4.1. Plant Materials, Growth Condition and Stress Experiment

The wild-type Arabidopsis thaliana Columbia-0 ecotype plants was used as a control. The var2 mutant seeds were kindly provided by Dr. Wataru Sakamoto (Institute of Plant Science and Resources, Okayama University). Plants were grown for 4 weeks on plates containing Murashige and Skoog plant salt mixture (Wako), pH 5.7, 8 µM nicotinic acid, 5 µM pyridoxine hydrochloride, 30 µM thiamine hydrochloride, 555 µM myoinositol, 3% sucrose and 0.25% Phytagel (Sigma-Aldrich) at 24 °C under 100 µmol m⁻² s⁻¹ of white LED light for 12/12-h photoperiod cycles. For heat stress, the plates were placed in an incubator at 45 °C in the dark for 3 h.