KMS XINJIANG INSTITUTE OF ECOLOGY AND GEOGRAPHY，CAS
| 梭梭（Haloxylon ammodendron） 对地下水位变化的响应和适应性研究 | |
| Alternative Title | A study on the response and adaptability of Haloxylon ammodendron to changes in groundwater level |
| 米晓军 | |
| Subtype | 硕士 |
| Thesis Advisor | 马健 |
| 2020-06-30 | |
| Degree Grantor | 中国科学院大学 |
| Place of Conferral | 北京 |
| Degree Discipline | 工程硕士 |
| Keyword | 地下水埋深 饱和膨压 渗透调节物质 同化枝生长 胡伯尔值 Groundwater depth full turgor point osmotic adjustment substances leaf growth rates Huber value |
| Abstract | 干旱区因降水稀少， 荒漠植被多直接或间接以地下水为主要水分来源。 荒漠植被中的灌木， 因个体高大， 生物量高， 投影盖度大， 成为荒漠生态系统中的主要生产者， 对群落组成的构建和系统功能的维持具有决定意义， 是该生态系统存在的基础。 梭梭作为典型的地下水湿生植物能通过将根系深入地下水毛细上升区从而获得持续稳定的有效水源。 荒漠灌木遭受干旱胁迫， 将导致生长速率减缓甚至停滞， 引起叶片水势及细胞膨压下降， 导致茎端和叶片发生下垂及萎蔫现象。植物通过水势差调节、 渗透调节、 形态调整等多种适应调节方式来应对干旱胁迫。本研究选择古尔班通古特沙漠建群种梭梭为试验对象， 在自然生境（5 个地下水埋深： 3.45、 9.08、 10.47、 13.27、 15.91 m） 和人为生境（2 个地下水埋深： 2.0、3.5 m） 不同地下水埋深处理下， 对梭梭的水分关系性状、 光合特性和形态性状等进行测量， 探究地下水位变化对梭梭同化枝水势、 细胞膨压、 同化枝光合、 同化枝生长、 同化枝渗透调节物质含量、 枝条水力导度、 水力安全范围和胡伯尔值的影响， 并对同化枝水势、 细胞膨压、 同化枝生长及枝条胡伯尔值之间的相互作用关系进行探讨。 主要研究结果如下：（1） 自然生境中， 地下水位下降对梭梭的植物水分生理产生不利影响， 梭梭的黎明水势（Ψpd） 、 正午水势（Ψmd） 、 同化枝含水量（θL） 、 饱和膨压（ΨFTP）、膨压消失点水势（ΨTLP） 等水分关系性状随地下水埋深的增加而显著降低， 植物的水分状况恶化， 同化枝水势差（ΔΨ） 随地下水埋深的增大而增大。 人工模拟生境中， 当地下水埋深为 2.0 m 时， 土壤水分蒸发引起的表层盐分积累， 会对梭梭产生盐分胁迫， 植物通过降低正午同化枝水势来促进吸水以应对土壤盐分胁迫引起的土壤水分有效性降低。（2） 饱和膨压沿地下水埋深的下降引起植物同化枝生长速率减缓， 梭梭通过在同化枝内积累糖类等渗透调节物质， 来改善由地下水位下降引起的植物水分状况恶化及生长速率减缓， 梭梭同化枝内的总糖含量随地下水埋深的增加而显著增大。（3） 沿不同地下水埋深， 梭梭胡伯尔值（Hv） 的变化规律与各位点的同化枝面积显著相关， 胡伯尔值随地下水埋深增加逐渐增大， 这主要由各位点同化枝生长速率不同造成的同化枝面积存在差异引起。（4） 在渗透调节、 水势差调节和形态调整的共同维持下， 梭梭同化枝的光合能力随地下水埋深增加未发生显著下降， 最大光合速率（Amax）、 光饱和点（LSP）和表观量子效率（AQY） 基本维持不变， 光补偿点（LCP） 随地下水埋深的增大而上升。（5） 自然生境中， 梭梭枝条水力导度损失 50% （Ψ50） 和 88%（Ψ88） 时对应的木质部水势分别为-3.87 MPa 和-7.33 MPa， 说明其具有较强的导管栓塞抗性，但随着地下水埋深的增加， 梭梭应对水力失调的水力安全范围逐渐变窄。 |
| Other Abstract | Due to the scarcity of precipitation in arid areas, desert vegetation mainlydepends on groundwater directly or indirectly. Shrubs in desert vegetation are themain productivity of desert ecosystem due to its large individual sizes, high biomassand large projection coverage, which make the shrubs as foundation to theconstruction of community composition and the maintenance of system function. As atypical phreatophyte, Haloxylon ammodendron can obtain a sustainable and stableeffective water source by deepening its root system into the capillary rising zone ofgroundwater. Under drought stress, the growth rate of desert shrubs will slow down oreven stagnate, causing the drop of leaf water potential and cell turgor, leading todrooping and wilting of terminal stem and leaf. Plants respond to drought stress byadjusting osmotic, morphology and water potential difference. In this study, a speciesof Haloxylon ammodendron was selected as target species growing in the southernfringe of Gurbantunggut Desert with different depths to groundwater (the depth togroundwater was 3.45, 9.08, 10.47, 13.27, 15.91 m) and growing in study plots withtwo artificial groundwater level (2.0 and 3.5 m).Plant hydraulic traits, physiologicaltrait, photosynthetic characteristics and morphological characters