Sunflower development is altered by a long-term cadmium and copper treatment

M.D. GROPPA; M.P. IANUZZO; M.L. TOMARO; M.P. BENAVIDES

Pinamar, Buenos Aires Argentina

Congreso; X Congress of the Panamerican Association for Biochemistry and Molecular Biology (PABMB). XLI Annual Meeting of the Argentine Society for Biochemistry and Molecular Biology (SAIB).XX Annual Meeting of the Argentine Society for Neurochemistry (SAN).; 2005

Sociedad Argentina de Investigación Bioquímica y Biología Molecular

In the last years, human activities have contributed to the environmental pollution by allowing the uncontrolled increment of waste products in the atmosphere, soil and water. Cadmium is not essential for plant growth and it is phytotoxic to living cells, even at very low concentrations and copper is an essential element for normal plant growth but toxic for plants at high concentrations. The aim of this work was to evaluate the effect of different concentrations (0.1, 0.5 and 1 mM) of Cd and Cu on sunflower growth and development during 16 days of treatment. Metal accumulation, shoot and root growth, relative water content (RWC), chlorophyll content, proline content and alterations in leaf morphology were evaluated. Sunflower roots accumulated a significantly great amount of metals than shoots. The magnitude of Cd accumulation in sunflower roots and shoots was significantly higher than that of Cu. However, a different pattern of accumulation was observed between both metals. Cadmium and copper at the higher concentrations produced an inhibition of shoot and root growth and a reduction of RWC. However, sunflower plants treated with 1 mM Cd were capable of preserving the pigment level over the controls up to day 10, when chlorophyll started to decrease, but still maintaining a higher level than that observed with 0.1 or 0.5 mM Cd. This result could be explained by the different cell organization of parenchymas and the greater number of chloroplasts observed on histological sections of cotyledons (10 days) and leaves (16 days) of Cd 1mM treated plants.