BIOLOGICAL ACTIVITY OF SOME COMPONENTS EXTRACTED FROM RED ALGAE

Abstract

Red algae are one of the sections of marine algae which include polysaccharides, proteins, polyunsaturated fatty acids, pigments, polyphenols, minerals, plant growth hormones. These components have well documented beneficial effect on human, animal and plant, mainly by protection of an organism from biotic and a biotic stresses and can be valuable components as fertilizer. Therefore, the aim of this study was concerned on two parts: Part I: Studying the effect of water extract or carrageenanes (1mg/ml) of C. crispus as antiviral agent to biocontrol potato virus Y in potato plants. Part II: Studying the effect of water extract of C. crispus as plant growth regulator. The present study was conducted in the Faculty of agriculture green house and farm; Ain shams University during the two successive seasons of 2012 and 2013. Potato tubers (Solanum tuberosum, Diamond) were grown in dark plastic bags. The potato seedlings inoculated with PVY, and treated with aqueous red algal extract (10, 20, 30%) and carrageenanes (1mg/ml), which were applied at three times. Wheat grains (Triticum aestivum L.) var., Sakha 93, was germinated in the field experience. The growing wheat plants were foliar sprayed twice (at flowering and grain development stages) by each of three concentrations of (10, 20 and 30 %) of Chondrus crispus extract under fertilizer recommendation of agriculture ministry. Part I: The results of potato experiment can be summarized as follows: (A) Potato leaves Photosynthetic pigments: The level of total chlorophylls (a, b) and carotenoids were significantly decreased in infected potato leaves by about 34% and 49% respectively. While, the foliar spraying with algal extract or carrageenan (1mg/ml) led to a significant increase in photosynthetic pigments concentration either pre or post virus inoculation. Proline concentration: Potato virus Y (PVY) inoculation caused a significant increase in proline concentration by about 17% than control plant. Also, foliar spraying with high concentrations of algal extract (20% and 30%) or carrageenanes (1mg/ml) led to a significant increase in proline concentration either pre or post virus inoculation. Total phenols concentration: Total Phenolic compounds concentration was significantly increased in infected potato leaves by about 21% than control plants. Foliar spraying with different concentrations of algal extract (10%, 20% and 30%) and carrageenan (1mg/ml) caused a significant increase in the level of phenols either in the presence or absence of PVY infection. Phenylalanine ammonia lyase activity: Potato virus Y inoculation led to a significant increase in phenylalanine ammonia lyase activity (PAL) by about 28% than control plant. Moreover, foliar spraying with different concentrations of algal extract (10%, 20% and 30%) or carrageenanes (1mg/ml) caused a significant increase in PAL activity either pre or post virus inoculation. Antioxidant enzymes: Infected potato leaves have significantly increased in peroxidase (POD) and polyphenol oxidase (PPO) activities by about 51% and 19% respectively. Foliar spraying with the highest concentrations of algal extract (20% and 30%) or carrageenanes (1mg/ml) either in the presence or absence of virus infection caused a significant increase in antioxidant enzymes activity than plant control.