Drought Resistance Research On Main Landscape Plants In Yan’an Urban Area

Researching and choosing appropriate landscape plants have important theoretical andpractical significance to build urban forest ecological system in different regional cities.Thispaper took the main landscape plants which included thirteen broad-leaved tree species, tenbroad-leaved shrub species and five conifer species in Yan’an urban area as studying objects.Through the methods of field survey and lab analysis, the leaf anatomical structures(thickness of leaves, thickness of upper epidermis, thickness of lower epidermis, cuticlethickness of upper epidermis, cuticle thickness of lower epidermis, thickness of palisadetissue, thickness of spongy tissue, thickness of vein, stoma length, stoma width, stoma densityand so on) and water eco-physiological characteristics (diurnal course of photosynthetic rate,diurnal course of transpiration rate, diurnal course of water utilization efficiency, diurnalcourse of water potential, water loss rate of excised leaves, water saturation deficit) were measuredsystematacially.On the basis of the analysis, the drought resistances of eight broad-leaved treespecies and eight broad-leaved shrub species were evaluated comprehensively by membershipfunction. The results provided theoretical reference for choosing garden plants in the arid andsemiarid region. The main results were as follows:1. The leaf anatomical structures of thirteen broad-leaved tree species and tenbroad-leaved shrub species were observed and the drought resistances between species wereevaluated by membership function. The results showed that the drought resistance capabilityof thirteen broad-leaved tree species was in the order of Sophora japonica f. pendula>Prunusserrulata>Fraxinus>Sophora japonica>Prunus cerasifera cv. Atropurpurea>Ailanthusaltissima>Salix matsudana>Acer truncatum Bunge>Koelreuteria paniculata>Euonymusmeaackii>Amygdalus persica>Salix babylonica>Prunus persica var. duplex; The droughtresistance capability of ten broad-leaved shrub species was in the order of Chaenomelesspeciosa>Forsythia viridissima>Amygdalus triloba>Syringa oblata>Ligustrum vicaryi>Rosa chinensis>Forsythia suspensa>Hibiscus syriacus>Buxus sinica>Berberis thunbergiicv. Atropurpurea.2. The analysis of diurnal average water potential showed that the drought resistancecapability of twelve broad-leaved tree species was in the order of Prunus cerasifera cv.Atropurpurea>Amygdalus persica>Prunus persica var. duplex>Euonymus meaackii >Ginkgo biloba>Sophora japonica>Sophora japonica f. pendula>Koelreuteria paniculata>Salix matsudana>Prunus serrulata>Salix babylonica>Ailanthus altissima; The droughtresistance capability of eight broad-leaved shrub species was in the order of Chaenomelesspeciosa>Syringa oblata>Amygdalus triloba>Rosa chinensis>Ligustrum vicaryi>Hibiscussyriacus>Forsythia viridissima>Forsythia suspensa;The drought resistance capability of fiveconifer species was in the order of Platycladus orientalis cv. sieboldii>Juniperus chinensis cv.kaizuka>Platycladus orientalis>Picea asperata>Pinus bungeana. The analysis of diurnalamplitude of water potential showed that the drought resistance capability of twelvebroad-leaved tree species was in the order of Prunus cerasifera cv. Atropurpurea>Amygdaluspersica>Euonymus meaackii>Ginkgo biloba>Sophora japonica>Koelreuteria paniculata>Prunus persica var. duplex>Sophora japonica f. pendula>Salix matsudana>Ailanthusaltissima>Prunus serrulata>Salix babylonica; The drought resistance capability of eightbroad-leaved shrub species was in the order of Chaenomeles speciosa>Amygdalustriloba>Ligustrum vicaryi>Rosa chinensis>Hibiscus syriacus>Syringa oblata>Forsythiaviridissima>Forsythia suspensa; The drought resistance capability of five conifer species wasin the order of Platycladus orientalis cv. sieboldii>Picea asperata>Platycladusorientalis>Pinus bungeana>Juniperus chinensis cv. kaizuka.3. The comparison of water loss rate of excised leaves(water retention capacity) showed thatthe drought resistance capability of twelve broad-leaved tree species was in the order ofGinkgo biloba>Amygdalus persica>Euonymus meaackii>Prunus cerasifera cv.Atropurpurea>Prunus serrulata>Koelreuteria paniculata>Sophora japonica>Salixmatsudana>Salix babylonica>Sophora japonica f. pendula>Ailanthus altissima; Thedrought resistance capability of eight broad-leaved shrub species was in the order ofForsythia viridissima>Ligustrum vicaryi>Rosa chinensis>Chaenomeles speciosa>Forsythiasuspensa>Amygdalus triloba>Hibiscus syriacus>Syringa oblata;The drought resistancecapability of five conifer species was in the order of Pinus bungeana>Platycladusorientalis>Platycladus orientalis cv. sieboldii>Picea asperata>Juniperus chinensis cv.Kaizuka. The comparison of water saturation deficit showed that the drought resistancecapability of twelve broad-leaved tree species was in the order of Salix babylonica>Salixmatsudana>Prunus serrulata>Euonymus meaackii>Koelreuteria paniculata>Sophorajaponica>Sophora japonica f. pendula>Amygdalus persica>Ginkgo biloba>Ailanthusaltissima>Prunus cerasifera cv. Atropurpurea; The drought resistance capability of eightbroad-leaved shrub species was in the order of Rosa chinensis>Forsythiaviridissima>Ligustrum vicaryi>Syringa oblata>Forsythia suspensa>Hibiscussyriacus>Chaenomeles speciosa>Amygdalus triloba; The drought resistance capability of five conifer species was in the order of Pinus bungeana>Juniperus chinensis cv. kaizuka>Platycladus orientalis>Picea asperata>Platycladus orientalis cv. sieboldii.4. The diurnal courses of photosynthesis of eight broad-leaved tree species and eightbroad-leaved shrub species were measured. The daily course curve of photosynthetic rate andtranspiration rate was single peak or double peak type. The comparisons of water utilizationefficiency showed that the drought resistance capability of eight broad-leaved tree species wasin the order of Prunus serrulata>Koelreuteria paniculata>Sophora japonica f.pendula>Sophora japonica>Ailanthus altissima>Amygdalus persica>Euonymus meaackii>Prunus cerasifera cv. Atropurpurea; The drought resistance capability of eight broad-leavedtree species was in the order of Forsythia viridissima>Syringa oblata>Rosachinensis>Hibiscus syriacus>Amygdalus triloba>Forsythia suspensa>Ligustrum vicaryi>Chaenomeles speciosa.5. Combined with leaf anatomical structures and water eco-physiological characteristics,the drought resistances of eight broad-leaved tree species and eight broad-leaved shrubspecies were evaluated comprehensively by membership function. The results showed that thedrought resistance capability of eight broad-leaved tree species was in the order of Prunuscerasifera cv. Atropurpurea>Prunus serrulata>Sophora japonica f. pendula>Sophorajaponica>Koelreuteria paniculata>Amygdalus persica>Euonymus meaackii>Ailanthusaltissima; The drought resistance capability of eight broad-leaved shrub species was in theorder of Rosa chinensis>Chaenomeles speciosa>Forsythia viridissima>Amygdalustriloba>Ligustrum vicaryi>Syringa oblata>Hibiscus syriacus>Forsythia suspensa.