Environmental factors impact the early life stages of Sargassum ilicifolium in laboratory

Carotenoid Differences and Genetic Diversity in Populations of Sargassum hemiphyllum and Sargassum fusiforme

Sargassum hemiphyllum and Sargassum fusiforme are important benthic seaweeds that grow along the southeastern coast of China. The content of carotenoids in each population was detected by ultra-high performance liquid chromatography (UHPLC). The research results will enrich the theoretical basis and data support concerning the influencing factors of carotenoids in Sargassum. The inter-simple sequence repeat (ISSR) technique was used to study the genetic diversity of four S. hemiphyllum and two S. fusiforme populations, and the results provide a reference for the artificial cultivation of Sargassum. The total carotenoid content of Sargassum ranged from 161.79 ± 4.22 to 269.47 ± 6.15 μg/g. Among the carotenoids, β-carotene and fucoxanthin accounted for 80%, and levels in S. hemiphyllum were generally higher than those in S. fusiforme. The carotenoid contents of S. hemiphyllum from different areas were significantly different (P < 0.05), and the total carotenoids content decreased toward the southern region. The average heterozygosity H ranged from 0.29 to 0.49, and the Shannon diversity index I ranged from 0.44 to 0.69. The polymorphic loci, genetic diversity, and other indicators of S. hemiphyllum populations were higher than those of S. fusiforme, and the diversity of cultivated populations was not significantly lower. The results showed that the genetic variation of Sargassum is limited, and thus, more sexual reproduction can be attempted in breeding. Considering morphological indicators, genetic diversity indexes, and carotenoid content, S. hemiphyllum appears to have a higher commercial development value.