近年来的研究表明，H2O2具有信号分子的作用，通过诱导许多抗逆相关基因表达，以提高植物对环境胁迫的抗性。课题组前期研究发现嫁接黄瓜耐盐性受H2O2信号的调控，但是具体机制尚不明晰。本申请项目拟以自嫁黄瓜和南瓜砧木嫁接黄瓜为材料，通过化学抑制剂以及外施H2O2来构建不同H2O2水平植株。利用组织化学染色、qRT-PCR等技术，分析嫁接黄瓜H2O2含量以及NADPH氧化酶在H2O2产生中的作用；研究嫁接黄瓜H2O2信号相关的MAPK、Ca2+、ABA信号途径及基因表达的变化，与抗氧化和Na+外排等耐盐生理生化参数进行相关分析，获得重要的H2O2信号途径和基因。在此基础上，利用药理学实验、以及转基因技术等，鉴定出H2O2调控嫁接黄瓜耐盐性的关键信号作用途径和基因。本课题完成后可揭示H2O2调控嫁接黄瓜耐盐性的信号转导机制，丰富园艺作物砧穗互作的基本理论和植物的耐盐机理，促进嫁接黄瓜的耐盐栽培。

H2O2 has been demonstrated as a stress signal in plants in recent years, which can induce expression of many stress tolerance genes and enhance plant tolerance to environmental stresses. We found that salt tolerance of grafted cucumber was mediated by H2O2 signal in previous studies. However, the regulated signal pathway was unclear. Using self- grafted and pumpkin- grafted cucumber as materials, the plants with different H2O2 levels was obtained by chemical inhibitor and exogenous H2O2 application. The H2O2 content of grafted cucumber and role of NADPH oxidase in the production of H2O2 were analyzed through histochemical staining and qRT-PCR techniques. The root Na+ exclusion and antioxidant system of grafted cucumber under salt stress were analyzed. Meanwhile, the MAPK, Ca2+ and ABA signalling pathway of grafted cucumber were analyzed, and were analyzed with salt tolerance related physiological and biochemical parameters. The important signalling pathway and genes involved in H2O2 signalling mediated salt tolerance can be obtained. Based on this evidence, the key signalling pathway and genes involved in H2O2 signalling mediated salt tolerance of grafted cucumber will be confirmed by pharmacology and transgenic approaches. The implementation of this project will provide signal transduction mechanism for the H2O2 mediated salt tolerance of cucumber and enrich the knowledge of rootstock-scion interaction of horticultural crops and plant salt tolerance mechanism, and will promote the cultivation of grafted cucumber under salt stress.