Phosphate effects in physiological responses and carbohydrate production in Ulva fasciata Delile (Ulvales, Chlorophyta) from two populations.xlsx

Bioproducts derived from Ulva
species have received increasing attention in several biotechnological fields
due to their economic potential and cosmopolitan distribution. This study
assessed the influence of different phosphate concentrations (0, 2 and 4 µM PO43-)
commonly found in eutrophic environments on carbohydrate production, growth
rate, tissue phosphorus, phosphate uptake and photosynthetic response in U. fasciata from two distinct sites
(Arraial do Cabo, an upwelling site, with cold and nutrient rich water, and Niterói
/ Rio de Janeiro – Brazil, a non-upwelling site). After fifteen days of the
experiment, the carbohydrate content increased in both populations and in all
treatments (p < 0.05) at
approximately 136 and 264 % for Arraial do Cabo and Niterói, respectively. In
Arraial do Cabo individuals, the carbohydrate content was high in all
treatments (71 % DW), while Niterói individuals cultivated in the highest
phosphate concentration presented the lowest carbohydrate content (46 % DW).
Individuals cultivated in the absence of phosphate (control) presented the
lowest tissue P and a progressive decline in the maximum quantum yield (Fv/Fm)
over the experimental period (p <
0.05). Altogether, the results indicate that phosphate concentrations in the
culture medium influenced the carbohydrate content of U. fasciata and that populations from sites with broad
environmental variations can present higher productivity. Moreover, the
different physiological responses and carbohydrate content throughout the
experimental period suggest that populations are ecotypes.