Night-time transpiration facilitates respiratory carbon dioxide release

Night-time transpiration accounts for a considerable amount of water loss in crop plants, yet its biological function, regulation and response to salt stress are poorly understood. Even et al. present data on barley plants, exposed to different regimes of NaCl stress, that address these questions.

Diurnal gravimetric transpiration analyses are combined with complementary analyses such as cuticle wax load, dark respiration, and leaf and cuticle conductance to CO2 and water vapour. It is concluded that the main biological function of night-time transpiration is the release of respiratory CO2 from leaves. Night-time transpiration is regulated in the short- and long-term, also under salt stress.