Stomatal conductance, leaf greenness, and height of species in the Jena-Ecotron experiment

This dataset contains stomatal conductance, leaf greenness, and height of species in the Jena-Ecotron Experiment in 2012. This experiment was conducted in the Montpellier European Ecotron (CNRS, France), an advanced controlled environment facility for ecosystem research, and aimed at understanding the impact of plant species richness (4 vs. 16 species) for ecosystem carbon and water fluxes.
The soil monoliths used in this experiment contained plant communities originating from the long- term Jena Experiment (50°57.1' N, 11°37.5' E, 130 m above sea level; mean annual temperature 9.3°C, mean annual precipitation 587 mm) established in May 2002. Twelve plots were selected for the Jena-Ecotron study according to the following criteria: (1) the four functional groups grasses, legumes, small and tall herbs were present, (2) realized species numbers were close to sown species richness, and (3) plots were equally distributed across the experimental field site to account for different soil textures. Large monoliths (2 m² surface area, diameter of 1.6 m, 2 m depth with a weight of 7 to 8 tons) including intact soil and vegetation were excavated in December 2011 and placed in lysimeters. In March 2012, before the start of the vegetation growth, the lysimeters were transported and installed in the Macrocosms platform of the Montpellier European Ecotron.
Stomatal conductance (gs, mmol/m²/s) was measured with a portable leaf porometer (SC-1 Leaf porometer, Decagon Devices, Pullman, USA). Measurements were done in the auto mode using the first 30 s of stomatal conductance data to predict the final stomatal conductance under true steady state conditions. Leaf greenness (SPAD; unitless), an estimate of chlorophyll concentrations, was obtained by measuring the absorption of two different wavelength (650 nm and 940 nm) with a portable chlorophyll meter (SPAD-502; Konica-Minolta, Osaka, Japan). The growth height of three shoots (Ind h; cm) per species and unit was measured with a ruler. Values of stomatal conductance, leaf greenness and growth height of the individual measurements were averaged per species per plot.

本数据集涵盖2012年耶拿生态桶实验（Jena-Ecotron Experiment）中各物种的气孔导度、叶片绿度及株高数据。本实验依托法国国家科学研究中心（CNRS）下属的蒙彼利埃欧洲生态桶（Montpellier European Ecotron）开展，该设施是用于生态系统研究的先进受控环境实验平台，旨在厘清植物物种丰富度（4种与16种组配）对生态系统碳、水通量的影响。

本实验所用的土壤柱体（soil monoliths）源自2002年5月建立的长期耶拿实验（Jena Experiment）的植物群落，该实验场地位于北纬50°57.1'、东经11°37.5'，海拔130米，年平均气温9.3℃，年平均降水量587毫米。本次耶拿生态桶研究共选取12个样地，筛选标准如下：（1）样地涵盖草本植物、豆科植物、小型草本与高大草本四大功能群；（2）实际定植物种数与播种设定的物种丰富度相近；（3）样地在实验场地内均匀分布，以兼顾不同土壤质地的影响。2011年12月，研究人员挖掘出包含完整土壤与植被的大型土壤柱体（表面积2平方米，直径1.6米，深度2米，重量7至8吨），并将其安置于渗漏计（lysimeters）中。2012年3月，在植被生长季开始前，这些渗漏计被转运并安装至蒙彼利埃欧洲生态桶的大型宇宙（Macrocosms）实验平台。

气孔导度（Stomatal conductance，缩写gs，单位：mmol·m⁻²·s⁻¹）采用便携式叶片气孔计（SC-1型叶片气孔计，美国普尔曼市Decagon Devices公司生产）进行测定。测定采用自动模式，利用前30秒的气孔导度数据预测真实稳态条件下的最终气孔导度值。叶片绿度（SPAD，无单位）是叶绿素浓度的估算指标，通过便携式叶绿素仪（SPAD-502；日本大阪柯尼卡美能达（Konica-Minolta）公司生产）测定650nm与940nm两种波长下的吸光度得到。针对每个物种样地，选取3个枝条，采用直尺测定其株高，测定指标记为Ind h，单位为厘米（cm）。将每个样地内各物种的单次测定气孔导度、叶片绿度与株高数据进行平均，得到最终统计值。