Physiological and Biochemical Responses of Pinus massoniana Superior Provenance Seedlings under Artificial Low Temperature Stress | 马尾松优良种源苗木对人工低温胁迫的生理生化反应

chinois. 以不同抗寒能力的2个马尾松优良种源针叶为材料，测定其叶绿素含量、可溶性糖含量、可溶性蛋白质含量、脯氨酸含量、内源保护酶系统以及膜脂反应产物等生化指标，分析各指标与抗寒能力的关系。结果表明：抗寒性强的种源具有较强的光合代谢能力，叶绿素含量随温度的下降呈现总体升高趋势；根据4和0℃时可溶性糖和游离脯氨酸含量的变化趋势可判断抗寒性大小，正值较强负值较弱；可溶性蛋白质含量变化幅度大则抗寒能力较差；SOD对0℃以上低温敏感，属冷害敏感型调节酶，0℃以上低温前达到的活性越高，持续的时间越长，抗寒性越强；POD对0℃以下低温敏感，属冻害型调节酶，0oC以下低温时活性升高越快，持续时间越长，抗寒性越强。SOD的启动时间早，POD启动晚。MDA含量越低，峰值出现的时间越晚其抗寒性越强。以上6个指标在低温逆境胁迫下相互协调，共同发生作用。

anglais. The needles of two superior provenances, with different cold tolerance, of Pinus massoniana were used as the materials to measure photosynthetic metabolism, nitrogen metabolism, endogenous protective enzyme system and membrane lipid reaction, and to examine relationships between these physiological and biochemical indices and the cold resistance. Chlorophyll content generally increased with the decrease of temperature, indicating a highly cold - resistant P. massoniana trees associated with high capability of photosynthesis. The changing trend of soluble sugar and proline contents at 0 ℃ and 4 ℃ temperatures could be used to estimate the cold resistance of P. massoniana. Their positive and negative values respectively represented strong and poor cold - resistance. Soluble protein content was inversely correlated with the cold resistance, and the higher content associated with poorer cold -resistance. Superoxide dismutase （SOD） was a chilling - sensitive regulating enzyme and peroxidase （POD） was a freezing - sensitive regulating enzyme. Trees had stronger resistance to cold when their SOD as well as POD activities increased and could remain at high level for longer time under the stress of low temperature. Under the stress, the activity of SOD started earlier than that of POD. However, trees with a stronger cold - resistance had lower content of malondialdehyde （MDA） and their MDA peak level arrived later. The six indices measured in the current study interacted with each other under the stress of low temperature.