Rapid Propagation Technique Of Michelia Compressa And Hormone Content Dynamics During The Cutting Process

Michelia compressa is an evergreen ornamental tree species. It also can be used as timber.However, it produces only a few seeds and its seed propagation is quite difficult. In this paper, weestablished the rapid propagation system of M. compressa by tissue culture and cutting. Wescreened a rooting agent and the suitable concentration for cuttings, preliminary discussed theroot mechanism. The main conclusions are as follows:The optimal time for explant sampling was from April to May for tissue culture. Terminalbuds from seedlings were more suitable as explants and explants were sterilized in0.1%mercuric chloride for12minutes. The suitable culture medium for lateral bud intuction was MSsupplemented with0.5mg/L6-BA and0.05mg/L IBA. The optimal culture medium for lateralbud proliferation was MS+1.2mg/L6-BA+0.1mg/L IBA+30g/L sucrose (pH5.2).Callus-inducing culture medium was MS+3.0mg/L6-BA+0.2mg/L NAA. The suitable culturemedium for seed germination was B5supplemented with0.5mg/L GA₃, the germination ratereached88.9%.In cutting process of M. compressa, the most important factors influenced rooting was thetree age of cuttings. Only cuttings collected from2to3years old seedlings could successfullyproduce roots,and the suitable cutting time was early July. The rooting agent ABT1couldimprove the rooting rate, the optimum concentration was800to1000mg/L.Auxin could promote adventitious root formation. In the early stage, the high concentrationsof IAA might benefit root formation and differentiation. Afterwards, lower concentrations of IAAwere more conducive to root elongation. Early rooting only need a low concentration ofcytokinin(ZT), then the concentration increased. A low level of ABA was beneficial to theformation of adventitious roots. The role of exogenous auxin made the ABA content of eachtreatment group overall lower, which improved the rooting rate. Gibberellin (GA3) inhibited rootformation; exogenous auxin could reduce endogenous GA3content.