KMS XINJIANG INSTITUTE OF ECOLOGY AND GEOGRAPHY，CAS
| 古尔班通古特沙漠南部两种梭梭属植物分布及其与地下水埋深关系 | |
| Alternative Title | Distribution of Two Haloxylon Plants and Their Relationship with Groundwater Depth in the Southern Part of the Gurbantunggut Desert |
| 吴雪 | |
| Subtype | 博士 |
| Thesis Advisor | 李彦 |
| 2019-06-30 | |
| Degree Grantor | 中国科学院大学 |
| Place of Conferral | 北京 |
| Degree Discipline | 理学博士 |
| Keyword | 干旱区 地下水埋深 生长分布 水分利用 生理响应 Arid region Groundwater depth Distribution Water use Physiological response |
| Abstract | 水分是陆地生态系统重要的限制因子之一，其有效性影响着系统内部植物的生长与生存，在很大程度上决定生态系统的结构、功能以及生产力水平。在干旱区，地下水是许多荒漠植物赖以生存的重要水源。近年来因人口数量增长及工农业用水需求增加，地下水被大量开发利用，这种不合理的水资源利用方式加速了局地地下水位的下降。局地水分循环和生态水文过程的改变必将会影响依靠地下水存活的植物的生长及生存，认识并确定这种影响及其程度成为亟待解决的现实问题。因此，本研究采取空间换时间的方法，利用古尔班通古特沙漠从边缘向内部地下水埋深逐渐增加的自然地形条件，以该区域的建群种梭梭(Haloxylonammodendron)和白梭梭(Haloxylon persicum)为研究对象， 开展野外植被调查、同位素样品采集分析以及生理监测等工作， 了解不同地下水埋深处梭梭和白梭梭的水分来源、数量、形态及生理特征，揭示地下水埋深变化对研究区两种梭梭属植物的影响并预测其未来发展。 实验结果如下：（1） 地下水埋深对两种梭梭属植物生长分布的影响梭梭和白梭梭的种群密度在不同地下水埋深之间差异显著（p < 0.05），且均与地下水埋深呈负相关。 当地下水埋深超过 13m 后，梭梭种群密度急剧下降，白梭梭取代梭梭成为更优势的物种。梭梭和白梭梭的最大株高和冠幅宽度在不同地下水埋深之间差异显著（p < 0.05），且与地下水埋深呈负相关； 梭梭的最大基径在不同地下水埋深之间也差异显著（p < 0.05）。 梭梭和白梭梭种群的地上、地下和总生物量在不同地下水埋深之间差异显著（p < 0.05），且与地下水埋深均呈负相关， 仅白梭梭的根冠比在不同地下水埋深之间差异显著(p < 0.05)，且与地下水埋深呈显著正相关（p < 0.05）。（2） 地下水埋深对两种梭梭属植物水分利用的影响梭梭与白梭梭具有不同的水分利用模式，他们通过二态性根系来应对土壤水有效性的时空变化。春季，梭梭和白梭梭分别主要利用浅层土壤水和中层土壤水；夏季和秋季，梭梭和白梭梭分别主要利用地下水和深层土壤水。 梭梭对地下水的依赖程度远远高于白梭梭， 但当地下水埋深增加时，梭梭和白梭梭对地下水的利用比例均明显减小。（3） 地下水埋深对两种梭梭属植物生理活动的影响梭梭和白梭梭的黎明前水势、正午水势、光系统Ⅱ最大光化学效率、光合性能指数等生理参数在不同地下水埋深之间差异显著（p < 0.05）； 梭梭的表观量子效率、最大净光合速率、 光补偿点、 气孔导度、蒸腾速率、胞间 CO2浓度、气孔限制值以及瞬时水分利用效率等生理参数在不同地下水埋深之间差异显著（p< 0.05），且多数生理参数与地下水埋深呈显著负相关（p < 0.05），而白梭梭各项生理参数保持良好和稳定。以上结果表明：地下水埋深的持续增加会限制该区域两种梭梭属植物的个体生长和生物量积累，不利于其种群的健康发展。梭梭和白梭梭具有不同的水分利用方式，所以二者生理活动对地下水埋深变化的响应具有明显的种间差异。地下水有效性的降低引起梭梭水分胁迫加剧，气体交换受阻碍，光合同化被破坏，而白梭梭依然维持良好的水分状况、稳定的气体交换和高效的碳同化速率。由于梭梭对地下水的依赖程度更高，地下水埋深增加对其未来生存更加不利。本研究通过探究古尔班通古特沙漠南部两种梭梭属植物的水分利用策略及其生长分布和生理活动对地下水埋深变化的响应与适应，深化了对荒漠植物-水分关系的认识和理解。研究结果可以为荒漠生态系统的管理与保护提供理论支撑，同时对社会生产实践以及资源利用具有重要的指导意义。 |
| Other Abstract | Water is one of the important limiting factors in terrestrial ecosystems. Itsavailability affects the growth and survival of plants, and largely determines thestructure, function and productivity of ecosystems. In arid regions, groundwater is animportant water source for desert plants. In recent years, due to the populationexpansion and the increasing water demand from industry and agriculture,groundwater has been over-exploited, which led to the decline of the groundwatertable. The changes of local water cycle and ecological hydrological processes willcertainly affect the growth and survival of groundwater-dependent plants, a betterunderstanding of these effects and their degrees is becoming urgent. Moving from thesouthern edge to the interior of the Gurbantunggut Desert, natural topographicvariability defines a spatial groundwater depth gradient, which provided a suitablesetting for the study. Therefore, the current study used the method of “space” for“time”, chose Haloxylon ammodendron and Haloxylon persicum, two edificators inthis region, as the research objects, conducted vegetation investigation, isotopicsample collection and analysis, and physiological monitor along the groundwaterdepth gradient, expecting to understand the water source, quality, morphology andphysiological characteristics of the studied species growing at different groundwaterdepths, so as to reveal the effect of groundwater depth variations on these twoHaloxylon plants and predict their future. The results as follow:(1) The effect of groundwater depth on the growth and distribution of the twoHaloxylon plantsThe population densities of H. ammodendron and H. persicum varied significantlyamong different groundwater depths (p < 0.05), and were negatively correlated withthe groundwater depth. When the groundwater depth