Effect of high temperature on chalazal plug removal and germination in Apeiba tibourbou Aubl.

We tested the effects of a two minute wet heat treatment at a range of temperatures on germination of Apeiba tibourbou seeds. Exposure to > 50 degrees C for two minutes resulted in an increase in germination from c. 0 to 80% and resulted in the removal of the chalazal cap. Physical removal of the chalazal cap or mechanical scarification of the seed coat allowed water uptake and subsequent germination. Our results indicate that A. tibourbou seeds exhibit physical dormancy that can be overcome with hot water treatment, chalazal cap removal or mechanical scarification of the testa.