The data comprise of four datasets for Spring wheat (Triticum aestivum L., cv. Mulika) from a season-long ozone exposure experiment in mesocosms: i) Yield and biomass data (including harvest index and individual grain weight) gathered at the end of the experiment; ii) measurements of chlorophyll content index (CCI) measured ad-hoc using a Soil-Plant Analyses Development (SPAD) chlorophyll meter throughout the experiment across all treatments; iii) measurements of leaf stomatal conductance, measured ad-hoc using a porometer throughout the experiment across all treatments; iv) results from four growth stage assessments conducted at different stages of the experiment. Yield and Biomass data are dry weights of non-edge plants, with a cutting height of 5cm above soil level. Leaf chlorophyll and stomatal conductance data were measured on the most recently fully expanded leaf (flag leaf from 28th May 2015 onwards) of randomly selected non-edge plants. The data are from an ozone and drought exposure experiment conducted during April-August 2015 at the Centre for Ecology & Hydrology Bangor solardome facility near Abergwyngregyn (Latitude 53.2387, Longitude -4.0176). The objective of the experiment was to determine how two abiotic stressors in combination - ozone and drought - would interact to influence growth and yield of wheat, and also what impact the timing of drought would have on the result. Spring wheat (Triticum aestivum L., cv. Mulika) was grown in rows within large 25-litre pots, and exposed to eight ozone treatments for 82 days. Plants experienced either (i) a well-watered regime (ii) a 10-day early-season drought event or (iii) a 10-day late-season drought event. The eight Ozone (O3) treatments ranged from a 24-hour mean of 27 parts per billion (ppb) in the lowest treatment to 57 ppb in the highest, with daily peaks ranging from 32 to 115 ppb This work was carried out as part of a Ph.D. funded by the Natural Environment Research Council (NERC) (NERC Reference NEC05014/3328/988) Full details about this dataset can be found at https://doi.org/10.5285/9678f446-0e2f-4f9c-860a-cbedfce4c7ec

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. Full details about this dataset can be found at https://doi.org/10.5285/f14b9056-ccc0-4887-812e-c004f613a138

The data are biomass and ozone-injury data for white clover (Trifolium repens). Dataset concerns a 2014 study on the effects of Jasmonic acid/cutting in modulating the response of clover to ozone. A short-term (4-week) ozone-exposure experiment was conducted in 2014 to investigate the interactive effects of cutting on ozone-induced responses in white clover (Trifolium repens). A strong interaction was found in root biomass and root nodule biomass in cut white clover plants in a high ozone background (45-67 parts per billion (ppb) treatment mean), suggesting ozone-impacts on root nodule biomass occur through limitation of carbon availability. The work was carried out as part of a NERC funded PhD. Full details about this dataset can be found at https://doi.org/10.5285/10c6df00-c7ef-444b-951f-33a2c0072bec

Data includes raw shoot biomass and yield, production and gas exchange, nodulation and N-fixation and forage quality data, including relative and consumable food values. The impacts of ozone on the growth and functioning of high-sugar ryegrass pasture mesocosms was assessed in year 2013. Pasture mesocosms, containing perennial ryegrass (Lolium perenne L) and white clover (Trifolium repens L), were grown in the early spring and exposed to ozone in solardomes from late April 2013 to the end of September 2013. Ozone (30, 35, 40, 45, 52, 67 parts per billion (ppb) treatment means) had a large effect on the pasture mesocosms. The work was carried out as part of a NERC funded PhD. Project number NEC04456. Full details about this dataset can be found at https://doi.org/10.5285/e0bcdc39-ab79-413c-bf76-d6ffbc510f15

The data are biomass measurements from an ozone exposure 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). Measurements were dry weight, with a cutting height of 7cm above soil level. The distribution of plant material within the canopy was determined by separating material growing in the upper canopy (>14cm) from the canopy edge and the inner canopy for both species. The experiments were carried out in the CEH Bangor Air Pollution Facility. Work was funded by the Centre for Ecology & Hydrology Integrating Fund Initiative. 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. Full details about this dataset can be found at https://doi.org/10.5285/5de90f7a-dec9-4bd5-af52-d0873a09d25d

Data includes impacts on root nodule biomass, stomatal conductance, injury rates, and N-fixation in the white clover cultivar (T. repens cv. crusader). An ozone-exposure experiment was conducted in solardomes during the spring and summer of year 2012 on modern clover (Trifolium spp.) cultivars. The effects of ozone pollution (30, 35, 40, 45, 52, 67 parts per billion (ppb) treatment means) on the growth and functioning of the clover cultivars was investigated. Both cultivars had positive increases in ozone-injury rates, although stomatal conductance was unaffected by ozone exposure. Reductions in root nodule biomass and nodule number occurred in white clover, and red clover displayed an increase in nodule density. Nitrogen fixation rates were suppressed in white clover, which could have important implications for the sustainability of managed pasture. The work was carried out as part of a NERC funded PhD. Project number NEC04456. Full details about this dataset can be found at https://doi.org/10.5285/b63fbb6c-5030-43a1-b0ea-160bb5a83078

The dataset consists of proportions of ozone injured or senesced leaves from a study which investigated how the presence of competing species in a community affects these two common responses to ozone. Monocultures and mixtures of Trifolium repens and Lolium perenne were grown in large containers and were exposed in solardomes to either a rural episodic ozone profile (AOT40 (Accumulated Ozone Threshold exposure of 40 parts per billion) of 12.86 ppm h) or control conditions (AOT40 of 0.02 ppm h) for 12 weeks. The proportion of ozone-injured or senesced leaves was determined in different regions of the canopy, the upper canopy (>14cm high), the canopy edge and the inner canopy, by separating injured/senesced leaves from healthy leaves. 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 Full details about this dataset can be found at https://doi.org/10.5285/bc4d0325-b67b-4fff-a14b-6e06edf397bd