Blue light (BL) induces stomatal opening through the activation of H+-ATPases with subsequent ion accumulation in guard cells. In most plant species, red light (RL) enhances BL-dependent stomatal opening. This RL effect is attributable to the chloroplasts of guard cell, the only cells in the epidermis possessing this organelle. To clarify the role of chloroplasts in stomatal regulation, we inve...

Coffee is one of the world's most traded agricultural products. Modeling studies have predicted that climate change will have a strong impact on the suitability of current cultivation areas, but these studies have not anticipated possible mitigating effects of the elevated atmospheric [CO2] because no information exists for the coffee plant. Potted plants from two genotypes of Coffea arabica an...

The magnitude and frequency of climatic extremes, such as drought, are predicted to increase under future climate change conditions. However, little is known about how other factors such as CO2 concentration will modify plant community responses to these extreme climatic events, even though such modifications are highly likely. We asked whether the response of grasslands to repeat extreme droug...

Rising atmospheric [CO2] is associated with increased air temperature, and this warming may drive many rare plant species to extinction. However, to date, studies on the interactive effects of rising [CO2] andwarming have focussed on just a few widely distributed plant species. Wollemi pine (Wollemia nobilisW.G.Jones, K.D.Hill, & J.M.Allen), formerly widespread in Australia, was reduced to a re...

Stomatal complexes in the epidermes of aerial plant parts are critical sites for the regulation of gas exchange between the plant and the atmosphere. Stomata consist of microscopic pores, each flanked by a pair of guard cells. Guard cells can increase or decrease the size of the pore via changes in their turgor status, hence regulating both CO2 entry into the leaf and transpiration, or the loss...

Plants have developed a finely tuned system to control the balance between assimilation of CO2 and transpiration of water vapour either by varying stomatal density or by adjusting guard cell turgor, which alters the aperture or stoma between adjacent guard cells (i.e. stomatal movement). Considerable knowledge has been gained over the years on stomatal movement (Mansfield, Hetherington & Atkins...

Since the first published measurements of stomatal density by Johann Hedwig (1793) and Alexander von Humboldt (1798), the counting and measuring of stomata has been one of themost typical botanical activities, with an important role across fields of plant biology (Willmer and Fricker, 1996). Stomatal density (d) and size (s) are indicators of acclimation and adaptation to contrasting environmen...

The pull of water from the soil to the leaves causes water in the transpiration stream to be under negative pressure decreasing the water potential below zero. The osmotic concentration also contributes to the decrease in leaf water potential but with much lesser extent. Thus, the surface tension force is approximately balanced by a force induced by negative water potential resulting in concave...

Mesophyll conductance (gm) has been shown to impose significant limitations to net CO2 assimilation (A) in various species during water stress. Net CO2 assimilation is also limited by stomatal conductance to water (gsw), both having been shown to co-vary with leaf hydraulic conductance (Kleaf). Lately, several studies have suggested a close functional link between Kleaf, gsw, and gm. However, s...