Involvement of ABA in Induction of Secondary Dormancy in Barley (Hordeum vulgare L.) Seeds.

LEYMARIE J., ROBAYO-ROMERO M.E., GENDREAU E. , BENECH-ARNOLD R.L.

PLANT AND CELL PHYSIOLOGY

Año: 2008 vol. 49 p. 1830 - 1839

0032-0781

At harvest, barley seeds are dormant because their germination is difficult above 208C. Incubation of primary dormant seeds at 308C, a temperature at which they do not germinate, results in a loss of their ability to germinate at 208C. This phenomenon which corresponds to an induction of a secondary dormancy is already observed after a pretreatment at 308C as short as 4–6 h, and is optimal after 24–48 h. It is associated with maintenance of a high level of embryo ABA content during seed incubation at 308C, and after seed transfer at 208C, while ABA content decreases rapidly in embryos of primary dormant seeds placed directly at 208C. Induction of secondary dormancy also results in an increase in embryo responsiveness to ABA at 208C. Application of ABA during seed treatment at 308C has no significant additive effect on the further germination at 208C. In contrast, incubation of primary dormant seeds at 208C for 48 and 72 h in the presence of ABA inhibits further germination on water similarly to 24–48 h incubation at 308C. However fluridone, an inhibitor of ABA synthesis, applied during incubation of the grains at 308C has only a slight effect on ABA content and secondary dormancy. Expression of genes involved in ABA metabolism (HvABA80OH-1, HvNCED1 and HvNCED2) was studied in relation to the expression of primary and secondary dormancies. The results presented suggest a specific role for8C. Incubation of primary dormant seeds at 308C, a temperature at which they do not germinate, results in a loss of their ability to germinate at 208C. This phenomenon which corresponds to an induction of a secondary dormancy is already observed after a pretreatment at 308C as short as 4–6 h, and is optimal after 24–48 h. It is associated with maintenance of a high level of embryo ABA content during seed incubation at 308C, and after seed transfer at 208C, while ABA content decreases rapidly in embryos of primary dormant seeds placed directly at 208C. Induction of secondary dormancy also results in an increase in embryo responsiveness to ABA at 208C. Application of ABA during seed treatment at 308C has no significant additive effect on the further germination at 208C. In contrast, incubation of primary dormant seeds at 208C for 48 and 72 h in the presence of ABA inhibits further germination on water similarly to 24–48 h incubation at 308C. However fluridone, an inhibitor of ABA synthesis, applied during incubation of the grains at 308C has only a slight effect on ABA content and secondary dormancy. Expression of genes involved in ABA metabolism (HvABA80OH-1, HvNCED1 and HvNCED2) was studied in relation to the expression of primary and secondary dormancies. The results presented suggest a specific role for8C, a temperature at which they do not germinate, results in a loss of their ability to germinate at 208C. This phenomenon which corresponds to an induction of a secondary dormancy is already observed after a pretreatment at 308C as short as 4–6 h, and is optimal after 24–48 h. It is associated with maintenance of a high level of embryo ABA content during seed incubation at 308C, and after seed transfer at 208C, while ABA content decreases rapidly in embryos of primary dormant seeds placed directly at 208C. Induction of secondary dormancy also results in an increase in embryo responsiveness to ABA at 208C. Application of ABA during seed treatment at 308C has no significant additive effect on the further germination at 208C. In contrast, incubation of primary dormant seeds at 208C for 48 and 72 h in the presence of ABA inhibits further germination on water similarly to 24–48 h incubation at 308C. However fluridone, an inhibitor of ABA synthesis, applied during incubation of the grains at 308C has only a slight effect on ABA content and secondary dormancy. Expression of genes involved in ABA metabolism (HvABA80OH-1, HvNCED1 and HvNCED2) was studied in relation to the expression of primary and secondary dormancies. The results presented suggest a specific role for8C. This phenomenon which corresponds to an induction of a secondary dormancy is already observed after a pretreatment at 308C as short as 4–6 h, and is optimal after 24–48 h. It is associated with maintenance of a high level of embryo ABA content during seed incubation at 308C, and after seed transfer at 208C, while ABA content decreases rapidly in embryos of primary dormant seeds placed directly at 208C. Induction of secondary dormancy also results in an increase in embryo responsiveness to ABA at 208C. Application of ABA during seed treatment at 308C has no significant additive effect on the further germination at 208C. In contrast, incubation of primary dormant seeds at 208C for 48 and 72 h in the presence of ABA inhibits further germination on water similarly to 24–48 h incubation at 308C. However fluridone, an inhibitor of ABA synthesis, applied during incubation of the grains at 308C has only a slight effect on ABA content and secondary dormancy. Expression of genes involved in ABA metabolism (HvABA80OH-1, HvNCED1 and HvNCED2) was studied in relation to the expression of primary and secondary dormancies. The results presented suggest a specific role for8C as short as 4–6 h, and is optimal after 24–48 h. It is associated with maintenance of a high level of embryo ABA content during seed incubation at 308C, and after seed transfer at 208C, while ABA content decreases rapidly in embryos of primary dormant seeds placed directly at 208C. Induction of secondary dormancy also results in an increase in embryo responsiveness to ABA at 208C. Application of ABA during seed treatment at 308C has no significant additive effect on the further germination at 208C. In contrast, incubation of primary dormant seeds at 208C for 48 and 72 h in the presence of ABA inhibits further germination on water similarly to 24–48 h incubation at 308C. However fluridone, an inhibitor of ABA synthesis, applied