Knowledge Resource Center for Ecological Environment in Arid Area
| 东天山草地植物碳同位素空间格局及其与气候因子的关系 | |
| 其他题名 | Spatial patterns of vegetation δ13C and their response to climate factors in in east Tianshan grassland |
| 刘泉均 | |
| 出版年 | 2018 |
| 学位类型 | 博士 |
| 导师 | 陈亚宁 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 植物碳同位素组成δ13C能够在一定的时空分布上有效映射自然界碳循环规律特征，为进一步理解陆地生态系统中碳循环机理特征提供基础信息。查清植物δ13C的空间分布规律及其对环境气候因子的响应机理将有益于全面深化解析全球气候变化背景下草地生态系统碳循环的反馈机制，并为科学认识和预测未来气候变化条件下草地生态系统的演进及发展模式提供科技支撑。本论文以中国新疆东天山巴里坤草地作为研究区域，基于中国国家气象局数据库，并结合野外样地调查与室内仪器检测，在群落水平上，重点分析讨论了植物叶片δ13C的空间分异特征及其对气候因子的响应，研究基本确定了影响植物叶片δ13C空间格局的主要控制要素。论文的主要研究结果如下：（1）通过对本研究区植物δ13C在不同器官、不同生活型以及不同草地类型间的特征及差异分析，发现中国新疆东天山巴里坤草地群落水平C3植物叶片δ13C的分布区间和分异程度均不及物种水平。实验结果还显示，不同生活型（主要是草本与半灌木植物）植物叶片δ13C与环境各指标间的差异存在截然相反的特征，这表示植物自身形态特征和其水分利用效率很可能会受外界其他因素扰动，间接使得叶片δ13C值发生变化，由此造成了植物叶片δ13C在不同生活型间存在较大差异的情况出现。（2）对比分析本研究区不同草地类型之间植物叶片δ13C值的特征及差异，结果显示，与隐域性低地草甸草原类抑或是高寒草甸草原类的草本植物相比，草原化荒漠类草地中的半灌木及杂类草的生境更加干旱，草本植物叶片δ13C值也相对较高，这也在一定程度上说明了植物为了适应更为干旱、水分胁迫较大的生境条件，其自身生理生态方面所作出的一种调节，结合第一条结论可以看出环境与植物之间保持着相互影响又相互适应的生存方式。（3）通过对该研究区不同分布位置的植物叶片δ13C进行分析，结果显示，植物叶片δ13C值随海拔的升高而减小，这与前人在其他地区所得出的研究结果并不相同，我们认为形成这一区别的原因可能有两方面：一方面在于局地环境、各种空间尺度下植物叶片碳同位素组成所具有的独特特征的形成要素不尽相同；另一方面，不同区域、不同生境条件下的植物类型存在较大差异，由此也会影响不同研究区植物叶片δ13C值空间格局的差异性。（4）通过对该研究区不同草地类型的植物叶片δ13C值分析，基本查明大气压强在影响植物叶片δ13C空间格局所有指标之中所占的比重最大。同时还发现，植物群落水平叶片δ13C值的波动程度以及与气候指标的相关性低于单一物种，换言之，当外界气候条件有所更替时，首先是与单一植物种碳同位素组成发生不同程度的作用，可若从群落方面进行分析，很大概率下群落作为一个整体会维持较为稳定的特征。（5）根据本文对植物叶片δ13C与叶片主要营养元素的分析，本研究区植物叶片δ13C与叶片主要营养元素包括元素比率之间的关系存在较大差异。其中，植物叶片δ13C与叶片氮N、碳磷比C/P以及氮磷比N/P之间呈正相关关系；与叶片碳C之间并未表现出明显的相关性甚至还存在负相关性；而与叶片磷P和碳氮比C/N之间则表现为负相关关系；植物叶片钾K与植物叶片δ13C之间呈显著的负相关关系。 一言以蔽之，在本研究区群落水平植物叶片δ13C随各类环境指标的变化率小于物种水平，这也意味着在全球气候变化条件下，生物多样性可能会对维持生态系统碳循环的稳定很有助益。另一方面，外界条件还可以影响植物叶片营养元素与光合作用效率、改变植物叶片的气孔导度或土壤氮有效性的关系，也就会在不同程度上改变植物叶片δ13C与叶片各主要营养元素之间的关系。 |
| 英文摘要 | Plant δ13C values can provide comprehensive information about natural carbon cycle in a certain spatial and temporal distribution, and can provide basic information for further understanding of the characteristics of carbon cycle mechanism in terrestrial ecosystems. Specifically, investigating the spatial variation of plant δ13C value and their response to climatic factors can help understand the effects of climate change on carbon cycling, and can also provide a scientific basis for understanding and predicting evolutionary and developmental trends of grassland ecosystems under the influence of climate change. This thesis presents the results of a study of the leaf δ13C values in the Barkol grassland area in the eastern Tianshan Mounmains, in Xinjiang, China. The spatial differentiation characteristics of δ13C and its response to climate factors are analyzed and discussed on the community level, based on the database of China's National Meteorological Bureau, combined with field survey and laboratory testing. The main aim was to characterize the spatial variation of the δ13C values of plant leaves in relation to climatic factors. The main results of this study are as follows:(1) Analyses of leaf δ13C values in different organs and different life forms between different grassland types reveal that the range and variation of leaf δ13C values of C3 plants was less than at the species level. In addition, the experimental results also showed that the difference between the leaf δ13C values of different life types (mainly herbaceous and subshrub plants) was opposite to the environmental indicators, suggesting that environmental conditions had an important influence on leaf δ13C via their effects on plant