Effect of water availability on the seed germination of Araucaria angustifolia (Bert.) O. Kuntze

Abstract

Seeds of Araucaria angustifolia (Bert.) O. Kuntze are of high ecological and economic importance, especially in southern Brazil, where they occur naturally with relative abundance. Several studies have focused on the germination and storage of this species seeds. Although it is known that A. angustifolia seeds are recalcitrant and that water content is important for their germination, studies on water availability in the environment are non-existent. In that sense, we evaluated the effect of water potential on the germination of A. angustifolia seeds. Twelve treatments with different water potentials (0, -0.2, -0.4, -0.6, -0.8, -1.0 MPa) were tested. A total 50 seeds (25 whole and 25 scarified) were allocated for each treatment and the germination rate was evaluated. Our results showed that water potential influenced inversely the germination rate, even with the moisture content inside seeds showing no significant variation. Although water availability in the environment does not interfere with water absorption, it does seem to hinder seed germination, probably reducing seed physiological viability.