外源脱落酸调控下辣椒叶片衰老过程的生理生化变化

Physiological and biochemical changes during leaf senescence under the regulation of exogenous ABA in Capsicum annuum L.

利用外源脱落酸预处理离体辣椒叶片后,进行暗培养模拟衰老,探讨外源脱落酸调控下辣椒叶片衰老和抗氧化酶活性,与叶绿素降解代谢相关酶基因的关系。结果表明,外源脱落酸促使叶片提早黄化,加速叶绿素降解和脂质过氧化物的积累。与清水处理相比,叶片过氧化氢酶活性无显著变化;超氧化物歧化酶活性显著降低,最大差值为74.62U·g^-1;过氧化物酶活性显著提高,最大差值为5.41μg·g^-1。在外源脱落酸诱导下,叶片叶绿素降解代谢相关酶基因CaCLH相对表达量呈下调趋势,最小相对表达量分别为处理前的0.18倍,清水处理的0.14倍;CaPPH、CaPAO和CaRCCR相对表达量呈上调趋势,最大相对表达量分别为处理前的10.25、4.20和10.87倍,清水处理的3.51、5.74和4.76倍;2个衰老相关基因CaCP、CaSGR相对表达量呈上调趋势,最大相对表达量分别为处理前的18.80、32.36倍,清水处理的15.63、22.70倍。

In order to explore the relationship between leaf senescence,antioxidant enzyme activities and chlorophyll degradation-related enzyme genes under the regulation of exogenous ABA in pepper,the detached leaves of pepper were pretreated with exogenous ABA and then put in the dark to simulate senescence.The results show exogenous ABA could accelerate chlorophyll degradation and accumulation of MDA,and make the leaves yellowing earlier.Compared with the control,ABA could promote the decrease of SOD activity and increase of POD activity,and the maximum difference was 74.62 U·g^-1 and 15.51μg·g^-1,respectively.Under the induction of exogenous abscisic acid,the relative expression of chlorophyll degradation and metabolism related enzyme gene CaCLH in leaves showed a downward trend.The minimum relative expression was 0.18 times that before treatment and 0.14 times that after water treatment.The relative expressions of CaPPH,CaPAO and CaRCCR tended to go up,and the maximum relative expressions were 10.25,4.20 and 10.87 times that before treatment,and 3.51,5.74 and 4.76 times that before water treatment,respectively.The relative expressions of CaCP and CaSGR of the two senescence related genes showed an upward trend,and the maximum relative expressions were 18.80 and 32.36 times before treatment,respectively,and 15.63 and 22.70 times that after water treatment.