Abstract

Screening of different cultivated bamboo species to find out potential variety of bamboo is most important. Structural variations in term of anatomy, physical and strength properties of 3 year-old cultivated Gigantochloa brang, G. levis, G. scotechinii and G. wrayi were investigated for screening purposes. The culms of these bamboos were selected, harvested and processed for subsequent studies. The results show that each species exhibited differences in the anatomy, physical and strength properties. Each species has differences in the fiber characteristics which showed significant differences between species in terms of length, diameter and lumen sizes. The vascular bundle for these genera were between 4-7/4mm² and were dense at the outer position in the cross section of the culm having 8.5 vascular bundle/4mm², middle 4.88 vascular bundle/4mm² and at the inner position having 3.4 vascular bundle per/4mm². The vascular bundle length was between 845-1183 um and a width of 530-759 um. The fibre lengths were between (1745.00-2039.98 um), diameter (17.26-22.75 um), lumen (3.83-8.66 um) and wall thickness (1.3 -5.31um). The moisture content (MC) of the bamboo in green condition ranged between 73-112%, the MC is higher at internodes (95%) compared to nodes (78%). Position at inner layer has MC at 126%, middle at 83% and outer at 41%. Density increases from outer to inner layer which started from 500 kg/m² at inner and increased to more than 820 kg/m² at outer part of bamboo at 12% moisture content. The specific gravity for all species tested was about 0.69 - 0.78, but the inner position is 0.58, middle 0.73 and outer positions is 0.94. Shrinkage at radial, tangential and the volumetric were at 5-9, 7-12, and 10-17% respectively for all species. Position in a higher rate of shrinkage were at inner (8.6, 13.50, 15.44%), follow by middle (6.85, 9.72, 12.57%) and outer (5.04, 6.52, 10.40%) respectively. The tensile strength for the bamboos ranged between 103.38-122.15 MPa. The tensile strength of dried bamboo is 138.87 MPa compared with 89.95 MPa for green bamboo. The tensile of modulus of air dried bamboo is 4003.85 MPa compared with 2786.96 MPa for green bamboo. The modulus of rupture (MOR) for the bamboos ranged between 91.19-132 MPa. The MOR for dried bamboo was 142.21 MPa compared to the green bamboo 99.56 MPa. The modulus of elasticity (MOE) varies between 11961.70-20430.40 MPa. MOE of air dried bamboo was 17610.00 MPa and green bamboo 13777.80 MPa.

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