Plant material and growth
Wild-type Col-0 seeds were obtained from the Nottingham Arabidopsis Stock Centre. Seeds possessing insertions in the gene At5g50950 (fum2.1 and fum2.2 ) encoding cytosolic FUM2 protein (Pracharoenwattana et al. , 2010) were kindly provided by Professor Steven Smith (University of Tasmania, Australia). Plants were grown in 3” pots containing peat-based multipurpose compost, in an SGC120 growth cabinet (Weiss Technik) with an 8-h photoperiod, to supress flowering, at a temperature of 20°C day/16°C night, and irradiance of 100 µmol m−2 s−1provided by warm white fluorescent tubes for 8 weeks in 3-inch pots containing peat-based compost. After 8 weeks, plants had reached growth stage 1.10 (Boyes et al. , 2001), with more than 10 leaves > 1 mm and persisted without development of flowers until 10 to 12 weeks. Plants for cold treatment were transferred to a similar cabinet at 4°C day/night 1 h prior to the start of the photoperiod. Leaves for metabolite measurements were harvested by flash freezing in liquid nitrogen under growth conditions.