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| Aims | |
| 作者姓名： | 李单凤 于顺利 王国勋 方伟伟 |
| 作者单位： | 中国科学院植物研究所植被与环境变化国家重点实验室, 北京 100093 中国科学院大学, 北京 100049 西北大学生命科学学院, 西安 710069 中国科学院生态环境研究中心, 北京 100085 |
| 基金项目： | 中国科学院战略性先导科技专项中国灌丛生态系统的固碳现状、变化和机制(XDA05050- 300)和国家自然科学基金面上项目(41171041) |
| 摘 要： | 为了探究黄土高原灌丛群落中优势物种的根、茎和叶等营养器官之间碳(C)、氮(N)、磷(P)及其比值等化学计量特征的环境分异性及其与土壤养分的耦合性, 在甘肃省和宁夏回族自治区境内的3个灌丛集中分布区(甘肃南部、宁夏北部和甘肃西部)沿水热梯度选取41个样点进行样地调查。结果显示: 1)甘肃、宁夏灌丛群落的有机物质含量及P资源相对匮乏, 而N资源相对丰富。2)从甘肃南部、宁夏北部到甘肃西部, 生长季温度递增、年降水量递减, 与此耦合, 土壤养分也逐级递减, 沿着土壤养分梯度, 黄土高原优势灌丛根、茎和叶的C、N、P储量减少, 根和茎的C:N下降, 根、茎和叶的N:P上升, 但在宁夏北部和甘肃西部间差异不显著。同时, 3个优势灌丛分布区的优势灌丛各器官间营养元素的分配格局不同。3)土壤养分相对较高的区域优势灌丛间各器官营养元素储量无差异, 而土壤养分较低区域亲缘关系较远的优势灌丛间各器官的营养元素储量差异显著, 而亲缘关系较近的优势灌丛各器官营养元素储量差异不显著。黄土高原优势灌丛各器官C、N、P化学计量特征是植物体与土壤中化学元素耦合的结果, 当土壤养分逐渐升高时, 植物体内的化学元素储量也逐渐增多。该研究不仅有助于认识黄土高原优势灌丛化学计量环境分异规律, 而且有助于洞察不同土壤条件下C、N、P在优势灌丛营养器官间的分配格局和植物资源分配策略, 并为黄土高原植被的管理和恢复提供一定的理论基础。 |
| 关 键 词： | 化学计量特征 黄土高原灌丛群落 耦合性 水热梯度 资源分配 |
| 收稿时间： | 2015-01-22 |
Environmental heterogeneity and mechanism of stoichiometry properties of vegetative organs in dominant shrub communities across the Loess Plateau |
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| LI Dan-Feng,YU Shun-Li,WANG Guo-Xun,FANG Wei-Wei.Aims[J].Acta Phytoecologica Sinica,2015,39(5):453-465. | |
| Authors: | LI Dan-Feng YU Shun-Li WANG Guo-Xun FANG Wei-Wei |
| Affiliation: | State Key Laboratory of Vegetation and Environmental Changes, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China University of Chinese Academy of Sciences, Beijing 100049, China College of Life Sciences, Northwest University, Xi’an 710069, China andResearch Center for Eco-Environmental Science, Chinese Academy of Sciences, Beijing 100085, China |
| Abstract: | Aims Exploring variation patterns of C, N, P contents and their ratios of plant vegetative organs along environmental gradient can provide insight on the resource allocation strategy of plants. In order to search the environmental heterogeneity and mechanism of stoichiometry properties of plant vegetative organs (including root, stem and leaf), we investigated the influences of different soil nutrients conditions on the element allocation among plant vegetative organs in the dominant shrub communities along a hydro-thermic gradient across Loess Plateau. Methods The species compositions and structures of 123 small quadrats (5 m × 5 m) of dominant shrub communities in 41 sites were investigated by standard community sampling method along the declined hydro-thermic conditions from southern Gansu Province to northern Ningxia Hui Autonomous Region and western Gansu. The data about height, coverage and number of the dominant shrub were recorded. At least 369 biological samples of plant vegetative organs (root, stem and leave) of dominant shrubs were collected and their fresh and dry mass were measured, respectively. About 123 soil samples were taken by earth boring auger and ring knife. C, N and P contents of all biological and soil samples were measured after lapping and sieving. Important findings 1) Organic matter content (mean concentration of leaf C ((424.11 ± 42.21) mg·g-1) in Gansu and Ningxia Hui Autonomous Region was relatively low, and nitrogen (mean concentration of leaf N ((23.00 ± 8.09) mg·g-1) was higher while phosphorous (mean concentration of leaf P ((1.18 ± 0.50) mg·g-1) was relatively deficient. 2) Along the increasing growing season temperature and declining annual precipitation from southern Gansu to northern Ningxia Hui Autonomous Region and western Gansu, soil nutrients content decreased, and the storage of C, N and P in root, stem and leaf decreased. The shift trends of C:N agreed with the N storage’s shift trends in root and stem while N:P in all organs were contrary to the P storage’s shift trends. Meanwhile, the allocation patterns of C, N and P among vegetative organs among the three regions dominated by shrub communities were much different. 3) In the region with high soil nutrients, the nutrient storage in vegetable organs were similar among different species in the same dominant shrub regions, but in the regions with low soil nutrients, the nutrient storage in vegetable organs displayed high variations. The variations of nutrient storage of vegetable organs for the same shrub communities from different regions were not significant. |
| Keywords: | stoichiometry properties dominant shrub communities across Loess Plateau coupling hydro- thermic factors resource allocation |
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