不同氮吸收效率品种油菜氮素营养特性的差异

采用土培盆栽试验，在不同供氮水平下对50份甘蓝型油菜进行氮吸收效率筛选，并比较其不同品种的氮素营养特性。结果表明，油菜的氮素营养特性表现出一定的品种差异，其中根系氮累积量及其占总吸氮量的百分比变异系数最大，超过50%，而生长前期植株含氮量的变异系数最小。不论氮素供应水平高低，油菜氮高效品种的总吸氮量和各器官的氮素累积量均显著高于氮低效品种，其中根系氮素累积量的差异最大，而果荚氮素累积量的差异最小；氮高效品种根系中累积的氮素比例均显著高于氮低效品种，而果荚中累积的氮素比例均显著低于氮低效品种；氮高效品种营养生长阶段地上部的含氮量与氮低效品种的差异不显著，而地上部的氮素累积量显著高于氮低效品种；营养生长阶段功能叶片的SPAD值也显著高于氮低效品种。随着供氮水平的改变，氮高效品种各器官的含氮量、氮素累积量和氮素分配比例的变化幅度均显著高于氮低效品种。不同品种油菜氮素营养指标的显著差异为通过遗传改良途径培育作物新品种和提高作物氮肥利用效率提供了基础。

Differences of Nitrogen Status between Different N-Uptake-Efficiency Rape-seed(Brassica napus L.)Cultivars

A pot experiment was conducted to test nitrogen(N)uptake efficiency(NUE)of 50 rapeseed cultivars at two N application levels.The differences of N status indexes between high-nitrogen-efficiency-genotype(HNEG)and low-nitrogen-efficiency-genotype(LNEG)were analyzed.The results showed that N status varied dramatically among different genotypes.The greatest variance was found on N accumulation in root and ratio of N accumulation in root to total N uptake(>50%)while the least variance was found on N content of aboveground part of rapeseed during vegetative stage.At both N application levels,HNEG had significantly greater total N uptake and N accumulation in different parts of plant than LNEG.The maximum difference of N accumulation was found in root between HNEG and LNEG while the minimum difference of N accumulation was found in silique husk.The ratio of N accumulation in root to total N uptake for HNEG was higher than that for LNEG.The ratio of N accumulation in silique to total N uptake was higher for LNEG than for HNEG.During vegetative stage,no significant difference of N content of aboveground parts was found between HNEG and LNEG.However,HNEG had remarkable higher N accu-mulation in aboveground parts and higher SPAD value of leaves than LNEG.Changes of N supply level led to the greater changes of N content,N accumulation and the ratio of N accumulation in any part to total N uptake for HNEG than those for LNEG.Significant differences of nitrogen status between different rapeseed cultivars provide a basis to create new crop varieties for increase nitrogen use efficiency.