during incubation of the grains at 308C has only a slight effect on ABA content and secondary dormancy. Expression of genes involved in ABA metabolism (HvABA80OH-1, HvNCED1 and HvNCED2) was studied in relation to the expression of primary and secondary dormancies. The results presented suggest a specific role for8C, and after seed transfer at 208C, while ABA content decreases rapidly in embryos of primary dormant seeds placed directly at 208C. Induction of secondary dormancy also results in an increase in embryo responsiveness to ABA at 208C. Application of ABA during seed treatment at 308C has no significant additive effect on the further germination at 208C. In contrast, incubation of primary dormant seeds at 208C for 48 and 72 h in the presence of ABA inhibits further germination on water similarly to 24–48 h incubation at 308C. However fluridone, an inhibitor of ABA synthesis, applied during incubation of the grains at 308C has only a slight effect on ABA content and secondary dormancy. Expression of genes involved in ABA metabolism (HvABA80OH-1, HvNCED1 and HvNCED2) was studied in relation to the expression of primary and secondary dormancies. The results presented suggest a specific role for8C, while ABA content decreases rapidly in embryos of primary dormant seeds placed directly at 208C. Induction of secondary dormancy also results in an increase in embryo responsiveness to ABA at 208C. Application of ABA during seed treatment at 308C has no significant additive effect on the further germination at 208C. In contrast, incubation of primary dormant seeds at 208C for 48 and 72 h in the presence of ABA inhibits further germination on water similarly to 24–48 h incubation at 308C. However fluridone, an inhibitor of ABA synthesis, applied during incubation of the grains at 308C has only a slight effect on ABA content and secondary dormancy. Expression of genes involved in ABA metabolism (HvABA80OH-1, HvNCED1 and HvNCED2) was studied in relation to the expression of primary and secondary dormancies. The results presented suggest a specific role for8C. Induction of secondary dormancy also results in an increase in embryo responsiveness to ABA at 208C. Application of ABA during seed treatment at 308C has no significant additive effect on the further germination at 208C. In contrast, incubation of primary dormant seeds at 208C for 48 and 72 h in the presence of ABA inhibits further germination on water similarly to 24–48 h incubation at 308C. However fluridone, an inhibitor of ABA synthesis, applied during incubation of the grains at 308C has only a slight effect on ABA content and secondary dormancy. Expression of genes involved in ABA metabolism (HvABA80OH-1, HvNCED1 and HvNCED2) was studied in relation to the expression of primary and secondary dormancies. The results presented suggest a specific role for8C. Application of ABA during seed treatment at 308C has no significant additive effect on the further germination at 208C. In contrast, incubation of primary dormant seeds at 208C for 48 and 72 h in the presence of ABA inhibits further germination on water similarly to 24–48 h incubation at 308C. However fluridone, an inhibitor of ABA synthesis, applied during incubation of the grains at 308C has only a slight effect on ABA content and secondary dormancy. Expression of genes involved in ABA metabolism (HvABA80OH-1, HvNCED1 and HvNCED2) was studied in relation to the expression of primary and secondary dormancies. The results presented suggest a specific role for8C has no significant additive effect on the further germination at 208C. In contrast, incubation of primary dormant seeds at 208C for 48 and 72 h in the presence of ABA inhibits further germination on water similarly to 24–48 h incubation at 308C. However fluridone, an inhibitor of ABA synthesis, applied during incubation of the grains at 308C has only a slight effect on ABA content and secondary dormancy. Expression of genes involved in ABA metabolism (HvABA80OH-1, HvNCED1 and HvNCED2) was studied in relation to the expression of primary and secondary dormancies. The results presented suggest a specific role for8C. In contrast, incubation of primary dormant seeds at 208C for 48 and 72 h in the presence of ABA inhibits further germination on water similarly to 24–48 h incubation at 308C. However fluridone, an inhibitor of ABA synthesis, applied during incubation of the grains at 308C has only a slight effect on ABA content and secondary dormancy. Expression of genes involved in ABA metabolism (HvABA80OH-1, HvNCED1 and HvNCED2) was studied in relation to the expression of primary and secondary dormancies. The results presented suggest a specific role for8C for 48 and 72 h in the presence of ABA inhibits further germination on water similarly to 24–48 h incubation at 308C. However fluridone, an inhibitor of ABA synthesis, applied during incubation of the grains at 308C has only a slight effect on ABA content and secondary dormancy. Expression of genes involved in ABA metabolism (HvABA80OH-1, HvNCED1 and HvNCED2) was studied in relation to the expression of primary and secondary dormancies. The results presented suggest a specific role for8C. However fluridone, an inhibitor of ABA synthesis, applied during incubation of the grains at 308C has only a slight effect on ABA content and secondary dormancy. Expression of genes involved in ABA metabolism (HvABA80OH-1, HvNCED1 and HvNCED2) was studied in relation to the expression of primary and secondary dormancies. The results presented suggest a specific role for8C has only a slight effect on ABA content and secondary dormancy. Expression of genes involved in ABA metabolism (HvABA80OH-1, HvNCED1 and HvNCED2) was studied in relation to the expression of primary and secondary dormancies. The results presented suggest a specific role forHvABA80OH-1, HvNCED1 and HvNCED2) was studied in relation to the expression of primary and secondary dormancies. The results presented suggest a specific role for HvNCED1 and HvNCED2 in regulation of ABA synthesis in secondary seed dormancy.and HvNCED2 in regulation of ABA synthesis in secondary seed dormancy.