Cell wall structure and formation of maturing fibres of moso bamboo ( Phyllostachys pubescens ) increase buckling resistance

Abstract

The mechanical stability of the culms of monocotyledonous bamboos is highly attributed to the proper embedding of the stiff fibre caps of the vascular bundles into the soft parenchymatous matrix. Owing to lack of a vascular cambium, bamboos show no secondary thickening growth that impedes geometrical adaptations to mechanical loads and increases the necessity of structural optimization at the material level. Here, we investigate the fine structure and mechanical properties of fibres within a maturing vascular bundle of moso bamboo, Phyllostachys pubescens, with a high spatial resolution. The fibre cell walls were found to show almost axially oriented cellulose fibrils, and the stiffness and hardness of the central part of the cell wall remained basically consistent for the fibres at different regions across the fibre cap. A stiffness gradient across the fibre cap is developed by differential cell wall thickening which affects tissue density and thereby axial tissue stiffness in the different regions of the cap. The almost axially oriented cellulose fibrils in the fibre walls maximize the longitudinal elastic modulus of the fibres and their lignification increases the transverse rigidity. This is interpreted as a structural and mechanical optimization that contributes to the high buckling resistance of the slender bamboo culms.

Bamboo fibre reinforced biocomposites: A review

“…ferulic and p-coumaric acids), are responsible for covalent bonding in the cell wall structure. This variation of different components across the cell wall provides novel design to bamboo fibre wall, enhancing its various mechano-physical properties [38,43,44]. Recently, two researchers reported extensive studies on structure of bamboo fibre of different species and investigated the cell wall structure of different bamboo species [45,46].…”

“…Non cellulosic components have enough contribution to fibre properties such as strength, flexibility, moisture, and even density [37]. The unidirectional arrangement of bamboo fibres in tissues and cell wall structure of bamboo is one of unique property of bamboo [38][39][40]. Bamboo fibres possess alternate broad and narrow polylamellate structure with alternating broad and narrow lamella as compared to sandwich like structure of wood fibre [41,42].…”

Changes in the cellulose crystallinity of moso bamboo cell walls during the growth process by X-ray diffraction techniques

“…The rigid bundle sheath, which aligns nearly parallel to the longitudinal axis of the culm, is found more in the outer section of the culm than in the inner side [2,6,7]. This optimized spatial construction gives bamboo culms better physical and mechanical properties [8][9][10][11]. Bamboo is also one of the fastest-growing plants, and can reach 15-30 m in height within 2-4 months [6].…”

Genome-Wide Transcriptional Profiling to Elucidate Key Candidates Involved in Bud Burst and Rattling Growth in a Subtropical Bamboo (Dendrocalamus hamiltonii)

“…With these characteristics, bamboos have been fascinating plants among researchers since long. To explore their remarkable growth characteristics, comparative histological studies, monoclonal antibody bank creation, biochemical, and proteomic profiling of various developmental stages of growing shoot of bamboos have been done (Lee and Chin, 1960; Zheng et al, 1998; Lin et al, 2002; Li et al, 2007; Wang et al, 2011; Cui et al, 2012). Candidate genes ( Sucrose synthase, Cellulose synthase, BoSUT2, BoPAL1, Invertase ) associated with growth have been characterized in Bambusa oldhamii (tropical bamboo; Chiu et al, 2006; Hsieh et al, 2006, 2011; Chen et al, 2010; Gao et al, 2010).…”