The breaking of dormancy mediated by reac-tive nitrogen species (RNS) is related to the accumulation of reactive oxygen species (ROS) in germinating embryos but the underlying mechanism is unclear. The objectives of this study were: (1) to explore the relationship between RNS-mediated dormancy release and ROS accumulation in germinating embryos of Sorbus pohuashanensis; and, (2) to investigate the relationships among germination time, ROS metabolism, and endogenous hormone synthesis. We studied the effects of exogenous nitric oxide (NO) donor sodium nitroprusside (SNP), the NO scavenger (4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO), abscisic acid (ABA), the exogenous ethylene donor ethrel, and the ethylene receptor inhibitor 2,5-norbornadien (NBD) on embryo germination and seedling growth. Embryos were released from dormancy by pretreatment with NO or ethylene, which was related to increased ethylene biosyn-thesis and decreased ABA levels. Breaking of dormancy by SNP was related to increased levels of ethylene, hydrogen peroxide, and glutathione, increased activities of superoxide dismutase and glutathione peroxidase, and decreased levels of ABA, superoxide anions, and malondialdehyde. These effects of nitric oxide were especially significant in seedling hypocotyls and radicles. These results demonstrate that NO can break S. pohuashanensis embryo dormancy by induc-ing ethylene biosynthesis, and that this signalling pathway is closely related to ROS accumulation and the antioxidant defence response.

Hao Wang;Shuoran Tang;Jianan Wang;Hailong Shen;Ling Yang

State Key Laboratory of Tree Genetics and Breeding,School of Forestry,Northeast Forestry University,Harbin 150040, People's Republic of China

林业研究（英文版）

[1]Hao Wang;Shuoran Tang;Jianan Wang;Hailong Shen;Ling Yang-.Interaction between reactive oxygen species and hormones during the breaking of embryo dormancy in Sorbus pohuashanensis by exogenous nitric oxide)[J].林业研究（英文版）,2022(02):435-444

tetramethylimidazoline,ethrel,norbornadien,radicles

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