Morphological and mechanical properties of three commercially important bamboo species from different geographic locations in the Philippines

Abstract

Selected morphological and physico-mechanical properties of the culms of three bamboo species namely bolo (Gigantochloa levis), kawayan tinik (Bambusa spinosa) and giant bamboo (Dendrocalamus asper) grown across various Philippine sites under different climatic types were evaluated. Likewise, DNA was extracted from leaf samples of the three species for genetic characterization. All the selected properties (culm wall thickness, culm diameter, green specific gravity, maximum volumetric shrinkage, modulus of elasticity, modulus of rupture, fibre stress at proportional limit in bending and compressive stress along the grain) for the three species were location dependent. Principal component analysis (PCA) revealed location-based differences in the mechanical and morphological properties of B. spinosa, G. levis, and D. asper. B. spinosa exhibited consistent properties across all locations, while G. levis and D. asper showed significant variations in the province of Rizal, where mechanical traits such as modulus of elasticity (MOE) and maximum compressive stress (MaxStress) were more pronounced. Additionally, D. asper samples from Bukidnon province displayed unique clustering, indicating distinct mechanical characteristics compared to other locations. DNA sequence analysis of individuals based on DNA barcode genes, matK and rbcL, revealed no sequence type variation among locations per species, confirming the correctness of their respective taxonomic identity, and that the choice of localities for collection based on the known distribution of the species appears justified.