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. ...

The hydraulic architecture of sunflower (Helianthus annuus L. cv. Margot) was studied in terms of the partitioning of the hydraulic conductance (Kleaf) of leaves inserted at progressively more apical nodes both in growing plants (GP) and in plants at full anthesis (mature plants, MP). Leaf conductance to water vapour (gL), leaf water potential (PsiL), leaf water potential at zero turgor (Psi tl...

Although the pressure chamber has gained wide acceptance as a convenient method for the measurement of plant water status, the relationship between the pressure observed in the chamber and other parameters of plant water status remains unclear. If one assumes that the spatial arrangement of water in the shoot is the same under pressure as it was in the intact plant, the positive pressure (P) an...

in order to study the reaction of barley genotypes to drought, an experiment was conducted in a factorialdesign based on crd for two wild ecotypes and four crop genotypes of barley in greenhouse. in thisstudy, the barley genotypes and wild ecotypes as the first factor and irrigation treatment with three levelsinclude 70 percent of water holding capacity of soil, 30 and 10 percent as the second ...

Photosynthesis requires sufficient water transport through leaves for stomata to remain open as water transpires from the leaf, allowing CO2 to diffuse into the leaf. The leaf water needs of soybean change over time because of large microenvironment changes over their lifespan, as leaves mature in full sun at the top of the canopy and then become progressively shaded by younger leaves developin...

The hydraulic conductance of the leaf lamina ( K lamina ) substantially constrains whole-plant water transport, but little is known of its association with leaf structure and function. K lamina was measured for sun and shade leaves of six woody temperate species growing in moist soil, and tested for correlation with the prevailing leaf irradiance, and with 22 other leaf traits. K lamina varied ...

Seasonal drought can severely impact leaf photosynthetic capacity. This is particularly important for Mediterranean forests, where precipitation is expected to decrease as a consequence of climate change. Impacts of increased drought on the photosynthetic capacity of the evergreen Quercus ilex were studied for two years in a mature forest submitted to long-term throughfall exclusion. Gas exchan...

Water-transport pathways through the leaf are complex and include several checkpoints. Some of these checkpoints exhibit dynamic behavior that may be regulated by aquaporins (AQPs). To date, neither the relative weight of the different water pathways nor their molecular mechanisms are well understood. Here, we have collected evidence to support a putative composite model of water pathways in th...

trees are an important source of wild germplasm for sustainable forestry. wild pear germplasm (pyrus boisseriana) was collected from a forest ecosystem and resistance potential to drought stress was surveyed in a greenhouse. in six-month seedlings, signs of leaf rolling appeared after 18 days without water (drought simulation). gas exchange parameters, such as net photosynthesis, stomatal condu...