不同玉米品种营养生长阶段叶片氮素吸收和转移的特征差异

Characteristics of Leaf Nitrogen Fluxes of Different Maizes during Vegetative Growth Stage

为探究不同品种玉米叶片在营养生长时期的氮通量特征,提高对玉米氮素利用机理的认识。本研究以玉米品种XY696和XY335为研究对象,在V6、V8和V10时期进行15N短期标记,分析不同叶位叶片在完全展开后碳氮含量、氮输入、氮输出以及氮周转特征。结果表明,XY696品种较XY335品种积累较多单位面积的氮。两品种玉米叶片在完全展开后均存在显著的氮输入且随着叶位下降而增大,XY696品种氮吸收能力高于XY335品种。各品种叶片虽然吸收氮素但也不断地进行氮周转,存在总氮输出和净氮输出,总氮输出远远大于净氮输出。XY335品种叶片净氮输出占总氮输出的比例高于XY696品种。综上所述,在营养生长时期,两品种叶片在完全展开后除了吸收氮素满足自身营养物质的合成外,还进行氮转移到其他器官。叶片的氮输入和氮输出具有空间异质性。XY696品种具有较高的单位面积氮和氮吸收能力。XY335品种具有较高衰老速率和氮转移能力,叶片在保持氮吸收能力基础上,尽可能增加氮素的转移,表现出氮高效品种的优势。

To illustrate differences of leaf N fluxes in different types maize will help people improve understanding of N utilization in maize,and to provide a theoretical basis for breeding high N efficiency maize cultivars.A pot experiment was conducted by using 15N technique for two types maize cultivars XY335 and XY696 during vegetative period(V6,V8 and V10).We determined N isotope compositions,N and carbon content of different developed leaves,and studied N import and export traits of leaves,and comprehensively analyzed and compared differences of leaf N mobilization of two types maize.Our results revealed that XY696 accumulated more N per unit leaf area(SLN).Two types of maize exhibited a significant leaf N import after full expansion,and the N import into leaves of XY696 was stronger than that of XY335.The relative N import increased in lower position leaf.There was also a significant turnover related N mobilization after fully expanded,which corresponding gross N export and net N export,gross N export was far more than net N export.The proportion of net N export in gross N export for XY335 was higher than XY696.To sum up,it exhibits leaf N turnover in two type’s maize after fully expanded during the vegetative stage.There is a significant N import into leaves for supporting the nutrient demand,and concurrently exporting N to other organs.N import and export in leaves shows a spatial heterogeneity.SLN and N import of mature leaves of XY696 are higher than that of XY335.XY335 shows a higher senescence rate and N export capacity,as well as increased N transfer on the basis of maintaining N absorption as the advantage of N efficient hybrids.