Study On The Propagation Technologies And Rooting Mechanism Of Green Branches Cutting In Tilia Miqueliana

Tilia miqueliana Maxim.is a tall deciduous tree in the Tiliaceae family.Tiliaceae,which is endemic to my country.It integrates greening ornamental value,economic value and medicinal value,and has a high comprehensive utilization value.It has strong resistance,less pests and diseases,and has unique regional cultural connotations.In order to meet the demand for large-scale production and promotion of T.miqueliana,give full play to the value of native tree species.In this study,the current year green branches of T.miqueliana were used as cutting materials,and the cutting facilities with transparent plastic film small arch shed and shading net were used to discuss the cutting propagation technology and rooting physiological mechanism,and observed the production and development process of its root primordium by morphological and anatomical methods.The main experimental results are as follows:1.In order to construct the simple propagation technology of T miqueliana green branch cuttings,several factors affecting cutting rooting were discussed,including cutting material location,cutting length,cutting substrate,type and concentration of rooting regulator,degree of shading,etc.The results showed that the location of the cuttings should be determined according to the degree of lignification of the current year branches.The cuttings with the length of 15-25 cm before the end of May should be cut from the lower part as cuttings.However,for cuttings with length over 35 cm after the middle of June,the upper and middle part of cuttings should be selected as cuttings,and the cuttings have a better rooting effect.In different cutting lengths(4-6 cm,7-9 cm,10-12 cm,12-14 cm),10-12 cm is the best.Among the ten different types of cutting substrates,the mixed substrate of perlite:peat:garden soil(1:1:1)had the best cutting effect.Among the six different rooting agents,IB A 100 mg/L immersion solution for 4 h had the best rooting effect.The results of different shading degrees(50%,80%,95%)showed that about 80%shading was the most suitable for the rooting survival of T.miqueliana.2.In order to explore the physiological mechanism of T.miqueliana rooting,the dynamic changes of the nutrient content,oxidase activity and endogenous hormone content in cuttings of T.miqueliana green branch during the rooting process were analyzed by using IBA 100 mg/L rooting agent and water treatment as the control.The results showed that during the rooting process of T.miqueliana,the increase of nutrient soluble sugar and soluble protein content can promote the rooting of cuttings;The increased activity of POD and PPO can promote the formation of root primordium,and when the IAAO activity is low,it is beneficial to induce the rooting of cuttings,Highly active IAAO can promote the elongation and growth of new roots;The increase of endogenous hormone IAA content and the increase of IAA/ABA ratio in cuttings can promote rooting.after IBA treatment,by adjusting the nutrient substances,enzyme activities and endogenous hormone content of cuttings,the process of adventitious root production can be shortened and the rooting of cuttings can be promoted.3.The changes of external morphological,the generation and development of root primordia during the rooting process were studied by means of morphological and anatomical observation,the results showed that T.miqueliana is a non-callus rooting type.The root primordium belongs to the induced root primordium,which originates at the junction between the pith ray and the pith zone.It belongs to a single origin,but it can be induced in multiple directions.The callus at the base of the cuttings originated respectively from the parenchyma cells in the cambium and the cortex,and the former formed earlier.No root primordial cells were found in the anatomical structure of the callus,which shows that there is no quantity correlation between the callus of T.miqueliana and the formation of adventitious roots.4.Using the above-mentioned optimized cutting technical parameters of T.miqueliana green branches,the cutting effects of seedbed in-situ cutting and nutrient bowl cutting were discussed.The results showed that the two cutting patterns can achieve good cutting effects under simplified daily management conditions,and the rooting rate of cuttings can reach more than 75%.In production,suitable cutting patterns can be selected according to actual needs.