The data was generated in the "Elevated CO2 and herbicide tolerance" experiment (2012). The experiment followed a randomised fully factorial design, with the factors being CO2 concentration (ambient or elevated) and herbicide treatment (recommended and double recommended label rate). Four glasshouses were used: two at the ambient and two at the elevated CO2 concentration.
Ten replicates of each weed species for each CO2 × herbicide treatment combination were grown. These were evenly split between the treatment glasshouses. Additionally, six replicates of each weed species were grown under each CO2 treatment to assess the biomass allocation each species at the time of herbicide application. This could not be done after herbicide treatment due to plant mortality. These plants were harvested into their above- and belowground components on the day of herbicide application and oven-dried at 60oC to constant weight (48 – 72 hours) before being weighed.
Pots were randomly rearranged within the glasshouses each fortnight to minimise any within-glasshouse effects. All pots were evenly spaced to minimise shading from neighbouring plants. As Lantana camara and I. indica were propagated from cuttings, they were re-potted into 2.8 L pots after eight weeks and six weeks respectively to allow them ample space for root development. The vine species A. cordifolia and I. indica were trained onto stakes. Pots were mist watered for one minute four times daily.
The elevated CO2 treatment was maintained by a dosing and monitoring system (Canary Company Pty Ltd, Lane Cove, NSW, Australia) at 550 ppm, from 6 am to 6 pm, with air continuously circulated within each glasshouse. The elevated CO2 treatment represents the predicted atmospheric CO2 concentration by 2030 under most emissions scenarios (IPCC, 2001). The ambient CO2 treatment was 380 ppm. The glasshouse temperature was set to 17°C at night and 24°C during the day