Abstract:  To investigate the difference in root morphology and nutrient accumulation of rapeseed (Brassica na? pus L.) with contrasting nitrogen (N) efficiency to low N stress (0.38 mmol/L), 2 rapeseed germplasm with contrasting N efficiency were investigated. Rapeseed seedlings were cultured in hydroponics and then harvested to compare the changes and differences in root morphology and nutrient accumulation. Results found that significant differences in root morphology and nutrient accumulation between the two N supplies (P< 0.01). Low N stress remarkably en? hanced the length of main roots and lateral roots, and reduced root lignification. Nutrient accumulations were also notably decreased. Between the 2 rapeseed germplasm, total root length, root surface area, root volume, lateral root number and main root length of N efficient germplasm were 30.96%, 22.02%, 24.13%, 28.20%, 40.62% higher than those of the N inefficient germplasm respectively. The accumulations of N, P (phosphorus) and K (potassium) in N efficient germplasm were 2.02, 1.89 and 3.37 folds as those of the N inefficient one. In addition, the number of divi? sion cells and the length of elongation cells of the N efficient germplasm were greater, which might result in the pro? motion of main root growth. It could be concluded that the N efficient germplasm had better tolerance to low N stress, with stronger root system and less nutrients decrease. Therefore, the N efficient rapeseed germplasm could meet with low N stress by developing stronger root system and accumulating more nutrients which compared with the N inefficient one.

Key words:  , rapeseed (Brassica napus L.)；low nitrogen stress；root morphology；nutrient accumulation