Knowledge Resource Center for Ecological Environment in Arid Area
| 黑河上游优势植物叶性状和植物群落特征及其与环境的关系 | |
| 其他题名 | Leaf traits of dominant plant species and characteristics of plant communities in the upper reaches of Heihe and their correlations with environmental factors |
| 管天玉 | |
| 出版年 | 2018 |
| 学位类型 | 博士 |
| 导师 | 郑元润 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 摘 要过去一个世纪以来，全球气候发生了重大变化，大气二氧化碳浓度升高和全球变暖的趋势日益明显。气候变化影响着全球植物的性状和分布，对植物群落的适应性和稳定性产生了深远影响。干旱半干旱区降水稀少、水资源缺乏、生态环境极其脆弱，植物对气候变暖非常敏感。我国西部干旱区高山是内陆河的发源地，也是绿洲的主要水分来源，研究干旱区山地植物群落分布及其生态适应性对区域生态环境建设具有重要指导意义。祁连山位于青藏高原北部和河西走廊以南，植被垂直分布明显，从山脚到山顶依次分布着荒漠、草原、针叶林、灌丛、草甸、高山植被、冰川等植被和地貌。本文在黑河上游祁连山排露沟流域及流域附近的低海拔地带，从低海拔到高海拔分别选取合头草(Sympegma regelii)、青海云杉(Picea crassifolia)、针茅(Stipa capillata)、短叶锦鸡儿(Caragana brevifolia)、金露梅(Potentilla fruticosa)、鬼箭锦鸡儿(Caragana jubata)和吉拉柳(Salix gilashanica)等典型植物群落，分析植物群落特征和优势植物叶性状与环境因子之间的关系，揭示随海拔升高植物对环境变化的响应机理。通过上述研究，得到如下结论：(1)采用土壤和气候数据，通过主成分分析建立的综合环境指数(ECI)可用于更好地分析植物群落与环境之间的关系，能够更好地表征干热到湿冷的各种环境变化。综合环境指数为正值时，表示植物群落所处区域为干热环境；负值表示湿冷环境；指数值接近0，表示区域环境适宜植物生长；综合环境指数绝对值越大，环境越不适宜植物分布。当指数值达到一定阈值时，植物群落发生变化。因而，综合环境指数不仅可以有效区分适宜分布和不适宜分布的环境，且能有效区分干热环境和湿热环境。 (2)黑河上游典型植物群落优势植物叶性状与综合环境指数的回归分析结果表明，排露沟流域7个物种分别占优势的13个植物群落中，叶碳、叶氮、叶磷、叶钾含量、叶片质量氮浓度(Nmass)和叶片水势(LWP)与综合环境指数显著相关，而叶片面积氮浓度(Narea)、叶片单位面积干质量(LMA)、叶片厚度(LT)及叶片组织密度(TD)与综合环境指数不存在相关性。除青海云杉以外的6个植物群落中，除叶钾含量外，所有叶片性状均与综合环境指数存在显著相关关系。7个青海云杉群落中，所有叶片性状均与综合环境指数存在显著相关关系。上述结果表明，本文采用的叶片性状代表性较强，可用来分析不同环境下植物的生态适应性。(3) 黑河上游典型植物群落优势植物的光合参数与综合环境指数相关性分析表明，综合环境指数与13个植物群落7个光合参数中的光饱和点和光补偿点显著相关，与除青海云杉外的6个植物群落7个光合参数中的光饱和点和暗呼吸速率显著相关，与7个青海云杉群落7个光合参数中的最大羧化速率和最大电子传输速率显著相关。相较于叶片光合参数而言，前面提到的叶性状能更好反应植物对环境的适应性。(4) 黑河上游典型植物群落叶面积指数随温度和综合环境指数的升高呈下降趋势，随海拔上升和降水增加呈上升趋势。叶面积指数与降水的相关性最高，R2为0.2917，与综合环境指数的相关性也较高，R2为0.2663。群落盖度随温度、海拔、降水、综合环境指数的升高呈先升高后下降趋势。群落盖度与海拔的相关性最高，R2为0.126；与温度、综合环境指数的相关性近似，R2分别为0.118和0.1086。群落生物量随温度的升高呈下降趋势，随降水增加呈升高趋势，随海拔和综合环境指数的升高有先升高后下降的趋势。干旱区植物具有较强的适应能力，能通过改变自身的形态结构和生理生态特征，适应气候和环境的变化，因此，可通过对优势植物叶性状、生理生态指标及群落指标的研究，分析植物对不同环境的适应机制。由于本文仅在生长季的一定时期分析植物叶性状与环境的关系，但植物在不同季节对环境的适应方式不尽相同，因此，未来需要在更长的时间尺度内进行系统研究，便于更加系统地理解干旱区山地植物对不同环境的适应机制。 |
| 英文摘要 | AbstractOver the past century, there have been major climate changes worldwide, with rising CO2 concentrations and increasing temperatures. Climate changes affect vegetation traits and distribution as well as plant adaptability and stability. Plant species in arid or semiarid areas are extremely sensitive to warming climates as these regions feature an extremely fragile environment owing to scarce precipitation and a lack of water resources. Mountains in the arid region of western China form the cradle of the inland rivers as well as the main source of moisture for oases. Thus, studying the distribution and dynamics of alpine vegetation in arid regions may have important implications for the conservation of the environment and vegetation.The Qilian Mountains are located to the north of the Qinghai-Tibetan Plateau, and to the south of the Hexi Corridor. There is a distinct altitudinal gradient regarding the vegetation in this region, which includes, from the foot to the top of the mountains, deserts, steppes, coniferous forests, scrubs, meadows, alpine vegetation, and glaciers. In this study, we investigated the leaf traits of the dominant species and plant communities under different environmental conditions in the Pailugou catchment and the surrounding low-altitude area in the upper reaches of Heihe, China. We analyzed Sympegma regelii (desert plant), Picea crassifolia (forest plant), Stipa capillata (steppe plant), Caragana brevifolia, Potentilla fruticosa , Caragana jubata, and Salix gilashanica (scrub plants), and examined how they interact with the environment. Plant responses to environmental changes were revealed, which may be relevant for predicting the adaptability and distribution of species under changing climates. The main results are as follows:(1) The environmental comprehensive index (ECI) established based on soil and climate data improved analyses of the relationship between plant communities and environmental conditions in arid areas (e.g., from the deserts at the foot of mountains to high-altitude scrub zones). A principal component analysis of environmental factors can be used to form