Oxidative stress and growth modifications in wheat seedling subjected to heavy metals stress

LB PENA; CE AZPILICUETA; SM GALLEGO

San Miguel de Tucumán

Congreso; XLV Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2009

SAIB

Germination and post-germination stage are critical in the plant life. Any disturbance of the optimum environmental conditions can limit the growth or affect survival and/or productivity of plants. In this work, the effect of different metals on germination and growth of wheat (Triticum aestivum L.) was study. Seeds were floated for 72 h on distillated water or adding with 10 and 50 µM AlCl3, CdCl2, CoCl2, CrCl3, HgCl2, NiCl2, ZnCl2. While most of the metals modified the seedling growth, Cd2+ and Hg2+ showed a similar behavior inhibiting germination with 50 µM metal and reducing significantly seedling growth with 10 µM metal. Cadmium was selected to continue the study. Seeds were treated with 1 and 10 µM CdCl2, 0,5 µM paraquat (PQ) or 1 mM H2O2 for 48 h. Treatments decreased root length 28 and 55% for 1 and 10 µM Cd2+, 54% PQ and 10% H2O2. Longitudinal sections showed changes in growth and cell proliferation. Treatments increased oxidation of proteins and catalase activity. Although membrane permeability increased with Cd2+ and H2O2, no cell death was observed by Evans Blue staining methods. These observations suggested that the oxidative imbalance in the system could be responsible of the growth inhibition observed in the cadmium treatment. More results are necessary to understand the relationship between the decrease in seedlings growth and the oxidative damages produced by metals.