An electrochemical sensor (10) for measuring biochemical parameters in the sap (L) of a plant (P), comprising: —a channel in which the sap (L) of a plant (P) flows; —a first electrically conductive filament (11) which crosses the channel; —a control electrode (12) which crosses the channel; wherein the channel comprises a conductor vessel (C) of a trunk (D) of the plant (P), and wherein the first filament (11) comprises a textile fiber (110) coated with a layer (111) of conductive polymer.