The role of polyamine in maize leaf growth under salt stress

RODRÍGUEZ ANDRÉS; RUIZ OSCAR; MAIALE SANTIAGO

Mar del Plata, Buenos Aires, Argentina

Congreso; 43 Reunion Anual de la Sociedad Argentina de Investigaciones en Bioquimica y Biología Molecular; 2007

Sociedad Argentina de Investigaciones en Bioquimica y Biología Molecular

The reduction of leaf expansion is one of the primary effects of salt stress. In previous works, we sowed that apoplastic reactive oxygen species (ROS) are necessary for leaf extension in maize. Decreased ROS concentration in the elongation zone (EZ) contributes to the reduction in maize leaf growth under salinity. Also, the polyamines (PAs) are low Mr organic polycations, involved in plant growth and development. Apoplastic PAs oxidation produces H2O2 (ROS). The PAs levels increase in plants under salinity. The purpose of this work was to assess the role of PAs in elongation growth in the expanding zone (EZ) of maize leaf blades, subjected to saline stress. Analysis of PAs in EZ segments (EZS) with highest elongation in control and significant difference with salinized plants did not show changes in total PAs However, the levels of putrescine and spermine (spm) respectively in salinized EZS, indicating a displacement of status to superior PAs, like spm. Parallelly, in elongation assays, salinized EZS tried with BE-4-4-4-4, an inhibitor of polyamine oxidase (PAO), catalytic enzyme of spm, reduced elongation in 25%. These preliminary results could indicate that the H2O2 from the spm oxidation in apoplast, contributes to maize leaf growth under salinity.