| Scutellaria tsinyunensis C. Y. Wu et S. Chow, the genus Scutellaria of the Labiatae,is a perennial national plant in Mt. Jingyun of Chongqing, one of the eight smallest populations species, and the first key protected wild plant in Chongqing. S. tsinyunensis is mainly distributed in the evergreen broad-leaf forest or mixed broadleaf-conifer forest at the altitude of 280-790 m, and has less population quantity, small scale, single habitat, and severe living conditions. In recent years, the population and individual number of S. tsinyunensis were rapidly reduced. Relying on the Southwestern University, the Chongqing Forestry Administration actively carries out the protection work. For the plant species with extremely small populations, population rejuvenation and population reconstruction are the most effective methods to protect these species.However, cutting propagation is the fastest method to realize fast seedling reproduction and population rejuvenation. In order to explore the most suitable conditions for cutting propagation and provide technical support for the rapid propagation of S. tsinyunensis.This experiment carried out the research on the cutting propagation technique and the rooting mechanism of S. tsinyunensis. In this study, the branch cuttings of S.tsinyunensis were carried out in different stages, different lignified degrees, different hormones and concentrations, and different cutting mediums. Meanwhile, we also studied the changes of different nutrients and enzyme activities during the process of rooting. The results of this experiment showed that:(1) Cutting in spring, the effects of different hormone types, hormones concentrations and treatment time on cutting of S. tsinyunensis with orthogonal regression design. The effects of the 9 treatments on the 6 rooting indexes of S.tsinyunensis cutting showed significant differences. In the orthogonal experiment, the treatment with 200 IBA mg.L-1for 10 hours had the best rooting effect. In the substrate experiment, the best substrate for rooting effect was the distilled water; secondly to the perlite and vermiculite(1:1, V/V) treatment, the average root length, the longest rootlength and rooting index had better effect. The treatment of river sand was better in rooting rate. Cutting in spring, the rooting effect of biennial branches was better than that of current branches.(2) Cutting in autumn, semi-lignified branches were the best choice, because it had the best rooting effect. while the worst is softwood. Different concentrations of NAA,IBA and ABT2 had different promoting effects on the rooting of S. tsinyunensis. The adventitious root formation of cuttings was also significantly influenced by the types and concentrations of exogenous hormones of cuttings. The rooting character of cuttings with the treatment of NAA 100 mg.L-1was the optimal. The rate of rooting was 93.33%,adventitious root appeared in 27.67 d, the average root number was 41.67, the average root length was 1.32 cm, and the longest root length was 6.93 cm. The treatment of 200 mg.L-1 and 400 mg.L-1 IBA also were conducive to the promotion of rooting. The same as 200 mg.L-1 and 300 mg.L-1 ABT2.(3) S.tsinyunensis field regression test showed that it was feasible to field regression by cuttage propagation of S.tsinyunensis。The group in the greenhouse and in the field both can survival, but the survival rate of cutting slips in the greenhouse was higher than these in the field, which was 96.67%, and the average number of sprouting is 3.67, the largest number of sprouting was 9.33.The survival rate of cutting slips in field group was relatively low, for 48.89%. The average number of sprouting was 1.52,most budding rate was 2.67.(4) The content of nutrients for the cuttings was changed with the process of the rooting. The soluble sugar content showed a trend of "decrease- rise- fall- rise".And soluble protein content showed a trend of "increase- decrease- rise".Tests showed the content of soluble sugar and soluble protein in cuttings were important factors to affect the rooting of cuttings. Hormone treatment could increase the content of sugar and protein in the cuttings and it was conducive to the rooting of cuttings.(5) The POD activity, PPO activity, SOD activity and contents of MDA in the rooting process have different level. Exogenous hormone significantly increased the POD activity, PPO activity, SOD activity of cuttings but decreased the content of MDA in Plants, and promoted the rooting of cuttings. The four change trend is first increased,then decreased, but the peak arrival time is not the same. Tests showed that the formation and development of adventitious roots of S. tsinyunensis cuttings were closely linked to POD activity, PPO activity, SOD activity and MDA content. |
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