Studies On The Wood Anatomical Characteristics Of Ginkgo Biloba L. Female Clones

The microstructure of opposite wood and compression wood of 48 Ginkgo biloba L. female clones which come from eight provinces of China and Japan was researched in the study under Microscope. Micromorphological research of some clones was conducted . The results obtained were as follows:(1) Compared with the opposite wood in the same growth ring, the growth ring is wider and more obvious on compression wood, and it was varied slowly from earlywood zone to latewood zone. The wood figure formed by growth ring parallel to each other on the radial section, and it presented inverted"V"-shap on tangential section. Both opposite wood and compression wood of Ginkgo biloba L. clones contained two types of tracheids, i.e. wide and narrow type. The tracheids of earlywood had big cell decomposition and thin wall, and it was just contrary of that on the latewood. The tracheids with different shap end, the earlywood tracheids with blunt-wider shap end, and the latewood tracheids with gradual-tip end.(2)The diameter of bordered pits had an increased trend from pitch to bark, and there were rarely warty on the bordered pits. The diameter of bordered pits that vertical to the tracheids long-axis was longer than that parallel to it. The diameter of bordered pits that on the radial wall of earlywood tracheids is bigger and more, most of the boreded pits on the earlywood tracheid radial wall were uniseriate, and minority were opposite in two rows. Boreded pits on the latewood tracheid radial wall were smaller and rare, uniseriate, discontinuous and distributed sparsely. The diameter of boreded pits and pit apertures on the tracheid tangential wall were smaller than that on the radial wall, and boreded pits usually concentrated on the late wood tracheids. Boreded pits on earlywood tracheid tangential wall were rare, uniseriate, disperse and arrangement in irregular, and five or six bordered pits occasional found on the tracheid wall that round the wood rays. Boreded pits on latewood tracheid tangential wall were uniseriate, minority in two rows, and distributed sparely on all the tracheid wall. The structure that similared to spiral thickening was found on the compression wood of C#, and special bordered pits were found on tracheid tangential wall on compression wood of C#,71# and 402#. The diameter of bordered pits on opposite wood were significantly biger than that on compression wood, and the diameter of opposite wood were significantly different, and the same to that on the compression wood. The diameter of cross field pits on compression wood were significantly bigger than that on opposite wood. The long-axis position of cross field pits changed from horizontal direction to vertical direction. Pit apertures presented as obique long ellipse or ellipse shape, it's long-axis position were inconsistent with that of the pit, and the range of the angles was very big. The angle which was formed by pit apertures long-axis and tracheids long-axis changed from 40°to 50°. Wood rays were uniseriate on ginkgo wood, and the wood rays on compression wood were longer and wider than that on opposite wood, but the difference were insignificantly.(3)Based on the microfibril angle, , there were very significantly differences between the double wall thickness and the tangential diameter among different growth ring on opposite wood of Ginkgo biloba L. clones; and it was the same to opposite wood. The differences among the microfibril angle, the double wall thickness, the ratio of cell wall to cavity and the tangential diameter in interaction of opposite wood and different growth ring all reached very significant level. The differences among the same index on compression wood was significantly or very significantly; There were very significantly differences in all indexes among compression wood of Ginkgo biloba L. clones; and the differences among indexes in interaction of compression wood and different growth ring all reached very significant level.(4)The tracheid length, double wall thickness, lumen diameter, radial diameter and tangential diameter of Ginkgo biloba L. clones all presented an increased trendency with the increase of growth ring, but the microfibril angle and the ratio of cell wall to cavity were on the contrary. The indexes of tracheids on compression wood , opposite wood, earlywood and latewood of Ginkgo biloba L. clones all followed the same rule as above.The tracheid on opposite wood were longer, the double wall were thicker, and the the ratio of cell wall to cavity were significantly bigger than that on compression wood, the microfibril angle, the lumen diameter, the radial diameter and the tangential diameter were on the contrary, and the difference were reached significantly or very significantly level. The differences of all the indexes were significantly or very significantly among compression wood and opposite wood. The microfibril angle of earlywood tracheid bigger than that of latewood. The double wall of latewood tracheid was thicker than that of earlywood, and the differences of double wall of tracheid between earlywood and latewood on opposite wood reached significantly level, but the differences were insignificantly on compression wood. Both the lumen diameter and the radial diameter of earlywood tracheid on comgpression wood and opposite wood were bigger than that of latewood, and their differences reached the significantly level. The tangential diameter of latewood tracheid was smaller than that of earlywood, the difference was significantly on compression and insignificantly on opposite wood.(5)The opposite wood of 203# and P2# belonged to one type, the comprehensive characters of tracheids were best of this type, its microfibril angle was the smallest, the double wall was the thickest and the radial diameter was the biggest, the lumen diameter was bigger, their tracheids were stronger, so that their tracheids were difficultly to be squeezed deformation; their tangential diameter was biggest, but their tracheids belonged to moderate size; And that the comprehensive characters of tracheids of 98# and 13# were the poorest. The comprehensive characters of tracheids on compression wood of six clones which included 200#,203#,210#,43#,318#,T11# were the best; and the eleven clones which included A13#,I#,G#,H#,07#,12#,03#,F#,98#,13#,14# was the poorest, the microfibril angle was biggest of the five types, the radial diameter was the smallest, the cell wall was thinner and the lumen diameter was smaller, the ratio of cell wall to cavity was biggest.The relationship of Ginkgo was discussed in this paper based on the study of dissection characteristics of wood of Ginkgo clones, and the relationship of tracheid characteristic indexes and woody characteristic was also discussed in this paper.