6. Salinity Effect on Antioxidant Enzymes in Leaves and Roots of Beans (Phaseolus vulgaris L.)

The effect of salt stress on the activity of antioxidative enzymes was studied in leaves and roots of bean plants (Phaseolus vulgaris L.), grown under control (nutrient solution) and salt stress (nutrient solution containing 100 mM NaCl and Na2SO4) conditions. In the leaves of salt-stressed plants, ascorbate connected enzymes (APX, MDHAR and DHAR) demonstrated increased activity and at the same time their activity was decreased the in roots. The increase of the enzyme activity was more pronounced under sodium sulfate compared with the chloride treatment in the bean leaves. In saltstressed roots the Na2SO4 application reduced the activity at a higher degree. As a result of the two salt treatments of bean plants the CAT activity were increased in the roots and decreased in the leaves as compared with the control.
The observed differences in the enzyme activities show the specific reaction in the different organs of the bean plants as well as the dependence on the kind of the applied salts.