Fig. 6.

Effect of heat stress on control (WT), apx1, apx2, and apx1/apx2 seedlings. (A) Root growth of WT, apx1, apx2, and apx1/apx2 seedlings under heat stress (38 °C). Five- to six-day-old plants were subjected to 1 or 6h heat stress, followed by a 4-day recovery period. (B) Acquired and basal thermotolerance of WT, apx1, apx2, and apx1/apx2 seedlings. Five-day-old seedlings were directly subjected to heat stress (45 °C) for 2h to measure basal thermotolerance, or treated at 38 °C for 1.5h, allowed to recover for 1h at 21 °C, and subjected to 45 °C for 2h to measure acquired thermotolerance.