Cadmium-induced root growth inhibition in wheat is related to increased polyamines and nitric oxide

GROPPA M.D.; IANNONE M.F.; ROSALES E.P.; BENAVIDES M.P.

Rosario, Santa Fé, Argentina

Congreso; XLII Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2006

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB)

Nitric oxide (NO) plays a key role as an intra and intercellular messenger in several processes in plants. Recently, it has been demonstrated that polyamines induce NO biosynthesis in plants. Since both molecules are related to developmental and defense processes, as well as in their biosynthetic pathways, the aim of this work was to study whether polyamines and NO were involved in cadmium root growth inhibition of wheat plants. Triticum aestivum seeds were germinated in Petri dishes and after 48 h, they were transferred to hydroponics with Hoagland solution (control) or with 0.1 mM CdCl2, 0.1 mM NO, 0.01 mM NO, 1 mM Spm exogenously added to the same nutrient solution. cPTIO was used as NO trap in control treatments. Plants were harvested after 7 days of growth and root elongation, polyamine content and NO formation were evaluated. All treatments caused an inhibition of root growth compared to the controls. This inhibition was accompanied by an increase in the level of the three main polyamines Put, Spd and Spm and an evident NO formation (detected with the fluorescent probe DAF-FM). When cPTIO was added together with Cd NO or Spm, a reduction of NO release and a partial reversion of root growth inhibition was observed. These results suggest that NO and polyamines could be involved in cadmium toxicity that leads to a significant root growth inhibition in wheat plants.