Knowledge Resource Center for Ecological Environment in Arid Area
| 基于稳定同位素技术的植物水分利用效率及水分来源研究-以敦煌地区为例 | |
| 其他题名 | Significance of stable isotope composition on the study of plant water use efficiency and water sources in arid regions_A case study of Dunhuang area |
| 崔永琴 | |
| 出版年 | 2011 |
| 学位类型 | 硕士 |
| 导师 | 马剑英 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 水分是干旱和半干旱地区决定荒漠生态系统结构与功能的重要环境因子，研究荒漠植物的水分利用效率和水分利用模式对保持荒漠生态系统的稳定性尤为重要。本文选择干旱区甘肃敦煌荒漠生态系统为研究对象，通过测量代表性荒漠植物骆驼刺（Alhagi sparsifolia）、泡泡刺（Nitraria sphaerocarpa）、苦豆子（Sophora alopecuroides）、雾滨藜（Bassia dasyphylla）、密花柽柳（Tamarix arceuthoides）、短穗柽柳（Tamarix laxa）、沙枣（Elaeagnus angustifolia）等的δ13C、δD和δ18O值，分析不同生境典型荒漠植物的水分利用效率(Water use efficiency, WUE)和水分来源特征，同时结合土壤含水量等指标，研究荒漠植物水分利用格局，分析植物在极端干旱环境下的适应策略，探讨植物在极端环境下的水分利用和适应机制。主要得到以下结论：\n \n1. 敦煌地区典型荒漠植物的水分利用效率\n 戈壁生境下，密花柽柳、骆驼刺、泡泡刺间的δ13C存在显著的差异，并且密花柽柳的δ13C值较其他两种荒漠植物的大，说明密花柽柳的WUE最高，更能适应戈壁生境；丘间地上，短穗柽柳、骆驼刺、沙枣之间的δ13C差异也显著，其中短穗柽柳的δ13C值最大，表明三种荒漠植物中，短穗柽柳的水分利用效率最高，适应丘间地生境的能力最强；固定沙丘生境下，三种植物雾冰藜、苦豆子、密花柽柳间的δ13C值并不存在显著差异，即他们的WUE差异不显著。表明不同植物自身生理特性的差异在很大程度上影响了植物的水分利用效率。\n相同植物物种生长在不同的生境上，其δ13C值存在明显差异，丘间地骆驼刺叶片的δ13C值明显小于戈壁上的骆驼刺；固定沙丘生境下的密花柽柳的叶片δ13C值明显低于戈壁的密花柽柳叶片的δ13C值。说明敦煌地区不同生境下典型荒漠植物的水分利用效率的差异明显。除植物本身的遗传特性外，环境因子（本研究中主要指土壤水分可利用性）对植物WUE的影响较大。\n2. 敦煌地区典型荒漠植物的水分来源\n 利用稳定同位素D和18O，研究了敦煌地区三种生境（戈壁、固定沙丘和丘间地）的荒漠植物的水分利用来源，结果表明：戈壁生境下，骆驼刺、泡泡刺与密花柽柳利用土壤水的深度层次由浅到深依次为：泡泡刺、骆驼刺、密花柽柳，其中泡泡刺可能主要利用较浅层土壤水（10-20cm）；固定沙丘生境下雾冰藜利用的水源最浅，主要吸收利用水库水或者60-80cm土层的土壤水，苦豆子和密花柽柳二者主要吸收更深土层（＞80cm）的土壤水；丘间地生境的三种植物都主要利用的深层土壤水（>80cm），其利用水源深度由浅到深依次为：沙枣、骆驼刺、短穗柽柳。表明敦煌地区典型荒漠植物的生长主要依赖更为稳定的深层土壤水（>80cm）。\n3. 丘间地上，骆驼刺与沙枣吸收利用土壤水源的深度相近，固定沙丘上的苦豆子与密花柽柳有相似的土壤水吸收层位，因此它们对水源的竞争比较大。说明干旱条件下，同一生境不同植物之间存在水分的竞争。 |
| 英文摘要 | Water is the most important factor limiting plant growth and ecosystem productivity in arid and semi-arid regions. It is significant to investigate the water use efficiency (WUE) and water source of plant for the stability of desert ecosystem in arid regions. Stable isotope technique is a powerful tool to explore plant WUE and water source utilization, which has been widely used in climate change and plant ecological research in China in recent years. In order to understand the adaptive strategies of desert plants developed under water stress condition and interpret the relationship between plants and environment in arid area in China, we measured δD, δ18O, and δ13C values of several dominant species in Dunhuang desert ecosystem in China. The main results of this study are summarized as follows.\n 1. The water-use efficiency of desert plant species in Dunhuang desert ecosystem.\n There were significant differences in δ13and Tamarix laxa with the highest δ13inter-dune lowland. While the variations in δ13C values (WUE) of three desert plant species in fixed dunes were not significant. Variation in plant physiology characteristics is the key factor affecting plant WUE in the same habitat.C value could well adapt to the arid environments in C values among Alhagi sparsifolia, Nitraria sphaerocarpa and Tamarix arceuthoides in the Gobi. Tamarix arceuthoides had the most positive δ13C value, which indicated Tamarix arceuthoides had the highest WUE and the strongest adaptability to Gobi desert habitat. There were also significant variations in δ13C values among Alhagi sparsifolia, Tamarix laxa and Elaeagnus angustifolia, \n The δ13inter-dune lowland and fixed dunes. There were obvious differences in water use efficiency of the same species grown under different habitats. Besides the genetic traits of plant itself, environmental factors also influenced WUE to a certain extent. In this study, soil water availability was the key factor affecting desert plants among different habitats.C values of the same species in different habitats were significantly different. Alhagi sparsifolia and Tamarix arceuthoides in the Gobi had higher δ13C values and drought tolerance than that in \n 2. The water sources characteristics of representative desert plants in Dunhuang desert ecosystem.\n The δD and δ18O values of stem water, soil water and reservoir water were compared to identify water sources for several dominant species in the Gobi desert, fixed dunes and inter-dune lowland. In the Gobi desert, the depth of soil water desert plants relied on from shallow to deep is as followed: Nitraria sphaerocarpa, Alhagi sparsifolia, Tamarix arceuthoides. Bassia dasyphylla was the most feasible plant in fixed dunes, and benefited effectively from reservoir water and water in soil layer of 60-80cm, whereas the growth of Tamarix arceuthoides and Sophora alopecuroides used the deeper water (>80cm). Tamarix laxa, Alhagi sparsifolia and Elaeagnus angustifolia in inter-dune lowland all depended on the water in deeper soil layer (>80cm). The results indicated the growth of representative desert plants mainly depended on the water in deeper soil layer (>80cm) in Dunhuang desert ecosystem.\n 3. Because of using the similar water source the competition for water may be fierce between Tamarix laxa and Elaeagnus angustifolia in inter-dune lowland and Tamarix arceuthoides and Sophora alopecuroides in fixed dunes. We concluded that competition for water always existed in vegetation growth under drought conditions, especially in the same habitat under water stress. |
| 中文关键词 | 荒漠生态系统 ; 稳定同位素 ; 水分来源 ; 水分利用效率（WUE） |
| 英文关键词 | desert ecosystem stable isotopes plant water sources water-use efficiency（WUE） |
| 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/2XILL650/286938 |
| 推荐引用方式 GB/T 7714 | 崔永琴. 基于稳定同位素技术的植物水分利用效率及水分来源研究-以敦煌地区为例[D]. 中国科学院大学,2011. |
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