氮胁迫条件下中国春-代换系小麦苗期耐低氮特征研究

Characterization of low-nitrogen tolerance capacities of Chinese Springsubstitution lines of wheat under deficient-N condition at the seedling stage

以一整套中国春背景的单染色体代换系和中国春、供体Synthetic 6x小麦为材料,研究了低氮胁迫条件下苗期氮效率的染色体效应。结果表明,低氮胁迫条件下,依据供试代换系植株干物质积累量可划分为高效组、中效组和低效组,以6D代换系单株干物重最大。不同效率组的株高、叶龄、根条数和单株叶面积等形态学性状及叶绿素含量、Fv/Fm和光合速率表现为随氮效率的降低而减小。单株干物重与单株氮累积量呈显著正相关,也与叶龄、单株叶面积、叶绿素a、叶绿素b含量和光合速率呈显著正相关,与含氮量及氮效率的相关程度较低。用供体Synthet-ic 6x单染色体对中国春相应染色体进行代换,会导致小麦的耐低氮胁迫能力发生明显变化。6D等低氮胁迫下表现为高效组的供体染色体含有耐低氮高效基因。可用叶龄、单株叶面积、叶绿素a含量、叶绿素b含量和光合速率作为鉴定小麦耐低氮能力强弱的形态和生理指标。

Using a whole series of Chinese Spring-substitution lines,Chinese Spring,and the chromosome donor Synthetic 6x as the materials,effects of each chromosome from genome A,B,and D on nitrogen efficiency under deficient-N condition were elucidated.It is found that the tested chromosome substitution lines,and the donor could be classified into three group,high-N efficiency,mid-N efficiency and low-N efficiency,by using the dry mass per plant.The line 6D has the highest dry mass per plant among them.With the decline of the N efficiency in the tested lines,the plant height,leaf age,root numbers per plant,leaf area per plant,chlorophyll content,Fv/Fm and photosynthetic rate are decreased.There is a significant positive correlation between the dry mass per plant and the accumulative N amount per plant.There are significant positive correlations between leaf age,leaf area per plant,chlorophyll a content,chlorophyll b content,and photosynthetic rate,while the correlation coefficient of nitrogen content and nitrogen efficiency is low.Therefore,the capacities for tolerance of deficient-N are modified largely resulted from the single chromosome substitution in wheat,and with the variable effects from different chromosomes.The donor chromosome 6D and other chromosomes that the substitution lines classified into high-N efficiency group contain the major genes regulating high-N efficiency.The morphological traits and physiological parameters,such as leaf age,leaf area per plant,chlorophyll a content,chlorophyll b content and photosynthetic rate,could be used as the potential criteria for evaluating the nitrogen efficiency of wheat under deficient-N condition.