Comparação entre métodos para a determinação da temperatura ótima de germinação de sementes florestais da Amazônia Central

Abstract

Optimum seed germination temperature (OT) was determined for 30 tree species with occurrence in Central Amazonia, for which germination had been tested at temperatures between 5 and 40 °C. On the same data set, three known methods were compared and a new formula for determination of OT is proposed in this study. Two germination criteria were compared: radicle protrusion and normal seedling development. OT determined by the three methods was rarely the same. The one determined by IVG was generally higher than with Olf´s formula, and some results were not consistent with the temperatures of the natural habitat. The formula proposed in this study considers germination capacity and velocity. The values were generally between the extremes indicated by the other methods and reflected better the environmental temperature range to which the plants are adapted. OT for most Amazonian species was between 25 and 30 °C. However, OT for normal seedling formation was in general lower than for radicle protrusion.