Studies On Asexual Propagation Techniques Of Liquidambar Formosana

Liquidambar formosana is an excellent foliage ornamental tree in autumn and winter in China,which can be planted as a shade tree,or planted alone or in clumps in grasslands,or mixed with fir and pine in mountains and hills to form mixed forests of needles and broad trees.As a native tree species,Liquidambar formosana has a wide distribution in southern provinces of China,and due to long-term natural selection,many different types have emerged,presenting different landscapes in autumn and winter.It is observed that there are light yellow,dark yellow,light red and dark red types in leaf color,among which dark yellow and dark red types tend to have better ornamental effects.In this paper,the preliminary study has selected four sources of Liquidambar formosana from 20 sources of Liquidambar formosana in Hunan with the best ornamental color leaves.In the past,Liquidambar formosana was mostly propagated by seeds,and it was difficult to maintain the good characteristics of the parent tree.In the research of asexual reproduction,only a few scholars have conducted some sporadic researches,and a complete technical system has not been formed yet.In this paper,we take the four selected seeds as the test material and conduct the research of asexual propagation technology of Liquidambar formosana,including cuttings,grafting and tissue culture,aiming to establish the technical system of asexual propagation of Liquidambar formosana,speed up the selection and breeding of excellent varieties,shorten the seedling breeding cycle,and meet the demand of high-quality foliage tree species for the construction of beautiful Hunan.The main research results are as follows:1.The rooting of Liquidambar formosana cuttings is influenced by various factors such as substrate,hormone concentration,spike length and type.The average rooting rate of perlite:peat soil:red loam=1:1:1(volume ratio)(A3)as substrate was the highest,reaching 85.93%,which was significantly different from the other three substrates;in terms of rooting promoter concentration,the average rooting rate of ABT1 rooting promoter concentration of 1000 mg/L(C3)was the highest,reaching 87.41%,followed by 800 mg/L(C2),reaching The average rooting rate of 15 cm(H3)was the highest with 74.81%,followed by 13 cm(H2)with 70.37%,with significant differences between H3 and other treatments,but not significant differences with H2;the average rooting rate of semi-woody spike was the highest with 71.85%,with significant differences with the other two spike types.The average rooting rate of semi-woody cuttings was 71.85%,which was significantly different from the other two types of cuttings.The best technical combination for Liquidambar formosana cuttings was to use a substrate of perlite:peat soil:red loam=1:1:1(volume ratio),soaked with 1000 mg/L concentration of ABT1 rooting promoter,and selected 15 cm semi-woody branches with an average rooting rate of about 80%.2.The survival of Liquidambar formosana spring grafting was affected by grafting methods,rootstock height,scion lignification degree,moisture measures and a combination of factors.The survival rate of cut grafting is the highest(90.00%),split grafting is the second highest(86.67%),and the survival rate of bud grafting is the lowest(65.00%),the difference between cut and split grafting and bud grafting is significant;the height of rootstock has a great influence on the survival rate of Liquidambar formosana cut and split grafting,the survival rate:30 cm>50 cm>20 cm.The average survival rate of semi-woody green branches was the highest,up to 85.93%,while that of brown old branches was the lowest,only 49.63%,and the average survival rate of semi-woody green branches was 1.25 times that of woody branches and 1.73 times that of brown old branches.The average survival rate of semi-woody green branches was 1.25 times that of woody branches and 1.73 times that of brown old branches,and the average survival rate of the three types of scions differed significantly from each other;after bagging treatment,the survival rate of Liquidambar formosana cut and split grafting differed significantly,and the average survival rate of rootstock bagged was 57.78%,while that of non-bagged was 74.81%,and the average survival rate of non-bagged was 1.29 times that of bagged.The best technical combination for spring grafting of Liquidambar formosana is to use 30 cm height rootstock,semi-woody green branches,using cutting as well as no bagging treatment,the average survival rate can reach about 86%.3.The results showed that the best disinfection of Liquidambar formosana explants was achieved by using carbendazim(1:1000)for 30 min+0.1%mercury for 17 min;at different sampling times,the contamination rate of the explants collected in March was low at 21.11%and the survival rate was high at 78.89%.November was the second best.Therefore,the suitable period for sampling in spring is March and in autumn is November;the basic medium and plant growth regulators have great influence on the initial culture induction and successional proliferation of Liquidambar formosana exosomes.The most suitable basic media for initial sprouting and secondary proliferation of exosomes were 1/2 MS medium and DCR medium,respectively.The best medium formulation for initial culture induction rate was 1/2 MS+6-BA 1.0 mg/L+ NAA 0.75 mg/L,and its induction rate was 68.89%,and the best medium formulation for secondary proliferation proliferation coefficient was DCR+6-BA 1.5 mg/L+KT 0.5 mg/L+IAA 0.4 mg/L+ IB A 0.5 mg/L,and the proliferation coefficient reached 3.30.