Variation in Photosynthetic Pigments, Antioxidant Enzymes and Osmolyte Accumulation in Seaweeds of Red Sea
- 1. Department of Biology, Faculty of Science, University of Tabuk, Saudi Arabia
Abstract
The present investigation was carried out to evaluate the response of two groups of
seaweeds of red sea to prevailing environmental conditions. Total four seaweeds were
selected from two groups viz. (i) Red seaweeds (Rhodophyta): Gracilaria salicornia
(Gs) and Digenea simplex (Ds); and (ii) Green seaweeds (Chlorophyta): Ulva reticulata
(Ur) and Chaetomorpha linum (Cl). The performance of seaweeds was assessed
in terms of photosynthetic pigments (Chl a, Chl b, total Chl content, Chl a: b ratio,
phycocyanin and phycoerythrin), thiobarbituric acid reactive substances (TBARS), H2
O2
content, accumulation of osmolytes (proline: Pro and glycine betaine: GB), activities of
antioxidant enzymes (superoxide dismutase: SOD; peroxidase: POX; and catalase:
CAT), and total protein and carbohydrates. The results show that green seaweeds
contain higher level of all the photosynthetic pigments except carotenoids, phycocyanin
and phycoerythrin which were higher in red seaweeds. Regarding activities of
antioxidant enzymes, red seaweeds show higher activities of POX and CAT except
SOD. Concentration of Pro, GB and total protein and carbohydrate were also higher
in red seaweeds. Taken together, all the four studied seaweeds show an immense line
of variation in their strategy of endurance under similar environmental conditions, but
red seaweeds possess higher levels of antioxidant enzymes and osmolytes, thus better
adapted to changing climatic conditions.