Effects of gibberellin and cytokinin on the tillers bud morphology of Cynodon dactylon

Tillering is a biological characteristic of graminaceous plants, and the number of tillers is one of the key indicators of turfgrass density. Cynodon dactylon is a continuous tillering grass of the grass family. Tillering promotes the production of new branches and plays an important role in the rapid regeneration and formation of dense lawns. In this study, C. dactylon ‘Xinnong No. 1’ was sprayed with 1 μmol·L⁻¹ gibberellin (GA₃) and cytokinin (6-BA), respectively, to analyze the formation of tiller buds in tissue sections, anatomical structures, and phenotypes. The results showed that the tiller base was formed at the three-leaf stage and new tiller buds were formed at the eight-leaf stage before breaking through the mother stem. The tiller buds formed 5 d earlier at the seventh leaf stage in the GA₃ treatment and 8 d earlier at the sixth leaf stage in the 6-BA treatment. The number of tillers and root length increased with both hormone sprays; the number of tillers increased the most with the 6-BA treatment compared to that with the CK by 1.18 times. By observing the anatomical structure of the tiller buds at the leaf formation stage under different hormone treatments, it was observed that in epidermal thickness, cortical thickness, and vascular bundle diameter, 6-BA > GA₃ > CK; moreover, these characteristics were 1.28 times, 2.33 times, and 1.34 times more under the 6-BA treatment than in the GA₃ treatment. The results showed that the spraying of 6-BA at the early stage of dog root tillering was better than the spraying of GA₃ in promoting the growth and development of the tiller buds.