| With Populus×euramericana (Dode) Guiner CL.'Zhonglin 46' as material, the 5 endougeneous hormones: indole -3 - Acetic acid (IAA), indole -3 - butyric acid (IBA), gibberellic acid (GA), zeatin (Z), and abscisic acid (ABA ) of cambium from different inclined stem were determined by HPCE tracking. The content of each hormone was compared in different position, different inclined angle and different sampling time to seek the distribution of endogeneous hormones in tension wood of poplar. The main wood properties were also determined to compare the difference between normal wood and tension wood. The results were as follows:1. The content of hormones in different position of the same inclined angle varied. The content of IAA in the upper side of the stem was lower than that in the lower side of the stem (but for the inclined angle of 30°) during the 3 measurments, while results of the comparison was contrary at the inclined angle of 30°on June and September. The content of GA in the upper side of the stem was lower than that in the lower side. The content of other 3 hormones didn't vary of any rule in different position at the same inclined angle.2. The content of hormones in different region at the same inclined angle varied, and the results were as follows:the content of IAA, IBA and GA determined on April and September had a little difference in tension wood region and opposite wood region, while each content varied determined on June. The content of Z determined on September also had a little difference in different regions, but varied on June. The content of ABA in tension wood region determined on September and December changed following the same rule (but for inclined angle of 60°), while the content determined on April at different inclined angle varied; the content of ABA in opposite wood region changed following different rules.3. The content of each hormones sampling at different time varied. The difference of IBA, GA and Z contents determined at different time were as follows: June>September>April>December; and the content of IAA was June>April>September>December. The content of ABA determined on different months varied following April>December>September>June.4.The G-layer was visible from the double-dyed cross section of tension wood, and the structure became common with the increasing inclined angle. The cell shape became abnormal from upright stem to inclined stem and the G-layer became thicker with the increasing inclined angle and came off easily. 5. The wood fibre length of different region and different inclined angle was different. The fibre length of tension wood region was longer than that of opposite wood region at the inclined angle of 15°and 30°; while that at the inclined angle of 45°and 60°was contrary, that is, the fibre length of tension wood region was shorter than that of opposite wood region. With the increasing inclined angle, the wood fiber length of tension wood region decreased, and that of opposite wood region increased. The difference was significant at 0.01 level between the inclined angle and the fibre length by analysis of variance, there was no difference between different regions and the fibre length and the difference was significant at 0.01 level between different inclined angles, different regions and the fibre length.6. The microfibrillar angle of tension wood region was larger than that of opposite wood region at the inclined angle of 0°, 15°and 30°; while it was smaller than that of opposite wood region at the inclined angle of 45°and 60°. With the increasing inclined angle, the microfibrillar angle of opposite wood region increased, and the microfibrillar angle of tension wood region varied as a broken line in the range of 17°-25°. The results of ANOVA were as follows: the differences were siginificant at 0.01 level respectively between the different inclined angles and the microfibrillar angle, the different wood regions and the microfibrillar angle, the different inclined angles, different wood regions and the microfibrillar angle.7. The basic density of tension wood regions was smaller than that of opposite wood regions at the inclined angle of 0°and 15°; while it is contrary at the inclined angle of 30°, 45°and 60°. With the increasing inclined angle, the basic density of tension wood region increased, while that of opposite wood region changed a little.8. The variation range of shrinkage in tension wood was wider than that in normal wood. The tangential shrinkage, radical shrinkage and logitudinal shrinkage in opposite wood region of air-dried wood were larger than that in tension wood region as a whole; the tangential shrinkage and logitudinal shrinkage in opposite wood region of oven-dried wood were larger than that of tension wood region as well, but the results of the radical shrinkage was opposite.
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