The Establishment Of Cutting Propagation Technology System Of Malus Hupehensis(Pamp.)Rehd.Var.Mengshanensis G.Z.Qian And Its Influencing Factors

Malus hupehensis（Pamp.）Rehd.var.mengshanensis G.Z.Qian belongs to Malus Mill,Maloideae,Rosaceae.Pingyi crabapple is a variety of M.hupehensis.It is mainly grown in Mengshan of Linyi City,Shandong Province and widely distributed in the range of altitude of 300-1100m in Mengshan.Pingyi crabapple is a precious and scarce apple rootstock resource in China.In order to meet people’s demand for this resource and provide technical supports for the asexual propagation and resource expansion of Pingyi crabapple,this paper systematically studied the cutting propagation technology of Pingyi crabapple from the aspects of exogenous hormones,cutting substrate,cutting season,cutting position,leaf retention method and so on.In addition,by measuring the nutrient content,endogenous hormone content and oxidase activity at different stages during the rooting process of cuttings,we explored the cuttage rooting mechanism of Pingyi crabapple.The results were as follows:1.The cutting rooting rate of Pingyi crabapple treated with single hormone was the highest when NAA was 600 mg·L^-1.The orthogonal experiments with different hormones,concentrations and treatment times confirmed that the concentration of NAA had the greatest impact on the cuttings of Pingyi crabapple.During these experiments,summer is the most suitable season for cutting Pingyi crabapple.Substrates,cutting positions,and leaf retention methods significantly affect the rooting of cuttage.A single vermiculite substrate is the best substrate for Pingyi crabapple cuttings.The middle of the branches is the most suitable part for Pingyi crabapple cuttings.Leaving two 1/2 leaves is the most suitable method for keeping roots from cuttings of Pingyi crabapple.From the observation of the external morphological changes during the rooting process of cuttings,it’s found that most of Pingyi crabapples were rooted by callus,and few of them were rooted from the swelling and cracking of the bark at the lower end of the cutting.2.During the cutting rooting of Pingyi crabapple,the metabolism of nutrients in the cuttings changed due to the stimulation from the exogenous hormone NAA.In the early cutting period,all the contents of soluble sugar,starch,and soluble protein decreased.After adventitious roots were observed,their contents tended to be stable.The contents of soluble sugar,starch,and soluble protein were significantly related to the rooting of cuttings in Pingyi crabapple.All of the three facts worked together to promote the rooting of cuttings.3.After the cuttings were treated with exogenous hormone NAA,the activity of POD and PPO increased and the activity of IAAO decreased.The lower activity of POD and IAAO was beneficial to the formation of adventitious roots,and the higher activity of them was beneficial to the growth of adventitious roots.The higher activity of PPO was beneficial to the callus of cuttings of Pingyi crabapple,the occurrence and growth of adventitious roots.4.After the cuttings were treated with exogenous hormone NAA,the content of endogenous hormones also changed significantly under external stimulation.Specifically,the contents of IAA and ZR increased and the content of ABA decreased.Higher concentrations of ABA and ZR were beneficial to the formation of Pingyi crabapple cuttings callus;higher concentrations of IAA and lower concentrations of ABA and ZR were beneficial to the occurrence of adventitious roots;lower concentrations of IAA and ABA and higher concentrations ZR were beneficial to the growth of adventitious roots.In terms of the ratio of endogenous hormones,lower IAA/ZR and IAA/ABA ratios were conducive to the formation of Pingyi crabapple cuttings callus,and higher IAA/ZR and IAA/ABA ratios were conducive to the occurrence of adventitious roots from Pingyi crabapple cuttings.