化学封顶棉花二次生长的生理效应与诱发机制

Artificial topping is the key factors limiting Xinjiang cotton mechanized cultivation, chemical topping is an effective approach to solve the problem. However, secondary growth of cotton with chemical topping often appears over a period of time, which has become a major bottleneck restricting the technology popularization and application. Secondary growth of chemical topping cotton will be a research object in this project. The secondary growth should belong to a special type of spindling or overgrowth. The field experiment and laboratory analysis will be both used to study the growth regularity and morphological characteristics, clarify the effects of secondary growth on the whole plant and organs of cotton in different development stages, related to reveal the relationship between secondary growth and variety, moisture, nitrogen fertilizer, DPC and population structure, and between other plurality of cultivation factors. The hormone physiological, biochemical change, nutrient distribution and root morphological parameters will be included, to reveal the physiological and mechanism effects of secondary growth of cotton with chemical topping. Revealing two growth induced. The results will be beneficial to formulate the reasonable application of chemical topping technology on cotton cultivation, and will be beneficial to make the reasonable control measures. The problem of secondary growth maybe effectively solved by referencing the research achievements, and the new measures by which cotton in Xinjiang could obtained high yield and quality, and also the development of topping agent will benefit from the foundation theory and technology of this study.

人工打顶是限制新疆棉花全程机械化栽培的重大难题，化学封顶是解决该问题的有效途径。然而，在封顶一段时间后时常发生二次生长，成为制约该项技术推广应用的主要瓶颈。本项目以化学封顶棉花的二次生长为研究对象，采用大田试验和室内分析两种手段，研究二次生长的发生规律和形态特征，阐明二次生长对棉花整株与器官生长发育的影响，揭示二次生长与品种、水分、氮肥、缩节胺以及群体密度等多个栽培因素之间的相关关系；从激素生理、生化物质变化、养分积累与分配及根系形态参数等角度研究二次生长棉花的生理效应，揭示二次生长的诱发机制。本项目旨在为化学封顶技术的合理应用与配套栽培调控措施的制定，有效解决二次生长问题以及研制适于新疆棉花高产优质的新型封顶剂奠定理论与技术基础。

棉花化学封顶技术具有省时、省力、节本、高效的特点，是目前代替人工打顶的最有效手段。然而，在化学封顶一段时间后棉株时常发生二次生长，成为制约该项技术推广应用的主要瓶颈。本项目以化学封顶棉花的二次生长为研究对象，通过大田试验和室内分析两种手段，研究了二次生长的发生规律和形态特征，分析了二次生长对棉花整株与器官生长发育的影响，揭示了二次生长与水分、氮肥及群体密度等多个栽培因素之间的相关关系；从激素生理、生化物质变化、养分积累与分配等角度分析了二次生长棉花的生理效应，初步明确了二次生长的诱发机制。项目实施达到了预期目标，较好地完成了各项研究任务，在国内核心期刊发表论文7篇，获国家发明专利1项，颁布技术规程（地方标准）1项，培养研究生5名，参加国内学术会议3次。研究主要得出以下结果：通过研究灌水频次、水氮运筹、外源物质和密度对化学封顶棉花生长发育的影响，发现化学封顶棉花植株对水敏感，灌水量及灌水频次均能影响化学封顶效果，其中灌水量是导致二次生长的主要因素；灌水量达到6000 kg/hm2 时易发生二次生长，二次生长率约为50 % ，氮肥及水氮交互对棉花二次生长影响不明显；喷施适宜浓度的外源物质（辛酸甲酯、调换酸钙）能有效调控化学封顶棉花的二次生长，降低其发生频率；种植密度越大封顶效果越好，越有利于减少棉花二次生长。以上各项研究的开展，较为全面系统地揭示了化学封顶棉花的发生规律，为丰富作物化学控制和化学封顶棉花高产栽培理论提供了支撑。相关研究结果为避免化学封顶棉花二次生长，进一步制定化学封顶棉花高产栽培技术和研发新型化学封顶剂提供了依据。