Abstract: To analyze the cold resistance of Parakmeria lotungensis, its membrane leakage, contents of dissociative praline, soluble sugar, POD and chlorophyll were investigated under the conditions of natural low-temperature in Nanjing. The major results were as follows: In study period, the trends of contents of chlorophyll were similar to the monthly even low temperature with a small radian. The membrane leakage continuously improved. The contents of soluble sugar was negatively correlative with the monthly even low temperature during the over-wintering. The contents of dissociative praline and the activity of POD firstly increased and then decreased.

Key words: Parakmeria lotungensis, natural low temperature, physiological characteristics, cold resistance

摘要： 通过对乐东拟单性木兰在南京自然降温过程中质膜相对透性、渗透调节物含量、POD活性、叶绿素含量等抗寒性指标的测定与分析，结果表明：测定期间乐东拟单性木兰叶片叶绿素总量与月平均温度呈现相似的变化规律；质膜透性不断增大；可溶性糖含量与月平均最低温度呈显著相关，游离脯氨酸、POD活性总体呈现低温诱导的规律，表现为先升高再降低的变化趋势。

关键词: 乐东拟单性木兰, 自然低温, 生理学特性, 抗寒性