Effectiveness of cuticular transpiration barriers in a desert plant at controlling water loss at high temperatures

Maintaining the integrity of the cuticular transpiration barrier even at elevated temperatures is of vital importance for hot-desert plants. In a new study published in AoB PLANTS, Schuster et al. investigated the effect of temperature on the leaf cuticular permeability of Rhazya stricta, an evergreen shrub from the Arabian Desert. Permeability increased 2.4-fold from 15° to 50° C, which is much less than in all other species studied so far. The authors propose that high amounts of pentacyclic triterpenoids (85.2% of total wax) act as fillers that mechanically stabilize the cuticle and thus prevent thermal disruption of the cuticular transpiration barrier.