Reaction of Pumpkin Plants on Separate and Combined Effects of Cadmium and Salinity

A specific character of physiological-biochemical stress responses of pumpkin plants to toxic effect of
cadmium under conditions of salinity in the course of their long-term cross-adaptation was investigated. Cd
(2 ppm) and NaCl (100 mM) were added either alone or in combination in Knop solution along with non-
treated controls. In 7- and 14-day plants, all the physiological processes studied (shoot and root growth,
bioaccumulation of fresh and dry biomass by them, nitrogen-protein metabolism and proteolysis in different
plant organs) were found to be more sensitive to inhibitory action of Cd excess than to NaCl effect.
However, in 21-day plants, especially in their roots, some activation of growth and biosynthetic processes
was observed in the presence of combined Cd and NaCl treatments than at their lone application. All this
indicates that an adaptation of plants to salinity is accompanied by some reduction in toxic effect of Cd on
plants growth and metabolism.