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Water and ion fluxes of abscisic acid‐treated root systems of pear, Pyrus communis
Author(s) -
Andersen P. C.,
Proebsting W. M.
Publication year - 1984
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1984.tb04555.x
Subject(s) - xylem , abscisic acid , chemistry , pyrus communis , botany , arrhenius plot , analytical chemistry (journal) , pear , horticulture , chromatography , biochemistry , biology , activation energy , gene , organic chemistry
Water and ion fluxes of intact root systems of Pyrus communis L. cv. Old Home × Farmingdale 97 immersed in a nutrient solution were determined at various pressures and temperatures. Water flux (J v was normalized on the basis of initial flow rates of a root system after 30 min at 0.50 MPa and 25°C, expressed as the ratio Q v . Q v responded linearly to pressures between 0.20 and 0.62 MPa, implying a constant root hydraulic conductivity (L p ) within this range. Similarly Q v was linearly related to temperatures between 7 and 35°C; however, large, rapid temperature changes resulted in a break of the Arrhenius plot of Q v versus the reciprocal of temperature, Abscisic acid (ABA) from 2 × 10 −6 to 10 −4 M , applied to intact root systems, increased Q v within 10–20 min, with the effect leveling off after 1.5 h. At a pressure of 0.50 MPa, ABA at 10 ‐4 M enhanced Q v by 28%. The stimulation of Q v was not due to the ethanol solvent since 0.13 or 1.33% ethanol decreased Q v‐ , The osmotic potential of the xylem fluid was determined and was used to calculate total normalized solute flux. The results suggest that ABA‐induced or ethano1‐induced changes in Q v were mainly due to changes in L p and not to changes in ion transport to the xylem.