Knowledge Resource Center for Ecological Environment in Arid Area
| 干旱区深根植物骆驼刺养分利用对潜水埋深的响应 | |
| 其他题名 | Responses of the nutrient utilization of a phreatophyte Alhagi sparsifolia Shap. under different groundwater depths in an arid region |
| 张波 | |
| 出版年 | 2018 |
| 学位类型 | 博士 |
| 导师 | 曾凡江 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 水分与养分是维持陆地生态系统（尤其是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。骆驼刺是生长在新疆南疆荒漠-绿洲过渡带的一种多年生优势深根植物和克隆植物，是维持干旱区绿洲生态安全的重要屏障。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骆驼刺为研究对象，通过人工模拟试验（潜水埋深分别为0.4米、0.8米、1.2米、1.8米和2.2米）和自然环境试验（潜水埋深分别为2.5米、4.5米和11.0米）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）在潜水埋深对植物生物量积累及分配的研究方面：适宜的潜水埋深有利于骆驼刺的地上生物量积累，并且叶片在地上生物量中占有最大的比重。过深或过浅的潜水埋深均显著（p<0.05）抑制骆驼刺的地上生物量积累和叶生物量分配。随着潜水埋深的增加，骆驼刺地上生物量在适宜潜水埋深（模拟试验中1.2米和野外试验中4.5米）处理达到最大，然后逐渐下降。同时，骆驼刺在处于宜潜水埋深的处理中，将更多的生物量分配在叶片，而刺和茎的生物量分配相应减少。这表明骆驼刺可以通过调整生物量的分配策略，以适应潜水埋深变化。本研究通过拟合骆驼刺地上生物量和潜水埋深之间的关系，发现本区域骆驼刺生长的适宜潜水埋深为7.3米。（2）在潜水埋深对土壤养分特征影响的研究方面：适宜的潜水埋深有利于土壤有效养分的累积，而过深或过浅的潜水埋深均显著（p<0.05）阻碍土壤有效养分的积累。不同潜水埋深条件下，土壤养分含量之间存在显著（p<0.05）的耦合关系。在两年的模拟试验中，土壤硝态氮、无机氮和土壤有效钾含量随着潜水埋深的增加，在1.2米潜水埋深达到最大，然后逐渐下降。土壤有机碳和土壤有效钾含量之间显著（p<0.05）正相关。但在持续较长时间的野外试验中，土壤硝态氮、无机氮、有效钾、有机碳和有效磷含量随着潜水埋深的增加，在11.0米潜水埋深达到最大。土壤有机碳、无机氮、有效磷和有效钾含量之间均存在显著（p<0.05）正相关关系。此外，在同时考虑大气温度、土壤温度、大气净辐射和降雨等气象因子的情况下，潜水埋深依然是显著（p<0.05）影响土壤养分变化的重要因子。在2015年-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%。因此，在干旱区荒漠生态系统中，潜水埋深变化是影响土壤养分变化不可忽略的重要因子之一。（3）在潜水埋深对植物生态化学计量学特征影响的研究方面：适宜的潜水埋深有利于中幼龄（1-2年生）骆驼刺叶片氮、磷、钾的积累，而对于多年生植株，适宜潜水埋深骆驼刺叶片磷含量较低，钾含量较高。随着潜水埋深的增加，当潜水埋深达到1.8米时，中幼龄骆驼刺叶、茎、刺中氮、磷、钾含量达到最大，然后逐渐下降。4.5米潜水埋深的多年生骆驼刺不同器官的磷含量显著（p<0.05）低于2.5米和11.0米潜水埋深，而钾含量在4.5米最高，在2.5米和11.0米潜水埋深显著（p<0.05）较低。多年生骆驼刺碳和氮的含量基本不受潜水埋深变化的影响。中幼龄骆驼刺碳和钾含量在不同器官无显著（p>0.05）差异，氮和磷的含量依次为叶>刺>茎。多年生骆驼刺叶片碳含量显著（p<0.05）低于茎和刺，氮和磷含量同样为叶>刺>茎，钾含量在不同器官中无显著差异（p>0.05）。此外，根据不同潜水埋深植物的生态化学计量学特征及生物量累积特征，可以得出在4.5米潜水埋深，多年生骆驼刺采取防御性的生长策略；而在2.5米和11.0米潜水埋深，多年生骆驼刺主要采用竞争性的生长策略。研究表明：不同潜水埋深条件下骆驼刺叶片中拥有更高的氮和磷含量，有利于光合作用的进行。与中幼龄骆驼刺相比，磷和钾在野外多年生骆驼刺适应潜水埋深变化过程中具有重要的作用。（4）在不同潜水埋深条件下土壤与植物养分含量相关性研究方面：中幼龄骆驼刺叶片碳、氮、磷含量具有显著（p<0.05）的耦合关系，而多年生骆驼刺叶片氮、磷、钾养分含量具有显著（p<0.05）的耦合关系。中幼龄骆驼刺叶片碳、氮和磷显著（p<0.05）受土壤碳、氮和磷含量的影响。而多年生骆驼刺叶片磷和钾含量主要受土壤氮、磷和钾含量的影响。在模拟试验中，中幼龄骆驼刺叶片碳、氮和磷含量之间显著（p<0.05）正相关。土壤碳、氮和磷含量与骆驼刺叶片碳、氮和磷含量显著（p<0.05）负相关。在野外试验中，多年生骆驼刺叶片氮和叶片磷含量之间显著（p<0.05）正相关、与叶片钾之间显著（p<0.05）负相关。叶片磷含量和叶片钾含量之间显著（p<0.05）负相关。土壤氮含量与叶片磷含量显著（p<0.05）正相关，与叶片钾含量显著（p<0.05）负相关。骆驼刺叶片钾含量与土壤磷和土壤钾含量显著（p<0.05）负相关。通过对潜水埋深、土壤养分和气象因子综合分析发现：潜水埋深是显著（p<0.05）影响骆驼刺叶片生态计量学变化的重要因子之一。2016年潜水埋深在模拟试验中对骆驼刺叶片生态计量学变化的贡献率高达21.4%，而在两年的野外试验中贡献率分别为12.1%和7.0%。研究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，但不受土壤钾含量的影响。而多年生骆驼刺主要受土壤氮、磷和钾含量的影响，不受土壤碳含量的影响。（5）在潜水埋深对植物养分吸收和回收特征的研究方面：中幼龄骆驼刺和多年生骆驼刺对潜水埋深变化的响应机制不同。潜水埋深会显著（p<0.05）影响中幼龄骆驼刺植株氮、磷、钾养分库及养分吸收和回收过程，适宜潜水埋深骆驼刺养分的吸收和回收效率显著（p<0.05）较低，但潜水埋深对多年生骆驼刺的养分吸收影响较小。本研究中，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，低于全球62.1%的均值，高于豆科植物苜蓿的16.2%。磷回收效率在29.1%-81.0%之间，接近于全球64.9%的均值。钾回收效率在7.2%-44.3%，低于全球70.1%的均值。骆驼刺养分利用效率与土壤养分含量及植物自身特性密切相关。骆驼刺属于可以固氮的豆科植物，因此多年生骆驼刺氮利用和回收不受潜水埋深的影响，但中幼龄骆驼刺依然会受土壤无机氮含量的影响。当地土壤较低的磷含量和较高的钾含量导致多年生骆驼刺植株拥有较高的磷回收效率和较低的钾回收效率。在模拟试验中，潜水埋深显著（p<0.05）影响中幼龄骆驼刺氮利用效率和回收度、磷生产力和利用效率及钾回收效率。其中1.2米潜水埋深骆驼刺养分利用和回收效率显著（p<0.05）低于其它潜水埋深。在野外试验中，潜水埋深仅对多年生骆驼刺植株磷和钾回收效率和回收度产生显著（p<0.05）影响。2015-2016年，4.5米潜水埋深的骆驼刺磷回收效率显著（p<0.05）高于2.5米和11.0米潜水埋深，钾回收度变化规律相反。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。研究表明：中幼龄骆驼刺通过全面调整植株氮、磷、钾的利用和回收来适应潜水埋深的变化，而多年生骆驼刺仅通过改变植株磷和钾的养分回收来适应环境的变化。 |
