Phenological aspects of <I>Padina gymnospora</I> (Kuetzing) Sonder (Dictyotales, Phaeophyta). I. First approach

Abstract

Sixty two plants of Padina gymnoapora, collected from populations located in different environments in regard to wave action, in the Northern shore of the State of Rio de Janeiro, were studied with respect to some phenological aspects. This species showed, on average, 4.6 cm height, 52.62 cm2 of total area and 18.22 cm2 of fertile area. The plants that presented the largest fertile area attainned 61% of their total area. The estimated mean values of the fecundity of each plant varied from 5.9 x 10⁵ (female gametes) to 3.5 x 10⁸ (male gametes). There is no significant difference between plants from protected and exposed sites, in relation to the mentioned characteristics, although the highest values were found in sporophytes collected in protected sites (11.0 cm, 187,94 cm² and 97.68 cm², respectively). Fertile female gametophytes and tetrasporophytes showed a significant difference (? = 0,05) in relation to the total area the number of reproductive structures of each plant. The studied phenological variables showed high and positive correlation values (r ? 0.69) at a 95% level of significance. The obtained results suggest that Padina gymnoapora, in the studied area, behaves like ephemeral or aseasonal annual and demonstrates some characteristics of an opportunistic species. This conclusion agrees with data previously mentioned in the literature regarding to other species of the same genus.