| The hybrid tulip tree (Liriodendron chinense×L.tulipifera) is a kind of tree which is badly in need of cultivation for ornamental and industrial material in recent years in China, and it was very difficult to reproduce by cutting. This paper carried out a research on the relationship between cutting propagation and enternal and external hormones of hybrid tulip tree, the annual growth dynamics of different provenances seedlings of L.chinense and steckling of hybrid tulip tree. The results were shown as follows: 1.The effect of different growth substances to the endogenous hormones changes during the rooting process of cuttings The treatment of growth substances, especially the NAA+BA, could increase the rooting rate and improve the root characters of the hardwood cuttings. The fluctuations of endogenous hormones were different between control and treatments with growth substances. NAA treatment and NAA+IBA treatment caused the similar, similar rooting rates and similar rooting time. The fluctuations of the five endogenous hormones were more active after NAA+BA treated. IAA,ZRs and iPAs were all participated in forming of the callus, while GA4 took an important role in forming of the root primordium. All growth substances treatments could not decrease the contents of ABA, while the fluctuations of ABA were more active compared to the control. The NAA+BA treatment decreased the content of IAA, while it could enhance the contents of iPAs,ZRs and promoted the climaxe of iPAs, ZRs and GA4 comging early, which were were accounted for the improvement of the rooting ability after treated with NAA+BA. 2.The endogenous hormones fluctuations during the rooting process of softwood cutting from different clones The fluctuations of five endogenous hormones were investigated during the rooting process of softwood cutting form 4 different rooting rate clones. Contents of IAA,ABA,iPAs and GA4 in cortex of n4 clone reached their climax after 13 days when it have many visible primordiums. The n4 clone began rooting after 19 days and those four endogenous hormones keep low levels after rooting. Other 3 clones were difficult to rooting for their ABA levels keeping high. 3.The rooting ability of different clones and the relation with endogenous hormones and ratio of carbon to nitrogen The rooting rate of either hardwood cutting in spring or softwood cutting in summer was components analysis could be used to evaluate the rooting ability of clones. With this methods, rooting characters and rooting rate were found as the same order. There was no relationship between rooting rate and IAA/IBA or C/N either for hardwood cutting in spring or for softwood cutting in summer. There is also no relationship in rooting rate between the hardwood cutting and the softwood cutting of the same clone. The rooting rate of cuttings collecting from the top of 2-years-old stecklings was lower than that collecting from the base of 7-years-old ortets for cuttings obviously for the later having lower C/N. 4.The annual growth dynamics of seedlings and steckling. Jingping provenance of L. liriodendron chinense was better than Lushan provenance in survival ratio, growth phase, height growth, while the caliper is similar. The growth process of the annual growth of height and caliper of the two provenance presented the rhythm of "Slow-Fast -Slow", and could be fitted into 'S'curve. The growth patterns also could be simulated with Logistic equation. 4 stages could be divided for the growth of height and caliper. Height growth process of the annual steckling of L. chinense×L.tulipifera presented the rhythm of "Slow-Fast-Slow-Fast-Slow", and could be fitted into 'S'curve. The growth patterns also could be simulated with Logistic equation. 5 stages could be divided for the growth of height and had two prosperous phases. |
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