冠菌素诱导棉花叶片脱落的生理机制及其对种子和纤维发育的影响

Normally, cotton plants are picked by hand in China. However, changes in its sociological and economical infrastructure have led to a shortage of workers to pick cotton plants and require mechanical harvesting.Efficient and safe defoliant and its application technology are key process to facilitate cotton mechanical harvesting. Abscission of plant organ can be induced by coronatine which mimics some biological activities of methyl jasmonate, but coronatine-induced cotton defoliation has not been explored. In the present project, microstructure of abscission layer and it's occurred scheduling in different aged leaves would be studied in coronatine-induced cotton defoliation process. Dynamic of chlorophyll degradation, activities of enzymes related to leaf senescence and abscission layer, and hormones would be detected. Expressions of senescence and abscission-specifically gene should be tested by qRT-PCR. Affection of coronatine on cotton seed and fiber qualities would be explored in the field. The results would reveal physiological and molecular mechanism of coronatine-induced cotton defoliation, and provide theoretical basis for creating efficient and safe defoliant which is of great benefit to cotton mechanical harvesting.

我国农业生产劳动力日渐短缺，棉花收获机械化成为必然趋势，而高效、安全的脱叶剂及其应用技术是机械采棉农艺配套技术的核心关键。新型植物生长调节物质冠菌素能引起植物器官脱落，但其诱导棉花叶片脱落及其生理机制未见报道。本项目拟在温室和大田条件下，研究冠菌素诱导棉花不同叶龄叶片离层形成的显微结构特征及其发生的时序性，从叶绿素降解动态、叶片衰老和离层形成相关关键酶的功能表达、激素信号转导等角度，探明冠菌素诱导叶片衰老和脱落的生理机制，分析叶片衰老和脱落特异性基因的表达，阐明离层形成的分子机理，并研究冠菌素对棉花种子质量和纤维品质的影响。研究结果对揭示冠菌素脱叶的生理和分子机理具有重要意义，为创制高效、安全的新型脱叶剂提供理论依据，对推动我国棉花收获机械化进程具有重要的理论意义和应用价值。

棉花生产全程机械化特别是机械收获关系到我国棉花产业的可持续发展，而建立高效、安全的脱叶催熟技术是实现机械采棉的前提和关键。探讨脱叶剂调控棉花叶片脱落的生理与分子机制对创制新型脱叶催熟剂具有重要的理论和实际意义。本项目从“形态—生理—分子”的角度入手，揭示了不同叶龄叶片对噻苯隆等脱叶剂的响应特征；重点研究了冠菌素和噻苯隆诱导棉花离层形成过程中乙烯合成与信号转导相关基因 (GhACS、GhACO、GhEIN3、GhERFs)、细胞壁水解相关基因(GhCEL、GhPG)的表达及相关酶活性变化，阐明了冠菌素和噻苯隆等脱叶剂诱导棉花叶片脱落的生理与分子机制；研究了冠菌素及其复配剂在田间的脱叶催熟效果，并阐明了冠菌素和噻苯隆对棉花种子质量和纤维品质的影响。