Knowledge Resource Center for Ecological Environment in Arid Area
| 黑河流域荒漠植物功能性状特征与需水规律研究 | |
| 其他题名 | Study on Functional Traits and Water Requirement Regulation of Desert Plant in the Heihe River Basin |
| 李善家 | |
| 出版年 | 2016 |
| 学位类型 | 博士 |
| 导师 | 苏培玺 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 干旱荒漠生境下生命特征和适应机制研究是地球科学与生命科学交叉的一个国际前沿领域。我国西北干旱区内陆黑河流域独特的荒漠生态系统类型，是理想的开展荒漠植物格局与过程研究的综合生态单元。荒漠植物在维系干旱区生态系统特征和功能方面具有重要作用和价值。植物功能性状及其群落分布格局作为植物与环境的综合表现形式，是各种生态过程在不同空间和时间尺度上相互作用的结果。选择内陆黑河流域山前、中游、下游荒漠植物主要分布区，以植物叶片、个体、种群、群落为研究对象，应用植物生理、群落生态、化学计量、土壤理化等理论，采用固定样地调查、定期观测采样、室内指标测试、数据统计分析相结合的方法，开展荒漠植物叶片水分功能性状、生态化学计量特征及其相互关系研究，不同土壤质地植物群落组成、结构与物种多样性及其植物群落分布格局研究，典型优势种植物生理需水、生态耗水及耗水规律研究；探寻荒漠植物适应逆境的特殊功能和机制，探究荒漠植物对于干旱环境的综合适应特征，分析生理指标与环境因子之间的定量关系，揭示荒漠、戈壁、沙漠植物群落演替的环境驱动力，从生理响应、生物学特征和生态调节的角度阐述干旱荒漠生态系统结构、功能及其稳定性，为该地区植被保育、生态恢复与建设的实践提供重要的科学数据和理论基础。主要研究结果和结论如下：1、对黑河流域荒漠区35种主要优势种植物115个样品的19项叶片功能性状和生态化学计量特征研究得出：(1) C3植物δ13C值的变化范围在-29.3‰~-20.0‰，平均值为-26.2‰；(2) 植物叶片束缚水/自由水比值的变异系数最大，为90.1%，鲜重含水量变异系数最小，为17.1%；(3) 比叶体积与鲜重含水量、束缚水含量、比叶面积之间存在极显著正相关关系(r=0.86，r=0.57，r=0.46，p<0.01)，与叶干物质含量之间呈极显著负相关关系(r=-0.81，p<0.01)。比叶体积可以作为反映荒漠植物叶功能性状特征的重要指标；(4) 荒漠植物叶片有机C含量平均值为57.5%、N含量平均值为21.4mg/g、P含量平均值为3.5mg/g；C:N平均值为31.9、C:P平均值为199.2，N:P平均值为7.1，显著低于全国(14.4)和全球(11.8)尺度的平均值，黑河流域荒漠植被生长主要是受到N元素的限制；(5) 叶片C与N含量之间呈极显著负相关(r=-0.30，p<0.01)、与P之间呈显著性负相关(r=-0.20，p<0.05)，N与C:P之间呈显著性负相关(r=-0.25，p<0.05)，N:P和C:N之间呈极显著负相关(r=-0.37，p<0.01)。2、对黑河流域24个荒漠植物群落样地进行了3年生态调查，共记录植物43种，其中灌木14种，草本29种，采用双向聚类分析(TWINSPAN)将其分为8个荒漠植物群落类型，冗余分析(RDA)将物种多样性和土壤营养与机械组成进行相关性排序，结果显示：Simpson优势度指数和Shannon-Wiener多样性指数主要受到土壤电导率、pH、中沙粒、粗沙粒、极粗沙粒和石砾的影响较大；Margalef丰富度指数与土壤温度、全磷、全钾、速效氮及粗粉粒具有极显著相关性；速效磷、极细沙粒则主要限制Pielou均匀度指数。土壤机械组成是影响干旱区荒漠植物物种多样性及群落分布的重要因素。群落分布特征表明：山前群落物种组成较少、盖度和生物量较大、优势种群结构单一；中游群落物种组成增多，盖度和生物量最大、优势种较多；下游群落物种组成再次减少、盖度和生物量最小、优势种稀疏。 3、在内陆黑河流域中、下游荒漠区，选择不同生活型典型荒漠植物种，建立Lysimeter实验观测场，分土壤含水量为田间持水量的50%(SF50%)和20%(SF20%)两种水分条件，2年同步进行相同植物种和不同典型种的实验观测。结果表明，在SF50%下，中游荒漠植物生理需水量占总耗水量的1/3，生态耗水量占2/3；下游荒漠植物生理需水量占总耗水量的22%，生态耗水量占78%。在SF20%下，中、下游荒漠植物都得出，生理需水量占总耗水量的42%，生态耗水量占58%。荒漠植物生理需水特征系数正常生长发育时是0.2，水分胁迫时是0.1；总耗水特征系数正常生长发育时是0.5，水分胁迫时是0.2~0.4；可利用这些系数和区域潜在蒸发量估算荒漠植物生理需水量和总耗水量。研究表明，黑河流域荒漠植物正常生长发育的总需水量为690~700mm，最低为310~340mm，临界需水量为130~140mm。在总耗水量中，生理需水量占1/3，小于或者大于此值，植物就处于水分胁迫状态。荒漠植物生理需水量和总耗水量随土壤湿度增加而增加，随空气湿度减小而增加；减少土壤含水量，使植物处于水分胁迫状态，生理需水量基本不变，但土壤蒸发量和总耗水量显著减少。 |
| 英文摘要 | Study on life characters and adaptive mechanism in desert habitat is an international frontier research field of earth science and life science. The unique desert ecosystem types of Heihe River Basin in arid inland areas of northwestern China, is an ideal comprehensive ecological unit of desert plant pattern and process study. Desert plant plays an important role and is valuable in maintaining ecological system characteristics and functions in arid areas. As a comprehensive manifestation of plants and environment, the plant functional traits and the community distribution patterns are the result of the interaction of all kinds of ecological process in different space and time scales.Choosing the Heihe River Basin piedmont, middle and lower reaches where desert plant main distribution area, using plant leaves, individual, population and community as the research object, application of plant physiology, community ecology, stoichiometry, soil physical and chemical theory, etc, combining with fixed plots investigation, regular measurement and sampling, laboratory test, data statistics and analysis method, we have studied leaf functional traits on desert plant, stoichiometry characteristics and the relationship of each other, plant community composition with different soil texture, structure, species diversity and distribution patterns of plant communities, typical advantage plant physiological water