In order to assess the xylem water potential in Coffea arabica L. plants, a field experiment was carried out in Mococa, São Paulo State, Brazil, from August 2005 to July 2006 with the following cultivars: Mundo Novo (MN), Obatã (OB) and Ouro-Verde (OV). The OB and OV cultivars were eight years old, and MN plants had been topped five years ago. Spacing among the plants were 3.6 x 1.0 m, 2.5 x 1.0 m and 3.5 x 0.75 m, respectively. Predawn leaf water potential (ψam) was measured each 15 days. Xylem water potential along the day (ψa) was measured at the end of April. Data concerning leaf ψam varied according to the soil water profile as affect by seasonal rainfall. ψam values were -1.29, -1.60 and -1.68 MPa during dry months and -0.06, -0.07 and -0.07 MPa during months of greater precipitations for MN, OB and OV, respectively. These values were important and relevant to Arabic coffee cultivars in order to characterize plant water status along the year, because the period of water stress was coincident with the phase of induction (February at June) and maturation of flowering buds; and the period of greater rainfall with the phase of grain filling and fruit maturation.
coffee; water stress; soil moisture; plant water potential