| 英文摘要 | Water and nutrients are the most important factors affecting the productivity maintenance of ecosystems (especially desert ecosystems in arid regions). Water is crucial to the survival and development of oases in arid areas. Alhagi sparsifolia Shap., a perennial dominant phreatophyte, is a clone plant that grows in the desert-oasis transition zone of southern Xinjiang, China. A. sparsifolia is important vegetation that maintains ecological security in oases. The survival and maintenance of phreatophytes are affected by climate change (variations in precipitation and decreased water flow from mountains) and human activities (large-scale development of land and intensification of groundwater resource utilization). The groundwater level, at the southern margin of the Taklamakan desert, the yearly decline in phreatophytes 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 the ecological security of oases are vital. Understanding the relationships among plant growth, nutrient uptake/use of dominant phreatophyte, and decreasing groundwater depth are essential to providing scientific data and theoretical basis for restoring vegetation, protecting, and utilizing regional vegetation. In the present work, we investigated A. sparsifolia, which is widely distributed in desert oasis 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 groundwater depth) experiments were conducted in 2015 and 2016, respectively. The aboveground biomass and allocation proportion, carbon, nitrogen, phosphorus, and potassium concentrations in the leaf, stem, and assimilative branch of A. sparsifolia as well as its utilization and resorption of nitrogen, phosphorus, and potassium, were examined. The main results were as follows:(1) Moderate groundwater depth was beneficial to the accumulation of the aboveground biomass of A. sparsifolia, and the leaf had the largest proportion in the aboveground biomass. The low and high groundwater depth significantly (p<0.05) inhibited the aboveground biomass and leaf biomass proportion. With increased groundwater depth, the biomass of A. sparsifolia was the largest at moderate groundwater depth (1.2 m in the simulated and 4.5 m in the field experiments) and then gradually decreased. A. sparsifolia had an increased leaf biomass and decreased stem and assimilative branch biomass at the moderate groundwater depths of 1.2 and 4.5 m. A simple quadratic function can be fitted between the aboveground biomass of A. sparsifolia and groundwater depth. The analysis shows that the most suitable groundwater depth for the growth of wild A. sparsifolia was approximately 7.3 m.(2) Moderate groundwater depth benefited to the accumulation of soil available nutrients. The low and high groundwater depth significantly (p<0.05) inhibited the soil available nutrient concentration. In our short-term simulated experiment, soil nitrate nitrogen, inorganic nitrogen, and available potassium concentrations significantly (p<0.05) increased groundwater depth. These concentrations were the highest at 1.2 m groundwater depth and then gradually decreased. Soil organic carbon concentration was significant (p<0.05) and positively correlated with available soil potassium concentration. In our long-term field experiment, soil nitrate nitrogen, inorganic nitrogen, available soil potassium, soil organic carbon and