Cultivation of Gelidium floridanum in different nitrate concentrations: morphophysiological effects
摘要
Gelidium floridanum is a seaweed of significant economic importance, rich in cell wall components utilized in biotechnology and widely distributed in coastal environments. However, many aquatic ecosystems have been polluted by anthropogenic activities. The use of seaweeds for mitigating pollution is an expanding field, particularly due to their potential in bioremediation and economic value. This study investigated the effect of varying nitrate (NO3−) concentrations on the morpho-physiology of G. floridanum. The seaweed was exposed to 0, 25, 50, and 100 mM of NO3− for 7 days. The highest growth rate and cell viability were observed at 25 mM, while photosynthetic pigment levels were elevated at 50 and 100 mM. Protein and enzyme quantification showed no significant differences across treatments. Light microscopy with histochemistry methods revealed an increase in starch grains in cortical cells and a lack of organized cell walls at 0 mM NO3−. Transmission electron microscopy showed thickened cell walls and the presence of plastoglobules at 25, 50, and 100 mM NO3−. In conclusion, G. floridanum exhibited optimal growth and development at 25 mM NO3−, with higher concentrations inducing stress in the thalli.