The photosynthetic characteristics of two contrasting varieties of common bean (Phaseolus vulgaris) have been determined. These varieties, Arroz and Orfeo, differ in their productivity under stress conditions, resistance to drought stress, and have distinctly different stomatal behaviour. When grown under conditions of high irradiance and high temperature, both varieties displayed evidence of p...

A series of controlled-environment experiments were conducted to elucidate the effects of Meloidogyne incognita on host physiology and plant-water relations of two cotton (Gossypium hirsutum) cultivars that differed in their susceptibility to nematode infection. Inoculation of M. incognita-resistant cultivar Auburn 634 did not affect growth, stomatal resistance, or components of plant-water pot...

The seasonal change in leaf water potential and its components, stomatal resistance, specific leaf weight, photosynthesis rate, the activities of ribulose-1,5-bisphosphate carboxylase and nitrate reductase, and soluble proteins were measured in flag leaves (ninth from base in position), seventh and fifth leaves of wheat Triticum aestivum L. cv Kalyansona. Flag leaves had a lower water and solut...

The leaves of quaking aspen (Populus tremuloides Michx.) have a flattened petiole that allows them to quake (oscillate and roll) under low wind velocities. It was hypothesized that this adaptation might enable the plant to respond to windy conditions that would increase transpirational losses. No effects of wind with or without leaf quaking on stomatal resistance were observed under controlled ...

This study examines some of the potential mechanisms of resistance in selected Pieris (Ericaceae) taxa to the Andromeda lace bug, Stephanitis takeyai Drake and Maa, based on differences in resistance to lace bug feeding, and the possible role of leaf parameters such as leaf wax, toughness, nutrient composition, and stomatal characters in plant resistance. Experiments with extracts of leaf-surf...

Sustained cyclic oscillations in stomatal conductance, leaf water potential, and sap flow were observed in young orange trees growing under natural conditions. The oscillations had an average period of approximately 70 min. Water uptake by the roots and loss by the leaves was characterized by large time lags which led to imbalances between water supply and demand in the leaves. The bulk of the ...

Two outstanding features of the flowering plant family Winteraceae are the occlusion of their stomatal pores by cutin plugs and the absence of water-conducting xylem vessels. An adaptive relationship between these two unusual features has been suggested whereby stomatal plugs restrict gas exchange to compensate for the presumed poor conductivity of their vesselless wood. This hypothesized conne...

The hydraulic architecture of leaves represents the final path along which liquid water travels through the plant and comprises a significant resistance for water movement, especially for grasses. We partitioned leaf hydraulic resistance of six genotypes of Sorghum bicolor L. (Moench) into leaf specific hydraulic resistance within the large longitudinal veins (rLV) and outside the large veins (...

Among different mechanisms of salt resistance, regulation of ion distribution among various tissues and intracellular compartmentation are of great importance. In this study, we investigated the effects of salt stress on growth, photosynthesis, and Na(+) accumulation and distribution in leaf apoplast and symplast of two canola (Brassica napus L.) cultivars (NYY 1 and BZY 1). The results showed ...