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...

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...

Close coordination between leaf gas exchange and maximal hydraulic supply has been reported across diverse plant life forms. However, it has also been suggested that this relationship may become weak or break down completely within the angiosperms. We examined coordination between hydraulic, leaf vein, and gas-exchange traits across a diverse group of 35 evergreen Australian angiosperms, spanni...

Advanced lines of Pima cotton {Gossypium barbadense L.) bred for higher yield potential and heat resistance have higher stomatal conductance and smaller leaf areas than those of obsolete !ines. In controlled experiments, five commercial lines of Pima cotton having increasing lint yield and heat resistance showed a gradient of increasing stomatal conductance and decreasing leaf size. In field ex...

Optimal allocation of leaf nitrogen maximizes daily CO(2) assimilation for a given leaf nitrogen concentration. According to the hypothesis of optimization, this condition occurs when the partial derivative of assimilation rate with respect to leaf nitrogen concentration is constant. This hypothesis predicts a linear increase of assimilation rate with leaf nitrogen concentration under constant ...

Recent studies have shown that stomata respond to changes in hydraulic conductance of the flow path from soil to leaf. In open-grown tall trees, branches of different heights may have different hydraulic conductances because of differences in path length and growth. We determined if leaf gas exchange, branch sap flux, leaf specific hydraulic conductance, foliar carbon isotope composition (delta...

abstract application of salicylic acid (sa) as a phytohormone has been increased due to its role in plant tolerance to environmental stresses such as drought. the main goal of this experiment was to evaluate the effects of sa on morphological and physiological characteristics of cucumber seedlings under drought stress. a factorial experiment based on completely randomized block design was condu...

net photosynthesis rate (pn), stomatal conductance (gs) and transpiration rate (e) of anise hyssop were measured during the four cloudless days, in reference to diurnal fluctuations of leaf temperature (tleaf), leaf vapor pressure deficit (vpd leaf) and photosynthetic photon flux density (ppfd) in well watered (ww), stressed (s) and recovered (r) plants. an analysis of measured data showed that...

Conductance to gaseous transfer is normally considered to be greater from the abaxial than from the adaxial side of a leaf. Measurements of the conductance to water vapor of peanut leaves (Arachis hypogaea L.) under well watered and stress conditions in a controlled environment, however, indicated a 2-fold higher conductance from the adaxial side of the leaf than from the abaxial. Studies of co...

Steady-state leaf gas-exchange parameters and leaf hydraulic conductance were measured on 10 vascular plant species, grown under high light and well-watered conditions, in order to test for evidence of a departure from hydraulic homeostasis within leaves as hydraulic conductance varied across species. The plants ranged from herbaceous crop plants to mature forest trees. Across species, under st...