高温条件下澳洲坚果叶片黄化的生理特性

为探明高温条件下澳洲坚果叶片黄化的生理特性,以澳洲坚果品种‘HAES344’的叶片为试材,对湛江地区2019年6月份的气温进行调查,初步研究叶片的一些生理生化指标的变化。结果表明：湛江地区6月份的昼/夜平均温度高达33.6 ℃/28.5 ℃,特别是遭遇了3次较长时间的温度高峰期,其每日的昼/夜平均温度均超过35 ℃/29 ℃,可能导致了黄化叶片发生。随着叶片黄化程度的加深,叶片的SPAD值、SOD活性以及叶绿素（Chla+Chlb、Chla与Chlb）含量及其荧光参数（F_o、F_m与F_v / F_m）均显著下降,而丙二醛（MDA）和过氧化氢（H₂O₂）含量以及POD活性均显著升高,CAT活性则保持相对稳定。但同正常叶片相比,黄化叶片的SPAD值、叶绿素含量及其荧光参数均显著降低,而MDA和H₂O₂含量以及POD与CAT活性却显著升高。相关性分析结果表明,F_o、F_m、F_v / F_m、MDA、Chla、CAT、SOD、POD等8个指标间存在一定的显著相关性。该结果对于了解澳洲坚果叶片黄化具有参考价值,为进一步开展相关分子机理研究奠定了基础。

Preliminary Study on Physiological Characteristics of Macadamia Leaf Etiolation under High Temperature

In order to find the physiological characteristics of macadamia leaf etiolation under high temperature,taking the leaves of‘HAES344’macadamia as the test materials,the trial studied the temperature of June,2019 in Zhanjiang area,and the changes of several related physiological indexes in the leaves were preliminarily investigated.The results showed that the average day/night temperature in June was as high as 33.6℃/28.5℃,especially the three long temperature peaks whose daily day/night average temperature exceeded 35℃/29℃,which probably caused the yellowing of the leaves.With the intensification of leaf etiolation,the SPAD value,SOD activity,chlorophyll(Chla+Chlab,Chla and Chlb)content and its fluorescence parameters(F_o,F_m and F_v/F_m)of the leaves decreased significantly,while the contents of malondialdehyde(MDA)and H₂O₂ and the activity of POD increased obviously,but the CAT activity remained relatively stable.However,compared with normal leaves,the SPAD value,chlorophyll content and fluorescence parameters of the etiolation leaves were significantly reduced,while MDA and H₂O₂ contents and POD and CAT activities significantly increased.The correlation analysis showed that there was a certain significant correlation among F_o,F_m,F_v/F_m,MDA,Chla,CAT,SOD and POD.The results would provide the reference value in understanding the yellowing leaves of macadamia and establishing a foundation for further research on relevant molecular mechanism.