Abstract: The role of stress-related enzyme activities in response to high temperature tolerance of three green bean genotypes [‘Balkız’ (heat-sensitive), ‘Ferasetsiz’ and ‘Local Genotype’ (heat-tolerant)] was investigated in this study. The seedlings were grown until 3-4 trifoliate leaves stages under controlled conditions at 30/15ºC (day/night) temperature with %65 relative humidity then transferred to climate chamber to expose to heat stress. The temperature was increased stepwise to 35, 40, 45 and 50ºC for 24 hours. The activities of nicotinamide adenine dinucleotide phosphate [NAD(P)H] oxidase and antioxidative enzymes, catalase (CAT), ascorbate peroxidase (APX), glutathion reductase (GR) and isoperoxidase activities significantly varied depending on heat tolerance of genotypes. Besides one acidic and four basic isoperoxidases were determined with differing intensities between genotypes and high temperatures. As a result, NAD(P)H oxidase activity may involved in determining genotype sensitivity to heat stress, and antioxidative enzymes involved in heat stress tolerance in green bean plant.
Keywords: antioxidant enzymes, high temperature, isoperoxidase, legumes, nad(p)h oxidase