SGS-LTER CO2 Elevation Study: Assimilation vs. intercellular CO2 response curves on Open Top Chamber species on the Central Plains Experimental Range, Nunn, Colorado, USA 1997 - 2001

This data package was produced by researchers working on the Shortgrass Steppe
Long Term Ecological Research (SGS-LTER) Project, administered at Colorado State University.
Long-term datasets and background information (proposals, reports, photographs, etc.) on the
SGS-LTER project are contained in a comprehensive project collection within the Digital
Collections of Colorado (http://digitool.library.colostate.edu/R/?func=collections&collection_id=3429).
The data table and associated metadata document, which is
generated in Ecological Metadata Language, may be available through other repositories
serving the ecological research community and represent components of the larger SGS-LTER
project collection. Additional information and referenced materials can be found: http://hdl.handle.net/10217/82454. Single leaf gas exchange (CO2 & H2O) was measured several times per season on important grass species in the shortgrass steppe open-top-chamber experiment. Cuvette CO2 levels were varied to investigate physiological adaptations to elevated CO2. C3 grass displayed photosynthetic acclimation, while C4 grass did not. Leaf water-use-efficiency was improved under ECO2. Absolute assimilation rates were more dependent on soil and plant water status than on CO2. This research was conducted at the Central Plains Experimental Range, near Nunn, CO; lat.40degrees 40 minutes N; long. 104 degrees 45 minutes W in the shortgrass steppe region of NE Colorado, USA and as a collaboration between SGS-LTER and USDA-ARS researchers.

本数据包由参与短草草原长期生态研究（Shortgrass Steppe Long Term Ecological Research, SGS-LTER）项目的研究人员编制，该项目由科罗拉多州立大学负责管理。
关于SGS-LTER项目的长期数据集与背景资料（包括研究方案、报告、影像资料等），均收录于科罗拉多数字馆藏（Digital Collections of Colorado）的综合项目馆藏中，访问链接为http://digitool.library.colostate.edu/R/?func=collections&collection_id=3429。
本数据集的数据表与配套元数据文档（采用生态元数据语言Ecological Metadata Language格式生成），亦可通过服务于生态研究共同体的其他仓储平台获取，且均属于SGS-LTER综合项目馆藏的组成部分。更多相关信息与参考资料可通过链接http://hdl.handle.net/10217/82454查阅。
本研究针对短草草原开顶箱实验（open-top-chamber experiment）中的重要禾本科物种，于每个生长季多次测定其单叶气体交换（CO₂与H₂O）参数。通过调节叶室CO₂浓度，探究植物对CO₂浓度升高的生理适应机制。研究发现，C3类禾草表现出光合驯化现象，而C4类禾草则无此特征；在CO₂浓度升高（ECO2）环境下，植物叶片水分利用效率得到提升。绝对同化速率更多依赖于土壤与植株的水分状况，而非CO₂浓度本身。
本研究在美国科罗拉多州东北部的短草草原区域开展，具体位于科罗拉多州努恩附近的中央平原实验牧场，地理坐标为北纬40°40′、西经104°45′，由SGS-LTER项目与美国农业部农业研究服务局（USDA-ARS）研究人员合作完成。