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Title: NIGHT-TIME CONDUCTANCE IN C3 AND C4 SPECIES: DO PLANTS LOSE WATER AT NIGHT?

Author
item Snyder, Keirith
item RICHARDS, J - UNIVERSITY OF CALIFORNIA
item DONOVAN, L - UNIVERSITY OF GEORGIA

Submitted to: Journal of Experimental Botany
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/16/2002
Publication Date: 2/1/2003
Citation: SNYDER, K.A., RICHARDS, J.H., DONOVAN, L.A. NIGHT-TIME CONDUCTANCE IN C3 AND C4 SPECIES: DO PLANTS LOSE WATER AT NIGHT? JOURNAL OF EXPERIMENTAL BOTANY. 2003. V. 54(383). P. 861-865.

Interpretive Summary: A long-held belief in plant ecophysiology is that plant stomata shut at night because there is no potential to fix carbon in the absence of sunlight. Since stomata are presumed to be closed, water loss through stomata is also believed to cease during dark hours. However, previous research with several desert shrub species found significant loss of water at night (nighttime transpiration). The current research surveyed a number of species to determine the occurrence and magnitude of nighttime transpiration loss in 17 species in a variety of habitats in the Great Basin Region. Substantial nighttime water loss was found in 11 of the 17 species. This pattern was found across a range of habitats and across a range of plant life history strategies, suggesting that loss of water through stomata at night may be a widespread behavior. The implications of this research are that plant processes previously believed to cease during dark hours may still be active, which may have important effects on plant competitive performance and ecosystem water loss and, generally, changes our understanding of how plants function at night.

Technical Abstract: Significant night-time stomatal conductance and transpiration were found for 11 out of 17 species with a range of life histories (herbaceous annual, perennial grass, shrub, tree), photosynthetic pathways (C3, C4), and habitats in the western United States. Across species and habitats, higher night-time conductance and transpiration were associated with higher daytime values. The prevalence, mechanisms and ecological implications of substantial night-time water loss deserve further investigation.