不同基因型小麦侧根生长对硝态氮的响应差异

以4个小麦品种石麦15、衡观35、H10和L14为供试作物,进行营养液培养试验,研究不同浓度硝态氮供应对小麦侧根发育的影响。结果表明:0.05~25.0 mmol/L硝态氮处理13 d,小麦生物量及侧根形态尚未受到明显影响;硝态氮处理22 d后,植株地上部生物量和氮含量明显增加,石麦15、H10和衡观35增加幅度较大,L14增幅较小;0.05 mmol/L低浓度硝态氮处理下,4个小麦品种的侧根平均长度较长。进一步研究发现,小麦侧根发育对不同浓度硝态氮供应的反应存在明显的基因型差异:0.05 mmol/L硝态氮处理下,石麦15的侧根长度和总根长增加,侧根密度无明显变化;H10的侧根总长度增加,侧根密度减少;衡观35的侧根密度减少,侧根总长度变化不大,而L14的侧根总长度和侧根密度均无明显改变。硝态氮处理浓度在2.5~20.0 mmol/L范围内,小麦侧根数量和长度均没有受到明显影响,在均匀供应硝态氮条件下,高浓度的硝态氮处理未影响小麦的侧根长度和数量。

Genotypic differences in response of wheat lateral root growth to nitrate supply

Nutrient solution culture experiment was conducted to study effects of nitrate supply on lateral root development and nitrogen uptake of wheat. Four wheat cultivars, Shimai 15(SM15), Hengguan 35(HG35), H10 and L14 were selected as the tested crops. The results showed that biomass and nitrogen content in shoots, and lateral root development were not significantly affected under the 0-25.0 mmol/L nitrate treatments for 13 days. After 22 days of nitrate applications, the biomass and the nitrogen content in shoots increased significantly, and the increased rates of SM 15, H10 and HG 35 were higher than those of L14. With nitrate treatments at the concentration range of 0.25-20.0 mmol/L, lateral root elongation and lateral root numbers of four genotypes of wheat were not significantly affected. However, when supplied with low nitrate(0.05 mmol/L), there were notable increases in the average lengths of lateral roots of the four genotypes. Without nitrate supply or under 0.05 mmol/L of nitrate supply, lateral root length and total root length of SM 15 increased and lateral root density did not change, total length of lateral roots of H10 increased and lateral root density decreased, lateral root density of HG 35 decreased, while there were no significant changes in the total length of lateral roots and lateral root density of L14. These results suggest lateral root growths of wheat with different genotypes are different under nitrate supply.