基于补偿效应的有限滴灌棉花根系高效供水机制及调控研究

The primary purpose of cotton production is the efficient use of limited irrigation water resources in Xinjiang. Our previous study indicated that cotton root activity could induce the compensation effect after re-watering within 1-2 days under limited drip irrigation conditions resulting in increased water use efficiency without sacrificing seed cotton yield. However, the formation regarding regulation mechanisms of cotton root compensation effect of water deficit stress and re-watering condition is still unknown. Exploring the genetic and physiological potential of cotton varieties as the starting point, starting from the study of the compensation effect of root system during water stress and re-watering, we investigated cotton root morphological, physiological and structural characteristics and their relationship with characteristics of water uptake and conductivity by root system under different drip irrigation modes. In addition, to clarify the mechanisms of high efficient water uptake and conductivity compensation effect of cotton root system with limited drip irrigation for achieving higher yield. Physiological mechanism of root growth and its distribution on the effects of dry matter distribution and water use efficiency was revealed. The characteristic of root quantification index in different growth stage and regulation technologies are proposed under high-yield and high water use efficiency condition. The results can provide the theoretical basis and for physiological indices further excavation of root biology potential to improve cotton yield under mulch drip irrigation system. Additionally, the results abstained will play an important theoretical and practical role in maintaing cotton production and breeding drought-resistant varieties in Xinjiang.

有限灌溉水资源的高效利用是新疆棉花生产的首要目标。我们前期研究发现，棉花有限滴灌条件下，根系活力可在旱后复水1~2 d 产生补偿效应，增强了水肥吸收能力，在不显著降低产量的基础上，提高了水分利用效率。然而，旱后复水棉花根系补偿效应形成及调控机制尚缺乏深入研究。本项目以挖掘棉花遗传及生理潜力为出发点，以旱后复水根系补偿效应为切入点，研究不同滴灌模式下根系形态、生理和结构特征及其与根系吸水、导水特性的关系，阐明棉花有限滴灌高产下根系高效供水补偿效应的形成机制，揭示根系生长及其分布对物质分配和水分利用效率影响的生理机理，提出实现棉花高产和水分高效利用的根系在不同生育时期的量化指标及调控途径，为干旱区棉花高产节水栽培技术体系的制定及抗旱品种的选育提供理论依据和生理指标。

充分利用和挖掘棉花生物节水潜力是保证干旱区棉花高效可持续发展的关键。项目以挖掘棉花品种的遗传特性及植株自身的生理潜力为出发点，以旱后复水补偿效应为切入点，研究不同滴灌模式下根系生理特性的动态变化及其与地上部关系、耐旱性不同棉花品种根系生物学特性及生物量累积与分配对滴水量的响应、有限滴灌模式下种植密度（化学调控）对产量形成和水分利用效率的调节效应等内容。取得的重要结果有：（1）明确了控水结束恢复到正常滴水定额后，棉花通过加速根系ZRs的合成，促进叶片气孔开放，减小了光合作用的气孔限制，根系活力的快速恢复，保证了光合作用所需的水分和矿质元素，从而使光合速率快速恢复；（2）揭示了耐旱性强棉花品种在0~120 cm土层内较均匀的根系分布，0-40 cm和80-120 cm土层内保持较高的根系活性，以及较高的根茎导管直径和数量，尤其是干旱条件下根系变粗、密度增大，并保持较高的根体积、CAT、POD、SOD活性，是其生育期间较低的土壤耗水和较高的水分利用效率的重要原因；（3）证实了有限滴灌高密度栽培模式下，通过保持盛铃期以后较高叶面积指数，调节叶倾角，保证冠层中、下部较高的光吸收率，增加冠层总光吸收率，最终提高了盛铃期以后的群体光合能力；（4）解析了有限滴灌配合减施缩节胺条件下，棉花通过增加“铃-叶系统”各组分的气孔密度、减少气孔宽度、增加果枝叶和铃壳的组织厚度及提高果枝叶的栅海比，进而增强开花后28-42天果枝叶光合能力的同时，改善铃壳的光合性能，在提高水分生产率的同时不显著降低产量。因此，在保证花铃期充足水分、适当减少蕾期和吐絮期水分供应的有限滴灌模式下，通过增加种植密度、减少化学调剂用量，可充分挖掘棉株旱后复水产生的补偿或超补偿效应，实现滴灌棉花的高产高效。项目共发表文章12篇，其中SCI/EI刊物8篇；授权专利2项；获新疆兵团科技进步奖一等奖1项；培养研究生3名。