Root length and plant vegetative characteristics under heat stress (HS). Root length (A), plant stem height (B), stem thickness (C), plant FW (D), number of leaves/plant (E), and average leaf FW (F) of WT and phyA and phyB1B2 mutants after exposing 4-week-old plants to HS conditions at 37 °C for 2 weeks in comparison with control conditions at 25 °C. Values represent the means ± SD (n = 4) from a representative of three biologically independent experiments. The asterisk symbol (*) represents statistically significant differences, while ns represents statistically nonsignificant differences, between each genotype individually under control and HS conditions according to Duncan’s test (p < 0.05).