requirement, ecological water consumption and water consumption rule, as well as the biology characteristics, the ecological control mechanism, and the physiological response. The goal of the present study is to realize the comprehensive adaptive characters of desert plant and their community. With respect to the environment, to clarify the survival threshold to soil of the plant, and to establish the quantitative relationship between the physiological indexes and environmental factors, and to reveal silt desert, gravel desert and sand desert plant community succession of environmental driving force, and eventually to reveal the stability and succession rule of the desert plant community in the Heihe River Basin. The present study will help to find special functions and mechanisms for desert plant to survive adversity, to put the physiological ecology fruit in practice, and to provide scientific theory basis for the effective protection and rational utilization of desert plant, as well as the regional society, ecology, and sustainable economic development. The main research achievements and conclusions are as follows:1. Photosynthetic organs (leaves or assimilating branches) traits are important embodiment of desert plants adapting to drought environment. They not only exhibit adaptive characteristics of eco-physiological for special habitat of plants, but also indicate the effective index of the instructed ecological system structures and functionalities. In this paper, the selected 35 dominant species 115 samples from the 8 plant communities in the Heihe River Basin are investigated, and 19 leaf functional traits and stoichiometry indexes are determinated. The results of this study showed that:(1) The value of C3 plant’s δ13C varies from -29.3‰ to -20.0‰, the average value is -26.2‰; (2) Ratio of plant leaf bound water over free water has the maximum coefficient of variation value, achieve 90.1%. Total water content has the minimum coefficient of variation value, achieve 17.1%; (3) The interrelationship between the traits obtained indicates that the specific leaf volume is extremely significant positive related to total water content, bound water content, and specific leaf areas (r=0.86，r=0.57，r=0.46，p<0.01), extremely significant negative correlated with the LDMC (r=-0.81，p<0.01). The specific leaf volume can serve as a key index of the characteristics of desert plants leaf traits; (4) The average organic matter content of the desert plant leaves is 57.5%, the average content of nitrogen is 21.4mg/g, the average content of phosphorus is 3.5mg/g, the average of C:N ratio is 31.9, the average of C:P ratio is 199.2, the average of N:P ratio is 7.1, these values significantly lower than the national (14.4) and global (11.8) scale; (5) The organic matter content of leaves is extremely significant negative related to the content of nitrogen (r=-0.30，p<0.01), is significant negative related to the content of phosphorus (r=-0.20，p<0.05); The content of nitrogen is significant negative correlated with C:P ratio, N:P ratio is extremely significant negative correlated with C:N ratio (r=-0.37，p<0.01).2. The study of the patterns of plant species diversity and the environmental factors impacting these patterns is fundamental to ecology and conservation biology. We investigated the environmental factors influencing individual plant species and the major plant communities from 2012 to 2014 in 24 plant plots located in the Heihe River Basin desert in inland China. Two-way cluster classification analysis was performed to determine desert plant community types. The relationship between species diversity and environmental factors was investigated using the redundancy analysis (RDA) ordination