After 10 days the seedlings were moved to two different temperature
treatments under greenhouse conditions: an ambient
temperature treatment with 15/10 ◦C (day/night) and an elevated
temperature treatment with 25/15 ◦C (day/night). The relative
humidity (RH) and the CO2 concentration were the same in the
ambient and elevated growth temperature treatments (50–60% RH
and 400 ppm CO2). Plants from the two temperature treatments
were exposed to a stress treatment at 40 ◦C in an open-top glass
chamber (OTC, 1
×
1
×
1.3 m) in the greenhouse