Spore Germination of Gleichenella pectinata (Willd.) Ching (Polypodiopsida-Gleicheniaceae) at Different Temperatures, Levels of Light and pH

Ano: 2010 | Volume: 53 | Número: 6

Autores: Eunice Pereira Gonçalves dos Santos, Débora Rosana Marques Lehmann, Marisa Santos, Áurea Maria Randi

Palavras-chave: gleichenella pectinata, germination, light, ph, temperatures

Resumo Português:

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% 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 °C. As mais elevadas porcentagens de
gametófitos com rizóides desenvolvidos foram
observadas sob 22 e 5% da luz natural e as
porcentagens mais elevadas de gametófitos
cordiformes foram observadas no pH 5,0.

Resumo Inglês:

This study investigated the effects of different temperatures (25 and 30 ± 2 ºC), light levels (62, 42, 22 and 5% 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% of
natural light (8.8 ± 2.3% and 11.3 ± 2.2% respectively) and the highest percentage of heart-shaped gametophytes
were observed at pH 4.5 and 5.0 (1.2 ± 0.8% and 2.2 ± 0.8%, respectively).