Epiphytic plants in the Bromeliaceae known as tank bromeliads essentially lack stems and absorptive roots and instead take up water from reservoirs formed by their overlapping leaf bases. For such plants, leaf hydraulic conductance is plant hydraulic conductance. Their simple strap-shaped leaves and parallel venation make them suitable for modeling leaf hydraulic conductance based on vasculatur...

Stomata are the pores on a leaf surface through which plants regulate the uptake of carbon dioxide (CO2) for photosynthesis against the loss of water via transpiration. Turgor changes in the guard cells determine the area of stomatal pore through which gaseous diffusion can occur, thus maintaining a constant internal environment within the leaf (Gregory et al., 1950). Stomata first occurred in ...

Effects of sulfur on photosynthesis in sugar beets (Beta vulgaris L. cv. F58-554H1) were studied by inducing sulfur deficiency and determining changes in the photosynthesis of whole attached leaves and of isolated chloroplasts. The rates of photosynthetic CO(2) uptake by intact leaves, photoreduction of ferricyanide, cyclic and noncyclic photophosphorylation of isolated chloroplasts, and the ra...

Tiny openings on the surfaces of leaves, stomata, control the flux of CO2, water vapor, and other gases between the atmosphere and the earth’s vegetated surface. An increase in atmospheric CO2 could have an effect on stomatal openings, causing indirect changes in many surface hydroclimatogical variables that could be comparable in magnitude to the direct radiative effects. Increased atmospheric...

The leaf hydraulic conductance (K(leaf)) is a major determinant of plant water transport capacity. Here, we measured K(leaf), and its basis in the resistances of leaf components, for fully illuminated leaves of five tree species that regenerate in deep shade, and five that regenerate in gaps or clearings, in Panamanian lowland tropical rainforest. We also determined coordination with stomatal c...

Members of the ALMT gene family contribute to the Al(3+) resistance of several plant species by facilitating malate efflux from root cells. The first member of this family to be cloned and characterized, TaALMT1, is responsible for most of the natural variation of Al(3+) resistance in wheat. The current study describes the isolation and characterization of HvALMT1, the barley gene with the grea...

Drought causes substantial reductions in crop yields worldwide. Therefore, we set out to identify new chemical and genetic factors that regulate drought resistance in Arabidopsis thaliana. Karrikins (KARs) are a class of butenolide compounds found in smoke that promote seed germination, and have been reported to improve seedling vigor under stressful growth conditions. Here, we discovered that ...

Heterotrimeric G-proteins have been proposed to be involved in many aspects of plant disease resistance but their precise role in mediating nonhost disease resistance is not well understood. We evaluated the roles of specific subunits of heterotrimeric G-proteins using knock-out mutants of Arabidopsis Gα, Gβ and Gγ subunits in response to host and nonhost Pseudomonas pathogens. Plants lacking f...