It was investigated whether the methyl-erythritol phosphate (MEP) pathway that generates volatile isoprenoids and carotenoids also produces foliar abscisic acid (ABA) and controls stomatal opening. When the MEP pathway was blocked by fosmidomycin and volatile isoprenoid emission was largely suppressed, leaf ABA content decreased to about 50% and leaf stomatal conductance increased significantly...

Stomatal transpiration is at the center of a crisis in water availability and crop production that is expected to unfold over the next 20 to 30 years. Global water usage has increased 6-fold in the past 100 years, twice as fast as the human population, and is expected to double again before 2030, driven mainly by irrigation and agriculture. Guard cell membrane transport is integral to controlli...

Elevated atmospheric CO2 has been shown to rapidly alter plant physiology and ecosystem productivity, but contemporary evolutionary responses to increased CO2 have yet to be demonstrated in the field. At a Mojave Desert FACE (free-air CO2 enrichment) facility, we tested whether an annual grass weed (Bromus madritensis ssp. rubens) has evolved in response to elevated atmospheric CO2 . Within 7 y...

Stomata are highly specialized organs that consist of pairs of guard cells and regulate gas and water vapor exchange in plants [1-3]. Although early stages of guard cell differentiation have been described [4-10] and were interpreted in analogy to processes of cell type differentiation in animals [11], the downstream development of functional stomatal guard cells remains poorly understood. We h...

[1] Using a simple dynamic vegetation model coupled to an intermediate complexity climate model Kleidon [2004] suggests that an optimum stomatal conductance exists at which vegetation productivity is maximized. It is suggested that this maximum is the result of two competing processes: 1) the increased supply of CO2 with increased stomatal conductance and 2) increased cloud cover, associated wi...

A suite of simulations with the HadCM3LC coupled climate-carbon cycle model is used to examine the various forcings and feedbacks involved in the simulated precipitation decrease and forest dieback. Rising atmospheric CO2 is found to contribute 20% to the precipitation reduction through the physiological forcing of stomatal closure, with 80% of the reduction being seen when stomatal closure was...

When stomata are open, the trade-off between water loss through transpiration and CO2 uptake via photosynthesis is a result of the evolutionary history of land plants from green algae. To supply the up to 1000-fold higher flux of water leaving the leaf compared with CO2 molecules entering the leaf during leaf gas exchange (Nobel 2009), plant hydraulics has evolved to be highly efficient. The in...