RESUMO
This study investigated the effects of different temperatures (25 and 30 ± 2 ºC), light levels (62, 42, 22 and 5 percent of natural light), and pH (4.0, 4.5, 5.0, 5.5, 6.0 and 6.7) on the spore germination of Gleichenella pectinata. To accomplish this, the spores were surface sterilized and sown in bottles containing mineral medium. The spores of G. pectinata are monolets and the perispore surface can show large and irregular deposits. During germination, filamentous gametophytes with and without developing rhizoids were observed. Only gametophytes which presented developed rhizoids were able to reach the heart-shaped developmental stage. Based on the collection, the rate of and gametophyte development were generally very low. The relative germination rates were higher at 25 ºC than at 30 °C. Moreover, the highest percentages of gametophytes with developed rhizoids were observed at 22 and 5 percent of natural light (8.8 ± 2.3 percent and 11.3 ± 2.2 percent respectively) and the highest percentage of heart-shaped gametophytes were observed at pH 4.5 and 5.0 (1.2 ± 0.8 percent and 2.2 ± 0.8 percent, respectively).
A finalidade deste estudo foi analisar o potencial germinativo dos esporos de G. pectinata e verificar os efeitos de níveis de luz (62, 42, 22 e 5 por cento da luz natural), das temperaturas de 25 e 30 ºC e de pHs entre 4,0 e 6,7 na germinação. Esporos de G. pectinata são monoletes e a superfície apresenta depósitos grandes e irregulares. Observamos três classes de desenvolvimento: esporos contendo cloroplastos, gametófitos filamentosos sem rizóides desenvolvidos e gametófitos filamentosos com rizóides desenvolvidos. Somente os gametófitos com rizóides desenvolvidos foram capazes de alcançar a fase cordiforme. As porcentagens de germinação foram mais elevadas à temperatura de 25ºC do que 30 ºC. As mais elevadas porcentagens de gametófitos com rizóides desenvolvidos foram observadas sob 22 e 5 por cento da luz natural e as porcentagens mais elevadas de gametófitos cordiformes foram observadas no pH 5,0.