Modulation of polyamine catabolism in pea seedlings by calcium during salinity stress

The relation of polyamine catabolism in the response of Pisum sativum to salinity stress was investigated. Pea seedlings were grown in increasing concentrations of Na⁺ or K⁺ or at different concentration ratios of these ions. We studied the effect of Ca²⁺ supplementation on plants exposed to salinity stress. The parameters measured in the roots and shoots of pea seedlings included biomass production, levels of Na⁺, K⁺, Ca²⁺ and polyamines and activity of enzymes of polyamine catabolism: diamine oxidase, aminoaldehyde dehydrogenase and peroxidases. Salinity induced increased polyamine levels and higher activity of enzymes participating in polyamine degradation. Supplementation of Ca²⁺ had a positive effect on biomass production and in most cases it stabilised both the polyamine level and the activity of the studied enzymes. Our results confirm the role of aminoaldehyde dehydrogenase and polyamine catabolism in defence mechanisms of pea plants under salinity stress.