KMS XINJIANG INSTITUTE OF ECOLOGY AND GEOGRAPHY，CAS
| 干旱区深根植物疏叶骆驼刺养分利用对潜水埋深的响应 | |
| 张波 | |
| Subtype | 博士 |
| Thesis Advisor | 曾凡江 |
| 2018-06-05 | |
| Degree Grantor | 中国科学院大学 |
| Place of Conferral | 新疆乌鲁木齐 |
| Degree Discipline | 理学博士 |
| Keyword | 干旱区 潜水埋深 深根植物骆驼刺 生态化学计量学 养分利用和回收 arid region groundwater level phreatophytic A. sparsifolia ecological stoichiometry nutrient utilization and recycling |
| Abstract | 水分与养分是维持干旱区荒漠生态系统生产力最重要的两大限制因子。水分直接决定着干旱区绿洲的生存和发展。由于受到气候变化（降水格局变化、山区来水减少）和人类活动（大规模开发土地、大量开发利用地下水资源）的双重影响，致使塔克拉玛干沙漠南缘区域深根植物赖以生存和维持的地下水埋深逐年下降，荒漠-绿洲过渡带大幅消失、自然植被出现严重退化，绿洲生态安全遭受巨大威胁。因此，加快荒漠自然植被修复、保护绿洲生态安全刻不容缓。充分了解和系统掌握区域优势荒漠深根植物生长、养分吸收/利用等与潜水埋深的关系，将为区域植被的修复、保护和利用提供科学数据与理论依据。本研究以塔克拉玛干沙漠南缘荒漠-绿洲过渡带多年生优势深根植物疏叶骆驼刺（Alhagi sparsifoliaShap.，简称骆驼刺） 为研究对象， 在 2015–2016 年通过人工模拟试验（潜水埋深分别为 0.4 m、 0.8 m、 1.2 m、 1.8 m 和 2.2 m）和自然环境试验（潜水埋深分别为 2.5 m、 4.5 m 和 11.0 m）相结合的方法，系统研究了不同潜水埋深条件下骆驼刺地上生物量积累及分配特征、植物叶/茎/刺中碳、氮、磷和钾的生态化学计量学特征以及植株内养分（氮、磷、钾）的吸收和回收效率，得到如下研究结论：（1） 潜水埋深对植物生物量积累及分配的影响：模拟试验中骆驼刺的地上生物量及叶茎比、叶刺比在 1.2 m 潜水埋深显著（p<0.05）高于其它潜水埋深处理。野外试验中骆驼刺的地上生物量及叶刺比在 4.5 m 潜水埋深显著（p<0.05）高于 2.5 m 和 4.5 m 潜水埋深。这表明骆驼刺在模拟试验中 1.2 m 和野外试验中4.5 m 潜水埋深时，积累了较多的地上生物量，并将更多的地上生物量分配在叶片中，减少了刺和茎的生物量分配。（2） 潜水埋深对土壤养分的影响：在两年模拟试验中，潜水埋深从 0.4 m增加到 1.2 m 时，土壤硝态氮、无机氮和土壤有效钾含量随之增加，在 1.2 m 潜水埋深达到最大，然后在 1.8 m 潜水埋深开始下降。在野外试验中，土壤硝态氮、无机氮、有效钾、有机碳和有效磷含量在 11.0 m 潜水埋深显著（p<0.05）大于2.5 m 和 4.5 m 潜水埋深。 2015–2016 年， 潜水埋深在模拟试验中对土壤养分变化的贡献率分别为 38.8%和 8.0%，在野外试验中的贡献率分别为 39.0%和 9.8%。（3） 潜水埋深对植物生态化学计量学特征的影响：模拟试验中 1–2 年生中幼龄骆驼刺叶、茎、刺中氮和磷含量均在潜水埋深 1.8 m 时达到最大，然后开始下降；钾含量在 2.2 m 潜水埋深最高；碳含量不受潜水埋深的影响。在野外试验中，多年生骆驼刺叶、茎、刺中的磷含量在 4.5 m 潜水埋深时均显著（p<0.05）低于 2.5 m 和 11.0 m 潜水埋深，钾含量在 4.5 m 潜水埋深显著（p<0.05）高于 2.5m 和 11.0 m 潜水埋深；多年生骆驼刺碳和氮的含量受潜水埋深变化的影响较小。2016 年模拟试验中潜水埋深对骆驼刺叶片养分含量变化的贡献率达 21.4%；在两年的野外试验中潜水埋深的贡献率分别为 12.1%和 7.0%。（4） 不同潜水埋深条件下土壤与植物养分含量的相互关系：模拟实验结果表明，在潜水埋深为 0.4–2.2 m 时， 1–2 年生中幼龄骆驼刺叶片碳、氮和磷含量与土壤碳、氮和磷含量显著（p<0.05）负相关。野外试验结果表明，在潜水埋深为2.5–11.0 m 时， 多年生骆驼刺叶片磷含量与土壤氮含量显著（p<0.05）正相关；叶片钾含量与土壤氮和磷含量显著（p<0.05）负相关。这表明在不同潜水埋深条件下中幼龄骆驼刺更容易受土壤碳、氮和磷含量的影响，多年生骆驼刺主要受土壤氮、磷和钾含量的影响。（5） 潜水埋深对植物养分吸收和回收的影响：不同潜水埋深条件下，中幼龄及多年生骆驼刺植株氮回收效率在 18.5%–55.1%之间， 磷回收效率在29.1%–81.0%之间， 钾回收效率在 7.2%–44.3%。模拟试验中幼龄骆驼刺氮利用效率和回收度在 1.8 m 潜水埋深时显著（p<0.05）大于其它潜水埋深处理；磷生产力和利用效率在 1.8 m 潜水埋深时显著（p<0.05）大于其它潜水埋深处理。骆驼刺钾的回收效率在 2.2 m 潜水埋深时显著（p<0.05）大于其它潜水埋深处理。野外试验骆驼刺磷回收效率和回收度在 4.5 m 潜水埋深时显著（p<0.05）高于 2.5 m和 11.0 m 潜水埋深；钾回收度在 11.0 m 潜水埋深时显著（p<0.05）大于 2.5 m 和11.0 m 潜水埋深；多年生骆驼刺植株内氮、磷、钾生产力、滞留时间和利用效率不受潜水埋深的影响。综上所述，潜水埋深显著影响骆驼刺的生长、生物量分配及土壤养分。骆驼刺中的磷和钾的含量受潜水埋深的影响较为明显，碳和氮含量受潜水埋深的影响较小。不同生长年限的骆驼刺对潜水埋深变化的响应机制不同。 1–2 年生中幼龄骆驼刺通过全面调整氮、 磷、 钾等养分利用和回收过程来适应潜水埋深变化，多年生成株仅通过调整磷和钾的养分回收过程来适应潜水埋深变化。本研究有助于深刻理解潜水埋深变化条件下荒漠深根植物的养分吸收和利用策略，对于荒漠深根植物的保护和人工恢复具有重要的科学意义和应用价值。 |
| Other Abstract | Water and nutrients are the most important factors affecting the productivitymaintenance of desert ecosystems in arid regions. Water is crucial to the survival anddevelopment of oases in arid areas. At the southern margin of the Taklamakan desert,survival and maintenance of phreatophytes are affected by groundwater, which areinfluenced by climate change (variations in precipitation and decreased water flowfrom mountains) and human activities (large-scale development of land andintensification of groundwater resource utilization). The yearly decline ingroundwater level has led to the disappearance of the desert-oasis transition zone,severe degradation of natural vegetation, and threats to oasis ecological security.Therefore, accelerating the restoration of desert natural vegetation and protecting theecological security of oases are vital. Understanding the relationships among plantgrowth, nutrient uptake/use of dominant phreatophyte