Thermodormancy and ABA metabolism in barley grains

Abstract

Incubation of barley primary dormant grains at 30°C, a temperature at which they cannot germinate results in a reinforcement of their sensitivity to temperature, and in particular in a loss of their ability to germinate at 15-20°C 1. Incubation of the grains at 30°C in the presence of GA3 (1 mM) or of isolated embryos prevents this induction of secondary dormancy. In such a condition, embryo ABA content was lower than that measured in embryos of seeds incubated at 30°C on water. Expression of genes involved in ABA metabolism (HvABA8’OH1, HvNCED1 and HvNCED2) was studied in isolated embryos incubated on water and in the presence of GA3 (1 mM). Expression of HvABA8’OH1, HvNCED1 and HvNCED2 was discussed in relation with ABA content and germination ability at 30°C.