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草业学报 ›› 2014, Vol. 23 ›› Issue (5): 40-48.DOI: 10.11686/cyxb20140505

• 论文 • 上一篇    下一篇

退化草地大针茅根系特征对氮素添加的响应

秦洁1,2,鲍雅静2*,李政海2,胡志超1,2,高伟3   

  1. 1.内蒙古大学生命科学学院,内蒙古 呼和浩特 010021;
    2.大连民族学院环境与资源学院,辽宁 大连 116600;
    3.内蒙古自治区乌海市规划局规划设计院,内蒙古 乌海 016000
  • 收稿日期:2013-09-06 出版日期:2014-10-20 发布日期:2014-10-20
  • 通讯作者: Email:byj@dlnu.edu.cn
  • 作者简介:秦洁(1987-),女,山西汾阳人,硕士。E-mail:qinjie331313@163.com

The response of root characteristics of Stipa grandis to nitrogen addition in degraded grassland

QIN Jie1,2,BAO Ya-jing2,LI Zheng-hai2,HU Zhi-chao1,2,GAO Wei3   

  1. 1.College of Life Science, Inner Mongolia University, Hohhot 010021, China;
    2.College of Environmental & Resource Sciences, Dalian Nationalities University, Dalian 116600, China;
    3.Institute of Planning and Design of Planning Bureau, Inner Mongolia Autonomous Region, Wuhai 016000, China
  • Received:2013-09-06 Online:2014-10-20 Published:2014-10-20

摘要:

以大针茅为建群种的草原是蒙古高原典型草原地带广泛分布的地带性植物群落。近几十年来,由于不合理的利用,大针茅草原出现不同程度的退化。氮素是半干旱草原植物生长的限制性因素,氮素的添加有利于退化草原的恢复,但在氮素影响下草原植物根系特征变化的相关研究很少。本研究分别选取内蒙古锡林郭勒典型草原区的轻度退化和重度退化草地,进行氮素添加实验(0,30,50,80 g/m2),研究在不同退化程度的草地中大针茅根系特征对氮素添加的响应。结果表明,在重度退化草地中,氮素的添加显著促进了大针茅的根系生长和地上部分生长,根系长度、面积、体积、深度以及地上高度均随氮素添加量的增加而显著增加,根系长度、面积、体积呈极显著正相关关系,根系深度与地上高度呈显著正相关关系;轻度退化草地中大针茅根系特征对氮素添加的响应不显著。比较2个样地,在无氮素添加的条件下,重度退化草地中大针茅的根系直径显著低于轻度退化草地;在高氮素(80 g/m2)添加条件下,重度退化草地中的大针茅根系长度、面积、体积、地上高度与根系深度显著高于轻度退化草地。重度退化草地中土壤氮素的增加,促使大针茅根系主要通过增加根系长度扩大在土壤中的空间分布。

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Abstract:

Stipa grandis forms zonal plant communities widely distributed in the typical steppe region of the Mongolian plateau. In recent decades, due to the over-utilization, the S. grandis grassland has shown different degrees of degradation. Nitrogen is a limiting factor for plant growth in semi-arid grassland. N addition is beneficial to the recovery of degraded grassland, but research on the influence of N addition to root characteristics of grassland plants is rarely undertaken. In order to study the response of root characteristics of S. grandis to N addition in grassland with different degrees of degradation, two sites (lightly degraded and heavily degraded grassland) were selected in Xilingol typical grassland region of Inner Mongolia, and a 2-year N addition experiment was performed (0,30,50,80 g/m2 NH4NO3). In the heavily degraded grassland, N addition led to a significant increase in root growth of S. grandis. Root length, surface area, volume, root depth and above-ground height were all significantly increased with increased nitrogen input rates, and these measures of plant response were all significantly correlated. In the lightly degraded grassland, however, the root characters of S. grandis were not responsive to N. Comparing the two sites, root diameter in heavily degraded grassland was significantly lower than that in lightly degraded grassland when no N was added. Root length, area, volume, above-ground height and root depth in heavily degraded grassland was significantly higher than that in lightly degraded grassland under high N (80 g/m2) conditions. In heavily degraded grassland, with increased level of soil N, the root system of S. grandis acquires N for development by increasing root length to colonise a greater soil volume.

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