三唑配合物的植物生长调节特性和盐胁迫应答机制研究

Triazoles have been characterized as broad-spectrum fungicides and plant growth regulators. Compared to virgin triazole, triazole-metal complexes have been demonstrated expanded to have spectrum against fungi and better controlled-release property. In this project, the influence of highly efficient triazole-metal complexes (namely copper-, silver- and zinc- compounds of tebuconazole, hexaconazole, triadimenol, propiconazole and difenoconazole) on the plant growth regulation, salt stress tolerance and molecular response mechanism will be investigated. .To explore regulation ability of the triazole-metal complexes for plant growth, a number of physiological and biochemical parameters, including chlorophyll fluorescence, photosynthetic rates, total foliar chlorophyll, foliar proline concentration, as well as superoxide dismutase and catalase activities will be examined. Proline is an important osmoprotectant for plant cells under osmotic stress imposed by NaCl, the effect of triazole-metal on the expression of the genes encoding Δ1-pyrroline-5-carboxylate synthetase (P5CS) and Δ1-pyrroline-5-carboxylate reductase (PC5R) will be investigated by RT-PCR analysis. Two-dimensional gel electrophresis experiments will be conducted to analyze the differential expression of proteins in response to osmotic stress imposed by NaCl. Base on these experiments, the impacts of triazole-metal complexes on the molecular metabolism of salt stress response will be described, and the correlations between functional complexes and the plant growth regulation will be built up. Meanwhile, the relationship between compound structure and functionality is cleared. New functional triazole-metal compounds with high fungicide activity and plant growth regulation can be screened and optimized. Thus valuable references for the research and development of novel agriculture chemicals will be provided.

三唑类杀菌剂兼具杀菌和植物生长调节功能，三唑金属配合物在抑菌效果和缓释性能上优于三唑配体。本研究以目前大量使用的、主流的三唑类杀菌剂（戊唑醇、己唑醇、三唑醇、丙环唑和苯醚甲环唑）银、铜和锌配合物为研究对象，针对其调节植物生长，增强植物的抗盐性能及分子响应机制进行研究。通过对三唑类金属配合物处理的小麦生长形态、生理和生化指标的测定，为确定配合物的植物生长调节功能提供实验基础；检测三唑类金属配合物对小麦植株在盐胁迫下抗氧化潜能和脯氨酸合成酶基因以及特异性蛋白表达的变化，明晰三唑类金属配合物对植物响应盐胁迫的应答机制；关联配合物结构与植物生长调节作用，总结配合物结构与功能复合的相关规律，优化出具有高的抑菌活性和良好生物调节功能的新型三唑类功能配合物，为新型农药的研制与开发提供相应的科学依据。

三唑类杀菌剂在农业生产中兼具杀菌和植物生长调节功能。三唑环具有强的配位能力和丰富的配位模式，易和过渡金属配位。本项目以苯醚甲环唑、三环唑、己唑醇为配体合成铜配合物。使用红外单晶-X射线衍射等手段表征获知其结构。所得配合物均能降低小麦幼苗株高，促进叶绿素合成，表现优于配体的植物生长调节活性。其中己唑醇硝酸铜配合物作用好于其他铜配合物，以己唑醇铜配合物浸种处理小麦种子，测定幼苗生理指标，并观察NaCl胁迫对小麦生理及抗性相关基因的表达差异，结果表明：60 umol•L-1己唑醇硝酸铜配合物处理后小麦幼苗植株延缓生长，光合作用增强，叶绿素含量和可溶性蛋白含量增加。同时配合物显著提高植株体内抗氧化物酶SOD、POD活性，增加脯氨酸含量，显著抑制MDA积累，表现抗性保护能力。进而，100 mmol•L-1 NaCl 胁迫幼苗24 h，己唑醇铜配合物持续增加POD和SOD活性，刺激幼苗脯氨酸积累，最大达到NaCl组的1.62倍，明显抑制MDA积累，其含量前6 h呈降低趋势。胁迫3 ~ 24 h脯氨酸合成酶基因p5cr、p5cs表达量显著上升；Na+/H+逆向转运蛋白基因sos1表达量在24 h胁迫内保持稳定，nhexl1c表达量持续升高，所得结果表明配合物可提高植物抗氧化潜能，积累渗透调节物，提高细胞内离子平衡等抗性机制，提高植株耐盐性。采用平皿菌丝生长速率法检测了三唑铜配合物对植物真菌病害生物活性的影响发现，配合物对番茄灰霉病菌，棉花枯萎病菌，小麦赤霉病菌，苹果轮纹病菌都有抑制作用，且作用能力高于配体；当配体相同，不同铜离子配合物对小麦赤霉菌的抑菌效率相当；尝试等温微量热法研究配合物抑制农作物病原真菌生长的代谢作用研究，通过检测301.15K时加入不同浓度的苯醚甲环唑硝酸铜配合物药液时小麦赤霉菌的生长代谢热谱图，计算拟合出生长速率常数k、总放热量Qtotal和抑制率I等热动力学常数，实验结果抑制率I与浓度c紧密相关，并且计算所得抑制率与平皿菌丝生长速率法结果相符，从中探索新的抑菌检测评价办法。试验了己唑醇硝酸铜配合物和4-(1H-1,2,4-三唑-1-亚甲基)苯甲酸三种金属配合物对质粒DNA分子的结合、切割作用，初步鉴定金属配合物的核酶作用。本项目从多方面探讨结构和生物活性的构效关系，实验结果对三唑类杀菌剂金属配合物的合成研究以及新型农药开发具有重要意义。