低碳土壤条件下供给葡萄糖调控苹果根系生长及构型机理研究

我国优势苹果产区多为丘陵和山地，土壤有机质含量低，清耕制及有机肥投入不足加剧了有机质矿化，果实及修剪枝条等又带走大量碳素物质，土壤碳长期入不敷出、质量呈下降趋势，严重制约果园生产力。通过补碳优化根区环境是解决上述问题的基本思路。关于外源碳与根区土壤碳库运转及果树根系生长之间的联系及调控机制仍未清晰阐释。本项目利用同位素示踪技术，研究低碳土壤供给葡萄糖后目标碳的去向，明确外源碳对苹果根系的影响及与土壤原有碳量和微生物之间的关系；结合环剥等处理，阐明低碳土壤背景下根系形态及拓扑结构响应外源葡萄糖处理的碳、氮代谢及IAA合成等级联反应模式；筛选外源碳调控EMP-TCA途径、GS-GOGAT循环及IAA合成的关键基因；构建遗传转化载体，关键基因和蛋白表达验证及表型鉴定，明确其在代谢网络中的作用；结合中长时间尺度田间调查，揭示低碳土壤供给葡萄糖对苹果根系生长及构型的调控机理，为土壤管理提供理论依据。

The dominant apple producing areas in China are mostly built in hilly and mountainous areas with lower soil organic matter (SOM). The mineralization of SOM is aggravated by clear tillage system and the insufficient input of organic fertilizer. Moreover, large amount of carbon is taken away from fruit and pruned branches, etc. The long-time less input than output and decreasing quality of soil carbon seriously restrict the orchard productivity. Optimizing the environment of root zone by carbon supplement is the basic way to solve the above problems. However, the molecular and physiological mechanisms and the relationship between the exogenous carbon and the turnover of soil carbon pool in the root zone and the root growth of fruit trees remain uncharacterized. In this project, isotope tracer technique will be used to explore the destination of target carbon after glucose supply inlow carbon soil, and clarify the influence of exogenous carbon on apple roots and the relationship between soil original carbon and microorganism. Subsequently, combined with girdling treatment, the cascading response patterns of root morphology and topology to carbon and nitrogen metabolism, and IAA synthesis under exogenous glucose treatment in low carbon soil will be elucidated. Furthermore, key genes involved in EMP-TCA pathway, GS-GOGAT cycle and IAA synthesis will be screened, and using key gene and protein expression verification and phenotypic identification to clarify their roles in metabolic networks. Combined with medium-long time scale survey in the field, the knowledge gained from this study will reveal, the regulation mechanism of glucose supply on the growth and configuration of apple roots in low carbon soil. These results will provide new insights into soil management.