Water relations of young potted rubber plants subjected to various degrees of water stress. In: Theobroma v. 9 p. 185-195. 1979.

Abstract

Youg plants of Hevea brasiliensis Muell Arg. (clone FX 2261) were subjected to three Irrigation regimes under greenhouse conditions: a) constant field capacity. b) irrigation witheld until soil reached - 8,0 bars and c) - 15,0 bars, Xylem leaf water potentials, leaf resistances variations in trunk diameter were measured as stress developed and after recovery for two stress cycles. Leaf water potentials were low and smowed little variation both during most hours of the day and along the stress cycle in all regimes, but reflected available soil moisture in the early morning and late afternoon, Diffusion resistances and trunk diameter variations reflected soil moisture status, but their recovery behavior differed. Trunkc diameters showed complete overnight recovery upon watering, while diffusive resistances did not. It is suggested lhat leaf water potentials are controled by soil moisture availability during lhe night and by diffusive resistance during the day hours.