不同品种油菜生长后期体内氮素转运及再分配差异研究

摘要

为探明影响油菜生长后期氮素再分配的生理因素及其与氮素利用效率的关系,本文在严格控制氮素供应水平的砂培条件下,采用15N示踪技术研究了不同氮素水平下2个油菜品种吸收氮素后在体内的分配、转运及损失情况.结果表明,供试2个油菜品种的生物产量、籽粒产量、籽粒含氮量、植株全氮、籽粒全氮、收获指数和氮收获指数均存在较大差异,且以上差异因氮素水平不同而有所不同.常氮处理下,品种“742”的生物产量、籽粒产量、籽粒全氮、收获指数和氮素收获指数均高于品种“814”;低氮处理下,品种“742”的植株含氮量、籽粒含氮量、收获指数和氮素收获指数高于品种“814”,而生物产量、籽粒产量、植株全氮和籽粒全氮低于品种“814”.采用15N示踪方法测定油菜生长后期氮素再分配的结果表明,供试油菜品种生长后期营养器官氮素减少量及其比例、转向生殖器官的氮素再分配量存在明显差异.不同氮素水平下,品种“742”大多数营养器官的氮素减少量均高于品种“814”,而且茎的减少量差异最为明显.常氮水平下,品种“742”根、叶中氮素减少比例均少于品种“814”,而茎中氮素减少量远远大于品种“814”;低氮水平下,品种“742”根、茎、叶中氮素减少比例均大于品种“814”.在常氮和低氮处理下转向生殖器官的氮素再分配量均表现为,品种“742”向角果皮再分配的氮素低于品种“814”,向籽粒再分配的氮素则高于“814”.T检验结果表明,2个品种除常氮条件下向角果皮再分配的氮素之外,其他再分配氮素的差异都达到显著水平,说明油菜生长后期由营养器官向生殖器官的氮素再分配有助于提高氮素利用效率.油菜生长后期氮素损失量表现为,品种“742”在常氮处理下的氮素损失量及其比例小于品种“814”,低氮处理时反之.%This paper used 15N tracer method in sand culture conditions to determine the physiological factors of N redistribution and its relationship with N utilization efficiency. The paper also studied the differences in N distribution, transshipment and loss under different N levels in different N-efficient oilseed rape cultivars. The results showed that different N levels had different outputs in terms of biomass, grain yield, grain N content, plant N content, plant total N, grain total N, harvest index, accumulated N and N harvest index of selected oilseed rapes. Under normal N level, oilseed rape cultivar "742" had higher biomass, grain yield, grain total N, harvest index and N harvest index than cultivar "814". However, rape cultivar "742" had lower grain N content, plant N content and plant total N than "814" at low N level. Oilseed rape cultivar "742" had higher plant N content, grain N content, harvest index and N harvest index at peduncle growth stage than "814". At harvest stage, however, "742" had lower biomass, grain yield, plant total N and grain total N than "814". 15N tracer method results showed decreasing N amount in vegetable organs and the proportions and redistributions of N in propagative organs were significantly different. Under different N levels, N decline in root and stem in cultivar "742" was higher than in "814". This difference was especially evident in the stems of the oilseed rape cultivars. Under normal N level, the proportions of N decline in roots and leaves were lower in cultivar "742" than in "814". However, the proportion of N decline in stems was much higher in cultivar "742" than in "814". Under low N level, the proportion of N decline in all vegetable organs was highest in cultivar "742". Under normal or low N levels, less N was redistributed to silique husk of cultivar "742" than in cultivar "814". However, more N was redistributed to grain of "742" than "814". T-test showed that the amounts of redistributed N were significantly different, except for silique husk under normal N level. This implied that N redistribution from vegetative organs benefited N use efficiency. Furthermore, with normal N level, N loss and proportion in oilseed rape cultivar "742" were higher than in "814", and the reverse was the case for low N level.