Gas exchange
Photosynthesis and respiration were measured under growth conditions in plant growth cabinets, using a CIRAS 1 infra-red gas analyser fitted with a standard broad leaf chamber (PP systems, Amesbury, USA), as previously described (Dyson et al ., 2016). Measurements of gas exchange under ambient growth conditions were taken on the 1st and 7th day for the cold (5 °C) and warm (30 °C) treatment, and under control conditions. The maximum capacity for photosynthesis (Pmax ) was estimated at 20 °C and under 2000 ppm CO2 and 2000 µmol m-2 s-1 light, as described previously (Herrmann et al ., 2019b). All measurements were taken between the 5-7th hour of the photoperiod and on a minimum of 4 biological replicates.