The hypothesis of optimal stomatal conductance predicts conductance should vary with changes of the vapor pressure difference between leaf and air (VPD) to keep the partial derivative of transpiration rate (E) with respect to assimilation rate (A) constant ( partial differentialE/ partial differentialA = lambda). Stomatal conductance of Amaranthus powellii Wats. decreased strongly with increasi...

A plantation trial of six selected clones of Dalbergia sissoo Roxb. laid out in randomized block design at four sites in northern India during July, 1996 was evaluated for growth, physiological and biochemical parameters. Genotype-site interactions were significant for collar diameter increment, photosynthetic rate, transpiration rate, stomatal conductance, photosynthetic pigments, total solubl...

Individual leaves of potato (Solanum tuberosum L. W729R), a C(3) plant, were subjected to various irradiances (400-700 nm), CO(2) levels, and temperatures in a controlled-environment chamber. As irradiance increased, stomatal and mesophyll resistance exerted a strong and some-what paralleled regulation of photosynthesis as both showed a similar decrease reaching a minimum at about 85 neinsteins...

The water permeability of the leaves of three deciduous plants (Acer campestre, Fagus sylvatica, Quercus petraea) and two evergreen plants (Hedera helix, Ilex aquifolium) was analysed in order to assess its role as a mechanism of drought resistance. Cuticular permeances were determined by measurement of the water loss through adaxial, astomatous leaf surfaces. Minimum conductances after complet...

introduction salinity has various effects on plant growth by affecting physiological processes. the decline in plant productivity under saline condition, frequently linked with the reduction of photosynthetic capability. it has been reported that efficiency of psii photochemistry (fv/fm) of numerous plant species have been decreased due to salt stress studies have shown that salicylic acid (sa...

While the fundamental trade-off in leaf traits related to carbon capture as described by the leaf economics spectrum is well-established among plant species, the relationship of the leaf economics spectrum to stem hydraulics is much less known. Since carbon capture and transpiration are coupled, a close connection between leaf traits and stem hydraulics should be expected. We thus asked whether...

Drought is a major constraint to crop production worldwide and landraces are one of the important genetic resources to crop improvement in the dry areas. The objective of this study was to investigate transpiration and yield responses of bambara groundnut (Vigna subterranea L. Verdc.) landraces exposed to a intermittent drought spell at an early reproductive stage. The four landraces (S19-3, Un...

Sap flux density in branches, leaf transpiration, stomatal conductance and leaf water potentials were measured in 16-year-old Quercus suber L. trees growing in a plantation in southern Portugal to understand how evergreen Mediterranean trees regulate water loss during summer drought. Leaf specific hydraulic conductance and leaf gas exchange were monitored during the progressive summer drought t...