ISHS Acta Horticulturae 137: Growth Regulators, XXI IHC
THE EFFECT OF ETHEPHON-INDUCED GUM ACCUMULATION IN SOUR CHERRY (PRUNUS CERASUS L.) ON SHOOT WATER RELATIONS AND HYDRAULIC CONDUCTANCE |
| Authors: | W.C. Olien, M.J. Bukovac |
| Abstract:
Excessive gum synthesis induced in Prunus species by ethylene or ethephon, (2-chloroethyl)phosphonic acid, altered shoot water relations and in severe cases caused shoot death. We sprayed Montmorency sour cherry trees (P. cerasus) with 0 to 69 mM ethephon. As shoot gum content increased, vessel gum content and number of occluded vessels increased, while shoot hydraulic conductance and water potential decreased. An increasing discrepancy between measured and predicted hydraulic conductance as gum content increased suggested that gum decreased xylem flow both by occlusion of vessels (reducing the number functional) and by increasing sap viscosity in functional vessels. Non-Newtonian flow of aqueous gum solutions occurred in a glass capillary at pressure gradients above 1.8 MPa m-1. | |
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