Relation of leaf water potentials with petiole xylem sap flow of excised leaves in grapevine

This paper reports the relations of leaf water potentials with petiole xylem sap flow of excised leaves in grapevine(Vitis vinifera L.).Leaf water potential,ranging 0-0.9 MPa,was reversely and much closely related with sap pressure gradient(R2=0.958 9),comparing that with sap flow rate(R2=0.668 4) and sap flow velocity(R2=0.694 6) in the xylem of petioles.It may be thus concluded that xylem sap pressure gradient can be used as a novel alternative parameter to monitor dynamic leaf water potential in plants.