嫁接对辣椒次生代谢的影响及其与青枯病抗性的关系

Effect of Grafting on Secondary Metabolism and Its Relationship with Bacterial Wilt Resistance in Pepper

【目的】探讨嫁接辣椒酚酸类物质代谢在提高青枯病抗性中的作用。【方法】以‘富根卫士’辣椒为砧木,以‘新丰2号’为接穗嫁接,自根嫁接辣椒为对照(CK),通过人工接种青枯假单胞杆菌(Ralstonia sdanacearumE.F.Smith)研究嫁接与自根辣椒电解质渗漏率(EL)和过氧化氢(H2O2)含量、酚酸类物质及其相关酶活性的变化。【结果】随着接种后时间的延长,嫁接与自根辣椒的EL快速增加,但嫁接辣椒的EL升高幅度显著小于自根的;接种初期,嫁接辣椒叶片与根系中的H2O2含量显著高于自根的,而6—8 d后显著低于自根的。与自根辣椒相比,嫁接辣椒的香草醛、水杨酸、木质素含量及苯丙氨酸解氨酶(PAL)和多酚氧化酶(PPO)活性均较高。【结论】嫁接辣椒次生代谢增强,酚酸类物质增多是其抗病性增强的重要原因,水杨酸和香草醛在提高嫁接辣椒青枯病抗性中发挥主要作用。

[Objective] The purpose of this study is to elucidate the phenolic acids metabolism in grafted pepper and its function in improvement of bacterial wilt resistancei＇ [Method] Changes of the electrolyte leakage （EL）, hydrongen peroxide （H202） content, phenolic acids and activities of the related enzymes in grafted （＇Xinfeng 2＇ scion grafted onto ＇Weishi＇） and own-root plants （＇Xinfeng 2＇, control） of pepper were investigated by manual inoculation. [Result] The results showed that the EL in leaves of grafted and own-root peppers all increased gradually after inoculation, whereas the increasing range in grafted plants was less than that in control plants. Grafted pepper showed an increase in H202 contents in leaves and roots at early stage, but a decrease after 6-8 days of inoculation. Compared with the control plants, grafted plants showed higher contents of vaniUin, salicylic acid and lignin, and activities of phenylalanine ammonia lyase （PAL） and polyphenoloxidase （PPO）. [Conclusion] The increased phenolic acids synthesis and secretion in grafted plants is one of the important reasons for enhancement in disease resistance. The salicylic acid and vanillin played the major role in improving disease resistance of grafted pepper plants.