4个北美冬青品种苗对低温胁迫的生理响应及抗寒性比较

【目的】探究不同品种北美冬青的抗寒性,为北美冬青新品种苗木的推广和研究提供参考。 【方法】以4个引进的北美冬青(Ilex verticillata)品种‘Red Sprite’、‘Gray’、‘Oosterwijk’和‘Winter Gold’2年生扦插苗枝条为试验材料,通过0、-7、-17、-27 ℃低温逐级降温分别处理24 h,研究4个品种北美冬青对低温胁迫的生理响应及抗寒性差异。【结果】4个品种的相对电导率和MDA(丙二醛)含量均随着温度的降低而增加,都在-27 ℃时达到最高。‘Red Sprite’、‘Gray’、‘Oosterwijk’和‘Winter Gold’的低温半致死温度(LT50)分别为-26.38、-24.26、-29.19和-20.04 ℃。随着处理温度的降低,渗透调节物质可溶性糖、可溶性蛋白及脯氨酸含量在处理温度>-17 ℃时都出现增加(‘Winter Gold’的可溶性糖含量最高点在-27 ℃),但各品种各指标峰值出现的温度点不同。H₂O₂含量与SOD(超氧化物歧化酶)、POD(过氧化物酶)酶活性同时在-17 ℃时达到最高,而CAT(过氧化氢酶) 酶活性在-27 ℃时急剧增加,说明3种酶对活性氧的清除存在温度效应。【结论】4个品种中‘Oosterwijk’与‘Gray’的抗寒性在整体水平上强于其他2个品种,通过隶属函数和权重综合分析,得出4个北美冬青品种的抗寒能力由强到弱依次为:‘Oosterwijk’、‘Gray’、‘Red Sprite’、‘Winter Gold’。

Physiological responses of seedlings of four Ilex verticillata varieties to low temperature stress and a comparison of their cold resistance

【Objective】 Investigating the cold resistance of four Ilex verticillata varieties provides a guidance and a reference for seedling promotion and research of these new varieties. 【Method】The physiological responses of four I. verticillata varieties (‘Red Sprite’, ‘Gray’, ‘Oosterwijk’ and ‘Winter Gold’) to low temperature stress were studied by exposing their branches to temperature treatments of 0 ℃, -7 ℃, -17 ℃ and -27 ℃ for 24 h. Cold resistance of the four varieties was compared. 【Result】The relative conductivity and malondialdehyde content of the four varieties increased with a decrease in temperature, and reached a maximum at -27 ℃. The low temperature semi-lethal temperatures for ‘Red Sprite’, ‘Gray’, ‘Oosterwijk’ and ‘Winter Gold’ were -26.38 ℃, -24.26 ℃, -29.19 ℃ and -20.04 ℃, respectively. Associated with the decrease in treatment temperature, there was an increase in the soluble sugar, soluble protein, and proline contents and osmotic regulators at > -17 ℃ (the soluble sugar of ‘Winter Gold’ reached its highest point at -27 ℃); however, the appearance of peak temperature for each variety was different. The H₂O₂ content and the activity of superoxide dismutase and peroxidase all reached their highest value at -17 ℃. The activity of the catalase enzyme increased sharply at -27 ℃, indicating that the three enzymes had a temperature effect on the scavenging of reactive oxygen species.【Conclusion】The cold resistance of ‘Oosterwijk’ and ‘Gray’ was stronger than that of the other two varieties as a whole. Through the comprehensive analysis of membership function and weight value, the order of cold resistance of the four I. verticillata varieties, from strong to weak was: ‘Oosterwijk’ > ‘Gray’ > ‘Red Sprite’ > ‘Winter Gold’.