玉米根分泌物响应局部供磷的时空动态特征及其根际调控机制

磷在土壤中的分布呈现高度的不均一性，植物在局部磷富集区的侧根增生与根分泌物的释放是高效获取异质性磷的重要策略。目前的研究主要集中在局部养分对根系形态的调控作用上，但对根分泌物响应局部供磷的特征及其根际调控机制并不清楚。这是深入理解作物根系对局部养分的响应及其磷高效利用机制的关键。我们前期研究发现，田间局部供应铵加磷显著促进玉米根系增生及根际酸化，增强了磷的活化与吸收。因此，本研究拟以玉米为研究对象，通过营养液及土培分根试验，以玉米根分泌物对局部供磷的响应及其调控机制为主线，利用高效液相色谱、非损伤微电极离子流技术、分子生物学等方法，并结合根际原位研究手段，明确局部供磷下玉米根系释放分泌物的时空动态特征，揭示局部供磷调控玉米根系释放磷活化专性根分泌物的机理，阐明局部供磷区玉米根分泌物活化磷的根际强化机制。本研究将为优化作物磷高效利用的根际调控途径，提高集约化玉米体系磷利用效率提供科学依据。

The distribution of phosphorus in the soil presents a high degree of heterogeneity. The root growth and the release of root exudates of plants in local phosphorus-rich patches are important strategies for efficient acquisition of heterogeneous soil phosphorus. Current research mainly focuses on the regulation of local nutrients on root morphology, but the characteristics and mechanisms of root exudates and the rhizosphere processes in response to local phosphorus supply are not clear, which is the key to deeply understand the response of crop roots to local nutrients and the mechanism of efficient phosphorus utilization. Our previous results showed that the local supply of ammonium and phosphorus in the field significantly promoted maize root proliferation and rhizosphere acidification, enhancing the mobilization and absorption of phosphorus. In this study, maize will be used as the research material. Based on nutrient solution and soil culture split-root experiments, the present study focuses on the maize root exudates in response to local phosphorus supply and its regulation mechanism. The studies are conducted with a series of advanced methods and techniques, including high performance liquid chromatography, non-damaging microelectrode ion flux estimation technique, molecular biological approach, as well as rhizosphere in-situ research methods. The present study will accurately quantify the temporal and spatial dynamic characteristics of the release of maize root exudates under local phosphorus supply, and reveal the mechanism of maize root exudates release regulated by local phosphorus supply. Finally, rhizosphere processes and their strengthening mechanism for efficient phosphorus mobilization and uptake of maize root under local phosphorus supply will be clarified. This study will provide a scientific basis for optimizing the rhizosphere regulation for improving the phosphorus utilization efficiency in sustainable maize production.