6个枇杷品种对低温胁迫的生理响应及抗寒性评价

为探究枇杷对低温胁迫的生理响应,综合评价不同枇杷品种的抗寒能力,本研究以6个枇杷品种为试验材料,研究了低温胁迫对枇杷幼果种胚相对电导率、丙二醛、脯氨酸、可溶性糖和可溶性蛋白含量的变化。结果表明：随处理温度的降低,各枇杷品种幼果种胚相对电导率REC呈现“小-大-小”的“S”型曲线变化,结合Logistic方程得出不同枇杷品种种胚的半致死温度介于-4.759 ~ -2.73 ℃之间,其中,WT（白肉芽变）幼果种胚的半致死温度最低,大五星幼果种胚的半致死温度最高;6个枇杷品种的脯氨酸（Pro）含量、丙二醛（MDA）含量随低温胁迫均呈现出先升高后降低的倒“V”型变化趋势,但增幅和达到峰值的时间点不同;可溶性糖和可溶性蛋白含量呈逐渐增加的趋势,均在-5 ℃时达到最大值;通过隶属函数综合分析,得出6个枇杷品种材料的抗寒能力表现为WT（白肉芽变）>冠玉>宁海白>龙泉5号>早钟6号>大五星。综上所述,WT（白肉芽变）对低温的胁迫具有较强的适应性,抗寒能力强;半致死温度LT₅₀结合隶属函数法的综合评价能准确鉴定枇杷品种的抗寒性。本研究为枇杷抗寒种质的筛选及寻找提高抗寒性的新途径提供理论依据。

Physiological Responses and Evaluation of Cold Resistance under Cold Stress for Six Varieties of Eriobotrya japonica (Thunb.)

In order to investigate the physiological response and comprehensively assess cold resistance of different varieties under low stress, six varieties of Eriobotrya japonica (Thunb.) under cold stress were analyzed to determine the dynamic changes of relative electric conductivity (REC), malonadehyde (MDA), free proline (Pro), soluble sugar and soluble protein. The results showed that the relative electric conductivity (REC) in vitro seed embryos of young fruits of six loquat varieties presented an ‘S’ type curve change pattern as temperature decreased. The semi-lethal temperature of the six loquat varieties ranging from -4.759 to -2.73 ℃ using logistic equation, the semi-lethal temperature of white bud mutation was the highest and the Dawuxing loquat was the lowest among them. The contents of free proline (Pro) and malonadehyde (MDA) presented an inverted “V” type curve change pattern with the different time point of reaching the peak, which generally increased first and then decreased under cold stress. Furthermore, the soluble sugar and soluble protein increased as temperature decreased with the maximum value was obtained at the time of 24 h when treated at -5 ℃. The cold resistance ability of the six loquat varieties evaluated as WT (white bud mutation) > Guanyu > Ninghaibai > Longquan No.5 > Zaozhong No.6 > Dawuxing. In conclusion, the WT (white bud mutation) showed strong adaptability to low temperature stress and strong cold resistance. The median-lethal temperature combined with comprehensive evaluation based on subordinate function analysis could accurately identify the cold resistance of loquat varieties, which would provide a theoretical foundation and reference for screening of cold materials and looking for a new approach to increase the cold hardiness of loquat.