| The rapid micropropagation technique and mechanism of cutting rootingof Broussonetia papyrifera were comprehensively studied in this paper.Thefactors affecting propagation,problems existing in this technipue and theirsolutions were also described, which provided the theoretical base andtechnical measures for industrial producing of plantlet.This experiment studiedthe promotion of outerhormones treatment in cutting rooting of soft wood andhard wood ,the origin position and anatomical structure of adventitious roots,the variation of nutrients,enzyme activity and changes endohormones duringrooting.Analysed the mechanism of cutting rooting of Broussonetiapapyrifera.Result indicated that the best time of extraction is the last ten-day ofApril, the bud is just growin in this period ,the contaminated rate(30%) anddied rate(31.42%) are lower than the other period;the best result of sterilizingagents is 70%alcohol(10s)+0.1%HgCl2 (8min).,the contaminated rate was33.33%.Macroelement,the concentration of organic substance and hormone werethe main parts of culture medium,and play a important role for the budmultiplication and shoot growth. The result indicated that MS was found tobe the most favorable to bud multiplication and shoot growth;The optimalmedia for bud multiplication and shoot growth were:MS+ NAA1.0mg·L-1MS+IBA0.5mg·L-1 MS+KT1.5mg·L-1 MS+6-BA1.0mg·L-1) From thecomprehensis result of 6-BA-KT-NAA on bud multiplication and shoot growthwe found that : The optimal mediums for bud multiplication were: MS+6-BA1.5mg·L-1+NAA1.0 mg·L-1+NAA1.0 mg·L-1 +KT0.1 mg·L-1. The most favorable media for shoot growth MS+ 6-BA1.5mg·L-1+NAA1.0 mg·L-1 .The optimal rooting medium was 1/2MS+IBA0.5mg·L-1 on the basis ofrooting index, The ex-vitro rooting technique of shoot was also studied,theexperiment was failure,the shoots were all rotten.so the specific operatingmethods need discuss.1/2MS + IBA0.5 -1 mg/L ;In the experiment of plantlettransplanting ,the result showed that the survival rate in the humus(85%)reached the highest,next is in the pearlite(31.7%),and lowest in thesand(23.3%). Study found thatf ABT and IBA can promote soft wood cuttage rootingrate ,the best treatment concentration of soft wood cuttage was that 500ppmABT for 20s or 100ppm IBA for 5minutes ,and the rooting rate wasirrespectively 88%,85%, which were both higher than the 22.5% of CK. The best root-promoting agent of hard wood cuttage was ABT, IBA wasnext,and the NAA was worst.The proper concentration of hard wood cuttagewas that the cuttage dip in in 200ppm of ABT or IBA 2h,the rooting rate were74.25% and 62.26% separately.When the concentration was reached 1000ppmthe rooting rate descreaed.Study found that NAA was not fit for rooting ofboth on soft wood and hard wood cuttages.The reason maybe relate with thethe characteristic of Broussonetia papyrifera. Soft and hard wood cuttage rooting rate showed positive correlation withcarbohydrates content ,C/N and showed nigative correlation with the totalnitrogen content. The treatment of hormone raised the carbohydratescontent,and the C/N,descresed the total nitrogen content,so they can promotedrooting. Study found that the rooting rate had positive correlation with theactivity of PPO,and negative correlation with the activity of IAAO,POD inboth soft wood cuttage and hard wood cuttage by the correlation analysis ofrooting rate and the activity of Enzyme. IAAO can oxidate IAA,POD canoxidate IAA too.they effected the rooting rate through adjusting the centent ofhormone.but PPO effected the cuttage rooting rate through creatIAA-Hydroxybenzene-Acid. The rooting rate showed positive correlation with the content of IAA... |
PDF Full Text Request