available phosphorus concentrations significantly (p<0.05) elevated with increased groundwater depth and were the highest at 11.0 m groundwater. Significant (p<0.05) positive correlations were observed among soil organic carbon, inorganic nitrogen, available phosphorus, and available potassium concentrations. Groundwater depth significantly (p<0.05) influenced variations in soil nutrients compared with atmospheric temperature, soil temperature, photosynthetically active radiation, and precipitation. The simulated experiment further showed that groundwater depths explained 38.8% and 8.0% of the total variability of soil nutrients in 2015 and 2016, respectively. The field experiment further revealed that groundwater depths explained 39.0% and 9.8% of the total variability of soil nutrients in 2015 and 2016, respectively. Therefore, groundwater depth was one of the vital factors affecting soil nutrient concentrations in the desert ecosystem in an arid region.(3) Moderate groundwater depth helped in the uptake of nitrogen, phosphorus, and potassium in young (1-2 years old) A. sparsifolia. The low phosphorus and high potassium concentrations of perennial A. sparsifolia were observed in the moderate groundwater depth. In the simulated experiment, with increasing groundwater depth, the nitrogen, phosphorus, and potassium concentrations in the leaves, stems, and assimilative branches of the young A. sparsifolia were the largest at 1.8 m groundwater depth and then gradually decreased. In the field experiment, phosphorus concentrations at 4.5 m groundwater depth in the different organs of perennial A. sparsifolia were significantly (p<0.05) lower than those at 2.5 and 11.0 m groundwater depth. However, the potassium concentrations at 4.5 m were significantly (p<0.05) higher than those at 2.5 and 11.0 mgroundwater depth. Groundwater depth hardly affected carbon and nitrogen concentrations in the different organs of perennial A. sparsifolia. No significant differences in the carbon and nitrogen concentrations were found in the different organs of the young A. sparsifolia. The nitrogen and phosphorus concentrations in the leaves were higher than those in the stems and assimilative branches of the young A. sparsifolia. The nitrogen and phosphorus concentrations in the stems were higher than those in the assimilative branch of young A. sparsifolia. The carbon concentrations in leaves were significantly lower than those in the stems and the assimilative branches of perennial A. sparsifolia under different groundwater depths. The nitrogen and phosphorus concentrations in the leaves were the highest than those in stems and assimilative branches of perennial A. sparsifolia. The nitrogen and phosphorus concentrations in the stems were higher than those in the assimilative branch of perennial A. sparsifolia. However, no significant difference in the potassium concentration was observed in the different organs of A. sparsifolia. Groundwater depth significantly influenced the ratios of carbon and phosphorus, carbon and potassium, nitrogen and potassium, and potassium and phosphorus in A. sparsifolia leaves. Moreover, A. sparsifolia at 4.5 m groundwater depth adapted through a defensive life history strategy. Conversely, a competitive strategy was observed at 2.5 and 11.0 m groundwater depths, as indicated by the variations in the ecological stoichiometry and aboveground biomass of A. sparsifolia, respectively. Results showed that high nitrogen and phosphorus concentrations in the leaves of A. sparsifolia were beneficial to photosynthesis under different groundwater depths. Compared with young A. sparsifolia, the phosphorus and potassium in perennial A. sparsifolia played important roles in the adaptation of changes in groundwater depth.