Abstract

Levels of peroxidase (POD) and catalase (CAT) enzyme activity were determined in 2 years-old walnut plants which were grown in environmental conditions characterized by high temperatures. It’s also high photosynthetic photon flux density levels and subjected to a different salinity levels for 60 days period. The present study, through an experimental campaign, was carried out on both normally irrigated and salt-stressed plants with CaCl₂ in order to comprehend the plant response to salt stress and its ability to recover. Leaf samples were collected and analyzed for POD and CAT enzymes activities before the experimental period. The levels of CAT and POD activity increased in parallel with the severity of salt levels in leaves of tolerant genotypes walnut especially the plants which treated by Ca⁺². This increase extended, after 6 days of salt stress usage. However, in all the treatments, POD and CAT activity was reduced significantly from 6 to 10 days after beginning the salt stress. The increase of antioxidant enzymes activity indicates its potential role in salt tolerant salt in promising walnut genotypes. The amount of antioxidant compounds increases in plant during the salt stress.

Key words: Enzyme activity, peroxidase, catalase, salinity, walnut.