Nitrate supply affects root growth differentially in two rice cultivars differing in nitrogen use efficiency

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 NH 4 + /NO 3 -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 NH 4 + /NO 3 -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. Nitratestimulated root length in Nanguang resulted mainly from root initiation rather than root elongation. Root biomass was similar between two rice cultivars under NH 4 + 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 NH 4 + 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.

Improving rice tolerance to potassium deficiency by enhancing OsHAK16p:WOX11‐controlled root development

“…The numbers of adventitious and lateral roots were directly counted as described by Song et al . () to detect the difference in elongation and initiation of roots among the plant materials. Root analysis machine (WinRhizoV4.0b; Regent instrument Inc., Quebec, Canada) was used to scan the roots of different treatments (Song et al ., ).…”

“…() to detect the difference in elongation and initiation of roots among the plant materials. Root analysis machine (WinRhizoV4.0b; Regent instrument Inc., Quebec, Canada) was used to scan the roots of different treatments (Song et al ., ). Then, the roots were placed in an oven at 105 °C for 30 min to inactivate the enzymes and finally dried to a constant weight at 70 °C for getting the root biomass.…”

Nitrogen Use Efficiency in Rice

“…Thus, soil N availability fluctuating greatly in both space and time affects root morphology, which could make plants uptake N efficiently [14]. Studies in rice have been confirmed that compared to sole NH 4 + nutrition, a mixture of NH 4 + and NO 3 − promoted root growth as well as N absorption and assimilation [85,86]. In the course of agricultural management, fertilizer type (i.e., controlled N release fertilizers, new potential N sources), methods of applying N fertilizers (e.g., the 4R nutrient stewardship framework: right source, right rate, right time, and right placement), soil types, tillage, transplanting density, cropping system, and microorganisms are governed to avoid nitrogen loss increasing fertilizer nitrogen use efficiency [87,88].…”

The auxin receptor TIR1 homolog (PagFBL 1) regulates adventitious rooting through interactions with Aux/IAA28 in Populus

“…The numbers of ARs were directly counted as described by Song and Xu () to survey the difference in emerged and outgrown roots among the plant materials. Roots from cuttings grown on TS1 (Klasmann Deilmann, Germany) at 24 ± 1 °C with well‐watered and natural light from April to August in the glasshouse (Chinese Academy of Forestry, Beijing) were scanned using a root analysis machine (WinRhizoV4.0b; Regent instrument Inc., Quebec, Canada), and then, the roots were dried in an oven at 105 °C to a constant weight for measuring the root biomass.…”