水磷一体化对新疆高产棉花根系形态与生理特性调节机制的研究

Xinjiang cotton production plays a decisive role in the development of the Chinese cotton industry. Water shortage and excessive phosphorus input primarily restrain the sustainable development of cotton in Xinjiang. Root is the main organ that absorbs soil water and phosphorus in cotton. Therefore, understanding the forms and functions of the root system is important to increase the water and phosphorus utilization of cotton. Previous research mainly focused on the root system regulatory effect of single soil water or phosphorus. Only few studies examined the regulatory effect of water–phosphorus integration on the forms and physiological properties of the cotton root system. In addition, clear regulation indices and technologies for the root system remain unavailable to date. Considering the growth characteristics of the cotton root system during drip irrigation under plastic films, this study analyzed the effects of water–phosphorus integration on the forms, physiology, and dynamic process of root systems in different cotton varieties. The spatiotemporal dynamical relationship between root system growth and soil water–phosphorus content was determined. Quantitative indices for an ideal root system, i.e., a root system capable of the highly efficient utilization of water and phosphorus at different growth stages, were introduced. The feasibility of culturing an ideal root system by regulating the space–time distribution of water and phosphorus in the root zone was discussed, and biological potentials of the cotton root system in water and fertilizer saving were developed. Finally, technologies for high-efficiency cotton production in arid regions were developed.

新疆棉花生产在中国棉业发展中具有举足轻重的地位。水资源匮乏、磷肥投入过大现已成为限制新疆棉花可持续发展的主要因素。根系是棉花吸收土壤中水分和磷素的主要器官，如何利用现代农业技术，提高根系对土壤水磷资源的吸收效率，实现棉花高产高效，一直是棉花栽培和育种工作者研究的重点和难点问题。本项目以膜下滴灌条件下水磷一体化棉花根系为研究对象，以培育水磷高效吸收理想根系为出发点，研究根系形态与生理及其动态过程和水磷利用效率的关系，探讨水磷一体化影响土壤水磷资源获取效率的生理机制，提出棉花高产水磷高效利用的理想根系在不同生育时期特征及其量化指标，以期为干旱区棉花高产高效生产技术措施的制定提供理论依据和技术参考。

土壤缺磷和干旱已经成为干旱区棉花生产的主要限制因素。本项目针对新疆棉区丰富的光热气候资源的特点，立足于膜下滴灌技术优势，以棉花根系构型特征为研究重点，开展了不同磷效率棉花品种的光合碳同化和物质生产特性、水磷胁迫对不同棉花品种产量及磷利用效率的影响、水磷供应对棉花根系生长与分布及生物量影响的研究工作。取得的重要结果有：（1）分析了不同磷效率棉花品种在丰、缺磷条件下棉花产量形成期光合生理参数及其关键酶活性的变化，揭示了磷胁迫条件下磷高效品种较高的光合速率是由于其具有较强的光反应活性、较强的CO2传输能力和较高的暗反应效率综合作用的结果。（2）解析了水分亏缺下施磷肥可提高根磷效率比、磷吸收效率及磷转移效率，增强棉花抗逆能力，显著提高棉花的生物量和产量。（3）证实了通过变动水磷供应，优化根系构型、增强根系生理功能，增加干物质累积及其向生殖器官分配比例，是实现棉花高产高效的关键。在系统研究的基础上，确立了以培育水磷高效利用根系构型为目标，通过集成磷高效利用品种及其配套技术，构建了棉花水磷高效利用调控技术体系。项目共发表文章5篇，其中SCI刊物2篇；获批专利2项。