| Syringa chinensis Will, has its own unique beauty and high ornamental value. It blooms in spring and autumn with long bloom duration and colorful flower. So it is an important landscape plant in northern gardens. In order to provide scientific guidance to the production practice of Syringa chinensis Will., we studied the effect of different hormone types, concentrations, different medium and different sources of cuttings on the rooting and growth of the branches and rooting mechanism in this paper. The main experimental results were as follows:1. Hormone types, concentration and treatment methods were different, the rooting effect was different. Results indicated that the most suitable treatment of low concentration NAA and IBA was 100 mg/L IBA with the rooting rate 90%, the root number 11.43, the primary root length 6.18, the longest root length 10.22 and the root effect index 2.37 after the cuttings were soaked for two hours, which were increased 5.75,1.85,2.15,1.78 and 8.12 times than that of the control significantly (P<0.01). The most suitable treatment of high concentration NAA and IBA was 1000 mg/L NAA+1000 mg/L IBA with the rooting rate 82.22%, the root number 8.60, the primary root length 3.86, the longest root length 7.56 and the root effect index 1.11 after the cuttings were soaked for twenty seconds, which were increased 5.17,1.37,0.77,1.06 and 3.27 times than that of the control significantly (P<0.01).2. The rooting effect was different with the different ratio of media. Peat, sand, perlite by 0.25: 0.50:0.25 was the suitable media of softwood cutting of Syringa chinensis Will., the rooting rate, the root number, the primary root length, the longest root length and the root effect index respectively to 87.78%,13.42,6.82cm,14.43cm and 3.04, which were increased 0.42,0.91,0.51,1.20 times than that of the sand significantly (P<0.01). Peat, sand, perlite by 0.30:0.60:0.10 was the suitable media of hardwood cutting, the rooting rate, the root number, the primary root length, the root effect index, the specific root length, the fresh weight of root shoot ratio, the dry weight of root shoot ratio and the shoot growth quantity were 77.78%,12.00,12.47,4.97,132.55,1.32,0.69,6.02, which were increased 0.19,0.64,0.60,1.60,0.55, 1.64,1.88 and 0.27 times than that of the media(Peat, sand, perlite by 0.20:0.70:0.10) significantly (P<0.01). The number of second lateral root and new shoots were 34.84 and 3.84, which were significant increased 0.42 and 0.23 times (P<0.05).3. Cuttings from different sources have different rooting effect. Compared with the naturally formed cuttings, the rooting rate, the fresh weight of root shoot ratio, the dry weight of root shoot ratio, the growth of new shoot from tree after excessive pruning have been increased 0.54,0.68,0.81 and 0.47 times significantly (P<0.01), the number of second lateral root of twig significant increased 1.55 times(.P<0.05). Hardwood cutting after overwintering sand storage, the rooting rate, the primary root length, the specific root length, the fresh weight of root shoot ratio, the dry weight of root shoot ratio, the number of new shoots and the new leaves were significant increased 0.11,0.38,0.64,0.80,0.60,0.36 and 0.44 times (P<0.05), the primary root number, the root activity and the root effect index were increased 0.58,0.33 and 1.19 times significantly (P<0.01).4. Rooting mechanism of heavy pruning. Compared with naturally formed cuttings, the content of soluble sugar and protein in the phloem of cuttings of heavy pruning significantly improved 16.54% and 13.15%(P<0.01); 15 days after cutting, the content of soluble starch in the phloem of heavy pruning significantly decreased 22.01%(P<0.01), the content of soluble protein significantly improved24.73% (P<0.01); 30 days after cutting, the content of soluble sugar decreased to the lowest, compared with the naturally formed cuttings early 15d. Thus cuttings with higher soluble sugar and soluble protein content before cutting, can provide more material and energy for the callus formation and adventitious root formation, so as to shorten the rooting time and improved the rooting effect.5. Rooting mechanism of hormone treatment.15 days after cutting, the content of starch in the phloem of cuttings that were treated with 100 mg/L IBA decreased to the lowest, and significantly decreased 26.49% than that of control (P<0.01); 30 days after cutting the content of starch of the control decreased to the lowest.30 days after cutting, the content of soluble sugar in the phloem of cuttings that were treated with 100 mg/L IBA decreased to the lowest; 45 days after cutting, the content of soluble sugar of the control decreased to the lowest. The content of soluble protein the phloem of cuttings that were treated with 100 mg/L IBA increased 0-15d and decreased 15-30d after cutting; and the control increased 0-30d and decreased 30-45d after cutting. So the treatment of suitable IBA could improve the rate of starch hydrolysis, and promote the formation of soluble protein in the phloem of cuttings. |
