中文摘要：

【目的】研究外源茉莉酸处理玉米地上部（或地下部）是否会系统性地影响到地下部（或地上部）的防御作用，探讨对玉米防御反应的影响是否与玉米的茉莉酸信号途径相关。【方法】以“高油115”玉米为材料，采用化学物质分析和基因表达分析方法，通过茉莉酸合成途径抑制剂水杨苷异羟肟酸（salicylhydroxamicacid，SHAM）预处理的对比实验，研究茉莉酸在玉米地上部与地下部诱导防御反应中的作用。【结果】外源茉莉酸处理玉米地上部能系统地影响到地下部防御物质的含量及防御相关基因的表达，处理地下部也能系统性地影响地上部。茉莉酸处理地上部以及茉莉酸处理地下部对玉米叶片防御反应的诱导均强于根系，而茉莉酸处理地上部对玉米同一部位的诱导作用强于茉莉酸处理地下部。茉莉酸处理地上部是通过激活茉莉酸自身合成来诱导叶片Bxl、Bx9、PAL、PR-1、MPI、FPS和TPS基因的表达、增加叶片丁布含量及降低咖啡酸含量的，同时系统诱导根系Bx6,Bx9、PAL和朋吻基因表达、增加香豆酸和咖啡酸含量以及降低丁香酸含量则与激活地上部茉莉酸自身合成相关。茉莉酸处理玉米地下部对根系Bx6,PR-2a和MPI基因表达的诱导以及总酚含量的降低也是通过激活茉莉酸自身合成来实现的，对地上部（叶片）防御相关基因Bx6、Bx9、PAL、FPS和TPS表达的间接诱导作用以及丁布、香豆酸、咖啡酸和丁香酸的增加作用则与激活地下部茉莉酸自身合成相关。【结论】外源茉莉酸处理地上部能系统影响到地下部的防御反应，反之亦然；茉莉酸对玉米的诱导防御以叶片为主；茉莉酸处理地上部对玉米的诱导作用强于地下部处理；茉莉酸处理玉米的地上部或地下部，对处理部位防御作用的影响主要是通过激活玉米体内茉莉酸自身合成起作用的；茉莉酸处理玉米对非?

英文摘要：

[Objective] The objective of this investigation was to study whether exogenous jasmonic acid treatment to the aboveground （or underground） could systemically affect the defense response of underground （or aboveground） in corn, and to find out whether the effect of defense response was related with the signal transduction ofjasmonic acid. [Method] Both chemical analysis and gene expression analysis were employed to study the role of jasmonic acid on the induced defense response of aboveground and underground in corn cultivar Gaoyou 115 by comparative studies prior to using the inhibitor salicylhydroxamic acid （SHAM） in jasmonic acid signaling pathway. [Result] The results showed that exogenous jasmonic acid applied to the aboveground of corn could systemically affect the content of defense chemicals and the expression of defense-related genes of underground, and vice versa. Jasmonic acid treatment to either aboveground or underground could result in much more obvious defense response in the leaves as compared to the roots, while jasmonic acid treatment to the aboveground could lead to much stronger induction in the same parts of corn than to the underground. Through activating the synthesis of jasmonic acid itself, aboveground application ofjasmonia acid could induce the expression ofBxl, Bx9, PAL, PR-1, MPI, FPS and TPS genes, increase DIMBOA content and decrease caffeic acid content in leaves; on the other hand, the systematic induction of gene expression of Bx6, Bx9, PAL and PR-2a, increase of contents of coumaric acid and caffeic acid, and decrease of syringic acid content in the roots were related with the activating ofjasmonic acid synthesis in the aboveground. Likewise, after the underground of corn was treated with jasmonic acid, the induced expression of Bx6, PR-2a and MPI genes as well as the decrease of total phenolics in the roots were achieved through activating the synthesis of jasmonic acid itself; while the indirect induction of expression of Bx6, Bx9, PAL, FPS and TPS genes as well as