morphology and water use efficiency. This results in a large difference in the leaf δ13C between different life forms. (2) The characteristics and differences of leaf δ13C values between different grassland types in the study area were compared and analyzed. The results showed that compared with the herbaceous plants of the hidden meadow steppe or the alpine meadow steppe, the semi shrubs and the heterozygous grass in the grassland desertification grassland are more arid. And the δ13C values of the herbaceous plants were also relatively higher, to some extent, This indicates that the plants are physiologically and ecologically adapted to drought and water stress larger habitat conditions. Combined with the first conclusion, it can be seen that mutual influence and mutual adaptation between the environment and plant survival way.(3) The distribution of leaf δ13C values in the study area reveals a decrease with increasing altitude, in contrast to the results of previous research. This is not the same as previous research results obtained in other regions. We believe that there are two possible reasons for this difference: on the one hand, the unique elements of the carbon isotope composition of plant leaves in the local environment and on various spatial scales have different formation factors; on the other hand, there is a large difference in plant types under different habitats, which results in the difference of spatial pattern of plant leaves under different regional and different habitat conditions. (4) Through the analysis of leaf δ13C values in different parts of the study area, atmospheric pressure can be identified as the most important factor affecting the spatial distribution of values. At the same time, it was also found that the fluctuations in the leaf δ13C values and the correlation with climate indicators on community level were lower than that of a single species. In other words, when the external climate conditions were replaced, the carbon isotope composition of a single plant species took different degrees of action, but will remain relatively stable at a community level with a high probability. (5) The relationship between leaf nutrient elements and leaf δ13C values varies in the study region due to the effects of environmental factors. For the Barkol area, leaf δ13C values are positively correlated with leaf N, C/P and N/P, and negatively correlated with leaf P, K and C/N; however, they are not correlated with, or may even be negatively correlated with, leaf C. In summary, in the study area plant leaf δ13C values at the community level show a lower rate of change than at the species level. This means that under the conditions of global climate change, biodiversity may become an important factor influencing the stability of the carbon cycle of ecosystems. On the other hand, external conditions can also affect the relationship between plant leaf nutrient and photosynthesis efficiency, change the stomatal conductance of plant laves or soil nitrogen availability, and will also change the relationship between the plant leaf δ13C and the main leaf nutrient elements to varying degrees. |
| 中文关键词 | 植物碳同位素组成 ; 空间格局 ; 气候因子 ; 叶片营养元素 |
| 英文关键词 | Plant δ13C spatial pattern climate factors foliar nutrient |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 自然地理学 |
| 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/2XILL650/288190 |
| 推荐引用方式 GB/T 7714 | 刘泉均. 东天山草地植物碳同位素空间格局及其与气候因子的关系[D]. 中国科学院大学,2018. |
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