Stomata are pores in the leaf surface that open and close to regulate gas exchange and minimize water loss. In Arabidopsis, a pair of guard cells surrounds each stoma and they are derived from precursors distributed in an organized pattern on the epidermis. Stomatal differentiation follows a well-defined developmental programme, regulated by stomatal lineage-specific basic helix-loop-helix tran...

Stomata are crucial in land plant productivity and survival. In general, with lower irradiance, stomatal and epidermal cell frequency per unit leaf area decreases, whereas guard-cell length or width increases. Nevertheless, the stomatal index is accepted as remaining constant. The aim of this paper to study the influence of ordinary epidermal cells and stomata on leaf plasticity and the influen...

Cyclin-dependent kinases (CDKs) are key regulators of the cell cycle. In yeasts, only one CDK is sufficient to drive cells through the cell cycle, whereas higher eukaryotes developed a family of related CDKs. Curiously, plants contain a unique class of CDKs (B-type CDKs), whose function is still unclear. We show that the CDKB1;1 gene of Arabidopsis (Arabidopsis thaliana) is highly expressed in ...

We used local microclimatic conditions and twig sap flow rates to interpret midday stomatal closure in the canopies of two 250-year-old Norway spruce (Picea abies (L.) Karst.) trees at a subalpine site in the Swiss Alps (1,650 m a.s.l.). Both trees showed midday stomatal closure on most clear summer days, despite the permanently wet soil. We used a modified Penman-Monteith formula to simulate p...

Stomatal conductance links plant water use and carbon uptake, and is a critical process for the land surface component of climate models. However, stomatal conductance schemes commonly assume that all vegetation with the same photosynthetic pathway use identical plant water use strategies whereas observations indicate otherwise. Here, we implement a new stomatal scheme derived from optimal stom...

BACKGROUND AND AIMS The inverse relationship between the number of stomata and atmospheric CO2 levels observed in different plant species is increasingly used for reconstructions of past CO2 concentrations. To validate this relationship, the potential influence of other environmental conditions and ontogenetical development stage on stomatal densities must be investigated as well. Quantitative ...

Suboptimal N nutrition increased the water potential for stomatal closure in water stressed cotton (Gossypium hirsutum L.) leaves. This increased sensitivity to water stress had two components, increased accumulation of abscisic acid (ABA) and increased apparent stomatal sensitivity to ABA. Low N increased the threshold water potentials for stomatal closure and ABA accumulation by about 4 bars ...

The spatial distribution of plant stomata is a model system to study epidermal cell pattern formation. Molecular genetic approaches have identified several key genes required for stomatal distribution patterning, but environmental conditions that perturb the stomatal spacing distribution have not yet been identified. We found that immersing hydroponic cultures in 1-5% sucrose solution induced a...

Recent work shows that transcription factors are necessary for stomatal movements in plants. Different members of the plant-specific R2R3-MYB transcription factor family are required for mediating stomatal opening in response to light and stomatal closure in response to darkness.

We studied the effect of scion donor-tree age on the physiology and growth of 6- to 7-year-old grafted Scots pine (Pinus sylvestris L.) trees (4 and 5 years after grafting). Physiological measurements included photosynthethetic rate, stomatal conductance, transpiration, whole plant hydraulic conductance, needle nitrogen concentration and carbon isotope composition. Growth measurements included ...