The Investigation Of Cupressaceae Resources And The Researches Of Propagation And Overwintering Ability Of Some Cultivars

Plant resources of Cupressaceae are abundant,new varieties were selected at home and abroad.Our country has rich resources,but the breeding work done less.In order to enrich the landscape materials,some species of Cupressaceae have been introduced in recent years,especially low and color varieties.Since the introduced varieties have different root-forming ability and age effect,to improve the asexual propagation coefficient is the core of popularization.In the present study,the origin and introduction Cupressaceae resources were investigated,and focused on the variation types of Juniperus Sabina which widely used in the northern region.On this basis,the cutting propagation techniques of different leaf color types of Juniperus sabina and some introduced varieties were studied,Then analyzed the relationship between anatomical structure and rooting ability and age effect.Finally,the overwintering adaptability of Junipreus communis 'Depressa Aurea' was explored after grafting and cultivation measures.This study has certain theoretical and practical value for the selection and promotion of Cupressaceae resources.The main results are as follows:1.Investigation of Cupressaceae resources:(1)There are 10 genus,173 species or varieties of Cupressaceae resources were recorded by literature review and field investigation.(2)Changes of leaf color of Juniperus sabina were tracked and recorded:the majority of leaf color is green(143-A)all year round,others performance different levels of yellow-green(1-D)and bluish-green(111-D).Different leaf color types of Juniperus sabina has their own trend of leaf color change under winter.2.Softwood cutting propagation of some Cupressaceae plants.(1)The cutting propagation of three kinds of leaf color variation types of Juniperus sabina was carried out,results showed that:IBA treatment significantly affected their rooting,the highest rooting rate of yellow green variation types reached 73.33%under IBA850mg/L?1h;the rooting rate of blue green variant and green Juniperus sabina reached highest under IBA450mg/L?30min.(2)The results of cutting propagation of 5 introduced varieties showed that:Suitable IBA concentration and the soaking time of cuttings could significantly improve the rooting level,the difference is:Juniperus procumbens'Nana' produced callus during rooting process,but no callus transformed into rooting,the optimal rooting rate was only 46.67%.(3)Junipreus communis 'Depressa Aurea' and Juniperus ×Pfitzeriana 'Pfitzeriana Aurea' cuttings were different in age effect,rooting rate of the former of 12-year-old still be 83.3%,but the rooting rate of latter of 12-year-old was only 6.7%3.Seven 3-year-old varieties and two of them with different age effect were selected to explore the relationship between anatomical structure and rooting ability and age effect.(1)In the type of rooting position,root primordium of Chamaecyparispisifera 'Boulevard' takes place in the cortex,which belong to the type of easy rooting;Other six varieties' root primordium were originated from the cambium and phloem area,resulting in a relatively slow rooting.(2)Rooting ability are affected by the number of layers and degree of closeness of thick-walled cells,the more number and closeler arranged of thick-walled cells,the more difficult to root.(3)The relative thickness of xylem and pith,also affect the rooting to some extent,when the proportion was high,the rooting more difficult4.In order to improve the overwintering adaptability of Junipreus communis 'Depressa Aurea',the effects of grafting and cultivation measures were studied:(1)The graft survival rate was 72%,and the grafted seedlings were better in the growth and wintering performance than cutting seedlings(2)The relative conductivity,Fv/Fm,?DPSII and leaf nutrient contents in the leaves of different cultivation measures all decreased the plant's overwintering stress in different degree.Among them,covered with transparent plastic film showing the best protection effect,all the plants survived the winter safely,only the leaf color changed.Other treatment showed the leaves and shoots dry in different degree in the following year.Drought can play a decisive role in the survival of plants.