Study On The Propagation And Rooting Mechanism Of Phoebe Zhennan

At present,the production of seedlings of Phoebe zhennan in China is mainly based on seed sowing,but its seed reproduction cycle is long,its yield and reproductive rate is low.Therefore,speeding up the breeding rate of Phoebe zhennan is an urgent problem to be solved,and cutting propagation is an effective way.In this paper,two-year-old Phoebe zhennan cuttings were used as experimental materials to study the effects of different substrates,cutting time,parent tree age,hormone types and concentrations on rooting of Phoebe zhennan.In addition,the effect of endogenous hormone(GA,IAA,ABA,ZT),enzyme activity(PPO,POD,IAAO)and nutrient(soluble sugar,soluble protein)on rooting of Phoebe zhennan were studied by using two-year and eight-year-old Phoebe zhennan cuttings as experimental materials,with a view to finding the cause of the difficulty in the rooting of the Perennial Phoebe zhennan.At the same time,experimental research was carried out on the plan of deconstruction,and the following results were obtained:1)The results of cutting experiment showed that different substrates,hormone types,hormone concentrations,cutting time and parent tree age had significant effects on the rooting of Phoebe zhennan.when the cuttings were treated with 2-year-old Phoebe zhennan cuttings and 200 mg/L NAA for 2 h,and perlite was used as the substrate.The rooting effect of cuttings in spring April was the best,and the rooting rate of cuttings was 94.2%.2)The content of endogenous hormones in different ages of Phoebe zhennan was also different.The change of endogenous hormone content was closely related to the rooting of Phoebe zhennan in different ages.Among them,the change of ZT(zeatin)content shows that the higher the age,the higher the content,which has an inhibitory effect on rooting.The increase in GA(gibberellin)content promotes adventitious root development to some extent.The change trend of ABA(abscisic acid)and IAA(auxin)content in 8-year-old cuttings was always delayed than that in 2-year-old cuttings and was inversely proportional to the rooting rate of cuttings.3)The activity of IAAO(indole acetic acid oxidase)in the early cutting stage of Phoebe zhennan was decreased at different ages,and the IAAO activity of 8-year-old cuttings was higher than that of 2-year-old cuttings.The high activity of IAAO inhibited the rooting of cuttings to some extent.The change of POD(Polyphenol oxidase)and PPO(peroxidase)activities showed the trend of 8-year-old cuttings being lower than that of 2-year-oldl cuttings,indicating that high activity POD and PPO content favored the development of adventitious roots.4)The content of soluble sugar and soluble protein showed different trend in the cuttings of Phoebe zhennan at different ages,and the difference was extremely significant.This also indicated that the main reason for the low rooting rate of perennial cuttings was the low amount of nutrients available,which led to the slow development of adventitious roots and the difficulty of rooting.5)The study of disaggregation in rooting process of Phoebe zhennan,it was found that there was no latent root primordium in the cuttings,which belonged to the induced root primordium.The process of adventitious root development is roughly divided into three stages:①Adventitious root induction period(0-25);②adventitious root formation period(25-40);③Adventitious root extension period(40-60).