氮素水平和种植密度调控甘薯块根形成的生理生态机制

氮素和密度管理可以优化作物根际微生物群落结构和数量，提高土壤酶活性，增强作物养分吸收和利用，促进生长发育，提高产量和品质。适量施氮和合理密植可以通过增加甘薯单株块根形成数量提高块根产量，并增加中等薯率（100-500克）。但氮素水平和种植密度调控甘薯块根形成的生理生态机制尚不清楚。本项目在甘薯块根形成期，以不同氮素水平和种植密度下根际微生物变化、土壤养分有效化、根系养分吸收和根系发育等甘薯-土壤-根际微生物互作研究为切入点，系统研究不定根向块根分化过程中潜在块根内源激素生物合成、木质素生物合成、淀粉生物合成和蔗糖转化酶催化的蔗糖水解等生物代谢过程。深入研究并阐明不同氮素水平和种植密度下根际微生物变化调控甘薯块根形成的生理生态机制，以期优化甘薯氮密运筹方案，为构建甘薯高产高效的作物-土壤综合管理技术体系提供重要的理论支撑。

Management of soil nitrogen level and planting density can optimise microbial community structure and quantity in the crop rhizosphere, improve soil enzyme activity, enhance crop nutrient absorption and utilisation, facilitate crop growth, and increase crop yield and quality. Proper nitrogen application and reasonable planting density can increase the number of storage roots per plant to promote the yield, and increase the proportion of storage roots weighing 100–500 g of sweet potatoes. However, the physiological and ecological influences of nitrogen level and planting density on the mechanism of regulation of storage root formation in sweet potato are not clear. In this project, sweet potato–soil–rhizosphere microbial interactions will be examined as the entry point, including changes in rhizosphere microorganisms, soil nutrient availability, sweet potato nutrient uptake, and root development during the stage of storage root formation in sweet potato. The following metabolic processes will be systematically studied, such as endogenous hormone biosynthesis, lignin biosynthesis, starch biosynthesis, and sucrose hydrolysis catalysed by sucrose invertase, during the differentiation of adventitious roots to storage roots. The physiological and ecological mechanism of rhizosphere microbial changes regulating storage root formation of sweet potato under different nitrogen levels and planting densities will be deeply studied and clarified in order to optimise the nitrogen level and planting density management of sweet potato, and provide important theoretical support for the construction of high-yield and efficient crop-soil integrated management technology system of sweet potato.