退化草原的稳定碳同位素特征及影响机理

发布时间：2018-11-09 08:23

【摘要】：本试验于2014年8月在全国七个类型草原取样,2014～2015年对样品进行处理和分析,试图探究退化草原的植物叶片、根系和土壤的稳定碳同位素值(δ~(13)C)的变化特征,揭示放牧(放牧处理和放牧强度)和地理因子(经纬度、海拔)对草原植物稳定碳同位素组成的影响机理,为退化草原监测提供了新方法、新思路。研究结果如下:(1)不同类型草原植物叶片、根系和土壤都有各自δ~(13)C取值范围,放牧之后不同科植物的13C叶值范围值变化幅度变大,δ~(13)C据的范围值有所扩大,向更负的方向扩展,放牧前后、不同深度δ~(13)C±范围值增减均不定。(2)大部分植被的δ~(13)C叶值放牧后有降低的趋势,三种植物的光合途径发生了转换。放牧对的δ~(13)C根值影响不大,放牧、根系深度、地区、放牧和地区的交互作用对δ~(13)C ±值的影响都达到了显著水平。(3)随着放牧强度增加,植物叶片、根系和土壤的δ~(13)C值都呈现整体变小趋势,其中δ~(13)C根值呈先升高后降低趋势。δ~(13)C沿植物轴线向下富集:δ~(13)C±δ~(13)C棍δ~(13)C叶。(4)植物叶片、根系和土壤的δ~(13)C值随着海拔梯度升高呈现有规律的变化趋势。放牧前后δ1C ±值、δ1C 根值和地理因素均呈现良好的回归关系。(5)七种类型草原的δ~(13)C 根和δ~(13)C ±二者在OG、NG区的差值△s-±oG、△根-±NG呈极显著的线性相关关系。
[Abstract]:In this experiment, samples were collected from seven types of grasslands in China in August 2014, and the samples were treated and analyzed in 2014-2015 to explore the characteristics of stable carbon isotope values (未 ~ (13) C) of plant leaves, roots and soils in degraded grasslands. The effects of grazing (grazing treatment and grazing intensity) and geographical factors (longitude, latitude, altitude) on stable carbon isotopic composition of steppe plants were revealed, which provided a new method and new idea for monitoring degraded grassland. The results are as follows: (1) the range of 未 ~ (13) C values in leaves, roots and soils of different steppe plants has their own range of 未 ~ (13) C. the range of 13C leaf values of different families of plants has changed greatly after grazing. The range of 未 ~ (13) C was enlarged and expanded to a more negative direction. Before and after grazing, the increase or decrease of 未 ~ (13) C 卤range of different depths was not constant. (2) the 未 ~ (13) C leaf value of most vegetation tended to decrease after grazing. The photosynthetic pathways of three plants changed. The effect of grazing on 未 ~ (13) C root value was not significant. The effects of grazing, root depth, area, grazing and area interaction on 未 ~ (13) C 卤value reached a significant level. (3) with the increase of grazing intensity, plant leaves reached a significant level. The 未 ~ (13) C values of root system and soil showed an overall decreasing trend. The root values of 未 ~ (13) C increased first and then decreased. 未 ~ (13) C enriched along the plant axis: 未 ~ (13) C 卤未 ~ (13) C bar 未 ~ (13) C leaves. (4) Plant leaves. The 未 ~ (13) C values of root system and soil showed a regular trend with the elevation gradient. (5) the difference between 未 ~ (13) C root and 未 ~ (13) C 卤未 ~ (13) C value in OG,NG area was good. (5) the difference between 未 ~ (13) C root and 未 ~ (13) C 卤未 ~ (13) C value in OG,NG area. Root-卤NG showed a very significant linear correlation.
【学位授予单位】：内蒙古农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S812

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