Dormancy release of Cotinus coggygria seeds under a pre-cold moist stratification: an endogenous abscisic acid/gibberellic acid and comparative proteomic analysis

Abstract

Seed dormancy is an adaptive trait that widely exists in angiosperms and gymnosperms. The mechanisms for the release of seed dormancy have been less well studied. Using smoke tree (Cotinus coggygria var. Cinerea Engler) seeds, the effect of cold moist stratification (5 °C, 18.5 % humidity and 0–75 days) on dormancy release, changes of respiration rate, ABA and GA3 content, and the differentially expressed proteins during dormancy release were investigated. Seed dormancy was released during cold moist stratification, seed respiration rate was increased while both ABA and GA3 concentrations were decreased. A total of 28 protein spots with significant changes in relative expression abundance were detected by two-dimensional electrophoresis. Among these protein spots, four proteins of ATPase β subunit, heat-shock cognate protein 70, aspartic proteinase 1 and actin were successfully identified by the matrix assisted laser desorption/ionization time-of-flight/time-of-flight mass spectrometry. These four proteins were all down-expressed during dormancy release, and their possible implications for dormancy release of C. coggygria seeds was discussed. A better understanding of seed dormancy release and germination has practical benefits to seedling production for forest regeneration purposes.