ENZYME ACTIVITIES OF CERTAIN PUMPKIN (CUCURBITA SPP) SPECIES UNDER DROUGHT STRESS

The aim of this study is to investigate the relationship between the drought tolerance capacity and antioxidant enzyme activity of 38 genotypes of different pumpkin species from different regions of Turkey. The seedlings from 38 different genotypes were put into pots containing Hoagland's solution to be stored in cultivation rooms under controlled climatic conditions. A 15% polyethylene glycol 6000 (PEG 6000) solution was added to the Hoagland's solution to create an osmotic potential equivalent to -0.60 M=Pa for the drought test application. The leaf weights were determined following the test under drought and control conditions. The relative water content, chlorophyll content, and antioxidative enzyme activities (superoxide dismutase, catalase, and ascorbate perwddase) were investigated. As a result, it was observed that the enzyme activities are extremely vital in the drought tolerance of the pumpkin genotypes; such as under dry conditions, the drought tolerant pumpkin genotypes use antioxidative enzymes more actively compared to the drought susceptible genotypes.