Developmental differences between germinating after-ripened and dormant excised Avena fatua L. embryos
1997
Myers, S.P. | Foley, M.E. | Nichols, M.B.
Based on physiological and molecular differences associated with the germination of after-ripened and dormant caryopses and excised embryos, it has been hypothesized that various methods of after-ripening are the only treatments that facilitate the transition of dormant wild oat embryos to a non-dormant state. To further investigate this hypothesis, analytical methods were used to evaluate physical and temporal changes associated with germination and subsequent growth of after-ripened and dormant excised embryos (AR-embryos and D-embryos, respectively) induced to germinate with fructose (Fru) and/or gibberellic acid (GA). While chemical treatments of Fru, GA, and Fru + GA have little effect on the germination and short-term growth of AR-embryos, they do induce germination of D-embryos. Growth following germination of D-embryos varied according to treatment with the combination of Fru + GA inducing the greatest growth over the duration of the experiment. Even considering differences in the time to complete germination, growth of D-embryos was not comparable with that of AR-embryos. This provides physical evidence that chemical treatments induce germination without fulfilling the requirements for normal after-ripening-enhanced germination/growth, and indicates that fructose and/or gibberellic acid do not remove the dormancy-block or rate limiting step in the same manner as after-ripening.
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