and decreasing groundwaterdepth are essential for providing scientific data and theoretical basis for restoringvegetation, as well as for protecting and utilizing regional vegetation. In the presentwork, we investigated Alhagi sparsifolia Shap., which is widely distributed in desertoasis transition zones at the southern rim of Taklamakan desert. Simulated (0.4, 0.8,1.2, 1.8, and 2.2 m groundwater depth) and field (2.5, 4.5, and 11.0 m groundwaterdepth) experiments were conducted in 2015 and 2016, respectively. The abovegroundbiomass and allocation proportion, as well as carbon, nitrogen, phosphorus, andpotassium concentrations in the leaf, stem, and assimilative branch of A. sparsifoliaand the utilization and resorption of nitrogen, phosphorus, and potassium, wereexamined. The main results were as follows:(1) Effect of groundwater depth on plant biomass and biomass proportion: In thesimulated experiment, the aboveground biomass as well as leaf: stem and leaf:assimilative branch ratios at 1.2 m groundwater depth were significantly (p<0.05)higher than those at other groundwater depths. In the field experiment, theaboveground biomass and leaf: assimilative branch ratios at 4.5 m groundwater depth were significantly (p<0.05) higher than those at 2.5 and 4.5 m groundwater depths.Results showed that A. sparsifolia at groundwater depth of 1.2 m in the simulated and4.5 m in the field experiments had greater biomass, increased leaf biomass, anddecreased stem and assimilative branch biomass.(2) Effect of groundwater depth on soil nutrient: In the two-year simulatedexperiment, soil nitrate nitrogen, inorganic nitrogen, and available potassiumconcentrations significantly (p<0.05) increased with the increase in depth ofgroundwater increased from 0.4 m to 1.2 m. The highest values were measured at 1.2m groundwater depth, and then gradually decreased. In the field experiment, soilnitrate nitrogen, inorganic nitrogen, available soil potassium, soil organic carbon, andavailable phosphorus concentrations at 11.0 m groundwater depth were significantly(p<0.05) higher than those at 2.5 and 4.5 m groundwater depths. The simulatedexperiment further showed that groundwater depths accounted for 38.8% and 8.0% in thetotal variability of soil nutrients in 2015 and 2016, respectively. The field experiment furtherrevealed that groundwater depths explained 39.0% and 9.8% of the total variability of soilnutrients in 2015 and 2016, respectively.(3) Effect of groundwater depth on plant ecological stoichiometry: In thesimulated experiment, nitrogen and phosphorus concentrations in leaf, stem, andassimilative branch of young (1–2 years old) A. sparsifolia were the highest at 1.2 mgroundwater depth and then gradually decreased. The highest potassiumconcentrations in A. sparsifolia were measured at 2.2 m groundwater depth, andcarbon concentration was unaffected by groundwater depth. In the field experiment,the phosphorus concentrations at 4.5 m groundwater depth in the different organs ofperennial A. sparsifolia were significantly (p<0.05) lower than those at 2.5 and 11.0 mgroundwater depths. However, the potassium concentrations at 4.5 m weresignificantly (p<0.05) higher than those at 2.5 and 11.0 m groundwater depths.Groundwater depth hardly affected the carbon and nitrogen concentrations in thedifferent organs of perennial A. sparsifolia. Groundwater depth explained 21.4% ofthe total variability of the leaf nutrients in the simulated experiment in 2016 and12.1% and 7.0% of the total variability in the leaf nutrients in the field experiment conducted in 2015 and 2016, respectively.