Epiphytic effects of Licmophora paradoxa on pigments of Pyropia yezoensis

Abstract

Epiphytic diatoms usually cause adverse effects on photosynthesis of the host plants due to shading light or by interfering with the biochemical pathways. The present study investigated the epiphytic effects of the diatom Licmophora paradoxa on the pigments of red alga Pyropia yezoensis, such as the chlorophyll-a (Chl-a), Phycoerythrin (PE), Phycocyanin (PC), Allophycocyanin (APC) and carotenoid contents. The results showed that Chl-a was significantly decreased while other pigments such as PE, PC, APC and carotenoid contents were significantly increased in P. yezoensis due to the attachment of epiphytic diatom L. paradoxa. The present results indicated that epiphytic diatoms produced negative effects on the host PSII reaction center by reducing its main pigment Chl-a. Whereas, antenna pigments of Phycobiliprotein, of P. yezoensis such as PE, PC and APC were increased to capture more light energy supplying photosynthesis. The increase in carotenoid content under this epiphytic situation implied an enhancement of its assisted function in light-harvesting, photoprotection and stress-tolerance mechanism. The present findings contribute to well understanding the response mechanism of host macroalgae to epiphytic microalgae.