Estimation of whole-plant resistance to gaseous exchange independent of leaf temperature measurement. [Triticum aestivum]

Journal Article · Sun Jan 01 04:00:00 EST 1978 · Plant Physiol.; (United States)

OSTI ID:6443726

Browne, C L; Fang, S C

For studies into the uptake of mercury vapor by wheat (Triticum aestivum), a simple theory and plant chamber were employed to estimate total leaf resistance of whole plants to water vapor exchange. The estimates were independent of leaf temperature, for which mean values were indirectly determined. The approach involved the measurement, at steady-state conditions, of the net change in water vapor flux per unit of leaf surface (..delta..q/sub v/) in response to a small induced change in absolute humidity (..delta..C/sub A/). Assuming that total leaf resistance (r/sub L/) was constant and that change in leaf temperature (T/sub L/) was negligible, total leaf resistance was calculated from the equation, r/sub L/ approx. = ..delta..C/sub A/ /..delta..q/sub v/ (sec cm/sup -1/). While the assumption concerning r/sub L/ and T/sub L/ may or may not be correct, evidence is presented which indicates that such assumptions did not significantly alter estimates of r/sub L/ from their true values for changes in ambient relative humidity ranging from 0.011 to 0.074. Total leaf resistance of groups of whole plants estimated in this manner did not differ for ambient temperature of 17, 25, and 33 C. Mean values of r/sub L/ ranged from 83 sec cm/sup -1/ in darkness to 2.4 sec cm/sup -1/ at an illumination of 12.8 klux.

• Research Organization: Oregon State Univ., Corvallis
• OSTI ID: 6443726
• Journal Information: Plant Physiol.; (United States), Journal Name: Plant Physiol.; (United States) Vol. 61:2; ISSN PLPHA
• Country of Publication: United States
• Language: English

Related Subjects

560303* -- Chemicals Metabolism & Toxicology-- Plants-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
BIOLOGICAL ACCUMULATION
CEREALS
DIFFUSION
ELEMENTS
EQUATIONS
FLUIDS
GASES
GRASS
HUMIDITY
LEAVES
MERCURY
METALS
PLANTS
STEADY-STATE CONDITIONS
TEMPERATURE MEASUREMENT
UPTAKE
VAPORS
WHEAT