Regulation of Energy Supply and Redox State in Bermudagrass: Role of H2O2 in Trimming-induced Tillering

Abstract Tillering/branching pattern plays a significant role in determining the structure and diversity of grass, and trimming has been found to induce tillering in turfgrass. Recently, it has been reported that hydrogen peroxide (H2O2) plays a part in regulating axillary bud development. However, the role of H2O2 in trimming-induced tillering in bermudagrass, a kind of turfgrass, remains unclear. This study reveals that trimming has a significant effect on inducing the sprouting and growth of tiller buds in the stolon node, as well as increasing the number of tillers in the main stem. Trimming serves to increase the content and relevant gene expression level of cytokinin and sucrose in axillary buds in a spatiotemporal-dependent manner. In addition, the partial trimming of new-born tillers results in an increase in sucrose and starch reserves in their leaves, which can be attributed to the enhanced photosynthesis capacity. Further research has revealed that trimming promotes a rapid H2O2 burst in the leaves of new-born tillers and axillary stolon buds. Exogenous application of H2O2 significantly increases the number of tillers after trimming by enhancing photosynthesis potential and energy reserves. Moreover, exogenous H2O2 increases the activity of antioxidant enzymes. Taken together, these results indicate that both endogenous production and exogenous addition of H2O2 enhance the inductive effects of trimming on the tillering process in bermudagrass, thus helping boost energy supply and maintain the redox state in newly formed tillers.