(4) Strong coupling relationships were observed among the leaf carbon, nitrogen, and phosphorus concentrations of young and the leaf nitrogen, phosphorus, and potassium concentrations of perennial A. sparsifolia. The leaf carbon, nitrogen, and phosphorus concentrations of young A. sparsifolia were significantly (p<0.05) affected by soil organic carbon, available nitrogen, and available phosphorus concentrations. The leaf phosphorus and potassium concentrations of perennial A. sparsifolia were significantly (p<0.05) influenced by soil inorganic nitrogen, available soil phosphorus, and potassium concentrations. Significant (p<0.05) positive correlations were observed among the leaf carbon, nitrogen, and phosphorus concentrations of young A. sparsifolia. The soil organic carbon, available nitrogen, and available phosphorus concentrations were significantly (p<0.05) and negatively correlated with the leaf carbon, nitrogen, and phosphorus concentrations of youngA. sparsifolia. The leaf nitrogen concentration of perennial A. sparsifolia was significantly (p<0.05) and positively correlated with the leaf phosphorus concentration but was significantly (p<0.05) and negatively correlated with the leaf potassium concentration. The leaf phosphorus concentration of perennial A. sparsifolia was significantly (p<0.05) and negatively correlated with the leaf potassium concentration. The soil nitrogen concentration was significantly (p<0.05) and positively correlated with the leaf phosphorus concentration but was significantly (p<0.05) and negatively correlated with the leaf potassium concentration. The leaf potassium concentration was significantly (p<0.05) and negatively correlated with the soil phosphorus and potassium concentrations. Compared with atmospheric temperature, soil temperature, photosynthetically active radiation, precipitation, and soil nutrients, groundwater depth significantly (p<0.05) affects the variations in the leaf carbon, nitrogen, phosphorus, and potassium stoichiometry of A. sparsifolia. The groundwater depth explained 21.4% of the total variability of the leaf carbon, nitrogen, phosphorus, and potassium stoichiometry in the simulated experiment and 12.1% and 7.0% of the total variability in the leaf carbon, nitrogen, phosphorus, and potassium stoichiometry in the field experiment conducted in 2015 and 2016, respectively. Results showed that the leaf carbon, nitrogen, and phosphorus concentrations of young A. sparsifolia were significantly affected by soil carbon, nitrogen and phosphorus concentration but were not affected by soil potassium concentration. The leaf phosphorus and potassium concentrations of perennial A. sparsifolia were significantly influenced by soil nitrogen, phosphorus, and potassium concentrations but not by soil carbon concentration. (5) The response mechanism of A. sparsifolia was different under different groundwater depths. Groundwater depth significantly (p<0.05) affected