Temperatura e regime de luz na germinação de sementes de Tabebuia impetiginosa (Martius ex A. P. de Candolle) Standley e T. serratifolia Vahl Nich. - Bignoniaceae

Abstract

The most traditionally used test in order to evaluation seed lots quality is the germination test. However, the germination test methodology is not well defined for Tabebuia impetiginosa (ipê-roxo) and T. serratifolia (ipê-amarelo) seeds. This is probably due to the little attention that the species received, specifically, about the definition of the ideals conditions for germination of these species. Thus, the objective of this research was to verify the effect of temperature and light on germination of T. impetiginosa and T. serratifolia seeds. The research was performed in a thermo-gradient table with temperature varying from 20,9ºC to 34,4ºC and in BODs with temperatures adjusted at 25ºC, 30ºC and 35ºC. To study the effect of light on germination for both species the seeds were incubated in BODs at white light/temperature 30ºC, alternate white with photoperiod 8 hours/temperature 20/30ºC and in the darkness/temperature 30ºC. The temperature of 30ºC was suitable for the germination of T. impetiginosa seeds, irrespective of the year of collection or physiological quality of the batches, while the effect of light on germination varied according to the year of collection. The ideal condition for accomplishment of the germination test in T. serratifolia seeds, irrespective of the provenance and year of collection, was under constant light at 30ºC.