Inhibition of pigments and phycocolloid in a marine red alga Gracilaria edulis by ultraviolet-B radiation

Abstract

Vegetative fragments of the subtidal macroalga Gracilaria edulis (Gmel.) Silva cultured under field conditions at Thonithurai were subjected in the laboratory to UV-B radiation (280 - 320 nm). UV-B inhibited the accumulation of chlorophyll and phycobiliproteins, and lowered agar yield (23 to 43 %) and its gel strength (22 to 36 %) under 12 to 72 h exposure. The longer the exposure to UV-B radiation the more significant impact on pigments and phycocolloid properties of Gracilaria edulis was observed.