香橼不同品系耐寒性的研究

 以24个果实性状优良的香橼（Citrus medica L.）品系为试材，采用田间鉴定法、细胞膜透性鉴定法，评价其耐寒性差异，并以耐寒性强、中、弱3类有代表性的10个品系进行人工低温处理，进一步研究其耐寒生理特性。结果表明：越冬期间24个品系寒害指数范围为2.00 ~ 3.40，半致死温度（LT50）范围为﹣14.84 ~﹣7.07 ℃。分别根据寒害指数和LT₅₀进行聚类分析，评价了24个香橼品系耐寒性强弱，其中，耐寒性强的品系有春江4#、春江5#、春江6#、新世纪9#、新世纪10#、香橼4#；其次为春江1#、春江2#、春江3#、春江8#、香橼1#、香橼2#、香橼5#、香橼6#、香橼7#、新世纪1#、新世纪3#、新世纪4#、新世纪5#、新世纪6#、新世纪7#、新世纪8#；耐寒性弱的品系为春江7#、新世纪2#。随处理温度降低，10个香橼品系叶片的丙二醛（MDA）、脯氨酸（Pro）、可溶性蛋白质含量及超氧化物歧化酶（SOD）活性总体均表现为先上升而后下降的趋势，其中耐寒性强的品系MDA含量低，Pro、可溶性蛋白质含量及SOD活性高；反之，耐寒性弱的品系MDA含量高，Pro、可溶性蛋白质含量及SOD活性低。

The Study on Cold Resistance of Different Citrus medica Strains

The cold resistance of 24 Citrus medica strains which have favorable fruit characters was studied by field identification,cell membrane permeability research and cluster analysis;The cold resistant physiological property of ten strains which belong to high cold resistance,medium cold resistance and poor cold resistance respectively were studied under low temperature stress. The results showed that the index of chilling injury was intervenient 2.00 and 3.40,and the range of semilethal temperature(LT50) was–14.84 to–7.07 ℃. The cold resistance of 24 Citrus medica strains was evaluated by cluster analysis based on index of chilling injury and LT50,Chunjiang 4,Chunjiang 5,Chunjiang 6,Xinshiji 9,Xinshiji 10 and Xiangyuan 4 had high cold resistance;Chunjiang 1,Chunjiang 2,Chunjiang 3,Chunjiang 8, Xiangyuan 1,Xiangyuan 2,Xiangyuan 5,Xiangyuan 6,Xiangyuan 7,Xinshiji 1,Xinshiji 3,Xinshiji 4,Xinshiji 5,Xinshiji 6,Xinshiji 7 and Xinshiji 8 had medium cold resistance;Chunjiang 7 and Xinshiji 2 had poor cold resistance. With the temperature decreasing,the contents of MDA,proline and soluble protein,the activities of SOD increased at first and then decreased. In high cold resistance strains,the contents of MDA was low,the contents of proline,soluble protein,and the activities of SOD were high; On the contrary,in low cold resistance strains,the contents of MDA was high,the contents of proline, soluble protein and the activities of SOD were low.