Integrated physiological unit (IPU) traits of Phyllostachys glauca McClure and their responses to habitat heterogeneity: Insights from 15N tracing

Running bamboo is a clonal plant group known for high utilization value and rapid range expansion. However, the integrated physiological unit (IPU), a fundamental physiological functional unit, remains poorly understood in running bamboo. This knowledge gap limits our understanding of the mechanisms underlying clonal growth and the strategies that enable adaptation to heterogeneous habitats. We used 15 N tracing to explore the demographic and translocation traits of a running bamboo ( Phyllostachys glauca ) grown in various heterogeneous habitats and to discern the response of the IPU traits to habitat heterogeneity. The IPUs consisted of nine to 20 ramets, with an average area of 4.95 ± 1.39 m 2 and a maximum integration distance of 2.82 ± 0.40 m. Compared to the clonal population, the IPUs were younger, consisting of ramets from 1a to 4a. The acropetal transport is stronger than basipetal transport within IPUs, and the translocation speed and amount were 1.06 ± 0.08 m day -1 and 4.24 ± 1.35 mg kg -1 , respectively. Habitat heterogeneity significantly influenced the spatial traits of IPUs (e.g., area, maximum ramet distance and ramet density) while having little effect on age structure or translocation traits (e.g., timing, speed and amount). Small areas of IPUs in high habitat heterogeneity and rhizome branching architecture might be the two reasons responsible for the negligible influence of habitat heterogeneity on translocation traits. The results promote the understanding of IPU traits and their responses to habitat heterogeneity in a running bamboo from the perspective of clonal ecology. Our findings from field experiments provide applications for the economic cultivation and ecological management of running bamboo. • Examined bamboo adaptive traits to habitats from the perspective of clonal ecology • Depicted vital traits of the integrated physiological unit of a running bamboo • The integrated physiological unit is younger than clonal population • Habitat heterogeneity shaped the spatial traits but not translocation traits • Provided applications for bamboo cultivation and preventing expansion