Disponibilidad de oxígeno al embrión y sensibilidad de la semilla al ABA: Dos mecanismos relacionados detrás de la dormición impuesta por el pericarpio en girasol (Helianthus annuus)

RODRÍGUEZ MARÍA VERÓNICA; DOMINGUEZ CONSTANZA PÍA; BATLLA DIEGO; BENECH-ARNOLD ROBERTO LUIS

Corrientes

Otro; XXXI Reunión Argentina de Fisiología Vegetal; 2016

Sociedad Argentina de Fisiología Vegetal

Dormancy displayed by sunflower achenes causes serious problems to the seed industry. In this crop, dormancy can be imposed by pericarp. This embryo-covering tissue might be interfering with the entry of oxygen to embryo (i.e., hypoxia) which, in turn, might interfere with the metabolism of germination inhibitors (e.g., ABA). We used an inbred line and a commercial hybrid both displaying pericarp-imposed dormancy which is evident at high incubation temperatures to evaluate the effect of different atmospheric oxygen concentrations combined with different incubation temperatures on i) germination of achenes and seeds (i.e. without pericarp) in both genotypes and ii) sensitivity to ABA in seeds of the inbred line. Results indicated that, in both genotypes, the germination of achenes decreased with increasing hypoxia at both temperatures. Seeds from the inbred line were very sensitive to hypoxia at 30ºC but not so sensitive at 12ºC. Seed sensitivity to ABA in the inbred line also increased with hypoxia and incubation temperature. Instead, seeds from the commercial hybrid displayed no sensitivity to hypoxia at any temperature. Embryo sensitivity to hypoxia explained the pericarp-imposed dormancy in the inbred line but not in the commercial hybrid. So, there was not a common mechanism behind this trait.