不同氮效率油菜种质苗期氮吸收转运与利用差异研究

氮效率研究是油菜营养性状遗传改良的前提,为探究不同氮效率油菜种质苗期氮吸收、转运和利用的异同,以2个氮效率差异油菜种质H6（氮高效）和L18（氮低效）为供试材料,利用水培营养液设置正常氮（CK）和低氮（LN）2个氮浓度处理,培养14d后检测植株氮含量,计算氮累积量、氮转运系数和氮利用效率。结果显示,不同氮浓度处理对油菜苗期氮的吸收、转运和利用效率影响的差异达到极显著水平（P＜0.01）。与CK相比,LN处理的油菜生物量、氮含量和氮累积量均显著降低,而氮利用效率和根冠比显著提高;氮高效油菜种质H6的生物量、氮累积量、氮转运系数和氮生理利用效率均显著大于氮低效种质L18,分别为L18的2.07、1.42、3.23和1.56倍。从氮的吸收、转运和利用3个方面探讨了低氮胁迫处理下油菜种质苗期氮效率差异的原因,对深入开展油菜氮高效机理研究及油菜品种氮效率改良具有一定的指导意义。

Difference in Nitrogen Absorption and Transportation and Utilization of Rapeseed Germplasms with Contrasting Nitrogen Efficiency

The study of nitrogen (N) efficiency is the prerequisite for genetic improvement of nutritional traits in rapeseed (Brassica napus L.). In order to investigate the possible differences in N absorption, transportation, and utilization of rapeseed with different N efficiency at seedling stage, two rapeseed germplasms with contrasting N efficiency, H6 (N-efficient germplasm) and L18 (N-inefficient germplasm), were used as the materials. By using hydroponic cultures with normal N (CK) and low N (LN) treatments for 14 days, the N content, N accumulation, N transport coefficient, and N utilization efficiency were measured. The results showed that the N absorption, transportation, and utilization efficiency in rapeseed seedlings at two N levels reached extremely significant levels (P<0.01). Compared with CK conditions, the biomass, N content, and N accumulation of rapeseed were significantly decreased under LN, while the N utilization efficiency and root-shoot ratio were significantly increased. In addition, the biomass, N accumulation, N transport coefficient, and N utilization efficiency of N-efficient rapeseed germplasm H6 were significantly higher than that of N-inefficient germplasm L18 under LN conditions. In detail, the biomass, N accumulation, N transport coefficient, and N physiological utilization rate of H6 were 2.07, 1.42, 3.23, and 1.56 times as much as L18, respectively. The possible mechanisms underlying rapeseed with different N efficiency at seedling stage were elucidated from the absorption, transportation, and utilization process of N. These results may provide useful information for investigating the mechanism underlying N efficiency and genetic improvement of N efficiency in rapeseed breeding.