method. During three years study, a total of 43 plant species, 14 shrubs and 29 herbs, were quantified in the study vegetation plots. Eight plant community types, corresponding with the biological traits of the shrubs and herbs and their responses to soil nutrient and texture gradients, were identified. The Simpson domination index and Shannon-Wiener diversity index across study vegetation plots were primarily influenced by electrical conductivity, pH and middle sand, coarse sand, extremely coarse sand and gravel content. The Margalef richness index strongly is correlated with the soil temperature, total phosphorus and potassium, available nitrogen and coarse silt content. Available phosphorus and extremely fine sand content were the main factors restricting the distribution patterns of the Pielou evenness index. These findings imply that the classification and ordination method satisfactorily assessed the relationships between plant community structure and soil preperties in the Heihe River Basin. Soil texture of particle composition is an important factor influencing the distribution patterns of arid desert plant communities and species diversity. This study provides insights into the habitat conditions, ecological needs and tolerance ranges of plant species and communities, and how these relate to soil properties. Community distribution characteristics showed that: desert plant species in community of piedmont is less than other communities, coverage and biomass are greater, with a single dominant species structure; desert plant species in the middle reaches increased, has maximum coverage and biomass, dominant species are more; desert plant species in the lower reaches reduce again, have a minimum coverage and biomass, advantage species are sparse.3. Plant transpiration (T), soil evaporation (E) and the proportion of evaporation in evapotranspiration (ET), and their patterns of change were analyzed in a desert habitat along the middle and lower reaches of the Heihe River Basin, Gansu Province, China. Typical desert plants with different life forms were selected and small lysimeter observations were conducted; various species were measured under two soil water regimes using 50% (FC 50%) and 20% (FC 20%) of field capacity in two years. Under the FC 50% treatment the observed ratio of T to ET of desert plants was less than one third, making the ratio of E to ET greater than two thirds; the proportion of T to ET of desert plants increased to above 40%, and that of E declined to below 60% under the FC 20% treatment. The lowest T of desert plants was 130–140 mm based on the plant crown projection area. The characteristic coefficient of ET of desert plants was twice that of the characteristic coefficient of transpiration. This study found that when ET was measured for the same desert plant species growing in different regions, the ET differed significantly (P<0.05) under the same water regimes; when comparing different plant species in the same region no obvious differences in the transpiration water requirement and ET were observed. The proportion of T in ET increased significantly and E in ET decreased markedly (P<0.05), if the soil moisture content declined to where the plants experienced water stress. |
| 中文关键词 | 荒漠植物 ; 叶片功能性状 ; 生态化学计量 ; 群落组成结构 ; 需水规律 |
| 英文关键词 | desert plants leaf functional traits ecological stoichiometry community composition and structure water requirement regulation |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 生态学 |
| 来源机构 | 中国科学院西北生态环境资源研究院 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/287682 |
| 推荐引用方式 GB/T 7714 | 李善家. 黑河流域荒漠植物功能性状特征与需水规律研究[D]. 中国科学院大学,2016. |
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