Collection And Preservation Of Impatiens Spp.

There are over 900 species in genus Impatiens in the world, of which approximately 220 species distribute in China. Diversity of Impatiens provides abundant gene resources for breeding herb flower species. But up to now our precious germplasm resources are still left in wild without sufficient researches on the breeding and horticultural culture, especially on the preservation of germplasm. Narrow distribution, rich endemism and which need a strict circumstance of Impatiens appear to correlate with human activity and environment changing closely.In view of above fact, using collected Impatiens species in China, this paper evaluated ornamental character and development value of them by Analytic Hierarchy Process, studied on interspecific relationship, seed germination characteristics and shading tolerance, which was based on summarizing cultivation techniques, and established germplasm preservation system in vitro by methods of slow growth preservation and cryopreservation. The main results were summarized as follows:1. 38 species, 2 varieties and 7 indeterminate species were collected for the first time, some of them are shown as sharp decreasing because of habitats destruction and invasive plant. Using analytic hierarchy process to evaluate ornamental characteristic and development value of 40 collceted species, the result showed that I. malipoensis, I. claviger var. auriculata, I. claviger, I. apalophylla, I.morsei, I. obesa and I. macrovexilla have better ornamental value and can be used for landscaping directly and preferentially on the premise of germplasm preservation. Development and utilization of aforeside 8 species should be considerated preferentially.2. The optimal reaction system of AFLP for Impatiens was established, the genetic diversity and relationship were analyzed between 40 Impatiens species. The PCR-based multi-locus DNA fingerprinting technique Amplified Fragment Length Polymorphism(AFLP)analysis of 40 species with 11 AFLP primer combinations produced multi-locus DNA fingerprint with a total of 1003 DNA fragments. Polymorphism rate was 97.11%. Result showed that species which had high similarity at parts of biological characteristics and habitat had nearer relationship. As classification foundation, habit and parts of biological characteristics had more reliability. More methods should be used in taxonomic studies of Impatiens. Result provided valuable evidence for estabilishing taxonomic system and crossbreeding in molecular level.3. Study on seed germination charactesistics of I. chinensis, I. morsei, I. obesa, I. macrovexilla showed that optimal germination condition of I. chinensis is seed soaking for 8h at 30℃, and germinating at 30℃, the germination rate was 70%. Optimal germination condition of I.morsei is seed soaking for 4h at 20℃, germinating at 20℃, germinating rate was 34%. Germination rate of I. obesa at 20℃was higher than at 30℃, the germination rate was 80%. Germination rate of I. macrovexilla was close to 100% both at 20℃and 30℃. Germination rate of I. obesa and I. morsei have already approximated to maximum on 24th day, I. obesa was on 15th day and I. morsei was on 6th day.4. At provided three kinds of light intensity, photosynthetic capacity of three Impatiens species(I. chinensis, I.macrovexilla, I. obesa) were discussed. Plant height, stem ameter, leaf number, leaf area, leaf thickness, chlorophyll content and photosynthesis capability were measured. The results showed that the shading adapability of I. macrovexilla was best, then was I. chinensis and I. obesa. Determination of photosynthetic indexes was more convenient and accurate way to judge shade tolerance. Photosynthetic characteristics of 21 Impatiens species had been tested. Three groups were identified based on light adaptability. Among them, I. siculifer, I. wilsonii and I. chlorosepala have better adaptability, I. claviger, I. yaoshanensis and indeterminate species(XingYi) had worse adaptability. Sorting according to requirement for light was, I. uliginosa>I. tomentella>I. siculifer>I. claviger>indeterminate species(XingYi)>I. wilsonii>I. rhombifolia>I. claviger var. auriculata>I. oxyanthera> indeterminate species(Rong An)>I. ruiliensis>I. chlorosepala>I. macrovexilla var. yaoshanensis>I. apaliphylla>indeterminate species ( Lin Gui ) >I. morsei>I. duclouxii>I. tubulosa>I.malipoensis>I.arguta. The light response curve fitting by equation [Pn=Pmax(1-C0 e-aPFD/ Pmax)] was a fairy ideal model to analyze the whole process of light reponse.5. Based on observation of collecting Impatiens species phenophase, cultivation techniques and control of diseases and insect pests were summarized according to seedling stage, seedling separation stage, seedling formation period and blooming stage. Mode of reproduction included seed propagation, cutting propagation and division propagation. Introduction of 11 species were succeeded. Restriction factors of introduction were tempreture and humidity.6. Tissue culture system of 11 Impatiens species were established. Optimal disinfection way, subculture medium and substrate composition were screened according to different species. Optimal subculture medium of I. platypatala, I. obesa, I. morsei and I. chinensis: MS+6-BA 1.0mg·L-1+NAA 0.1mg·L-1, optimal subculture medium of I. arguta, I. macrovexilla var. yaoshanensis, I. macrovexilla, I. commellinoides and I. oxyanthera: MS+6-BA 1.0mg·L-1+NAA 0.05mg·L-1, Optimal subculture medium of I. rhombifolia and I. ruiliensis: MS+6-BA 0.5mg·L-1+NAA 0.05mg·L-1. Optimal transplanting medium of I. platypatala, I. oxyanthera and I. chinensis: perlite and peat was 2:1, optimal transplanting medium of I.obesa and I. morsei: perlite and vermiculite was 2:1, optimal transplanting medium of I. arguta, I. macrovexilla var. yaoshanensis, I. commellinoides and I. ruiliensis: perlite and vermiculite was 4:1, Optimal transplanting medium of I. rhombifolia: vermiculite and peat was 1:1.7. Different species need different ways of slow growth preservation in vitro. More ideal treatment of all was 4℃, at this tempreture, I. platypatala had been preserved for 270d, I. obesa had been preserved for 210d, I. macrovexilla had been preserved for 240d, and I. chinensis had been preserved for 180d. After transplanting, there were no differences between tissue culture seedling after slow growth preservation and normal seedling on plant height, leaf number and branch number, except treaments of adding mannitol of I. platypatala and I. macrovexilla .8. Shoot tips excised from healthy in vitro plants of I. platypatala and I. obesa were successfully cryopreserved by vitrification. A suitable procedure was established as follows:dissecting shoot tips of 2mm were loaded in a mixture of 2mol·L-1 glycerol plus 0.4 mol·L-1 sucrose for 20min(I. obesa) or 30min(I. platypatala) at 20℃. Following that, a highly concentrated cryoprotective solution (PVS2) was then added at 0℃. After dehydration at 0℃for 30min(I. obesa) or 40min(I. platypatala), the shoot tips were directly plunged into liquid nitrogen. After rapid thawing in a water bath at 40℃for about 60s, the tips were washed twice with 1.8ml of 1.2 mol·L-1 sucrose solution for 10min each time and then transferred onto subculture medium for recovery growth. The highest survival of shoot tips were 19%(I. obesa) or 23%(I. platypatala).