Concomitant changes in high temperature tolerance and heat-shock proteins in desert succulents

Raising the day/night air temperatures from 30°C/20°C to 50°C/40°C increases the high temperature tolerated by Agave deserti, Carnegiea gigantea, and Ferocactus acanthodes by 6°C to 8°C; the increase is about half completed in 3 days and fully completed in 10 days. A 25 to 27 kilodalton protein concomitantly accumulates for all three desert succulents upon transfer to 50°C/40°C, while accumulation of other heat “heat-shock” proteins is species specific. Some of the induced proteins are more abundant at 3 days, while others (including the 25-27 kilodalton protein) remain after completion of high temperature acclimation.