高寒草甸植被细根生产和周转： 三种方法的比较研究

Abstract

PDF HTML阅读 XML下载 导出引用 引用提醒 高寒草甸植被细根生产和周转的比较研究 DOI: 10.5846/stxb201307031831 作者: 作者单位: 宁波大学建筑工程与环境学院,中国科学院大学生命科学学院,中国科学院大学生命科学学院,南京师范大学虚拟地理环境教育部重点实验室,宁波大学建筑工程与环境学院,中国科学院大学 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金（31200367，41230750）；浙江省自然科学基金（LQ12C03001） Estimation of root production and turnover in an alpine meadow：comparison of three measurement methods Author: Affiliation: Ningbo University,,,,,University of Chinese Academy of Sciences Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:植物根系是陆地生态系统重要的碳汇和养分库，细根周转过程是陆地生态系统地下部分碳氮循环的核心环节，在陆地生态系统如何响应全球变化中起着关键作用。在全球变化敏感地区之一的青藏高原，对该地区的主要植被类型矮嵩草草甸同时采用根钻法、内生长袋法和微根管法3种观测方法研究细根生产和周转速率，并探讨了极差法、积分法、矩阵法和Kaplan-Meier法等数据处理方法对计算值的影响。研究结果显示：在估算细根净初级生产力时，根钻法宜采用积分法，内生长袋法宜选用矩阵法；由此进一步以最大细根生物量为基础，根钻法和内生长袋法估测的细根年周转速率分别为0.36 a-1和0.52 a-1，内生长袋法的估算结果是根钻法的1.44倍。对于微根管法，将其观测得到的细根长度转换为单位面积的生物量值后，采用积分法计算出细根周转速率为0.84 a-1，远高于传统方法的估算结果；若采用Kaplan-Meier生存分析方法，则计算出的细根周转速率更高达3.41 a-1。 Abstract:Plant roots are the most important carbon (C) sink and nutrient pool in the terrestrial ecosystem. Root turnover is the key process in belowground C and nitrogen cycles, and it profoundly affects how belowground ecosystems respond to global climate change. Therefore, an accurate estimation of the plant root turnover rate is crucial for reliable predictions of the structure and function of ecosystems in the future. Research on fine roots and the methods to analyze them have been hot spots in the field of root ecology. However, the suitability of the different methods, and the comparability of the results obtained from them, have rarely been assessed based on data from one study site. Grassland root systems, especially fine root turnover, have also been poorly studied-these topics have remained largely unexplored for herbaceous plants in China. The Qinghai-Tibetan Plateau in western China was one of the first areas to be affected by climate change, because its ecosystems are fragile and sensitive to changes in climatic conditions. The study was conducted in a Kobresia humilis meadow, one of the dominant vegetation types on the Qinghai-Tibetan Plateau. Previous studies suggested that meadow ecosystems play the most important role in both uptake and storage of C in the plateau. The ecosystem is considered to be an active CO2 sink. Roots may be one of the most important components of this sink, because root systems have a large biomass for storage and translocation of C into soil. To assess the suitability of the different measurement methods, we used sequential coring, ingrowth cores, and a minirhizotron to investigate the root production and turnover rates. To test the effects of the different calculation methods on the value of the root production and turnover rate, we used the max-min, integral, decision matrix, and Kaplan-Meier methods to calculate the root production and turnover rate from the measurements obtained using the three methods. The results of the comparative analysis showed that the integral calculation method was suitable to estimate the root production using data from the sequential coring method, while the decision matrix method was more suitable for calculations using data obtained by the ingrowth core method. In 2009, the root turnover rate was determined to be 0.36 a-1 using the sequential coring method, but 1.44 times higher, 0.52 a-1, using the ingrowth core method. The calculation methods more strongly affected the results obtained using a minirhizotron. The turnover rate determined using the integral method was 0.84 a-1, 2.33 times that determined using the sequential coring method and 1.62 times that determined using the ingrowth core method. The root turnover rate was estimated at 3.41 a-1 by Kaplan-Meier analysis, much higher than the values obtained using the sequential coring and ingrowth core methods. In conclusion, at this study site, the lowest root turnover rate was determined by the sequential coring method, the mid-range rate was determined using the ingrowth core method, and the highest rate was determined using a minirhizotron. The methods of data analysis will also affect the variations among results obtained using these three methods. Our results provide a basis to understand the roles of root production and turnover in the Kobresia humilis meadow and in the C and nutrient cycles in this ecosystem. 参考文献 相似文献 引证文献