关键词: 气候季节, 气候季节, 开始日期, 季节长度, 气候变化, 北京

Abstract: The aim is to find optimal hormone concentration and optimal rooting site suitable for rooting of layering for Tilia europaea and to provide technical support for rapid propagation. The 8-year-old branches of Tilia europaea were taken as test materials,the branches were treated with different site by using different concentration gradient of hormones with NAA and IBA.the soil moisture and soil temperature were continuously measured by EM50 data logger ,In the later period, it could be obtained the significant differences by observing and recording the indexes of root number, root length, root diameter and calculated rooting rate nextly.The results indicated that the rooting effect of layering was highest when the layering plants of Tilia europaea were treated with IBA solution of 500 mg/L, the rooting rate reached 80%, the average main root number, the average main root length, the average main root diameter , the average lateral root number and the average lateral root length could be reached 29.6(roots), 19.74 (cm), 2.75 (mm), 15.8 (roots), 8.64 (cm) respectively.The suitable rooting site for rooting of layering in Tilia europaea was in the middle segment of the branch, the rooting rate reached 77.8%, the average main root number, the average main root length, the average main root diameter , the average lateral root number and the average lateral root length could be reached 10.7(roots), 16.67(cm), 1.9 (mm), 10.8 (roots), 5.15 (cm) respectively.The results indicate that appropriate hormone concentration treatment can promote rooting rate and survival rate of layering plants in Tilia europaea ; IBA is better than NAA and control in rooting effect; the suitable rooting site for layering plants of the tree is in the middle segment of the branch.