You are not currently logged in.
Access JSTOR through your library or other institution:
If You Use a Screen ReaderThis content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
How Do Stomata Read Abscisic Acid Signals?
Carlos L. Trejo, Alison L. Clephan and William J. Davies
Vol. 109, No. 3 (Nov., 1995), pp. 803-811
Published by: American Society of Plant Biologists (ASPB)
Stable URL: http://www.jstor.org/stable/4276870
Page Count: 9
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Preview not available
When abscisic acid (ABA) was fed to isolated epidermis of Commelina communis L., stomata showed marked sensitivity to concentrations of ABA lower than those commonly found in the xylem sap of well-watered plants. Stomata were also sensitive to the flux of hormone molecules across the epidermal strip. Stomata in intact leaves of Phaseolus acutifolius were much less sensitive to ABA delivered through the petiole than were stomata in isolated epidermis, suggesting that mesophyll tissue and/or xylem must substantially reduce the dose or activity of ABA received by guard cells. Delivery of the hormone to the leaf was varied by changing transpiration flux and/or concentration. Varying delivery by up to 7-fold by changing transpiration rate had little effect on conductance. At a given delivery rate, variation in concentration by 1 order of magnitude significantly affected conductance at all but the highest concentration fed. The results are discussed in terms of the control of stomatal behavior in the field, where the delivery of ABA to the leaf will vary greatly as a function of both the concentration of hormone in the xylem and the transpiration rate of the plant.
Plant Physiology © 1995 American Society of Plant Biologists (ASPB)