Abstract:

【Objective】 The aims of this study was to explore the anatomical characteristics and radial variations in eight poplar clones or cultivars and to analyze the influence of cloning and aging on anatomical characteristics. This study provides a theoretical basis for selecting poplar clones and cutting management of fast-growing plantations. 【Method】 Clone 50 (P. deltoides 55/65), cultivar ‘Zhonglin46’ (P. euramericana cv. Zhonglin46), ‘108’ (P. euramericana cv. Guariento), clone 36 (P. deltoides 2KEN8), clone N179 (P. nigra N179), cultivars Danhong (P. deltoides cv. ‘Danhong’), ‘Sangju’ (P. euramericana cv. Sangju), and ‘Nanyang’ (P. deltoides cv. Nanyang) which were about nine to ten years old were cut from Jiaozuo forest farm in Henan province, China. The samples were segregated and sectioned, and the characteristics of fiber, vessel, ray, and tissue proportions were measured using microscopic imaging. 【Result】 The average ring width, fiber length, and fiber width were 7.44-9.64 mm, 971.06 -1152.94 μm, and 15.38-19.84 μm. The mean ranges of vessel length, vessel width, and vessel frequency were 409.88-491.71 μm, 59.30-63.12 μm, and 44.31-51.84 inds/mm². The double-wall thickness and lumen diameter ranges were 3.23-4.36 μm and 11.22-15.90 μm. The average ranges of fiber length to width ratio, wall to lumen ratio, lumen to width ratio, and microfibril angle were 56.85-78.91, 0.26-0.41, 0.72-0.82, and 16.34-19.16°. Proportions of fiber, vessel, and ray were 59.45%-67.7%, 21.40%-29.9%, and 10.20%-14.80%. The ray heights and width were 260.76-306.59 μm and 7.13-8.24 μm. From the pith to the bark, the ring width and vessel diameter first increased and then decreased, and the fiber length, fiber width, fiber length-to-width ratio, double wall thickness, vessel length, and ray height first increased along the radial direction and then stabilized. The microfibril angle, proportion of fiber, and proportion of rays first decreased along the radial direction and then stabilized; the vessel frequency decreased first and then increased, while the lumen diameter, wall-to-lumen ratio, lumen-to-width ratio, and ray width changed slightly along the radial direction. The ANOVAs analyses showed that clone and age had significant effects on anatomical characteristics. 【Conclusion】 Considering the growth rate and anatomical characteristics, Danhong showed the best properties, and the rotation age of the poplar clones was determined as 8-9 years.

Key words: poplar, clone, wood, anatomical characteristics, radial variation