ABSTRACT

       The objective of this study is to describe and evaluate the development gametophytes and sporophytes of the M. pyrifera, under laboratory conditions. Fertile sporphylls from native populations of Tierra del Fuego (53°18´11.4´´S; 70°23´30.5´´W) were submitted to sporelling, obtaining a homogenous solution of zoospores, which were inoculated on microscope slides. The experiment was performed in a cultivation chamber at a temperature of 8 ± 2 °C, photoperiod of 12:12 and light intensity of 40 µEm^-2 s^-1, as a cultivation mean, filtered sea water was used, enriched with Provasoli Medium, (20 ml lt^-1), which was changed once weekly basis. The culture was monitored every three (3) days, from the zoospores stage to obtain sporophytes. The average daily growth was determined for the gametophytes and sporophytes, using an integrated microscopic system and software to process images. The average diameter of the germlings was 17,9µm ± 2,99 with an average growth rate of 9,43 % day^-1. The gametofitic (microscopic) stage was developed during a five (5) day cultivation period. After 15 days development of the first sporophytes began, with an average growth rate of 8,35 % day^-1. The average length reached at the end of the study (65 days of cultivation) was 2920µm ± 674,98.