细胞膜热稳定性及保护酶和大白菜耐热性的关系

Cell Membrane Thermostability, Protective Enzymes and Heat Tolerance in Chinese Cabbage

耐热性强弱不同的大白菜品种在细胞膜热稳定性上存在明显差异。经２８～３８℃的短期（１天）高温锻炼能提高细胞膜热稳定性，而常温的脱锻炼又能使细胞膜热稳定性发生可逆变化。持续１０天３２和３６℃的高温处理在提高细胞膜热稳定性的同时，也使植株产生明显的热害症状，耐热性弱的品种比耐热性强的品种更为严重、对保护酶系统酶活性的研究表明：高温导致过氧化物酶（ＰＯＤ）活性降低、过氧化氢酶（ＣＡＴ）活性升高，耐热性强的品种ＰＯＤ活性高于耐热性弱的品种，且超氧化物歧化酶（ＳＯＤ）活性在高温下也较为稳定。

Membrane thermostability varied between heat-tolerant and heat-sensitive genotypes of Chinese cabbage (Brassica campeslris ssp. pekinensis). It was markedly increased in high temperature environment ranging from 28 to 38℃ for one day. However,reversible changes tookplace after transfer to normal growth conditions. Lesions in leaves appeared in the high temperature environment (32℃. and 36℃) for ten days while the membrane thermostability was improved. Enzymatic analysis showed that peroxidase (POD) activity decreased and catalase (CAT) activity increased during high temperature treatment; POD activities of heat-tolerant genotype were higher than those of heat-sensitive genotype in both control and heat treatment; SOD activity of heat-tolerant genotype was more stable than that of heat-sensitive genotype in high temperature.