EGI OpenIR  > 研究系统  > 荒漠环境研究室
Thesis Advisor陈亚宁
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植物碳同位素组成 空间格局 气候因子 叶片营养元素 Plant δ 13C Spatial pattern Climate factors Leaf nutrient
Abstract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。
Other AbstractPlant δ13C values can provide comprehensive information about natural carboncycle in a certain spatial and temporal distribution, and can provide basic informationfor further understanding of the characteristics of carbon cycle mechanism interrestrial ecosystems. Specifically, investigating the spatial variation of plant δ13Cvalue and their response to climatic factors can help understand the effects of climatechange on carbon cycling, and can also provide a scientific basis for understandingand predicting evolutionary and developmental trends of grassland ecosystems underthe influence of climate change.This thesis presents the results of a study of the leaf δ13C values in the Barkolgrassland area in the eastern Tianshan Mounmains, in Xinjiang, China. The spatialdifferentiation characteristics of δ13C and its response to climate factors are analyzedand discussed on the community level, based on the database of China's NationalMeteorological Bureau, combined with field survey and laboratory testing. The mainaim was to characterize the spatial variation of the δ13C values of plant leaves inrelation to climatic factors. The main results of this study are as follows:(1) Analyses of leaf δ13C values in different organs and different life formsbetween different grassland types reveal that the range and variation of leaf δ13Cvalues of C3 plants was less than at the species level. In addition, the experimentalresults also showed that the difference between the leaf δ13C values of different lifetypes (mainly herbaceous and subshrub plants) was opposite to the environmentalindicators, suggesting that environmental conditions had an important influence onleaf δ13C via their effects on plant morphology and water use efficiency. This resultsin a large difference in the leaf δ13C between different life forms.(2) The characteristics and differences of leaf δ13C values between differentgrassland types in the study area were compared and analyzed. The results showedthat compared with the herbaceous plants of the hidden meadow steppe or the alpine meadow steppe, the semi shrubs and the heterozygous grass in the grasslanddesertification grassland are more arid. And the δ13C values of the herbaceous plantswere also relatively higher, to some extent, This indicates that the plants arephysiologically and ecologically adapted to drought and water stress larger habitatconditions. Combined with the first conclusion, it can be seen that mutual influenceand mutual adaptation between the environment and plant survival way.(3) The distribution of leaf δ13C values in the study area reveals a decrease withincreasing altitude, in contrast to the results of previous research. This is not the sameas previous research results obtained in other regions. We believe that there are twopossible reasons for this difference: on the one hand, the unique elements of thecarbon isotope composition of plant leaves in the local environment and on variousspatial scales have different formation factors; on the other hand, there is a largedifference in plant types under different habitats, which results in the difference ofspatial 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 thespatial distribution of values. At the same time, it was also found that the fluctuationsin the leaf δ13C values and the correlation with climate indicators on community levelwere lower than that of a single species. In other words, when the external climateconditions were replaced, the carbon isotope composition of a single plant speciestook different degrees of action, but will remain relatively stable at a community levelwith a high probability.(5) The relationship between leaf nutrient elements and leaf δ13C values variesin 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 negativelycorrelated with leaf P, K and C/N; however, they are not correlated with, or may evenbe negatively correlated with, leaf C.In summary, in the study area plant leaf δ13C values at the community level showa lower rate of change than at the species level. This means that under the conditionsof global climate change, biodiversity may become an important factor influencing the stability of the carbon cycle of ecosystems. On the other hand, external conditionscan also affect the relationship between plant leaf nutrient and photosynthesisefficiency, 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 leafnutrient elements to varying degrees.
Subject Area自然地理学
Document Type学位论文
First Author Affilication中国科学院新疆生态与地理研究所
Recommended Citation
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]. 新疆乌鲁木齐. 中国科学院大学,2018.
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