Physiological and biochemical traits in Korean pine somatic embryogenesis

Abstract

Korean pine broadleaf mixed forest is an important ecosystem for maintaining biodiversity in Northeast China. Korean pine is also an important species for the production of timber and nuts in the mountainous areas of Northeast China. In this study, we compared three types of Korean pine callus and found that embryogenic callus had high amounts of storage substances (protein, sugar and starch). Non-embryonic callus had high levels of polyphenols and polyphenol oxidation, while callus that lost somatic embryogenesis potential had lower levels of storage substances (protein, sugar and starch) and higher contents of peroxidase and catalase. These results indicate that high contents of storage substances (protein, sugar and starch), and low levels of polyphenols and polyphenol oxidase can be used as physiological markers of callus with somatic embryogenic potential. During the development process of Korean pine somatic embryos, fresh weight and dry weight gradually increased, while water content gradually decreased. Soluble protein, starch, soluble sugar and superoxide dismutase also increased during development, while peroxidase and catalase levels reduced over time. These results indicate that somatic embryogenesis involves energy storage, and antioxidant enzymes cooperate to regulate the occurrence and development of embryos. These results provide physiological markers for identification of embryogenic callus with somatic embryogenesis, to evaluate callus suitable for somatic embryogenesis, and provide basis for further research on the molecular mechanisms of somatic embryogenesis.