氮素营养对马铃薯块茎形成的影响及其机制

Potato tuber, the economic organ of the crop, originates from stolon tip enlargement. Nitrogen supply is an important precondition for higher tuber yield, therefore plenty of researches on potato yield and nitrogen management have been done already. However,we have no basic understanding about the influences of nitrogen supply on tuber formation,development as well as its physiological mechanism at present. Since the time of tuber formation relates to tuber yield directly,the application of nitrogen fertilizer is necessary in the production of potato, and potato commercial characters such as tuber shape, are easily influenced by nitrogen, it is of siginificance to conduct the researches on the relationship between potato tuber formation and nitrogen nutrition, and its physiological mechanism. By tissue culture, pot experiment and field experiment, the influences of N supply amount and time on the formation and development of potato tubers will be studied. From aspects of the phytohormone metabolism and plant C:N ratio changing, the physiological mechanism how N affect tuberization will be studied as well. Finally,the nitrogen management strategy aimed to regulate potato tuber formation and development will be proposed in this projet.

马铃薯的块茎由地下匍匐茎顶端膨大而成，是马铃薯的经济器官，充足的氮素供应是获得块茎高产的重要条件，因此国内外关于马铃薯氮肥管理技术的研究早已不再新鲜。但是，关于氮素供应对马铃薯块茎形成与发育的影响及其机制，目前尚缺乏基本的认识。由于块茎形成早晚直接关系到其最终的产量，施用氮肥又是生产中获得马铃薯高产的有效措施，而且马铃薯块茎形状等商品指标极易受氮肥影响，因此有必要围绕马铃薯块茎形成过程与氮素营养的关系及其生理机制进行深入研究。本项目将采用组织培养、盆栽试验和田间试验相结合的办法，系统研究氮素供应数量、时间对马铃薯块茎形成及发育的影响规律，并从激素代谢以及植株C:N 变化等方面阐明其影响机制，在此基础上提出调控马铃薯块茎发育的氮素管理策略。

增加单株块茎数和促进块茎形成是马铃薯生产的重要目标，因此了解环境因素对块茎形成的影响及其规律具有极为重要的理论意义和实践价值。本项目采用温室组织苗试验和田间试验相结合的办法，系统研究了氮素供应数量、时间对马铃薯植株C/N比及块茎形成与发育的影响规律，并改变温室中CO2浓度，观察了植株C:N 变化以及块茎发育的变化。结果表明，随着CO2浓度的增加，马铃薯植株的C/N比值增加，高CO2浓度处理的马铃薯植株形成块茎较早，而N供应水平的降低导致了植株C/N比值的提高和块茎形成的提早。因此，植株C/N比与马铃薯块茎形成相关的假设得到了检验。此外，在不同CO2或N供应水平下，植株C浓度保持稳定，说明马铃薯植株中C/N的变化主要是由于N浓度的变化引起，植株N浓度随着环境CO2浓度的增加而降低，而随着氮供应水平的增加而增加。在上述研究结果基础上，本项目还针对马铃薯商品薯生产和种薯繁育的不同生产目的，分析提出了调控马铃薯块茎发育的氮素管理策略。