Study of morphological, anatomical characteristics and metabolic assay of some Ulva species (sea lettuce) in the coastal waters of the Persian Gulf, Iran

The genus Ulva L. (Sea lettuce), one of the most valuable marine macroalgae, is found in shallow coastal areas and in brackish and fresh water around the world. Ulva species have nutritional and medicinal values in addition to other applications, and contain various compounds such as lipids, proteins and carotenoids. These species have high phenotypic plasticity and varied in response to different environmental conditions. In this study, 38 populations of 10 species of Ulva from the coastal areas of the Persian Gulf and Oman Sea, from different areas of Bushehr, Hormozgan and Sistan and Baluchestan provinces, were studied and identified on the basis of morphological and anatomical traits. Different populations showed variations in characteristics such as height, shape and color of thallus, number of pyrenoids and cell dimensions. Metabolites such as total protein, total oil, chlorophyll a, b and carotenoids contents were measured and compared among the different populations. The results should that the percentage of protein was highest in U. prolifera of Shif Island from Bushehr province as compared with the Ulva species studied, with about 26.5% of dry weight, and the percentage of total oil was lowest in U. flexuosa of Hakhamanesh region from Hormozgan province as compared with the species studied, with about 4.8% of dry weight. These results show that different environmental conditions affect the morphological and anatomical structure of species and the content of their metabolites. Due to the high-protein and low-calorie content of the Ulva genus and the importance of finding new and sustainable resources for food and pharmaceutical industries, the species of this genus have valuable potentials.