嫁接辣椒根腐病抗性及其与苯丙烷类物质代谢的关系

通过人工接种根腐病菌,观察不同品种辣椒砧木的发病率和病情指数变化,发现卫士发病晚,发病率低,病情指数最小,说明卫士的抗病性最强。以卫士为砧木,以赤峰特选甜椒(Capsicum annuumL.var.grossum Bailey)为接穗,自根辣椒为对照,研究嫁接对辣椒根腐病抗性及苯丙烷类代谢的影响,结果表明,嫁接植株的发病率和病情指数显著低于对照,高于砧木。接种前砧木与嫁接辣椒根系中的可溶性糖、苯丙氨酸解氨酶(PAL)活性显著高于对照,而叶片中的显著低于对照;酚类物质和木质素含量与对照差别不大。接种后辣椒根系中的可溶性糖含量逐渐降低,PAL活性、酚类物质和木质素含量先逐渐升高,10d后趋于平稳或有所下降。与对照相比,砧木和嫁接植株根系中的PAL活性、可溶性糖、酚类物质和木质素含量均显著增加,叶片中除可溶性糖含量显著降低外,其他指标也有不同程度的增加。说明嫁接可显著提高辣椒的根腐病抗性,其抗病机理与苯丙烷类物质代谢增强密切相关。

Relationship between Root Rot Resistance and Phenylaprapanoid Metabolism in Graft Capsicum

Changes of disease incidence and disease index of root rot in different rootstock varieties of capsicum（Capsicum annuum L.）were investigated by manual inoculation，with ‘Chifengtexuan’（Capsicum annuum L. var. grossum Bailey）as control．The result showed that‘Weishi’was taken sick later，and had the lowest disease incidence and disease index．This indicated it possessed strong disease resistance among the four rootstock varieties and the control．Effect of grafting on root rot resistance and phenylaprapanoid metabolism of capsicum were investigated with‘Chifengtexuan’scion grafted onto‘Weishi’rootstock．The own-root plant was acting as control．The results showed that the disease incidence and disease index of grafted plants were lower than those of CK，but higher than those of rootstock plants．Before inoculation，rootstock and grafted plants showed higher soluble sugar content and PAL activity in roots，but lower soluble sugar content and PAL activity in leaves，compared with the control．Similar phenolic compounds and lignin contents were found in roots and leaves of rootstock，grafted and control plants before inoculation．The soluble sugar content in roots of rootstock，grafted and control plants decreased gradually after inoculation，PAL activity，contents of phenolic compounds and lignin increased at earlier stage，but trended to stabilize or decrease 10 days later．Rootstock and grafted plants showed significantly higher PAL activity and contents of phenolic compounds and lignin in roots and leaves than the control plants．Soluble sugar content in roots of rootstock and grafted plants were also higher than that of the control plants，but in leaves were lower than the control plants．These data indicated that grafting could significantly increase the root rot resistance in capsicum，and its disease resistant mechanism is closely related to the increase of phenylaprapanoid metabolism.