Variations in characteristics of bamboo vascular bundles between Dendrocalamus and Bambusa

Abstract

Unraveling the characteristics of bamboo vascular bundles is critical for understanding their physiology and mechanical properties. However, different bamboo species have different vascular bundles, leading to significant variations in their industrial applications. In this paper, the You Only Look Once algorithm was applied to examine the vascular bundles of several species representatives within Dendrocalamus (Dendrocalamus farinosus, Dendrocalamus asper, and Dendrocalamus latiflorus) and Bambusa (Bambusa pervariabilis, Bambusa textilis, and Bambusa arundinacea), considering their economic and ecological importance. The analysis included the classifications of vascular bundles, their dimensions, and the areas of fiber sheaths. The results showed that the vascular bundles of Dendrocalamus and Bambusa were mainly broken-waist type. Along the radial direction, both Dendrocalamus and Bambusa exhibited gradient variability in vascular bundles, suggesting a similar underlying structural pattern. Quadratic functions could be employed to represent the radial distributions of vascular bundle size and fiber sheath area. Statistically, the fiber sheath area was positively correlated with vascular bundle size (P<0.05). In addition, significant differences in vascular bundles were detected among different bamboo species, which may lead to substantial variations in their mechanical properties. In particular, Bambusa arundinacea had the highest vascular bundle length (724.57 μm) and length/width ratio (1.69), while Dendrocalamus asper had the highest vascular bundle width (552.20 μm) and fiber sheath area (0.22 mm2). Nevertheless, principal component analysis indicated substantial similarity in the vascular bundles of Dendrocalamus and Bambusa. Moreover, the interspecific variations in vascular bundles were notably more pronounced within Dendrocalamus compared to those observed within Bambusa. Overall, our study examined the variations in vascular bundles between Dendrocalamus and Bambusa, offering insights that hold significant potential for bamboo taxonomy and the design of bio-inspired materials.