DOI: 10.5285/9678f446-0e2f-4f9c-860a-cbedfce4c7ec
title: Plant physiology data for the spring wheat cultivar Mulika, in response to combined ozone and drought exposure in 2015

description: 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)
description: Yield/Biomass data: This data was collected at the end of the experimental season, during August 2015. The total number of plants per pot was first counted, and all non-edge wheat plants were then cut at a level of 5cm above the soil surface. Ears were separated from the rest of the plant material, and ears were then threshed using a hand thresher to extract the wheat grains. Grain weight, ear weight and straw weight was measured before plant sampled were dried for one week in an oven at 65 degrees Celsius. Dry weight of all samples could then be measured. Data were recorded on paper data tables, and subsequently entered into Microsoft Excel. Calculation of particular harvest parameters (e.g. yield in kh/ha, harvest index) was conducted in Excel, and data was later exported as a comma separated value (csv) file for ingestion into the Environmental Information Data Centre. Calculation of certain harvest parameters (e.g. yield in kg/ha, harvest index) was carried out in Microsoft Excel following data entry.

Stomatal conductance data: This data was collected throughout the season, with measurements taken using an AP4 leaf porometer (Delta-T devices, Cambridge) over 9 separate days throughout the 2015 season. Measurements were intentionally made across a range of meteorological conditions to allow for model parameterisation at a later stage. Data were recorded on paper data tables and subsequently entered into Microsoft Excel. Each measurement of stomatal conductance was later paired with the concurrent temperature, vapour pressure deficit (VPD) and photosynthetically active radiation (PAR) as measured by on the solardome canopy computer automated monitoring system;. this data was downloaded from the computer system periodically throughout the season. The final data file was exported as a comma separated value (csv) file for ingestion into the Environmental Information Data Centre.

Chlorophyll content index data: This data was collected throughout the season, and measurements were made using a chlorophyll meter (CCM-200, Opti-sciences, Hudson, USA). Some measurements were made simultaneously with measurements of stomatal conductance, while others were not. Data were recorded on paper data tables and subsequently entered into Microsoft Excel. The final data table was later exported as a comma separated value (csv) file for ingestion into the Environmental Information Data Centre.

Growth stage assessment data: This data was collected on four days throughout the experiment: the 9th June, 30th June, 14th July and 27th July 2015. Growth stage assessment was carried out according to the decimal system described by Tottman (1987; The decimal code for the growth of cereals, with illustrations. Annals of Applied Biology 110, 441-454). Plants within each pot were examined and the maximum (i.e. most progressed) observed growth stage was recorded. Four pots per ozone and drought treatment were examined. Data were recorded on paper data tables and subsequently entered into Microsoft Excel. Data was exported as a comma separated values (csv) file for ingestion into the Environmental Information Data Centre.