WJ Makeen K Wang DS et al.. Nitrate supply affects root growth differentially in two rice cultivars differing in nitrogen use efficiency. Plant and Soil 2011 343(1-2): 357-368. (IF 2.773 农林科学，一区）
Abstract
Partial nitrate nutrition was testified to improve rice (Oryza sativa L.) growth. However how partial nitrate nutrition is related to root growth in rice cultivars with different N-use efficiency is still unclear. Two rice cultivars Nanguang (high N-use efficiency) and Elio (low N-use efficiency) were grown on six ratios of NH4+-NO3– in the solution. The response of root growth to partial nitrate nutrition was investigated and N status and auxin concentration were recorded in order to elucidate the mechanisms by which the optimal ratio of NH4+-NO3– that controls the architecture of the root system. The length of adventitious and lateral roots was stimulated only in cv. Nanguang by partial nitrate nutrition. Nitrate-stimulated root length in Nanguang resulted mainly from root initiation rather than root elongation. Root biomass was similar between two rice cultivars under NH4+ supplied while higher root biomass was observed in cv. Nanguang than in cv. Elio under 25% nitrate supplied for 10 weeks. Significant IAA increase was recorded in cv. Nanguang under 25% nitrate presence in the nutrition compared to under sole NH4+ solution. The presence of nitrate increased root initiation in the rice with high N-use efficiency which led to faster biomass accumulation and higher N-use efficiency at later growth stages.
