AUTHOR=Chen Jing-zhong , Huang Xiao-long , Xiao Xue-feng , Liu Ji-ming , Liao Xiao-feng , Sun Qing-wen , Peng Liang , Zhang Lan 

TITLE=Seed Dormancy Release and Germination Requirements of Cinnamomum migao, an Endangered and Rare Woody Plant in Southwest China

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.770940

DOI=10.3389/fpls.2022.770940

ISSN=1664-462X

ABSTRACT=<p>Seed dormancy is a complex adaptive trait of plants that are influenced by several physiological and environmental factors. The endangered plant <italic>Cinnamomum migao</italic> is also known to exhibit seed dormancy and low germination, which may influence its regeneration; however, these characteristics remain unexplored. To our knowledge, this study is the first to examine the type of dormancy and improve the germination percentage of <italic>C. migao</italic> seeds. We evaluated the structure and characteristics of the embryo and endocarp of <italic>C. migao</italic> seeds as well as the effects of endogenous inhibitors. Furthermore, we assessed the effects of light, stratification, alternating temperature, and gibberellic acid 3 (GA<sub>3</sub>) on the dormancy release of these seeds. The embryo was well developed the endocarp was water-permeable, and no obvious mechanical hindrance to germination was observed. However, the endocarp and embryo contained phenols and other germination inhibitors. The seed extracts of <italic>C. migao</italic> delayed the germination of cabbage and ryegrass seeds, which indicates the presence of endogenous inhibitors. These findings suggest that <italic>C. migao</italic> seeds exhibit physiological dormancy. Light and an alternating temperature (15/20°C) did not influence germination. However, GA<sub>3</sub> pretreatment, alternating temperatures, and warm stratification relieved dormancy. GA<sub>3</sub> pretreatment combined with the 15°C stratification treatment was most effective in rapidly releasing the <italic>C. migao</italic> seed dormancy. Our findings may facilitate the storage and conservation of this endangered plant, which is currently underrepresented in <italic>ex situ</italic> collections.</p>