Interaction of Epiphyte Polysiphonia sp with Kappaphycus alvarezii Host Based on Anatomical Structure and Phytochemical Profile

Polysiphonia sp is the dominant epiphyticmacroalgae species in the K. alvarezii host on the Lombok cultivation centre. The existence of this epiphyte has a negative influence on cultivation activities and the resulted product. The dominance of this species is influenced by the anatomical characteristics of Polysiphonia sp, K. alvarezii and the content of metabolites found in the thallus surface of the host. This study aimed to analyze the relationship between Polysiphonia sp and K. alvarezii. The sample used was K. alvarezii, overgrown by the epiphyte Polysiphonia sp. Anatomical data obtained by making cross-sections were then stained with CBB. For the epiphyte anatomy, it was done by staining all parts of the thallus using the same dye. Surface metabolite data of K. alvarezii thallus were obtained by dissolved it in methanol as solvent for 30 second, and compound analysis was carried out using GCMS. Correlation analysis between Polysiphonia sp and K. alvarezii was carried out descriptively. The results showed that the thallus diameter of Polysiphonia sp was about 400-700 mm, 1-1.5 cm long. It had a rhizoid holdfast and could produce large amounts of spores. Host anatomy shows an uneven surface, with cortical cells forming a dome that can potentially increase the epiphyte attachment rate. The results of GCMS analysis showed that the infected K. alvarezii thallus obtained as many as 20 compounds, while in the healthy thallus, only ten compounds. One of the metabolites produced by infected thallus was Benzoic acid (CAS) retardex which plays a role in stimulating abiotic and antimicrobial stress tolerance.