5个常绿阔叶园林树种对低温变化的生理响应

以南京地区引种的5个常绿阔叶园林树种为研究对象，探讨各树种叶片的膜透性、可溶性糖含量、POD酶活性、多胺含量等生理生化指标对低温变化的响应。结果表明：(1)在测定期内，除乐东拟单性木兰外，其余4个树种叶片的细胞膜透性均表现出先升高后降低再升高的变化趋势。浙江樟的质膜透性相对比较稳定，红花木莲变幅最大。(2)5个树种叶片可溶性糖含量，游离脯氨酸含量，叶片POD活性，腐胺(Put)、亚精胺(Spd)及精胺(Spm)含量与多胺总含量等均呈现先上升后下降趋势。(3)在最低气温到来前叶片可溶性糖含量调整到最大值；随低温时间延长和低温强度加剧各树种叶片中游离脯氨酸含量逐渐积累，变化幅度最大的是秃瓣杜英和乐东拟单性木兰；乐东拟单性木兰POD活性最大值出现较早且稳定，浙江樟POD活性较高且稳定，红花木莲与乐昌含笑的POD活性变化不稳定。(4)浙江樟和乐东拟单性木兰各月低温半致死温度(LT50)均较低。除浙江樟外，其他树种的LT50与采样前10天的日平均最低气温显著相关。(5)除乐昌含笑外，其他树种通过调节多胺含量适应外界低温变化。

Physiological responses of five evergreen broadleaved ornamental tree species to low temperature variations during winter season

A study was conducted on responses of some physiological and biochemical indices,such as leaf electrolyte leakage of cell membrane,soluble sugars,free praline,POD and polyamine in five evergreen broadleaved tree species introduced from other provinces and cultivated in Nanjing,to variations of low temperature during winter season.The main results were described as follows:(1) The trend was represented that the electrolyte leakage of leaf cell membrane of all five tree species except Parakmeria lotungensis i...