the concentrations, pools, nutrient uptake and resorption of nitrogen, phosphorus, and potassium of young A. sparsifolia. The nutrient utilization and resorption efficiency of young A. sparsifolia at moderate groundwater depth were significantly (p<0.05) lower than those at other groundwater depths. Groundwater depth had no effects on the nutrient uptake of perennials A. sparsifolia. The nitrogen-resorption efficiencies of the young and perennials A. sparsifolia in this study were 18.5%-55.1%, which were lower than 62.1% of a global level and higher than 16.2% of alfalfa. The phosphorus-resorption efficiencies were 29.1%-81.0%, which were close to the global average of 64.9%. The potassium-resorption efficiencies were 7.2%-44.3%, which were lower than the global average of 70.1%. The nutrient utilization efficiency was strongly related to soil nutrient concentration. A. sparsifolia is a leguminous plant that can fix atmospheric N2. Therefore, the nitrogen-use efficiency and nitrogen-resorption efficiency in perennials A. sparsifolia were not affected by groundwater depth. However, the nitrogen-use efficiency and nitrogen-resorption efficiency in the young A. sparsifolia were still influenced by soil inorganic nitrogen concentration. The low phosphorus and high potassium concentrations in the local soil resulted in high phosphorus-resorption efficiency and low potassium-resorption efficiency in young and perennial A. sparsifolia. In the simulated experiment, groundwater depth significantly influenced the nitrogen-use efficiency and nitrogen-resorption proficiency, phosphorus productivity and phosphorus-use efficiency, and potassium-resorption efficiency in young A. sparsifolia. Nutrient-use efficiency and nutrient-resorption efficiency of nitrogen, phosphorus, and potassium at 1.2 m groundwater depth were considerably lower than those at other groundwater depths. Groundwater depth significantly influenced the nutrient-resorption efficiency and nutrient-resorption proficiency of phosphorus and potassium in perennial A. sparsifolia in the field experiment. In 2015-2016, the phosphorus-resorption efficiency at 4.5 m groundwater depth was significantly (p<0.05) higher than those at 2.5 and 11.0 m groundwater. However, the potassium-resorption efficiency at 4.5 m groundwater depth was significantly (p<0.05) lower than those at 2.5 and 11.0 m groundwater depth. Groundwater depth hardly affected the nutrient productivity, mean residence time, and nutrient-use efficiency of nitrogen, phosphorus, and potassium in perennialA. sparsifolia. These results showed that A. sparsifolia grown for 1-2 years adjusted the nutrient utilization and resorption of nitrogen, phosphorus, and potassium to adapted varying groundwater depths. Perennial A. sparsifolia adjusted only its nutrient resorption of phosphorus and potassium to adapted different groundwater depths. |
| 中文关键词 | 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 |
| 英文关键词 | arid region groundwater level phreatophytic A. sparsifolia ecological stoichiometry nutrient utilization and recycling |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 生态学 |
| 来源机构 | 中国科学院新疆生态与地理研究所 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/288155 |
| 推荐引用方式 GB/T 7714 | 张波. 干旱区深根植物骆驼刺养分利用对潜水埋深的响应[D]. 中国科学院大学,2018. |
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