小麦群体冠层光合作用及根系吸收能力与籽粒产量密切相关，根冠平衡是实现小麦高产高效的基础，而作物群体冠层光合能力和根系分布均随农田水肥条件而改变。因此，研究小麦生长发育过程中的根冠权衡策略与养分分配特征，对探究作物产量形成中资源高效利用具有重要意义。本项目在黄淮南片麦区，以团队长期施氮麦田小麦为研究对象，以多年监测的根冠生理生态参数为基础，通过对群体光谱和光合特性的测定，研究植被特征与冠层的光能利用情况；通过原位监测小麦根系生长动态和形态结构，定量评价根系形态结构与细根消亡变化的关系；探讨光合同化物在植株根冠群体的再分配，揭示化学计量比与群体发育的关系；采用极差法对根冠系统相关指标进行归一化处理，量化小麦群体生态功能在作物产量形成过程中的权衡关系，定量分析水氮利用与根冠的互作机制，寻求小麦群体的根冠平衡阈值，为阐明小麦群体水肥利用过程中根冠互馈作用机理、促进粮食丰产增效提供理论依据。

The photosynthesis and absorption capacity of canopy and root are closely related to the grain yield of wheat, root-shoot balance is the basis of high yield and high efficiency, however, the photosynthetic capacity of canopy and distribution of roots for crop population have changed with the water and nutrient conditions. Therefore, studying the strategy of root-shoot balance and the characteristics of nutrient distribution have great significance for exploring the effective utilization of resources during crop yield formation. In this project, the wheat in the South of Huang-Huai region where nitrogen having been applied for a long time, will be investigated, based on the physiological and ecological parameters have been monitored for many years, the characteristics of population vegetation at different water and nutrient conditions will be analyzed by spectrometry, in combination with the population photosynthetic rate to study the light energy utilization capacity of canopy population; we plan to use root growth monitoring system to visualize root growth dynamics and morphology, then quantitatively evaluate the relationship between root morphology and the extinction characteristics of the fine roots; the redistribution of assimilates in root and canopy population will be analyzed to clarify the relationship between the stoichiometric ratio and population development; by using the range method to proceed the normalization processing for the related root-shoot indexes, quantify the trade-off relationship of ecological function of wheat populations during crop yield formation, and to analyze the interactional mechanism between water-nitrogen and root-shoot, then discover the balance threshold of root and canopy for wheat population. This project would improve our understanding of mutual feedback mechanism of root and canopy during the utilization of water and fertilizer, and provide theoretical basis for the crop development of high-yield and high-efficiency.