Tissue-Specific Responses in Soybean Plants Exposed to Cadmium

Abstract

Cadmium seriously affects plant growth, development, homeostasis and yield production. The effect of two doses of cadmium (10 and 100 mg.kg-1 Cd2+) on plants of sensitive soybean variety (Glycine max L. cv. Kyivska 98) were studied after short treatment in a pot experiment. Several parameters were determined in roots and leaves, including cell viability, the content of malondialdehyde and proline, and activity of defense proteins (catalases, guaiacol peroxidases, ascorbate peroxidases, superoxide dismutases, chitinases, β-1,3-glucanases). Changes caused by cadmium depended both on the concentration of cadmium, as well as on the type of plant organ and its developmental stage. Soybean tissues generally showed low levels of oxidative stress and reduced proline content likely due to activity or depletion by different mechanisms (respectively). The activity of catalases and guaiacol peroxidases was inhibited by cadmium concentrations only in younger leaves. The enzymatic activities of superoxide dismutases, chitinases and β-1,3-glucanases were highly variable depending on the cadmium concentration as well as the soybean organ analyzed. Our experiments revealed differences in defense strategies and regulatory mechanisms between plant organs as well as developmental stages of leaves in response to cadmium toxicity.