Relationship between H2O2 accumulation and NO synthesis during osmotic stress: promoted somatic embryogenesis of Fraxinus mandshurica

• Published in: Journal of forestry research 2021-06, Vol.32 (3), p.917-925
• Main Authors: Yang, Ling, Guo, Hanyang, Liu, Yingying, Zhang, Dongyan, Liu, Hongnan, Shen, Hailong
• Format: Article
• Language: English
• Subjects: Accumulation; Antioxidants; Biomedical and Life Sciences; Catalase; Chemical synthesis; Cotyledons; Embryonic growth stage; Embryos; Explants; Forestry; Fraxinus mandshurica; Hydrogen peroxide; Intracellular; Intracellular signalling; Life Sciences; Nitric oxide; Original Paper; Osmotic stress; Peroxidase; Reactive nitrogen species; Reactive oxygen species; Signaling; Somatic embryogenesis; Trees
• ISSN: 1007-662X; 1993-0607
• DOI: 10.1007/s11676-020-01115-9

Osmotic stress promotes somatic embryogenesis of Fraxinus mandshurica , which leads to accumulation of reactive oxygen species (ROS). The single pieces of cotyledons of F. mandshurica were used as explants to induce somatic embryogenesis in osmotic-stress medium. Furthermore, the hydrogen peroxide (H 2 O 2 ) content of explanted cells was varied by adding exogenous H 2 O 2 or catalase solution to assess the effects of the exogenous H 2 O 2 on somatic embryogenesis, intracellular H 2 O 2 accumulation, and the relationship between signaling mediated by ROS or reactive nitrogen species. The results revealed that exogenous H 2 O 2 (100‒300 μmol L –1 ) increased the number of somatic embryos. On 60th day of exogenous H 2 O 2 (200 μmol L –1 ) treatment, the number of somatic embryos of explants treated, which was 136.54%, was higher than the control. Moreover, exogenous H 2 O 2 (100 μmol L –1 ) significantly increased the intracellular H 2 O 2 content and enhanced the activities of superoxidase dismutase and peroxidase. Finally, exogenous H 2 O 2 (100 μmol L –1 ) activated the intracellular non-enzymatic pathway for nitric oxide (NO) synthesis. The somatic embryogenesis in broadleaf trees increases with the change of endogenic ROS content, and depends on the upregulation of antioxidant enzymes. Both H 2 O 2 and NO, as signaling molecules, were found to be involved in the process of somatic embryogenesis in broadleaf trees. In the process of exogenous H 2 O 2 promoting somatic embryogenesis, NO synthesis depended on non-enzymatic reactions. These results provide a scientific basis for resolving the mechanism by which ROS levels are regulated during somatic embryogenesis of broadleaf trees and establish a reasonable and efficient technology system for regulating somatic embryogenesis of trees.