Abstract:
Investigations of variations in the anatomical structure of Ailanthus excelsa wood with height and radial distance from the pith
This investigation aimed at studying any variations in anatomical structure of ailanthus wood at three different heights levels on the tree and four radial zones. These locations included top height, mid height and bottom height. At each height level four radial zones with different distances from the pith were selected. Zone one is the outer most zone while zone 4 was the nearest to the pith. Microscopic slides were prepared from all this locations. The slides included cross sectional slides and slides for macerated fibers. These slides were examined under the microscope and analyzed using stereological techniques to look for any variations or trend in the anatomical properties with height on the tree and radial distance from the pith. The anatomical properties studied included: volume fractions for cell components and different cell types. They also included cross sectional dimensions of different cells, in addition to fiber length. These properties were calculated from stereological data using some statistical geometrical formulae which relate stereological data to anatomical structure. The result were analyzed statically using analysis of variance and Duncan's Multiple Range test seeking and significant variations and trends in these properties with height and radial distances from the pith (zones). Results revealed that the average fiber length decreased gradually from top height to bottom height Average fiber length at top height 1.33mm while that at bottom height 1.25mm. There were no significant differences in the volume fractions of cell components (cell walls and lumens) between different heights except for fiber lumen and parenchyma lumen, both of which showed a gradual decreased from top height to bottom height. There were no significant differences in volume fractions of different cell components between different zones (radial distance from the pith) except for vessel walls and Parenchyma lumens. With regards to volume fractions of the cell types, the volume fractions of vessels decreased from top height to bottom height, while it decreased from zone 1 zone 3 and then increased in zone 4. No trends were observed with other cell types. With regards to cell dimensions, averages vessel diameters decreased from top height to bottom height. They also decreased from zone 1 to zone 3 and then increased at zone 4- the same trend as for vessel volume fraction. Average fiber diameter increased from zone 1 to zone 4, but no trend was observed between heights. On the other hand, average parenchyma diameter showed the same trend as the vessel diameters with height- a decreased from top height to bottom height. It also increased from zone 1 to zone 3 and then decreased in zone 4. Double cell wall thickness, on other hand, increased from top height to bottom height and also from zone 1 to zone 4.
