Reprodução sexuada em musgos acrocárpicos do Estado de Pernambuco, Brasil

Abstract

RESUMO -(Reprodução sexuada em musgos acrocárpicos do Estado de Pernambuco, Brasil). A freqüência de reprodução sexuada através da produção de esporófito foi determinada para musgos acrocárpicos, coletados no Estado de Pernambuco e depositados no Herbário UFP. Cada exsicata foi observada ao estereomicroscópio para verificação da ocorrência e do estádio de desenvolvimento do esporófito. Às informações obtidas acrescentaram-se dados de coleta e outros específicos pesquisados em literatura. Examinaram-se 770 exsicatas, pertencentes a Ii falllllias e 59 espécies. Destas, 26 são monóicas, 27 dióicas e as seis restantes têm sistema reprodutivo desconhecido. A ocorrência de esporófito por amostras foi de 3: I, de monóica em relação à dióica. Apresentaram esporófito 88% das espécies com maior riqueza de amostras , havendo tendência, entre as dióicas, de produção ocasional ou rara de esporófito. A análise do estádio de desenvolvimento dos esporófitos por ocasião da coleta demonstrou que a produção ocorre principalmente durante o período chuvoso. Confirmase então a importância da umidade e da autofecundação na reprodução sexuada destes musgos.Palavras-chave -musgos acrocárpicos, fenologia, esporófito, monóicos, dióicos ABSTRACT -(Sexual reproduction in acrocarpous mosses ofPernambuco State, Brazil). The frequency of sexual reproduction in acrocarpous mosses collected in Pernambuco State, and subsequently deposited in the UFP Herbarium, was determined based on sporophyte production. Each voucher was observed under a dissecting microscope for recording the presence of the sporophyte and its developmental stage. The data obtained from literature was also registered. 770 voucher, distributed in Ii families and 59 species, were examined. 26 species have a monoecious reproductive system, 27 a dioicous one, and the six remaining ones have an unknown breeding system. The rate of fruiting specimens was higher in monoicous (3: I) than dioicous ones. Sporophytes were found in 88% of the best represented species. The frequency of fruiting specimens of dioicous species is either occasional or rare. The analysis ofthe developmental stages of sporophyte throughtout the year demonstrated that the production of sporophytes mainly occurs during the rainy season. Finally, humidity and self-fertilization play an important mIe in the sexual reproduction of the acrocarpous mosses.

Seasonality of reproduction of epiphytic bryophytes in flooded forests from the Caxiuanã National Forest, Eastern Amazon

“…A similar result was found for Calymperes erosum and Radula javanica concerning their fertility in relation to the forest type. The other studied species presented fertility constant, independent of the period and/or the forest type, which indicates an opportunist strategy adopted by some species in tropical forest, as those environments possess warm temperatures and high water availability, providing that these plants produce constantly sexual structures (Oliveira and Pôrto 1998, Maciel-Silva and Válio 2011.…”

“…Regarding the mosses, were observed 10 sporophytes, distributed in four species: two monoicous acrocarpous (Fissidens guianensis with fi ve sporophytes and F. prionodes with just one) and two monoicous pleurocarpous (Leucomium strumosum and Pilotrichum bipinnatum with two sporophytes each). The monoicous mosses are often found with higher production rates of sporophytes than the dioicous and it is believed that the proximity between the gametangia on the branches of monoicous species facilitates, independent of the habitat, the fecundation and subsequent growth of the sporophytes Schuster 1983, Oliveira andPôrto 1998). In the monoicous species, although the self-fertilization prevents genetic exchange, it ends up being a way to guarantee that sexual reproduction occurs Schuster 1983, Oliveira andPôrto 1998).…”

“…The bryophytes have different strategies for their reproduction and the studies on this subject have risen through the last decades (Lloret Maya 1987, Oliveira and Pôrto 1998, 2001, LaakaLindberg 2005, Maciel-Silva and Válio 2011, Maciel-Silva et al 2013. The reproduction of bryophytes can be sexual (gametophytic and sporophytic phase) or asexual (with production from the gametophyte, gemmae, propagules, and other structures) (Vanderpoorten and Goffinet 2009).…”

“…In Brazil, the works performed on the reproductive biology of bryophytes are concen trated in the Atlantic Forest biome (Oliveira and Pôrto 1998, 2001, Maciel-Silva and Válio 2011, Maciel-Silva et al 2012. The reproductive behavior parameters of bryophytes in two different habitats of dense ombrophilous forest, in the Atlantic Forest were investigated by Maciel-Silva et al (2013).…”

Briófitas na Estação Ecológica da Universidade Federal de Minas Gerais, Brasil

“…Espécies de briófitas monoicas são geralmente encontradas com esporófitos (Longton 1992, Oliveira & Pôrto 1998, Maciel-Silva et al 2012. Esse padrão deve-se possivelmente à proximidade entre os gametângios nos ramos de uma mesma planta, o que permite maiores chances de fecundação (Glime 2013).…”