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BRANCALION, Pedro Henrique Santin; NOVEMBRE, Ana Dionisia da Luz Coelho; RODRIGUES, Ricardo Ribeiro and CHAMMA, Helena Maria Carmignani Pescarin. Effect of light and different temperatures on germination of Heliocarpus popaanensis L. seeds. Rev. Árvore [online]. 2008, vol.32, n.2, pp. 225-232. ISSN 0100-6762. http://dx.doi.org/10.1590/S0100-67622008000200005.
Heliocarpus popayanensis is a pioneer tree species used in Brazil mainly for forest restoration. The aim of this research was to evaluate the effect of light and temperature on the germination of H. popayanensis seeds. Seeds were put to germinate inside transparent and black plastic boxes and incubated in chambers at 25ºC for light evaluation on germination. For temperature evaluation, nine intervals of constant temperatures between 15ºC and 35ºC and two alternate temperatures (15-35ºC and 20-30ºC) were analyzed in thermo-gradient table. For both experiments, seeds were distributed on the top of two blotter paper sheets and the daily photoperiod was eight hours of light. Germination was evaluated from primary root protrusion and formation of normal seedlings, and three lots of seeds were studied. The results showed that H. popayanensis seeds are non-photoblastic, the optimum temperature interval is between 28.1ºC and 30.2ºC, temperatures around 35ºC stimulated seed impermeability overcome, and the primary root protrusion was not efficient to determine the optimum germination temperature, since the formation of normal seedlings is more indicated for this determination.
Keywords : Jangada-brava; photo-blastism and eco-physiology.