谢孟林, 李强, 查丽, 朱敏, 程秋博, 袁继超, 孔凡磊. 低氮胁迫对不同耐低氮性玉米品种幼苗根系形态和生理特征的影响[J]. 中国生态农业学报(中英文), 2015, 23(8): 946-953. DOI:10.13930/j.cnki.cjea.150194
引用本文: 谢孟林, 李强, 查丽, 朱敏, 程秋博, 袁继超, 孔凡磊. 低氮胁迫对不同耐低氮性玉米品种幼苗根系形态和生理特征的影响[J]. 中国生态农业学报(中英文), 2015, 23(8): 946-953.DOI:10.13930/j.cnki.cjea.150194
XIE Menglin, LI Qiang, ZHA Li, ZHU Min, CHENG Qiubo, YUAN Jichao, KONG Fanlei. Effects of low nitrogen stress on the physiological and morphological traits of roots of different low nitrogen tolerance maize varieties at seedling stage[J]. Chinese Journal of Eco-Agriculture, 2015, 23(8): 946-953. DOI:10.13930/j.cnki.cjea.150194
Citation: XIE Menglin, LI Qiang, ZHA Li, ZHU Min, CHENG Qiubo, YUAN Jichao, KONG Fanlei. Effects of low nitrogen stress on the physiological and morphological traits of roots of different low nitrogen tolerance maize varieties at seedling stage[J].Chinese Journal of Eco-Agriculture, 2015, 23(8): 946-953.DOI:10.13930/j.cnki.cjea.150194

低氮胁迫对不同耐低氮性玉米品种幼苗根系形态和生理特征的影响

Effects of low nitrogen stress on the physiological and morphological traits of roots of different low nitrogen tolerance maize varieties at seedling stage

  • 摘要:采用水培方法, 以2个耐低氮品种和2个不耐低氮玉米品种为材料, 以正常氮处理B315 mmol(N)·L1为对照, 研究2个低氮胁迫水平B10.05 mmol(N)·L -1、B20.5 mmol(N)·L -1对不同耐低氮性玉米品种苗期根系形态和伤流量及氮代谢关键酶活性的影响。结果表明: 与正常供氮处理相比, 在B1和B2低氮胁迫处理下, 玉米幼苗根系伤流量和硝酸还原酶(NR)、谷氨酰胺合成酶(GS)、谷氨酸脱氢酶(GDH)活性均下降, 耐低氮品种上述各指标的降幅(29.8%和8.7%、46.9%和39.6%、7.3%和4.4%、31.3%和19.8%)均小于不耐低氮品种(37.0%和27.5%、68.8%和56.6%、24.5%和18.7%、60.7%和42.7%), 且在B1处理下耐低氮品种根系NR、GDH活性分别是不耐低氮品种的1.4倍、1.35倍。低氮胁迫对玉米苗期地上部生长的影响大于对地下部生长的影响, 使地上部干重显著降低, 根冠比显著增大, 根数减少; 在B1和B2处理下, 不耐低氮品种根冠比增幅(81.6%和25.4%)、根数降幅(22.2%和31.1%)均大于耐低氮品种(61.0%和21.1%、19.8%和19.4%)。随着低氮胁迫程度的增大, 耐低氮品种根长增长, 根粗减小, 对低氮胁迫的响应能力增大, 表现为根系伸长变细以增加对氮的吸收面积。与不耐低氮品种相比, 低氮胁迫下耐低氮品种根系形态较好, 根系生理活性和对低氮胁迫的耐性较强, 能维持较稳定的生长; 随着低氮胁迫时间的延长, 耐低氮品种对低氮胁迫的适应性增强, 不耐低氮品种则降低。

    Abstract:Nitrogen (N) is a key nutrient that influences the growth, yield and quality of maize. In order to determine the effects of low N stress on the physiological and morphological traits of roots of maize at seedling stage, a hydroponic experiment of four maize varieties was carried out. The experiment consisted of two low N tolerant varieties (‘ZH311’ and ‘CD30’), two low N sensitive varieties (‘XY508’ and ‘SB2’) and three N treatments N concentration at normal of 15 mmol·L -1(B3), low N stress at 0.05 mmol·L -1(B1) and low N stress at 0.5 mmol·L -1(B2). Root morphological indexes (root length, root diameter, root number, root volume, root surface area), bleeding intensity and activities of nitrate reductase (NR), glutamine synthelase (GS) and glutamate dehydrogenase (GDH) were measured on the 7th and 14th days after low N stress. The results showed that the bleeding intensity and activities of NR, GS and GDH of the root system of maize varieties with different low N tolerance at seedling stage declined under low N stress treatments B1 and B2. There were remarkable differences among the maize varieties in terms of the above indexes. The decreasing ranges of the above indexes of the low N tolerant varieties (29.8% and 8.7%, 46.9% and 39.6%, 7.3% and 4.4%, 31.3% and 19.8%) were less than those of the low N sensitive varieties (37.0% and 27.5%, 68.8% and 56.6%, 24.5% and 18.7%, 60.7% and 42.7%). The NR and GDH activities of the low N tolerant varieties were respectively 1.4 and 1.35 times those of the low N sensitive varieties under B1 treatment. The effects of low N stress on the growth of aboveground system of maize seedling were greater than those on the belowground system. This significantly decreased shoot dry weight, significantly increased root-to-shoot ratio and decreased root number. Root-to-shoot ratio of low N sensitive varieties increased by 81.6% and 25.4% and root number declined by 22.2% and 31.1% against those of the low N-tolerant varieties (61.0% and 21.1%, 19.8% and 19.4%) under B1 and B2 treatments, respectively. With increasing of low N stress degree, root length of low N tolerant varieties increased and root diameter decreased. This resulted in root elongation and thinning, increasing N absorption area and responsiveness to low N stress. Compared with low N sensitive varieties, low N tolerant varieties had better root morphology and stronger root physiological activity to respond to low N stress. The low N tolerant maize varieties also had relatively stable growth and better adaptability to low N stress. Adaptability to low N stress of low N tolerant maize varieties increased, while that of low N sensitive varieties decreased with prolonged low N stress time.

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