Study On Resources And Ornamental Period Of Ornamental Flower Plants Of Four Seasons In Two Universities Of Nanjing

Ornamental flower plants is one of the important plant materials in urban green space construction,and its flowering period has a high ornamental value.However,the research and application of the best ornamental period of ornamental flower plants are mostly focused on the spring,and the research and application of ornamental tree species in summer,autumn and winter are paid less attention to.In order to improve the service quality of green space and extend the ornamental period of community,it is particularly important to study the best ornamental period of ornamental flower plants and configuration mode.Therefore,this study conducted a one-year field survey on the resources and flowering phenology of ornamental flower plants in the greenbelt of universities.In Nanjing Normal University(Suiyuan campus)and Nanjing Forestry University(Xinzhuang campus),107 sample communities dominated by ornamental flower plants are selected by using the center-point quarter sampling of plotless sampling.By analyzing and sorting out the characteristics of the community of ornamental flower plants in the green space of two Nanjing universities and the distribution time of the best ornamental period,the paper summarizes the configuration mode of the community of ornamental flower plants in universities.It can provide some guidance for the whole season application of ornamental flower plants in the green space construction of Nanjing and the selection and collocation of ornamental flower plants in the planning of Nanjing.The main research results of this paper are as follows:(1)In the research of plant community,there are 66 species of the ornamental flower plants in green space of universities,belonging to 22 families and 42 genera,of which there are 37 species of trees,28 species of shrubs and 1 specie of climbing plant.The species are relatively rich,mainly concentrated in Rosaceae(22 species in 10 genera),Oleaceae(6 species in 5 genera),Leguminosae(6 species in 4 genera),Magnoliaceae(7 species in 3 genera),Caprifoliaceae(7 species in 3 genera).The family of ornamental flower plants is more concentrated,but the genus is more dispersed.Among the species of ornamental trees,there are 36 species of native tree species,accounting for 55%of the total.The flower color are dominated by white(39%)and pink(26%),the spend appearance are dominated by dense flower phase(39%),cluster flower phase(18%)and covered flower phase(17%),showing strong floral sense and high ornamental value.(2)By summarizing the important values of arbor and shrub layers in the two universities,the dominant species of ornamental flower shrub are Osmanthus fragrans(1 4.3),Chimonanthus praecox(1 3.2),Deutzia scabra var candidissima(8.8),Cercis chinensis(8.5)and Punica granatum(8.3),they have higher prioritization rank in the important values ranking of shrub layer.In the important values ranking of arbor layer,the trees in front of rank are mainly street trees and shade trees which with a large volume,and the ornamental flower arbor are generally in the back,among which Magnolia grandiflora(7.6),Prunus cerasifera Ehrhar f.atropurpurea(6.4),Magnolia denudata(6)are the dominant species of ornamental flower arbor.Distribution of important values in tree and shrub layers is uniform,it indicates that the community landscape of ornamental flower plants in green land of universities is relatively rich,especially in the middle and lower landscape level,but the influence of ornamental flower plants on the overall appearance and structure of the community is limited.By comparing the ranking of the important values in the different functional divisions of the two universities,it is found that the two universities have their own plant configuration characteristic,while the campus of Nanjing Forster University has no unified style and has a high landscape richness.Nanjing Normal University campus has a unified style,different functional areas also have their own landscape characteristics.(3)The best ornamental period of ornamental flower plants is mainly 11-20 days and 21-30 days.The species with a ornamental period longer than 50 days are Hibiscus syriacus(101),Lonicera fragrantissima(98),Chimonanthus praecox(67).Cassia bicapsularis(62),Lagerstroemia indica(60).According to the classification of seasons,there are 54 species(83%)of spring flowers,with the dominant spend appearance of cluster and dense flower phase,and the dominant flower color is white and pink.In summer,there are 9 species of ornamental flower plants,with the dominant spend appearance of covered,cluster and dense flower phase,and the dominant flower color are pink and yellow.In autumn,there is only one kind of Osmanthus fragrans,which with yellow flower and scattered flowers phase.In winter,there is three species of ornamental flower plants,with the dominant spend appearance of scattered and line flower phase,and the dominant flower color are white and yellow.The two universities have different flower landscapes in four seasons,among which the Nanjing Forest University has formed the characteristic spring flower landscape with Cerasus yedoensis,Prunus cerasifera Ehrhar f.atropurpurea,Magnolia denudata and Magnolia soulangeana.Nanjing Normal University has formed the characteristic winter flower landscape with Camellia japonica,Chimonanthus praecox,Armeniaca mume,Lonicera fragrantissima.However,on the whole,the green flower landscape of the two universities was successfully constructed in spring,summer and winter.There are many faults or weak periods in autumn flower landscape,and the application of ornamental trees in autumn is neglected.(4)The most abundant ornamental flower plants in the green space of two universities are Osmanthus fragrans(35),Chimonanthus praecox(23),Prunus cerasifera Ehrhar f.atropurpurea(20)Magnolia grandiflora(19),Magnolia denudata(16),Malus halliana(15),Lagerstroemia indica(14)and Magnolia soulangeana(12),each with common associated species,among which Osmanthus fragrans has good associated relations with other main ornamental flower plants.Based on the analysis of the abundance and importance value of ornamental flower plants,it can be seen that the configuration combination of Magnolia grandiflora+Osmanthus fragrans+Chimonanthus praecox,Prunus cerasifera Ehrhar f.atropurpurea+Osmanthus fragrans,Magnolia denudata+ Osmanthus fragrans is formed in the green space of two universities.Based on this,combined with the distribution table of the best ornamental period for ornamental flower plants,this paper puts forward three configuration modes with ornamental flower plants as the main according to the different characteristics of sectorization in universities,and puts forward suggestions for the plant configuration of green space in colleges.