The plants of all cultivars grown at 25 ◦C had a slightly increased
tolerance of the photosynthetic apparatus to heat stress, and a better
recovery compared to plants grown at 15 ◦C. This might be due to
the acclimation of the plants to the higher temperature improving
the heat stability of PSII. Havaux (1993) observed that the exposure
of potato leaves to 35 ◦C for 20 min significantly increased
the stability of PSII to heat stress (>42◦ C). Maize plants grown at
elevated temperature also showed a greater heat stability to heat
stress and post-stress recovery than the plants grown at ambient
control temperature