低温严重影响我国北方玉米的苗期质量与生育后期的物质转运能力，制约着玉米产量的稳定性。本项目在玉米发芽、苗期和灌浆后期分别设置低温环境，系统研究玉米不同生育期耐冷能力的相关性及品种间的差异性。同时，在营养生长阶段进行化学试剂调控，研究生育前期化学调控能否提高玉米灌浆后期的耐冷能力，以提高调控措施在农业生产中的应用性。.本项目通过室内试验研究玉米萌发、苗期耐低温机理及品种间差异性；在大田条件下，通过推迟播种实现灌浆后期低温环境，研究低温条件下不同玉米品种的物质转运能力及化学调控效应。此外，通过籽粒离体培养，研究低温条件下玉米籽粒吸收营养物质的能力。从种子萌发、生理生化特征、物质生产与转运效率、维管束、胞间连丝超微结构、产量形成等方面分析玉米不同生育期的耐冷机理以及化学试剂的调控效应，进一步系统揭示玉米对低温的响应机制，为更好地防治低温冷害提供理论和技术依据。

Chilling stress has restricted yield improvement of maize in China by influencing germination and seedling growth, as well as biomass transport in the late grain-filling period. This project aimed to reveal (i) the correlation of chilling resistance between different growth periods of maize, (ii) chilling-resistant variance in different maize varieties, (iii) early chemical regulation on chilling resistance at late growth period of maize..This project combined pod experiment and field experiment; the former focused on chilling at germination and seedling stage, and the later focused on chilling at late growth period by the method of late sowing. To achieve the above objectives, germination characteristics, seedling growth, photosynthesis, processes of biomass loading – transport – unloading, yield and yield components were measured. Kernel cultivation in vitro was used to detect the ability of seeds to absorb nutrition at chilling stress. Dynamics and structures of vascular bundle and plasmodesmata at different growth stages of maize were also closely observed..In all, this project will provide underlying theories and techniques for prevention of chilling injury in maize at the morphological and physiological levels.