科研之友
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摘要
the germination behaviour of vellozia leptopetala goeth. et henr., a shrubby species growing on rocky outcrops, and of v. epidendroides mart. ex schult. %26 schult., an herb growing in grasslands of serra do cip車, 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.
