MICROALGAE (Chlorella vulgaris)-MEDIATED SECONDER METABOLITES AND ANTIOXIDATIVE DEFENSE SYSTEM IMPROVE PLANT GROWTH AND SALT TOLERANCE IN MELON

Abstract

Microalgaes, such as Chlorella vulgaris (green algae) are beneficial microscopic organisms that may result in a plant having improved nutrient uptake, growth, and abiotic stress tolerance. In this study, an investigation of tolerant and sensitive melon genotypes, grown under salt-stress conditions, with regards to the impact of microalgae on physiological, morphological, and enzymatic activity was performed. Microalgae applications significantly increased shoot length, and fresh and dry weight, and leaf number and area, and photosynthetic pigments and of melon plants compared to the only salt stress treatment. In addition, following the above-mentioned procedures, there were significant increases in the relative water content, total phenolic and flavonoid contents, K and Ca ion contents, and superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase (GR) activity. However, the malondialdehyde (MDA), Na and Cl^-ions contents were significantly decreased. Hence, the results support the administration of a foliar application to the microalgae in order to increase the melon plant’s defense system, enabling it to tolerate the negative effects resulting from salinity.