Relationship between leaf and xylem water potentials in rice plants

Leaf and xylem water potentials were measured in rice plants with and without transpiration using a thermocouple psychrometer and a pressure chamber. The leaf water potential practically coincided with the xylem water potential in leaves without transpiration, while the latter was 3–5 bars lower when intense transpiration was occurring. The pressure chamber should not be used to measure leaf water potential during intense transpiration in the field. The water status in transpiring leaves is discussed.