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Plant resistance to drought depends on timely stomatal closure

Stomata play a significant role in the Earth’s water and carbon cycles, by regulating gaseous exchanges between the plant and the atmosphere. Researchers from INRA reported a previously unreported phenomenon: the existence of an absolute limit by which stomata closure must occur to avoid rapid death in drought conditions.

Updated on 09/19/2017
Published on 09/19/2017

Stomata play a significant role in the Earth's water and carbon cycles, by regulating gaseous exchanges between the plant and the atmosphere. Under drought conditions, stomatal control of transpiration has long been thought to be closely coordinated with the decrease in hydraulic capacity (hydraulic failure due to xylem embolism).

The researchers tested this hypothesis, by coupling a meta-analysis of functional traits related to the stomatal response to drought and embolism resistance with simulations from a soil-plant hydraulic model. They report here a previously unreported phenomenon: the existence of an absolute limit by which stomata closure must occur to avoid rapid death in drought conditions. The water potential causing stomatal closure and the xylem pressure at the onset of embolism formation were equal for only a small number of species, and the difference between these two traits (i.e. safety margins) increased continuously with increasing embolism resistance.

The findings demonstrate the need to revise current views about the functional coordination between stomata and lead to a mechanistic framework allowing to model plant mortality under drought conditions with leaf and hydraulic traits.

Scientific reference

Martin-St Paul N., Delzon S. and Cochard H., (2017), Plant resistance to drought depends on timely stomatal closure, Ecology Letters, DOI:10.1111/ele.12851