Photosynthesis of Trifolium repens versus Lolium perenne after ozone exposure in solardomes

The dataset consists of ACi (net CO2 assimilation rate, A, versus calculated substomatal CO2 concentration, Ci) curve data from an ozone experiment during which Trifolium repens and Lolium perenne were exposed as both monocultures and two-species mixtures to an episodic rural ozone regime in large, well-watered containers within solardomes for 12 weeks. Treatments were elevated ozone (AOT40 (Accumulated Ozone Threshold exposure of 40 parts per billion) of 12.86 ppm h) or control conditions (AOT40 of 0.02 ppm h). ACi curves were carried out mid-way and at the end of the exposure period using a Portable Photosynthesis System, CIRAS (PP-Systems) to calculate the photosynthetic parameters Jmax (maximum rate of photosynthetic electron transport) and Vcmax (maximum rate of Rubisco carboxylase activity). The observed decreases in photosynthetic efficiency and capacity in elevated ozone indicate that the ability of such ubiquitous vegetation to act as a sink for atmospheric carbon may be reduced in future climates. The experiment was carried out at the CEH Bangor Air Pollution Facility. This work was funded by the Centre for Ecology & Hydrology Integrating Fund Initiative.

本数据集涵盖一项臭氧胁迫实验中的ACi曲线数据，该曲线指净CO₂同化速率（net CO₂ assimilation rate, A）与计算得到的气孔下腔CO₂浓度（substomatal CO₂ concentration, Ci）的关系曲线。实验中，白三叶（Trifolium repens）和黑麦草（Lolium perenne）以单作（monocultures）及两物种混作（two-species mixtures）的种植模式，于太阳穹顶（solardomes）内浇水充足的大型容器中暴露于间歇性乡村臭氧环境，处理时长为12周。实验设置两种处理条件：臭氧升高组（AOT40：累积40ppb臭氧阈值暴露量，即Accumulated Ozone Threshold exposure of 40 parts per billion，为12.86 ppm·h）与对照组（AOT40为0.02 ppm·h）。分别在处理周期中途及结束时，使用便携式光合测定系统CIRAS（PP-Systems）测定ACi曲线，以计算光合参数最大光合电子传递速率（maximum rate of photosynthetic electron transport, Jmax）与Rubisco羧化酶最大活性速率（maximum rate of Rubisco carboxylase activity, Vcmax）。观测到臭氧升高条件下植物光合效率与能力出现下降，这表明此类广布植被作为大气碳汇的能力在未来气候情境中可能会降低。本实验于CEH班戈空气污染实验基地（CEH Bangor Air Pollution Facility）开展，研究工作由生态与水文研究中心整合基金计划（Centre for Ecology & Hydrology Integrating Fund Initiative）资助。