KMS XINJIANG INSTITUTE OF ECOLOGY AND GEOGRAPHY，CAS
| 胡杨水分选择性利用的定量分析 | |
| 陈晓林 | |
| Subtype | 硕士 |
| Thesis Advisor | 陈亚鹏 |
| 2018-06-01 | |
| Degree Grantor | 中国科学院大学 |
| Place of Conferral | 新疆乌鲁木齐 |
| Degree Discipline | 理学硕士 |
| Keyword | 塔里木河下游 胡杨 水分来源 模型构建 The lower reaches of Tarim River Populus euphratica Water source Model building |
| Abstract | 荒漠河岸林植物的生长与分布与水分关系密切，胡杨作为极端干旱区荒漠河岸林生态系统中的优势建群种，对其水分来源的研究可以掌握胡杨水分利用的规律，对于改善干旱区环境、保护并合理利用水资源、建立良好的生态系统群落、抑制荒漠化过程等方面具有十分重要的意义。目前利用氢氧同位素技术对胡杨的水分来源进行研究已经取得了很多成果，但由于氢氧同位素技术在水分来源定量应用时前提条件的限制以及模型（IsoSource 模型等）等计算时存在的问题均给准确区分植物的水分来源带来不确定性。因此需要构建适于干旱区胡杨水分来源的定量模型，探讨不同地下水埋深下胡杨水分来源的差异性，为干旱区植物水分来源的定量分析提供方法参考，为干旱区荒漠河岸林的保育、 修复和可持续发展提供科学依据。本研究通过塔里木河下游不同地下水埋深条件下胡杨的黎明前叶片水势、蒸腾量、木质部水同位素组成和土壤水、地下水等潜在水源的同位素组成以及对土壤水势等的测量与分析， 探究胡杨水分传输特征的基本规律； 将稳定同位素技术和植物水分传输过程相结合，构建适于胡杨水分来源估算的定量模型； 利用构建的定量模型，分析胡杨在日内和季节内，以及不同地下水埋深环境下胡杨对不同深度土壤水分的选择性利用。主要结果如下：1.在极端干旱的塔里木河下游，胡杨的树干液流变化具有明显的昼夜节律。白天胡杨液流速率的日变化曲线呈多峰型；夜间液流速率保持在一个较平稳状态。 研究分析： 太阳净辐射是影响该地区胡杨树干瞬时液流速率的最主要环境因子。2.在 6~8 月之间，胡杨黎明前叶水势和正午叶水势无显著差异，说明在观测期间胡杨水分来源未发生明显变化，胡杨吸收水分的主要土层在各月间差异不大，加上黎明前水势较高，即该研究区胡杨在观测期间可能主要利用深层土壤水或地下水。 而且， 黎明前叶水势数据说明胡杨仍在遭受轻微的水分胁迫。3.基于简单的植物生理过程，将植物水势数据和根系分布函数同稳定同位素技术结合起来，构建了适于估算胡杨水分选择性利用的定量模型。4.模型计算结果表明：塔里木河下游地区的胡杨主要利用 200cm 深度以下的土壤水和地下水，几乎不从 0~100cm 土壤层中吸收水分；在不同时间段内，各层来源水分对距河道不同距离样地胡杨的贡献率存在差异； 并且，在 6~8 月期间，胡杨吸收土壤水分的深度有随着时间的增加向深层土壤发展的趋势。与IsoSource 模型相比本文所构建的模型具有十分明显的优势。 |
| Other Abstract | The growth and distribution of riparian forest plants are closely related to water.Populus euphratica is a dominant group species in the desert riparian forestecosystem in the extreme arid region.The study on its water use regularity is ofsignificance to improve the environment of arid area, establish good ecosystemcommunity, protect and rationally use water resources. At present, manyachievements have been made in the study of water sources of P. euphratica byhydrogen and oxygen isotope technology, but the errors caused by the precondition ofhydrogen and oxygen isotope technology and the calculation of model (Isosourcemodel, etc.) all give uncertainty to distinguish the water source of plant accurately.Therefore, it is necessary to construct a quantitative model suitable for estimating thewater source of P. euphratica, which can help to discuss the difference of watersource of P. euphratica under different groundwater depth, to provide a reference forthe quantitative analysis of plant water sources in arid area, and to provide scientificbasis for conservation and restoration of desert riparian forest in arid area.In this study, the basic laws of water transfer characteristics of P. euphraticawere investigated by measuring and analyzing the water potential, transpiration, theisotopic compositions of the woody parts, the latent water sources such as soil waterand groundwater, and the soil potential in the Tarim River downstream under differentgroundwater depths. The stable isotope technology and the plant water transferprocess were combined to construct a quantitative model suitable for the estimation ofwater source of P. euphratica. The quantitative model was used to analyze theselective utilization of P. euphratica to different depths of soil water in days andseasons, and under different groundwater depth environment. The main results are asfollows:1. In the aird lower reaches of the Tarim, the change of sap flow of P.euphraticahas obvious circadian rhythm. The diurnal curve of the sap flow rate of P.euphraticawas multiple peaks in daytime. The velocity of the sap at night remained in a stable state. Analysis shows that: the Solar net radiation is the most important environmentalfactor affecting the instantaneous flow rate of P.euphratica in this area.2. In 6~8 months, the midday leaf water potential had no significant difference ofP. euphratica before dawn, indicating that P. euphratica water sources did not changesignificantly, and mainly soil moisture absorption little difference among month. Thepredawn water potential is state that the water source of P. euphratica is deep soilwater and groundwater, and also indicated that P. euphratica still suffers slight waterstress.3. Based on simple plant physiological processes, combine with the plant waterpotential data, root distribution function and stable isotope techniques to construct aquantitative model suitable for estimating the water selective utilization ofP.euphratica.4. The model calculation results show that P. euphratica in the lower reaches ofthe Tarim River mainly uses 200cm of soil water and groundwater, and absorb from0-100cm soil depth little. At different time periods, the contribution rate of the soilmoisture to p. euphratica is different in two sites. And, during June-August, The depthof soil water absorbed by P. euphratica has a tendency to develop toward deeper soilsover time. Compared with the Isosource model, the model constructed in this paperhas obvious advantages. |
| Subject Area | 自然地理学 |
| Language | 中文 |
| Document Type | 学位论文 |
| Identifier | http://ir.xjlas.org/handle/365004/14959 |
| Collection | 研究系统_荒漠环境研究室 |
| Affiliation | 中国科学院新疆生态与地理研究所 |
| First Author Affilication | 中国科学院新疆生态与地理研究所 |
| Recommended Citation GB/T 7714 | 陈晓林. 胡杨水分选择性利用的定量分析[D]. 新疆乌鲁木齐. 中国科学院大学,2018. |
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