Guard cells surround stomatal pores in the epidermis of plant leaves and stems. Stomatal pore opening is essential for CO2 influx into leaves for photosynthetic carbon fixation. In exchange, plants lose over 95% of their water via transpiration to the atmosphere. Signal transduction mechanisms in guard cells integrate hormonal stimuli, light signals, water status, CO2, temperature, and other en...

trees, age 25--30 years, were subjected to two soil-nitrogensupply regimes and to elevated atmospheric CO2 concentrations by the branch-in-bag method from April 15 to September 15 for two or three years. Gas exchange in detached shoots was measured in a diffuse radiation field. Seven parameters associated with photosynthetic performance and two describing stomatal conductance were determined to...

A reduction in leaf stomatal conductance (g) with increasing leaf-to-air difference in water vapour pressure (D) is nearly ubiquitous. Ecological comparisons of sensitivity have led to the hypothesis that the reduction in g with increasing D serves to maintain leaf water potentials above those that would cause loss of hydraulic conductance. A reduction in leaf water potential is commonly hypoth...

High-resolution imaging of chlorophyll a fluorescence from intact tobacco leaves was used to compare the quantum yield of PSII electron transport in the chloroplasts of guard cells with that in the underlying mesophyll cells. Transgenic tobacco plants with reduced amounts of Rubisco (anti-Rubisco plants) were compared with wild-type tobacco plants. The quantum yield of PSII in both guard cells ...

The stomatal behavior of ferns provides an excellent system for disentangling responses to different environmental signals, which balance carbon gain against water loss. Here, we measured responses of stomatal conductance (gs ) to irradiance, CO2 , and vapor pressure deficit (VPD) for 13 phylogenetically diverse species native to open and shaded habitats, grown under high- and low-irradiance tr...

this study investigated the variation between two sugar beet (beta vulgaris l.) cultivars with respect to growth parameters and photosynthetic rates of individual attached leaves during salinization. sugar beet plants grown in sand culture were gradually exposed to different levels of salinity (0, 50, 150 , 250, and 350 mm, nacl+cacl2 in 5:1 ratio). salt concentrations significantly decreased a...

Stomata play a key role in the control of plant water relations and photosynthesis. A rapid non-destructive method to study the stomatal behaviour in aerial parts of plants is important for researchers in plant sciences and agricultural fields. Stomata close in response to drought stress. Stomatal closure causes lower availability of CO2 inside the leaf and thus a decrease in the rate of carbox...

By applying the inverse relation between numbers of leaf stomata and atmospheric CO2 concentration, stomatal frequency analysis of fossil birch leaves from lake deposits in Denmark reveals a century-scale CO2 change during the prominent Holocene cooling event that occurred in the North Atlantic region between 8,400 and 8,100 years B.P. In contrast to conventional CO2 reconstructions based on ic...

Atmospheric CO2 concentrations are predicted to double within the next century. Despite this trend, the extent and mechanisms through which elevated CO2 affects plant diseases remain uncertain. In this study, we assessed how elevated CO2 affects a foliar fungal pathogen, Phyllosticta minima, of Acer rubrum growing in the understory at the Duke Forest free-air CO2 enrichment experiment in Durham...