Abstract: As a clonal plant, Phyllostachys edulis, commonly called moso bamboo, can grow rapidly with a complex belowground branching system. Owing to the lack of effective research method and the strong clonal expansion ability of belowground rhizome system, few researches have been conducted on the horizontally spatial hierarchical system and its relation to the functional attributes of bamboo rhizome. Here, a hierarchical system of bamboo rhizome and its standing culm of P. edulis were presented. Then, the change of both diameter and length of bamboo rhizome with rhizome order, and the correlations between rhizome and its rhizome root and between belowground rhizome and its standing culm, were examined. Both diameter and length of moso bamboo rhizome decreased with the increasing rhizome order; in other words, they increased from the proximal end to the distal end. The relationship between biomass of bamboo rhizome and its corresponding rhizome root was best characterized by a power function. The diameter of belowground bamboo rhizome was significantly correlated to the diameter at breast height of the first four-order standing culms, but not to that of the fifth order. Regression analysis indicated that the first two orders contributed more to the growth of belowground bamboo rhizome than both the third and the fourth orders of standing culms. These results of the present paper suggested that the belowground rhizome system of P. edulis is a highly heterogeneous hierarchical system, and the hierarchical rhizome system proposed here is conducive to carry out a more in depth research into bamboo rhizome hierarchical structure and its functional attributes.

Key words: species distribution models (SDMs), joint species distribution models (JSDMs), biogeography., ecological niche, latent variable models (LVMs)