Rapid Propagation Technique For Ilex Verticillata (L.) A. Gray

Ilex verticillata (L.) A. Gray(winterberry) is a deciduous shrub in Aquifoliaceae native to northeast USA. It is dioecious plant with white flowers and3-6female and dozens of male flowers aggregate in leaf axils. It is a great ornamental plant for its wide adaptability and red globular fruits, which persist throughout the entire winter. Unfortunately, regeneration difficulty limits its popularity. The cutting propagation techniques keep the excellent properties of mother trees and tissue culture propagation ones produce a great quantity of excellent clones of winterberry. This study concentrates on cutting propagation and tissue culture propagation technology, in order to find out the effective way to improve the reproduction quantity and quality, save germplasm of I.verticillata and provide theoretical and technical support for the seedling industrial production.Effects of stem type, stem length, rooting hormone type and concentration, and collecting time, on rooting of I.verticillata cuttings had been investigated. The results were as follows:(1)Semi-hardwood stem cuttings rooted significantly higher than that of softwood and hardwood cuttings. The rooting percentages of semi-hardwood cuttings reached53.12%, while hardwood and softwood ones were15.63and3.13%respectively. The total rooting length of the semi-hardwood stems was the highest, which was35.52cm.(2)The effect of cutting length was different. The length of cuttings should be5cm with3nodes, which yielded46.88%rooting and hormones significantly improved rooting rate and root quality. Cuttings treated with both liquid (K-IBA) and powder (Hormondin#1) at1OOOmg/L had68.75%rooting rate and excellent root quality.(3)Cuttings in Perlite:peat (3:1)matrix had highest rooting percentages, the average total volume, and average root number reached71.88%,116.938cm3and12.91respectively, yielded the best quality of roots.(4)Both plastic film covering and mist system were suitable for cutting propagation of winterberry. The film covering yielded better quality of roots.(5)Effects of rooting hormone type and concentration of on rooting of stems collecting from different time were different. Hormondin#l powder combined K-IBA2000mg/L liquid significantly improved rooting rate and root quality of stems collecting at June8,2011, August12,2011and October12,2011,whose rooting rate, average total volume and average rooting number were higher than that of other treatments.(6)The survival rate of winterberry liners (rooted cuttings) were86.58%after transplanting.The research results further improved I. verticillata cutting propagation technology and promoted it popularity in the market.Establishment of sterilization system, initial culture, proliferation, rooting and transplanting on plant tissue culture of I.verticillata had been investigated. The main results were as follows:(1)Explant sterilization methods:The most suitable sterilization method for leaf explants was using with70%alcohol for30s combined0.1%mercuric chloride for5min; the most appropriate sterilization method for stem explants was using with70%alcohol for30s combined0.1%mercuric chloride for7min; add1-2drops of Tween-80can enhance the effect of sterilization.(2)Initial culture:Taking WPM as basic culture medium, callus induction from leaf and adventitious shoots from stem segments were better; WPM+NAA2.0mg/L+6-BA l.Omg/L medium was more suitable for leaf callus induction; add1.0mg/L GA3enhanced adventitious shoots.(3)Differentiation culture:The more suitable callus differentiation medium was WPM+6-BA0.5mg/L+2,4-D O.lmg/L, the differentiation rate was up to37.50%.(4)Proliferation culture:the optimum medium for shoot proliferation was WPM+NAA0.02mg/L+6-B A1.0mg/L, the proliferation coefficient was11.40.(5)Rooting culture:Many factors affect rooting process.Took WPM as the basic culture medium,add20g/L sucrose, IBA1.0mg/L or NAA1.5mg/L, the rooting rate, average rooting number and average rooting length were the best.(6)Seedling and transplanting:The survival rate of tissue culture seedlings was up to93.10%after transplanting.The findings had been applied for the standard regeneration of I, verticillata in the industry, which ultimately brought this important ornamental plant to our Chinese markets.