Banana, one of the largest rhizomatous herbs in the world, is the fourth most important global food crop. It has a high water requirement, but the whole-plant water use in the ®eld has not been determined satisfactorily. In this study, whole-plant water use in potted and ®eld-grown banana plants (Musa'Cavendish' cv. Williams) was successfully determined using a xylem sap¯ow method. This was achieved using Granier sensor probes implanted into the central cylinder of the banana corm. The

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... nt water use in ®eld-grown bananas was 9±10 l plant ±1 d ±1 . The values of daily total sap¯ow in potted plants correlated closely with gravimetric measurements (r 2 =0.92) and with changes in soil water status (r 2 =0.77). In well-watered, mature, ®eld-grown plants, hourly sap¯ow also closely correlated with changes in solar radiation, vapour pressure de®cit and evapotranspiration. The study indicates that sap¯ow measurement is a sensitive and accurate method for determining whole-plant water use in bananas under potted as well as ®eld conditions.