Interactions between biomass production and ethylene biosynthesis in copper‐treated rice

Abstract

Rice (Oryza sativa L.) plants were grown over a 30‐day‐period in nutrient solutions containing increasing copper (Cu) concentrations (0.002, 0.01, 0.05, 0.25, 1.25, and 6.25 mg/L). It was observed that in both root and leaf tissues the total activity of l‐aminocyclopropane‐l‐carboxylate synthase decreased at concentrations above 0.05 mg/L Cu treatment, whereas the total activity of the ethylene forming enzyme slightly increased until the 1.25 mg/L Cu treatment. In the root and leaf tissues, the 1‐aminocyclopropane‐l‐carboxylic acid concentrations decreased after the 0.05 mg/L and 0.01 mg/L Cu treatments, respectively, whereas the ethylene production decreased in both tissues after the 0.05 mg/L Cu treatment. It is proposed that excess Cu in both root and leaf tissues decrease the conversion of S‐adenosylmethionine to 1‐aminocyclopropane‐l‐carboxylic acid through the inhibition of the total l‐aminocyclopropane‐l‐carboxylate synthase activity. The concomitant effect of this inhibition on adventitious root formation and leaf senescence is evaluated.

Notes

Plant Physiology Department, Estacão Agronómica Nacional, Quinta do Marquês, 2780 Oeiras, Portugal.