不同基因型玉米品种氮积累与根区土壤氮转化过程差异研究

Differences in Nitrogen Accumulation and Root Zone Soil Nitrogen Transformation in Different Maize Genotypes

【目的】明确影响玉米氮利用的关键过程和主导因素,为提高玉米植株氮肥利用效率和选育高氮吸收效率玉米品种提供科学依据。【方法】以伟科702(WK702)、隆平206(LP206)、农华101(NH101)和先玉335(XY335)4个玉米品种为材料,设置0(CK)和220 kg/hm^(2)(N)2个氮素水平,在人工气候室条件下研究不同玉米品种氮素积累和根区土壤氮素转化过程差异。【结果】WK702和LP206地上部氮素积累量在不同氮肥施用水平下均高于NH101和XY335。CK处理下,WK702和LP206根区土壤硝化势和反硝化能力均低于NH101和XY335;WK702和LP206根区土壤中氨氧化细菌和氨氧化古菌丰度显著低于NH101;nirK、nirS和nosZ基因丰度均为NH101和XY335高于WK702和LP206;土壤pH和NO_(3)^(-)-N含量是影响硝化和反硝化基因丰度的主导因子。施氮处理下,WK702和LP206根区土壤反硝化作用也低于NH101和XY335,但硝化作用没有差异;WK702、LP206和NH101根区土壤nirK、nirS和nosZ基因丰度均显著低于XY335。【结论】WK702和LP206根区土壤硝化和反硝化作用损失的氮素少是其地上部氮素积累量高的主因。在高氮吸收效率玉米选育过程中,应关注低氮条件下的土壤反硝化损失。

[Purpose]To clarify the key processes and leading factors affecting maize nitrogen utilization, providing a basis for improving nitrogen use efficiency and breeding of maize varieties with high nitrogen uptake efficiency. [Methods]Four main maize varieties, Weike702(WK702), Longping206(LP206), Nonghua101(NH101) and Xianyu335(XY335) were used as materials under artificial climate conditions with two nitrogen levels of 0(CK) and 220 kg/hm~2(N), to clarify the differences of nitrogen accumulation and soil nitrogen transformation of different maize varieties.[Results]At both nitrogen levels, the aboveground nitrogen accumulation of WK702 and LP206were higher than NH101 and XY335. In CK treatment, nitrification potential and denitrification capacity in the root zone of WK702 and LP206 were lower than those of NH101 and XY335;the abundance in the root zone of ammonia-oxidizing bacteria and ammonia-oxidizing archaea of WK702and LP206 soil was significantly lower than that of NH101;the abundance of nirK, nirS and nosZ genes were higher in NH101 and XY335 than in WK702 and LP206;the nitrification and denitrification gene abundance were mainly influenced by soil pH and NO^(-)_(3)-N content. In the nitrogen treatment, the soil denitrification in the root zone of WK702 and LP206 was also lower than that of NH101 and XY335, but there was no difference in nitrification;the gene abundance of nirK, nirS and nosZ in the root zone of WK702, LP206 and NH101 were significantly lower than that of XY335.[Conclusion]The high aboveground nitrogen accumulation in WK702 and LP206 depends on the low loss of nitrogen by the root zone soil nitrification and denitrification. In the future, more attentions should focus on the nitrification and denitrification losses of nitrogen under low nitrogen conditions for breeding maize with high nitrogen uptake efficiency.