Ecofisiologia de Cyatheaceae (Monilophyta): fenologia, banco de esporos, anatomia e germinaÃÃo

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

The objective of this study was: to define the fenolÃgico standard of the species of Cyatheaceae, to evaluate the formation of the bank of spores of Cyatheaceae in the of Atlantic Forest of the RPPN of Frei Caneca, to the long one of the year, to define excellent conditions of growth of the species, and also to define anatomical standard of fronds of two species of Cyathea. The study it was developed in the bushes of the Mountain range of the Quengo and the Bernardina. To evaluate the formation of spores of bank, the ground superficial was collected in ten points of each bush, to the end of the dry and rainy stations. The samples ground had been kept 25ÂC and photoperiod of 12h in growth chamber. The criterion to consider the germination of spores of bank was the appearance of the first rizoidal cell of the gametophyte. During the initial development, the gametophytes had been grouped in tricomades and not tricomades. The fast germination of spores and formation of gametophytes was observed in the samples from first and second the month of culture of the ground of Mata of the Mountain range of the Quengo and the Bernardina, respectively. In the two places, 80% of the morphotypes of formed gametophytes had not presented tricomas. From the third month reproductive structures had been observed, or either, antheridium and arquegonium, in the samples of the two bushes and, to the end of five months had formation of sporophytes. For the fenological study, collections of data had been carried through during one year, where ten individuals of each species of Cyatheaceae duly had been marked, identified. The three species of Cyathea had kept the production of walking sticks to long of the year and the constant development. The category aborted walking stick was observed for the species Cyathea microdonta and C. praecincta. The production of fronds barren was kept during all the year for the three species of Cyathea. Alsophila setosa, presented production of walking stick per all year. Frond was not observed fertile and few had been fronds barren gifts. Young individuals of this species had not been observed. For the anatomical study, fronds collected had been fixed in FAA 50% and later kept in ethanol 70%. Transversal cuts by hand exempt had been carried through, clarifications with hypochlorite of sodium (50%), washed in water distilled and later with Safrablau. After the coloration the cuts, had been mounted halfpermanent blades in glycerinate water 50%. Cyathea corcovadensis and Cyathea microdonta present anatomy classified with Cyathea type, corroborating with studied literature. To characterize studies of germination and development of gametophytes, spores of C. corcovadensis collected disinfested and distributed in erlenmeyers contend 25mL of nutritional solution of Mohr with nistatina fungicide. The treatment of photoblastism was kept in chamber of growth with temperature of 25ÂC and photoperiod of 12h. The experiments of quality of light and luminous intensity had been kept in chamber of growth with temperature of 25ÂC and continuous light. In all the experiments the criterion to consider spore germinated was the emission of the rizoidal cell. For the photoblastism study, erlenmeyers under light and dark continuous had been placed. The continuous treatment dark was gotten with the use of three black plastic bags. The luminous intensity was analyzed the 100, 70, 50 and 30% with use of screens of sombrite with different filters of light ticket. The germinated spores had been followed per 30 days for the study of development of gametophytes. The spores of C. corcovadensis are aclorophillous and had presented corpuscles lipidics. The spores of C. corcovadensis are considered photoblastics positives, a time that was not observed germination in dark exactly after the 30 days of culture. When analyzed the effect of the quality of light in the germination, it was observed germination from 4Â day and stabilization of the curve of germination in 100% in 12Â day for white light and occurred a delay of four days in the stabilization of the curve for the too much treatments, being then the curve stabilized in 16Â day of culture. The gametophytes submitted to the treatments of white light and red light had had a fast development of its protaliais cells. A variation in the standard of development of the gametophytes in the treatments of blue light and light was observed redextremity. In these treatments, bigger frame number was observed and the same ones had revealed more prolongated. The effect of the luminous intensity was observed in the different treatments, having been the germination from 4Â day of culture and stabilization of the curve of germination (in 100%) from 16Â of germination for displayed spores the 100% of light, 18Â day for the treatments of 30 and 50% of shade and in 20Â day for the treatment of 70% of shade. To the 21 days of germination an along of the protaliais cells was observed characterizing stiolament of the cells, in the treatment of 70% of shade, this in result of low the happened luminous intensity on the corcovadensis gametophytes of C. corcovadensis. Gametophytes, with 30 days, cultivated under 100% of light and 30% of shade had presented the form spatulated with beginning of development without synchronies of the sections, having had the section right if developed more than the left section. In the too much luminous intensities (50 and 70% of shade), the gametophytes had presented the filamentous form of development. In the experiments of quality of light and luminous intensity, it is clearly that the ideal development for species of corcovadensis Cyathea that the treatments of white and red light, and 100% of light and 30% of shade are ideal coconditions for the development of gametophytes and consequence formation of new plants

ASSUNTO(S)

cyatheaceae - germinaÃÃo cyatheaceae - anatomy pteridÃfitas - fisiologia pteridophytes - physiology cyatheaceae - anatomia botanica cyatheaceae - germination

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