SOD(超氧化物歧化酶)、CAT(过氧化氢酶)、POD(过氧化物酶)、及GR(谷胱甘肽还原酶)等抗氧化酶系响应特点。铝胁迫设5个梯度,即0,25,50,75,100μmol/L;酸胁迫设4个pH水平,即4,5,6,7。结果表明,铝和酸胁迫下,2种苜蓿根瘤菌的ODA600均显著降低,生长受到抑制,且天蓝苜蓿根瘤菌的ODA600显著高于紫花苜蓿根瘤菌。在pH水平为4和5时,紫花苜蓿根瘤菌没有生长。在铝毒胁迫下,天蓝苜蓿根瘤菌的SOD酶活性一定程度减小后缓慢上升,而CAT、POD和GR酶活性随铝浓度增大显著下降;紫花苜蓿根瘤菌的SOD,CAT及GR酶活在低Al胁迫下无显著变化,在高铝胁迫下显著下降。随着pH水平的下降,天蓝苜蓿和紫花苜蓿根瘤菌均表现为SOD、CAT、POD、GR酶活性的显著下降。在不同铝及酸胁迫下,天蓝苜蓿根瘤菌各抗氧化酶活性显著高于紫花苜蓿根瘤菌。综合分析认为天蓝苜蓿根瘤菌较之紫花苜蓿根瘤菌有较强的耐酸、耐铝性。
lecting acid tolerant rhizobium strains is believed to be important for planting Medicago sativa in acid soils. M. lupulina and M. sativa belong to the same genus and their rhizobia can infect each other and form nodules. Field studies have shown that M. lupulina could grow in acid soils, suggesting that its rhizobium might be acid tolerant. Therefore, in the current experiment, rhizobium strains from M. lupulina （R1） and M. sativa （R2） were isolated from the fields in Beibei, Chongqing, and propagated on YMA （Yeast Malt extract Agar） solid culture medium. The responses of growth and activities of antioxidant enzymes of the two strains to aluminum and acidity were studied. There were five aluminum levels （0, 25, 50, 75, and 100/μmol/L）, and four pH levels （4, 5, 6, and 7）. The ODA600 of rhizobia isolated from both cultivars reduced significantly after aluminum and acidity stress. The ODa600 from R1 was significantly higher than that from R2. No obvious growth of rhizobium from R2 was observed at less than pH 4 and 5. With increasing aluminum concentrations SOD activity of rhizobium from R1 decreased initially and then increased, while the activities of CAT, POD and GR significantly decreased. The activities of SOD, CAT and GR of rhizobium from R2 hardly changed under low A1 concentrations, but decreased at high A1 concentrations. All enzyme activities of rhizobia from R1 and R2 de- creased with increasing soil acidity. Enzyme activities of rhizobium from R1 were significantly higher than those from R2. Overall, R1 had better tolerance to A1 and acid than R2. Further study is needed to analyse the affinity between Rhizobium strains from M. lupulina and M. sativa.
出处
《草业学报》
CSCD
北大核心
2013年第3期146-153,共8页
Acta Prataculturae Sinica
基金
重庆市科技攻关项目(CSCT2010AC1010)资助
关键词
铝胁迫
酸胁迫
根瘤菌
天蓝苜蓿
紫花苜蓿
抗氧化酶系
aluminum stress
acid stress
rhizobium
Medicagolupulina
M. sativa
antioxidant enzymes activity
