| Phoebe bourne（ihemsl.）Yang, a subtropical evergreen broad leave tree for the productionof cherished timber and ornamental purpose, is a rare and endangered plant which is taken as aplant of the second-class protection in china. In order to offer scientific guidance for thepromotion of seedling cultiavion quality and the enhancement of resources protection forPhoebe bournei, the technique for soft branch cutting propagation was studied through fivetreatment methods of culture substrate, plant growth regulators and its concentration, thecuttings parts, styles of keeping leaves and planting seasons; meanwhile the rooting mechanismof Phoebe bournei was revealed by monitoring of the content of endogenous hormones andnutrients, as well as oxidation enzymes activity.The results were as follows:（1） The mixture substrate of50%peat soil and50%vermiculite （v/v） was the best rootingmeduim for soft branch cutting. Dynamic monitoring of temperature and humidity dataindicated that cuttings were not easy to root at the environment daily temperature ranging from16℃to24℃，when The environment temperature was from25to33℃,the softwoodcutting of Phoebe bournei show better.The rooting of cuttings was significantly influenced bythe types and concentration of regulators. The rooting capability of cuttings treated with IBAwas higher than that treated with IAA, NAA and ABT1#. The rooting effectiveness of cuttingswith the treatment of IBA1000mg·L-1was the optimal, and planting in April was mostbeneficial to promote the growth of cuttings based on the experiment of different plantingseason. The rooting effectiveness of cuttings was significantly influenced by the different partsand the numbers of keeping leaves with the highest rooting rate of cuttings using the tip partwith three pieces of half leaf from two-year-old branch.（2） Judged from the location of adventitious roots emergence of the cuttings of Phoebebournei, the adventitious roots of the species were mostly originated from cortex of the bottomsection for cuttings were hard to root when callus was formed, On the basis of rooting process,the formation of adventitious roots of Phoebe bournei cutting could be divided into3stagesafter cutting：①0-35days, the peroid of root induction and genesis;②36-45days, the period of adventitious roots formation;③after45days, the period of adventitious roots emergenceand development.（3） Rooting rate was positively correlated with the content of IAA,ZR and IAA/ZR, butnegatively with the content of ABA. Rooting effect was the best when the base of cuttingscontained higher content of IAA, GA, ZR and ratio of IAA/ZR toghether with lower ratio ofABA/IAA through dynamic measurement of the content of endogenous hormones..（4） Analysis of the relationship between nutrient content inside soft branch cuttings ofPhoebe bournei and rooting ability showed that rooting rate had a significantly positivecorelation with the content of soluble sugar, starch and soluble protein, indicating that highconcentration of those was in favor of the formation and development of adventitious roots.（5） Rooting rate of soft branch cuttings was significantly corelated with the activity ofIAAO, POD and PPO inside of cuttings of Phoebe bournei. among which rooting rate wasnegatively correlated with the activity of IAAO, but positively with that of POD and PPO. Theactivity of IAAO was significantly influenced by the content of IAA. The activity of POD incuttings treated with growth regulators was higher in the stage of the formation of adventitiousroot cells than that in the other two stages, while the activity of PPO inside cuttings in treatedgroups was always higher than that in CK group, leading to early and fast rooting of cuttingstreated with IBA. |
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