草甘膦对杂草残株化感作用的影响及其次生代谢机理

广泛施用草甘膦控制杂草将对农田生态过程产生深远影响，其产生的大量杂草残株分解会对作物生长产生化感干扰作用，但尚不清楚该过程机理。本项目以草甘膦的作用位点与植物化感物质合成途径的结合点——莽草酸—分支酸途径为突破口，研究草甘膦通过影响杂草次生代谢与残株化感物质成分进而干扰作物生长和根际微生物群落的过程机理。项目以具强化感作用的加拿大一枝黄花为研究对象，设置草甘膦浓度梯度处理，量化草甘膦处理后杂草残株对作物、根际微生物化感活性的变化，并从残株和根系分泌物中提取和鉴定引起化感活性变化的特征次生物质；通过阐明草甘膦对莽草酸—分支酸途径关键酶活性和主要代谢组分含量的影响，分析推断上述特征化感物质的代谢来源，明确受草甘膦影响的关键代谢步骤和次生物质。项目整合研究杂草残株化感作用—化感物质—次生代谢的协同性和相关性，为深入研究草甘膦对农田生态过程的影响，评估其对作物生长的间接干扰效应和合理施用提供依据。

Long-lasting excessive glyphosate application may interfere crop growth and rhizosphere microorganism community via its effects on weeds residues allelopathy. Experiments have showed that glyphosate affected allelopathy of some plant species significantly. However, the mechanisms underlying this altered allelopathy are still poorly understood. We here hypothesize that “glyphosate may alter plant allelopathy via effects on Shikimate-Chorimate pathway, which is a major source of allleopathic substances” To test this hypothesis, the project will utilize Solidago canandensis with strong allelopthy activity as a model plant species o study the effects of glyphsoate on its growth, allelopathy activity and Shikimate-Chorimate pathway. The characteristics substances in the residues and in the root exudates affected by glyphosate will be identified and its source will be inferred from the the effects of glyphosate on Shikimate-Chorimate pathway. The key enzymes and metabolites group will be related to allelopathy activity. This project will reveal a mechanism for glyphosate to indirectly interfere crops growth via its effects on weeds shikimate-Chorimate pathway and alllelopathy activity. Therefore it serves to provide a basis to optimize glyphosate application and reduce crop growth loss.