background and objectives: infunction of the photosynthetic apparatus of halophytes plays an important role in their salinity tolerance. kochia as a halophyte, is of high ability in biomass production in salinity stress conditions. thus study photosynthesis and the related factors salinity stress can provide appropriate physiological view for better understanding of the plant mechanisms of in s...

Many authors have attempted to explain the adaptive response of tropical plants to drought based on studies of water relations at the leaf level. Little attention has been given to the role of the xylem system in the control of plant water requirements. To evaluate this role, we studied the hydraulic architecture and water relations parameters of two tropical canopy trees with contrasting leaf ...

rootstock and cultivar selection is the most critical decision at the time of an apple orchard establishment. tree size, yield and fruit quality are affected by roostock and cultivar. non-sufficient study of rootstocks and cultivars effects on mentioned traits will lead to incorrect result or failure in orchard managing. in this study the effects of three vegetative rootstocks (mm106, mm111 and...

Understanding stomatal regulation during drought is essential to correctly predict vegetation-atmosphere fluxes. Stomatal optimization models posit that stomata maximize the carbon gain relative a penalty caused by water loss, such as xylem cavitation. However, mechanism allows behave optimally unknown. Here, we introduce model of results in similar behaviour without presupposing an optimality ...

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...

A Jarvis based [Philos. Trans. R. Soc. London, Ser. B 273 (1976) 593] model of canopy stomatal conductance was evaluated in context of its application to simulating transpiration in a conifer forest covered watershed in the Central Sierra Nevada of California, USA. Parameters influencing stomatal conductance were assigned values using Monte Carlo sampling. Model calibration was conducted by eva...

Tropospheric ozone concentrations have increased by 60-100% in the Northern Hemisphere since the 19(th) century. The phytotoxic nature of ozone can impair forest productivity. In addition, ozone affects stomatal functions, by both favoring stomatal closure and impairing stomatal control. Ozone-induced stomatal sluggishness, i.e., a delay in stomatal responses to fluctuating stimuli, has the pot...

[1] Scaling transpiration from trees to larger areas is a fundamental problem in ecohydrology. For scaling stand transpiration from sap flux sensors we asked if plot representativeness depended on plot size and location, the magnitude of environmental drivers, parameter needs for ecosystem models, and whether the goal was to estimate transpiration per unit ground area (EC), per unit leaf area (...

The effect of potassium starvation on stomatal conductance was studied in olive trees and sunflower plants, two major crops with greatly differing botanical characteristics. In both species, K(+) starvation inhibited water-stress-induced stomatal closure. In olive trees, potassium starvation favoured stomatal conductance and transpiration, as well as inhibiting shoot growth, in the three cultiv...

Root hydraulic conductivity in plants (Lp(r)) exhibits large variations in response to abiotic stimuli. In this study, we investigated the impact of dynamic, aquaporin-mediated changes of Lp(r) on leaf growth, water potential, and water flux throughout the plant. For this, we manipulated Lp(r) by subjecting roots to four independent treatments, with aquaporin inhibitors applied either to transp...