a virtual environmental axis ranging from xerothermic to clammy environments. Positive and negative ECI values corresponded to xerothermic and clammy environments, respectively, while an ECI value close to zero indicated a suitable environment for vegetation. Increasing absolute ECI values were associated with decreases in the suitability of the environment for plants. The plant community varied at threshold ECI values. Therefore, the ECI not only distinguishes between environments that are favorable and unfavorable for plant growth, it also discriminates between xerothermic and clammy environments. (2) A regression analysis of the leaf traits and the ECI of typical vegetation (i.e., 13 communities comprising seven species) in the upper reaches of the study area indicated that leaf C, N, P, and K concentrations, leaf mass-based N concentration, and leaf water potential were significantly correlated with the ECI, unlike the leaf area-based N concentration, leaf dry mass per area, leaf thickness, and leaf tissue density. An examination of six plant species communities (i.e., excluding P. crassifolia communities) indicated that with the exception of leaf K concentration, all leaf traits were significantly correlated with the ECI. An analysis of seven P. crassifolia communities revealed that all leaf traits were significantly correlated with the ECI. These results suggest that the selected leaf traits are highly applicable for assessing the adaptability of plant communities in different environments.(3) An examination of the relationships between seven photosynthetic parameters of the typical vegetation and the ECI indicated that the ECI was significantly correlated with the light saturation point (LSP) and the light compensation point in 13 plant communities. The ECI was also significantly correlated with the LSP and dark respiration in six plant communities, as well as the maximum rate of carboxylation and the maximum rate of electron transport in seven P. crassifolia communities. These observations imply that leaf traits reflect the relationships between species and environments better than photosynthetic parameters.(4) The leaf area index of typical plant communities decreased with increasing temperature and ECI value, and increased with increasing precipitation in the upper reaches of Heihe. The highest correlation (R2 = 0.2917) was observed between leaf area index and precipitation, but the correlation (R2 = 0.2663) between leaf area index and ECI was also high. The community coverage increased and then decreased with increasing temperature, elevation, precipitation, and ECI value. The highest correlation (R2 = 0.126) was observed between community coverage and elevation, although similar correlations were detected between community coverage and temperature (R2 = 0.118) and ECI (R2 = 0.1086). The community biomass decreased with increasing temperatures, increased with increasing precipitation, and increased then decreased with increasing elevation and ECI value. Plants in the analyzed arid areas effectively adapted to changes in climate and other environmental conditions by altering their shape and structure. Thus, we were able to identify changes in plants induced by different environments by examining the leaf traits, physio-ecological parameters of typical communities and community indices in these regions. However, because we only analyzed the relationships between leaf traits, community indices and environmental conditions, we cannot rule out the possibility that other mechanisms contribute to plant adaptations to the environment in different seasons. Thus, systematic and long-term investigations are required to characterize the adaptation of plant species to mountainous environments in arid regions. |
| 中文关键词 | 祁连山 ; 叶性状 ; 生理生态 ; 综合环境指数 ; 生态适应性 |
| 英文关键词 | Qilian Mountains Leaf Traits Physio-ecology Environmental Comprehensive Index Adaptability |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 生态学 |
| 来源机构 | 中国科学院植物研究所 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/288210 |
| 推荐引用方式 GB/T 7714 | 管天玉. 黑河上游优势植物叶性状和植物群落特征及其与环境的关系[D]. 中国科学院大学,2018. |
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