Abstract:

The global seagrass bed ecosystems are facing multiple threats. For instance, the seagrass Phyllospadix (Zosteraceae) is of great ecological importance and fishery value. And one of the seagrasses surfgrass, Phyllospadix, is relatively poorly studied. In particular, there are more study gaps in the description, micro-observation and germination process of the main breeding carrier, seeds of surfgrass, as well as in the identification of DNA molecules. In this study, Phyllospadix iwatensis was used as the study object to describe its growing environment, external characteristics of seeds, internal structure, germination process, etc. in both qualitative and quantitative ways, and the results show that fruits and seeds of surfgrass have the adaptability on external form and internal structure in the marine environment, and have the advantage of becoming tool species for vegetation restoration in coastal zone. External morphological features include unique fruit inflorescence and fruit shape, as well as wing-like structure and medial mane, of which the fruit inflorescence is curved shrimp-shaped with an average length of 3.4 cm and the fruit is horseshoe-shaped with a diameter of 3-4 mm. The internal structural features include a large proportion of endosperm and complex anatomy of the peel and seed coat. This study complements the lack of in-depth study on the seeds of marine submerged plants, such as surfgrass, and provides valuable suggestions and reference contents for the protection of surfgrass and other types of seagrass seed banks, as well as the restoration of seagrass beds, and also yields a basis for the practical application of surfgrass in seedling restoration.

Key words: seagrass, Phyllospadix iwatensis, fruit, seed, morphology