Influência de fatores ambientais sobre o crescimento in vitro de Hypnea musciformis (Wulfen) Lamouroux (Rhodophyta)

Abstract

Hypnea musciformis (Wulfen) Lamouroux (Hypneaceae, Gigartinales) is an important carrageenan resource of Brazil used in the industry of phycocolloid gelling agent. The objective of this study was to investigate the influence of temperature (20 ºC and 25 ºC), enriched seawater with Provasoli’s solution and aeration on the in vitro development of this species. Thalli of H. musciformis were collected from Prainha, Arraial do Cabo (RJ) in two different seasons of the year 2000 (April and July). In the laboratory, apical fragments weighing 0.2 g (15 mm long) were excised from the thalli and prepared for incubations at different abiotic factors. In decreasing order, multifactorial analysis of variance showed that the factors of higher influence on the growth of fragments were: water nutrient enrichment, aeration, temperature and season. All fragments increased in biomass and showed high phenotypic plasticity. The best results were obtained in nutrient enriched medium, aeration and at 25 ºC (biomass of 17 g and specific growth rate of 20.79 %.day-1 ). On the other hand, H. musciformis did not respond well in non nutrient enriched medium, absence of aeration and at 25 ºC (biomass of 0.7 g and specific growth rate of 0.07 %.day-1 ). The thalli collected in different seasons of the year did not demonstrate any sharp differences. We concluded that cultivation of apical fragments of H. musciformis produces good results that can provide a basis for future applications.