Ornamental Characteristics Evaluation And Garden Application Analysis Of Impatiens In Middle And Low Altitude Areas Of Guangxi

The genus Impatiens L.belongs to the Family Balsaminaceae A.Rich.Members of the genus Impatiens are primarily annual or perennial herbs with few shrubs or subshrubs.More than 1,000 species occur worldwide,mainly in tropical and subtropical environments,with some in northern temperate regions.China is one of the important bio-diversity distribution areas of the genus Impatiens,rich in wild germplasm resources.However,only Impatiens balsamina L.,I.walleriana Hook.f.,I.hawkeri W.Bull,and I.usambarensis Grey-Wils.are used in the landscape trade.The rest of the genus Impatiens of China are not well known.Therefore,this study focuses on the perennial species of the genus Impatiens in Guangxi in the middle to low-altitude areas（alt.>1000 m）.Based on the research of germplasm resources,introduction and cultivation tests and tissue culture tests,the ornamental characteristics evaluation and garden application analysis of Impatiens in middle and low altitude areas of Guangxi were carried out.It is expected to provide theoretical support and data reference for the development of garden horticulture and the garden application mode of Impatiens.1.Based on field explorations,literature and specimen review,57 species（including subspecies）of Impatiens in Guangxi were obtained.The habitats of the genus Impatiens in Guangxi were grouped into three types,namely,wet type,rock type,and cave type.;The horizontal distribution pattern of the genus Impatiens in Guangxi generally shows more in the west and less in the east,more in the north and less in the south,and more in the inland areas and less in the coastal regions.And the altitude of200-800m is the most bio-diversity distribution vertical space.2.36 species were found in the middle-low altitude areas of Guangxi were selected for introduction and cultivation tests.The results indicate that 29 species were introduced and survived,17 of which have potential for landscape use.The main limiting factors for introduction and cultivation tests were temperature and humidity.3.Tissue culture system of 5 Impatiens species were established.Optimal disinfection way,subculture medium and transplanting medium were screened according to different species.（1）Optimal disinfection way of I.pingxiangensis,I.polyneura and I.angulate:75%alcohol 30 s+10%NaClO 15 min;Optimal subculture medium of I.pingxiangensis,I.polyneura and I.angulate:MS+6-BA 1.5 mg·L^-1+NAA 0.1 mg·L^-1.（2）Optimal disinfection way of I.damingensis and I.macrovexilla var.yaoshanensis:75%alcohol 30 s+10%NaClO 10 min;Optimal subculture medium of I.damingensis and I.macrovexilla var.yaoshanensis:MS+6-BA1.0 mg·L^-1+NAA0.1 mg·L^-1.（3）Optimal transplanting medium of I.damingensis:vermiculite and peat was 1:1;optimal transplanting medium of I.macrovexilla var.yaoshanensis:peat and perlite was2:1.4.Comprehensive ornamental evaluation criteria of 31 species of Impatiens in middle and low altitude areas of Guangxi,by DTOPSIS method and grey relational degree analysis based on entropy weight.13 species of which with higher ornamental and exploitation value were selected,including I.macrantha,I.hunanensis,I.hunanensis,etc.5.According to the conclusion of the above study and the characteristics of their ornamental period,habitat types and biological characteristics.The garden applications of the Impatiens can include potted plants,hedges,flower borders,road greening,and barge greening.Specialized botanical gardens can be divided into medicinal plant specialty gardens and rock gardens,according to their application value and habitat type.