(4) Effect of groundwater depth on the relationship between soil and plantnutrients concentrations: In the simulated experiment, with increased depth ofgroundwater from 0.4 m to 2.2 m, the leaf carbon, nitrogen, and phosphorusconcentrations of young A. sparsifolia were significantly (p<0.05) affected by soilorganic carbon, available nitrogen, and available phosphorus concentrations. In thefield experiment, with increased depth of groundwater from 2.5 m to 11.0 m, the leafphosphorus and potassium concentrations of perennial A. sparsifolia weresignificantly (p<0.05) influenced by soil inorganic nitrogen, available soil phosphorus,and potassium concentrations. Results showed that leaf nutrients of young A.sparsifolia were significantly (p<0.05) affected by soil carbon, nitrogen, andphosphorus concentrations. The leaf nutrients of perennial A. sparsifolia weresignificantly (p<0.05) influenced by soil nitrogen, phosphorus, and potassiumconcentrations.(5) Effect of groundwater depth on plant nutrient utilization and resorption: Thenitrogen-resorption efficiencies of the young and perennial A. sparsifolia ranged from18.5%–55.1%. The phosphorus-resorption efficiencies were within 29.1%–81.0%,and the potassium-resorption efficiencies ranged from 7.2%–44.3%. In the simulatedexperiment, the nitrogen-use efficiency and nitrogen-resorption proficiency of 1–2years A. sparsifolia at 1.8 m groundwater depth were considerably lower than those atother groundwater depths. The phosphorus productivity and phosphorus-use efficiency of1–2 years A. sparsifolia at 1.8 m groundwater depth were significantly (p<0.05) lowerthan those at other groundwater depths. The potassium-resorption efficiency of 1–2years A. sparsifolia was greatest at 2.2 m groundwater depth. In the field experiment,the phosphorus-resorption efficiency of perennial A. sparsifolia at 4.5 m groundwater depthwas significantly (p<0.05) higher than those at 2.5 and 11.0 m groundwater. Thepotassium-resorption efficiency perennial A. sparsifolia at 11.0 m groundwater depth wassignificantly (p<0.05) higher than those at 2.5 and 4.5 m groundwater depth. Groundwaterdepth hardly affected the nutrient productivity, mean residence time, and nutrient-useefficiency of nitrogen, phosphorus, and potassium in the perennial A. sparsifolia.In general, groundwater depths significantly affected the growth and biomass proportionof A. sparsifolia and soil nutrients. Moreover, groundwater depths significantlyinfluenced the phosphorus and potassium concentrations in A. sparsifolia, but carbon andnitrogen concentrations were hardly affected by groundwater depth. The response mechanismof A. sparsifolia was different under different groundwater depths. A. sparsifolia grown for1–2 years adjusted the nutrient utilization and resorption of nitrogen, phosphorus, andpotassium to adapt to varying groundwater depths. Perennial A. sparsifolia adjustedonly its nutrient resorption of phosphorus and potassium to adapt to differentgroundwater depths. This study will deepen our understanding of nutrient absorptionand utilization strategies of desert phreatophyte under changing groundwater depthand enhance protection and artificial restoration of desert phreatophyte. Therefore, ithas important scientific significance and application value. |
| Subject Area | 生态学 |
| Language | 中文 |
| Document Type | 学位论文 |
| Identifier | http://ir.xjlas.org/handle/365004/14945 |
| 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 | 张波. 干旱区深根植物疏叶骆驼刺养分利用对潜水埋深的响应[D]. 新疆乌鲁木齐. 中国科学院大学,2018. |
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