Construction and Growth Differences in Mother Bamboo Ramet Systems of Typical Monopodial Bamboos Under Different...

Bamboo forests are formed by the interlacing of multiple ramet systems. However, the interaction relationships between ramet systems remain unclear. To determine the effects of initial planting density on the construction of ramet systems in typical monopodial bamboos, and to clarify the differentiation rules of underground clonal architecture for bamboo species with different culm diameters, in this study, we selected large-diameter species Phyllostachys edulis and small-diameter species Phyllostachys praecox as study species. A pot experiment with root restriction was conducted using three density gradients of low, medium, and high. Rhizome morphology, underground bud bank dynamics, branching types, and the spatial distribution of the ramet systems were determined. The results showed that density significantly affected rhizome elongation, node allocation, the ratio of dormant buds to germinated buds, and branching hierarchy distribution of ramet systems, with pronounced differences between species. In P. edulis, longer rhizomes, higher dormant bud accumulation, and the branching hierarchies concentrated in low-to-moderate grades were observed at low density. In contrast, rhizome growth and branching were significantly inhibited with increasing density. For P. precox, multistage rhizome extension, higher sprouting activity, and wider branching distribution in the middle and posterior segments of the rhizomes occurred under low- and medium-density conditions. Under high density, however, the peak of dormant buds shifted backward, and a sprouting compensation effect occurred. The initial density reshaped the spatial architecture of ramet systems by altering the intensity of underground competition and preferentially inhibiting the development of new branches and high-grade rhizomes. This study focused on monopodial bamboos during the early establishment stage of mother bamboo development. First, it explored density-driven effects governing ramet system formation. Second, it elucidated contrasting clonal trade-off responses between large- and small-diameter bamboo species. The results will supplement theories on the population construction of woody clonal plants. In addition, they can guide rational close planting and targeted regulation of ramet systems in artificial bamboo stands.