Abstract

Nitrogen (N) uptake and root systems were compared between a hybrid (Y-liangyou 087) and an inbred rice cultivar (Yuxiangyouzhan) in a 15N-tracer pot experiment. Although there was no significant difference in the N uptake from inorganic fertilizer between the two cultivars, the N uptake from soil and total N uptake were, respectively, 31 and 27% higher in Y-liangyou 087 than in Yuxiangyouzhan. The differences in root biomass and in length and surface area of coarse roots were not significant between the two cultivars. However, the length and surface area of the fine roots in Y-liangyou 087 were 33–38% greater than those in Yuxiangyouzhan. These results indicate that (1) the hybrid cultivar Y-liangyou 087 has higher ability to absorb indigenous soil N than the inbred cultivar Yuxiangyouzhan, and (2) larger fine-root system is responsible for the higher ability to absorb indigenous soil N in the hybrid cultivar Y-liangyou 087. This finding could be subject to the constraints of pot cultivation, but differences are substantial and probably apply to field conditions. These results should encourage more research into root system morphology and physiology.