Mechanisms of gibberellin in regulating sprouting growth via sugar metabolism and root development in stumped Pinus yunnanensis

Gibberellin and sugars play key regulatory roles in plant growth and development. They may influence the sprouting growth of Pinus yunnanensis through the integration of hormone signaling and energy metabolism. The results revealed that exogenous GA₃ treatment significantly promoted the sprouting capacity of P. yunnanensis stumped seedlings. Compared to the control and paclobutrazol treatments, the GA₃ application notably increased sprout number and extended the duration of the rapid-growth stage, thereby promoting the growth of new shoots following stump regeneration. Analysis of sugar content in the root-collar sprouts of P. yunnanensis showed that the trehalose and glucose levels were relatively higher in the GA₃-treated group. Correlation analysis revealed two key findings. First, trehalose correlated more strongly with sprout number than glucose. Moreover, the trehalose-to-other-sugars ratio showed an even stronger correlation than trehalose content. Biomass analysis revealed that biomass allocation was concentrated in the roots in the early stage and then shifted to the sprouts in the later stage. In addition, the correlation analysis between trehalose and root morphology indicated that both of them were positively correlated with sprouts to a certain extent, which further confirmed that trehalose and roots might jointly participate in the synergistic regulation of sprouting growth in P. yunnanensis and collaboratively promote the occurrence of its sprouts.