Differential daytime and night‐time stomatal behavior in plants from North American deserts

Abstract

Summary• Night-time stomatal conductance (g night ) occurs in many ecosystems, but the g night response to environmental drivers is relatively unknown, especially in deserts.• Here, we conducted a Bayesian analysis of stomatal conductance (g) (N = 5013) from 16 species in the Sonoran, Chihuahuan, Mojave and Great Basin Deserts (North America). We partitioned daytime g (g day ) and g night responses by describing g as a mixture of two extreme (dark vs high light) behaviors.• Significant g night was observed across 15 species, and the g night and g day behavior differed according to species, functional type and desert. The transition between extreme behaviors was determined by light environment, with the transition behavior differing between functional types and deserts. Sonoran and Chihuahuan C 4 grasses were more sensitive to vapor pressure difference (D) at night and soil water potential (W soil ) during the day, Great Basin C 3 shrubs were highly sensitive to D and W soil during the day, and Mojave C 3 shrubs were equally sensitive to D and W soil during the day and night.• Species were split between the exhibition of isohydric or anisohydric behavior during the day. Three species switched from anisohydric to isohydric behavior at night. Such behavior, combined with differential D, W soil and light responses, suggests that different mechanisms underlie g day and g night regulation.

On the persistence of memory

“…Recent evidence suggests otherwise. Nocturnal water loss often contributes around 10% of the total transpired water (although it can exceed 25% of the total water loss in some desert plants 7 ). The temporal pattern of nocturnal stomatal conductance (g s ) under non-limiting water supply is often characterized by an initial decline during the first hours after dusk, and a posterior increase that peaks around dawn.…”

Sensitivity and uncertainty analysis of the carbon and water fluxes at the tree scale inEucalyptusplantations using a metamodeling approach

“…While high sensitivity to g 1 (the slope between the GPP and TR), as shown by Bauerle and Bowden (2011), was expected, the minimum stomatal conductance (g 0 ) had a greater effect on TR, LUE, and WUE. While g 0 has commonly been assumed to be close to zero with little effect on water fluxes (Caird et al 2007;Zeppel et al 2010), recent studies have shown that g 0 could be higher than previously expected in many ecosystems (Ogle et al 2012) and that its value could change seasonally (Barnard and Bauerle 2013). In a recent study using MAESTRA, it was shown that g 0 had a large effect on TR (Bowden and Bauerle 2008).…”

Processes driving nocturnal transpiration and implications for estimating land evapotranspiration

“…However, there is growing evidence at the leaf and plant scales that incomplete stomatal closure and subsequent transpiration overnight are widespread and significant4. Recent studies estimate that the equivalent to 10–15% of daytime leaf and plant water losses occur overnight4, with values reaching 25–30% in desert and savanna plants56, and with some extreme species reaching higher night-time than daytime transpiration7.…”