Germination response of two species of Vellozia (Velloziaceae) from the "campos rupestres" of Minas Gerais, Brazil

The germination behaviour of Vellozia leptopetala Goeth. et Henr., a shrubby species growing on rocky outcrops, and of V. epidendroides Mart. ex Schult. & Schult., an herb growing in grasslands of Serra do Cipó, was evaluated under controlled light and temperature conditions. Seeds were sown at temperatures ranging from 15 to 40 ºC in continuous light or darkness, in four treatments with 25 seeds each. Both species produce small seeds; 1.31 ± 0.06 mm and 1.15 ± 0.01 mm for V. leptopetala and V. epidendroides, respectively. V. leptopetala seeds grown in light had high germinability (95-100%) between 20 and 35 ºC, and lower percentages at 15 and 40 ºC (34 and 29%, respectively). When grown in total darkness, significant germination occurred only at the highest temperatures, reaching 68% at 30 ºC and 3% at 40 ºC. V. epidendroides seeds grown in light had high germinability (91-84%) between 30 and 40 ºC, which gradually decreased at lower temperatures to no germination at 15 ºC. In darkness germination was successful between 20 and 40 ºC (3 to 88%), and was significantly higher at 35 and 40 ºC. The production of seeds capable of germinating in different temperature and light conditions may be of great value to a species, because it allows colonization of a greater diversity of habitats, including dark rock crevices, a common situation for V. leptopetala, or thick grass cover, for V. epidendroides.

photoblastism; campos rupestres; temperature; Vellozia leptopetala; Vellozia epidendroides