biologia plantarum

Biologia plantarum 38:297, 1996 | DOI: 10.1007/BF02873864

Embolism vulnerability of an evergreen tree

M. A. Sobrado¹

¹ Laboratorio de Biologia Ambiental de Plantas, Departamento de Biologia de Orgcmismos, Universidad Sión Bolívar, Apartado, Caracas, Venezuela

Leaf bearing stems ofCuratella americana L. were very susceptible to induced cavitation: embolisms began at a pressure of 0.5 MPa (15 %) and at 2.0 MPa most of the conductivity was lost (85 %). Nevertheless, in nature similar leaf specific conductivities, of about 90 x 10^-5 kg m^-2 s^-1 MPa^-1 during both wet and dry seasons indicated absence of drought induced embolisms. Leaf water potentials were neither very negative or considerably different between seasons but stomatal conductance decreased from 236 mmol m^-2 s^-1 measured during wet period to 100 mmol m^-2 s^-1 during drought season. Therefore, it was concluded thatCuratella had an accurate homeostatic balance of leaf water status to keep up xylem integrity.

Keywords: Curatella americana L; hydraulic conductivity; stomatal conductance; water deficit; water potential

Received: June 13, 1995; Accepted: September 12, 1995; Published: June 1, 1996  Show citation