exceeded 13m, the populationdensity of H. ammodendron dropped sharply, H. persicum replaced it becoming a more dominant species. The max tree height and canopy width of H. ammodendronand H. persicum varied significantly among different groundwater depths (p < 0.05),and were negatively correlated with the groundwater depth. The max basal stemdiameter of H. ammodendron varied significantly among different groundwater depths(p < 0.05). The aboveground, belowground and total biomass of H. ammodendron andH. persicum differed significantly among different groundwater depths (p < 0.05), andwere negatively correlated with the groundwater depth. But only the root-shoot ratioof H. persicum displayed a significant difference among different groundwater depth(p < 0.05), and showed a significant positive correlation with groundwater depth (p <0.05).(2) The effect of groundwater depth on the water use of the two Haloxylon plantsH. ammodendron and H. persicum employed different water uptake patterns andcoped with temporal and spatial changes in water availability through their dimorphicroot systems. In spring, H. ammodendron and H. persicum mainly made use ofshallow and middle soil water respectively; in summer and autumn, they mainlyextracted groundwater and deep soil water respectively. Compared to H. persicum, H.ammodendron was more groundwater dependent, but both two species reducedgroundwater use with the increase of groundwater depth.(3) The effect of groundwater depth on the physiological activities of the twoHaloxylon plantsH. ammodendron and H. persicum exhibited significant differences in the predawnand midday water potential, the maximal photochemical efficiency of PSⅡ, and theperformance index of photosynthesis among different groundwater depths (p < 0.05),but only the apparent quantum efficiency of photosynthesis, the maximum netphotosynthetic rate, the light compensation point, the stomatal conductance, thetranspiration rate, the intercellular CO2 concentration, the stomatal limited value andthe instantaneous water use efficiency of H. ammodendron varied significantly amongdifferent groundwater depths (p < 0.05). Most physiological parameters of H.ammodendron decreased with the increase of groundwater depth, while those of H.persicum could maintain well and stable.The above results show that: the continuous increase of groundwater depthrestricted the individual growth and biomass accumulation of the two Haloxylonplants in this region, which caused negative effects on their healthy development. Thetwo Haloxylon plants had different water use patterns, thus they exhibited significantinter-species difference in physiological responses to groundwater depth variations.The decreasing groundwater availability led to intensified water stress in H.ammodendron, disturbed its gas exchange and carbon assimilation, whereas H.persicum could maintain superior water status, stable gas exchange and highphotosynthetic rate. Because H. ammodendron was much moregroundwater-dependent, the increase of groundwater depth will be more adverse forits future survival.Through exploring the water use strategies of the two Haloxylon plants as well astheir growth, distribution and physiological responses to groundwater depth variations,the current study improved the understanding of desert plant-water relationships.These research results not only provided theoretical support for desert ecosystemmanagement and protection, but also had important guiding significance for socialproduction practice and resource utilization. |
| Subject Area | 生态学 |
| Language | 中文 |
| Document Type | 学位论文 |
| Identifier | http://ir.xjlas.org/handle/365004/15363 |
| 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 | 吴雪. 古尔班通古特沙漠南部两种梭梭属植物分布及其与地下水埋深关系[D]. 北京. 中国科学院大学,2019. |
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