Oxalic acid is a virulence factor of several phytopathogenic fungi, including Sclerotinia sclerotiorum (Lib.) de Bary, but the detailed mechanisms by which oxalic acid affects host cells and tissues are not understood. We tested the hypothesis that oxalate induces foliar wilting during fungal infection by manipulating guard cells. Unlike uninfected leaves, stomatal pores of Vicia faba leaves in...

Container-grown black spruce (Picea mariana (Mill.) B.S.P.) seedlings were planted in trays containing a sand and peat mixture, and placed in a climate-controlled greenhouse. One group of seedlings was kept well-watered, and another group was subjected to three cycles of drought. Gas exchange analysis showed that mesophyll photosynthetic function was largely unimpaired by drought. In contrast, ...

Stomata are microscopic variable aperture pores on the surfaces of leaves. In response to different environmental stimuli, they control the exchange rate of both water vapor and carbon dioxide between the air and the leaf interior, making their role an important determination of the status of plant life on Earth. This study is based on a recently developed stomatal model in which the aperture s...

Proper stomatal responses are essential for plant function in an altered environment. The core signaling pathway for abscisic acid (ABA)-induced stomatal closure involves perception of the hormone that leads to the activation of guard cell anion channels by the protein kinase OPEN STOMATA1. Several other regulators are suggested to modulate the ABA signaling pathway, including the protein ENHAN...

Water use efficiency (WUE) is considered as a determinant of yield under stress and a component of crop drought resistance. Stomatal behavior regulates both transpiration rate and net assimilation and has been suggested to be crucial for improving crop WUE. In this work, a dynamic model was used to examine the impact of dynamic properties of stomata on WUE. The model includes sub-models of stom...

Increasing levels of atmospheric CO2 concentration [CO2] has caused a debate in the scientific community over how vegetation responds to this increase — specifically in the stomatal resistance increase (SRincrease) and the transpiration decrease (TRdecrease). This paper presents results in changes of stomatal resistance and transpiration from two canopy model simulations under varying environme...

Climate modelling studies predict that the rain forests of the Eastern Amazon basin are likely to experience reductions in rainfall of up to 50% over the next 50-100 years. Efforts to predict the effects of changing climate, especially drought stress, on forest gas exchange are currently limited by uncertainty about the mechanism that controls stomatal closure in response to low soil moisture. ...

Bundle sheath extensions (BSEs) are key features of leaf structure with currently little-understood functions. To test the hypothesis that BSEs reduce the hydraulic resistance from the bundle sheath to the epidermis (r(be)) and thereby accelerate hydropassive stomatal movements, we compared stomatal responses with reduced humidity and leaf excision among 20 species with heterobaric or homobaric...

to evaluate morphological markers linked with drought stress resistance for screening almond genotypes in the breeding programs the effect of drought stress was studied on six nominated almond genotypes seedlings. the six pre-selected water stress mimposed almond genotypes included: homozygote sweet (butte from university of california), heterozygote sweet (shahrood12, shahrood18, shahrood21 an...