豆梨和杜梨叶片多胺代谢与高温胁迫关系的探讨

Research on endogenous polyamine metabolism in leaves of Pyrus calleryana Dcne and P.betulaefolia Bunge with high temperature stress

以杜梨和豆梨实生苗为试材,比较45℃温度处理下两种砧木叶片落叶率的变化,以及30和45℃温度处理后供试材料叶片内源多胺种类、形态和含量变化。结果表明:豆梨达到65%落叶率的时间比杜梨早8d;两种砧木叶片中均存在腐胺、己二胺、亚精胺和精胺;杜梨叶片游离态和结合态腐胺含量显著高于豆梨;处理16d后,豆梨游离态腐胺含量快速下降至10nmol·g-1以下,与平均落叶率达到65%所需时间一致。表明多胺代谢变化与供试材料的耐高温胁迫能力有密切关系,高温胁迫使得两种砧木叶片游离态和结合态腐胺含量逐步下降,并且导致游离态亚精胺和精胺含量增加,其中杜梨增加幅度更大。

Pyrus calleryana and P.betulaefolia were used as experimental materials in this article.The changes in defoliation rate of two rootstocks under 45 ℃ were compared,and content changes of free and conjugated polyamines in leaves of two rootstocks under 30 ℃ and 45 ℃ were analyzed.The results showed that the time when defoliation rate reached 65% in P.calleryana was 8 d earlier than that in P.betulaefolia.Four kinds of polyamines,free and conjugated putrescine（Put）,hexanediamine（Hex）,spermidine（Spm）,spermine（Spm） existed in leaves of the two rootstocks,and content of free and conjugated Put in P.betulaefolia was higher than that in P.calleryana.It took 16 d under 45 ℃ treatment when free Put content in P.calleryana quickly dropped to 10 nmol·g-1（FW）.The time was in accord with the number of days when defoliation rate of P.calleryana arrived to 65%.The research indicated that high temperature tolerance of different experiment materials was influenced by the polyamine metabolism.High temperature stress could gradually reduce free and conjugated Put content and induce free Spd and Spm content to increase during processing in the two rootstocks.Spd and Spm content increased more in P.betulaefolia than that in P.calleryana.