Search Results

You are looking at 71 - 80 of 424 items for :

  • "leaf water potential" x
Clear All

., 2000a , 2000b ). Changes in root growth and development may subsequently influence soil water extraction and translocation of root-derived signals ( Rogiers et al., 2010 ). Moriana et al. (2003) found that the leaf water potential and stomatal

Free access

Abstract

Spring- and summer-flush pecan [Carya illinoensis (Wangenh.) C. Koch] leaves were evaluated to determine climatological factors affecting leaf gas exchange, biophysical factors affecting growth, and to investigate the potential impact of a summer growth flush on alternate bearing. Expanding leaves had a higher osmotic potential, lower turgor pressure (ψp), poorer stomatal control, higher cuticular conductance, and a lower bulk modulus of elasticity than expanded leaves. Stomatal closure occurred at a progressively lower leaf water potential (ψw) as leaves aged. Net CO2 assimilation rate and leaf conductance to water vapor (g1) of pecan in the field did not decline in response to high atmospheric water stress and minimum midday ψw of −1.4 to −1.9 MPa when trees were supplied with adequate soil moisture. Leaf elongation rate was exponentially related to with marked reductions in growth occurring at ψp below 0.6 MPa and a complete cessation in growth below ψp = 0.3 MPa. Net CO2 assimilation rates of expanded leaves were up to 22 μmol·s−1m−2, several times higher than previously reported. Net CO2 assimilation rate was not inhibited by 41.5°C leaf temperature, 2000 μmol·s−1m−2 photosynthetic photon flux, and 3 kPa vapor pressure deficits (VPD). Transpiration rate (E) increased greatly with increasing VPD. Values of gl and E were generally higher than those reported for woody C3 perennials. The efficient water transport system of pecans under conditions of nonlimiting soil moisture may be a consequence of evolution in a floodplain ecosystem.

Open Access

Abbreviations: ET c , crop evapotranspiration; DOY, day of year; K c , crop coefficient; LWP, leaf water potential; RWC, leaf relative water content; VPD, air vapor pressure deficit. 1 Plant Physiologist. 2 Agronomist. 3 Agricultural Engineer. 4

Free access

Abbreviations: DAFB, days after full bloom; DC, drying cycle; E pan , potential water use measured from a Class A pan; ET, evapotranspiration; k c , crop coefficient; WU, water use; Ψ 1 , leaf water potential. 2 Senior Lecturer. 3 Professor. Current

Free access

( Hinckley et al., 1978 ) and growth. Transplanted trees are considered to be established when leaf water potential (ψ L ), gas exchange, and growth are similar to those of nontransplanted trees ( Beeson and Gilman, 1992 ). However, research on gas exchange

Free access

, y i   and y i + 1 are the values of the severity scale that were obtained at every evaluation time, and ( t i + 1 − t i ) is the time interval between evaluations. g S and leaf water potential. g S and leaf water potential (Ψ wf ) were

Open Access

µmol·s −1 ). Leaf water potential. Leaf water potential was measured on young, fully expanded leaves, nine leaves from each replicate, on the same day that observations of gas exchange parameters were made (on the third or fourth leaves from the plant

Free access

, medium, or high salt-tolerant. We monitored changes in leaf water potential and plant quality of sea hibiscus, a high salt-tolerant plant, exposed to increasing EC and Na levels. Because measuring water potential is impractical for a grower, for

Open Access

; leaf water potential at 36, 55, 67, 75, and 90 DAS; and leaf temperature, transpiration, and stomatal resistance at 36, 55, and 90 DAS. We sampled three plants per plot for each sampling date. The gaseous exchange measurements from the porometer LI-1600

Free access

all the water used for any given 24-h period. However, Gucci et al. (1997) reported that A. deliciosa does not demonstrate low midday leaf water potential values under water deficit as effective stomatal closure allows water conservation. But

Free access