of Haloxylonammodendron were measured. To explore the influence of groundwater level changeon the leaf water potential, cell turgor, leaf photosynthesis, hydraulic safety margin,Huber value, content of osmotic substances in leaf and leaf growth rate. Therelationships between leaf water potential, cell turgor, leaf growth and Huber valuewere studied. The results show that:(1) The decrease of groundwater level has a negative effect on the waterphysiology of Haloxylon ammodendron. The water relations properties such aspredawn leaf water potential (Ψpd), midday water water potential (Ψmd), leaf watercontent (θL), full turgor point (ΨFTP), turgor loss point (ΨTLP) were dropdownsignificantly with the increase of buried depth of groundwater. The values of differences in predawn and midday leaf water potential were decreased with theincreasing depth to groundwater. When the local groundwater level is relativelyshallow, 2.0 m, the surface salt accumulation caused by the evaporation of soil water.This will cause salt stress on Haloxylon ammodendron. It can respond to salt stress byreducing the midday water potential and promoting water absorption.(2) The decrease of full turgor point along the groundwater depth gradient causesthe growth rate of plant leaves to slow down. By accumulating osmotic substancessuch as glucose in the leaves, Haloxylon ammodendron can keep absorb water fromdry soil or more deep wet soil layers and at the same time slow down of growth rateas response to the decline of groundwater level. The glucose content in the leaf ofHaloxylon ammodendron increased significantly with the increase of groundwaterdepth, which play an important role in osmotic adjustment.(3) Along the gradient of groundwater, the change of Huber value of Haloxylonammodendron was significantly correlated with the leaf area of each point. Thegradient of Huber value increases gradually along the groundwater depth, which ismainly caused by the difference of leaf area caused by different leaf growth rates ateach point.(4) Under the co-maintenance of osmotic water potential difference regulationand morphological adjustment, the photosynthetic capacity of leaves did not decreasesignificantly along the groundwater level gradient. The maximum photosynthetic rate(Amas) light saturation point (LSP) and apparent quantum efficiency (AQY) remainedunchanged along the groundwater gradient. The light compensation point (LCP) risesalong the gradient of the groundwater level.(5) The xylem water potential was -3.87 MPa and -7.33 MPa when branchhydraulic conductance loss of 50% (Ψ50) and 88% (Ψ88), respectively. However, withthe decline of groundwater level, the hydraulic safety ranges of Haloxylonammodendron get narrow. |
| Subject Area | 环境工程 |
| Language | 中文 |
| Document Type | 学位论文 |
| Identifier | http://ir.xjlas.org/handle/365004/15448 |
| Collection | 中国科学院新疆生态与地理研究所 研究系统 |
| 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 | 米晓军. 梭梭（Haloxylon ammodendron） 对地下水位变化的响应和适应性研究[D]. 北京. 中国科学院大学,2020. |
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