%0 Journal Article
%T Fase gametof¨ªtica del helecho Microgramma nitida (Polypodiaceae)
%A Ma. del Rosario Ram¨ªrez
%A Blanca P¨¦rez-Garc¨ªa
%J Revista de Biolog¨ªa Tropical
%D 1998
%I Universidad de Costa Rica
%X Se describe la fase gametof¨ªtica del helecho Microgramma nitid con esporas de Veracruz, M¨¦xico (siembra promedio 40 esporas/ cm2). La morfog¨¦nesis se caracteriza por: germinaci¨®n tipo Vittaria, un filamento inicial de seis c¨¦lulas prot¨¢licas; gametofitos j¨®venes espatulados que se transforman en gametofitos adultos cordiformes-alargados, con m¨¢rgenes ondulados y tricomas unicelulares-capitados en los margenes y en las superficies; aparici¨®n de una c¨¦lula meristem¨¢tica obc¨®nica apical, que es reemplazada r¨¢pidamente por un meristemo pluricelular. Los anteridios y arquegonios son del tipo usual de las Polypodiaceae s.str. El desarrollo prot¨¢lico es del tipo Drynaria. Ocho meses despu¨¦s de la siembra apareci¨® la primera hoja del esporofito; ¨¦sta es espatulada, con m¨¢rgenes lisos y una hilera de c¨¦lulas aclorof¨ªlicas, tricomas pluricelulares, bifurcados y estomas anomoc¨ªticos. Las c¨¦lulas epid¨¦rmicas de la hoja del esporofito tienen paredes laterales onduladas en las superficies dorsal y ventral. The development of the gametophytic phase of Microgramma nitida is described based on spore samples that was obtained of fertil specimens gathered on Veracruz State, Mexico. The spore sowing density was 40 spores/cm2 ; it is characterized by Vittaria-type germination of the spore, a germinal filament of six cells; young gametophytes are naked, spathulated and later are transformed in cordate-elongated adult gametophytes with wavy borders; marginal, superficial capitated, unicellular hairs; the meristematic cell is wedge-shaped and is quickly replaced by a pluricellular meristem. The antheridia and archegonia are of the usual Polypodiaceae s. str.type. Prothallial development is thus of the Drynaria-type. The first leaf of the sporophyte appeared eight months after spore sowing. The leaf is spathulated, with smooth borders and the margin has a row of cells without chlorophyll; bifurcated and pluricellular hairs; anomocytic stomata; the epidermic cells of the sporophyte have wavy walls on upper and lower surfaces.
%K Gametophyte
%K M¨¦xico
%K Microgramma
%K morphogenesis
%K Polypodiaceae s. str
%U http://www.scielo.sa.cr/scielo.php?script=sci_arttext&pid=S0034-77441998000300012