Study On Cold Resistance Of Nine Garden Tree Species In Shuozhou

Garden trees,such as shrubs,trees and vines,are suitable to be planted on the urban green space and scenic area.In this paper,we select nine representative garden tree species in the northern area as experimental materials,which are Weigela florida cv.Red Prince,Ulmus pumila cv.jinye,Prunus × cistena,Ulmus pumila L.,Populus simonii,Lonicera maackii(Rupr.)Maxim.,Salix matsudana Koidz.,Fraxinus chinensis and Syringa oblata Lindl..Through setting different artificial low temperature treatment and then recovery test,under the low temperature stress,we get the observation of the germination growth of thetest species and mensurate several important data including relative conductivity,malondialdehyde(MDA.)content,soluble sugar content,soluble protein content,superoxide anion radical(O 2-)generation The rate and protective enzyme(SOD)activity;we ascertain the semilethal temperature by Logistic equation(LT50);we analyze the indexes by using the method of principal component,and then make the comprehensive evaluation of the tree species by both the membership function method and the principal component method.The results are as follows:1,Through analying the physiological and biochemical indexes of the branches of each species with the principal component analysis method.SOD activity,relative conductivity and MDA content have an important relation with the braanches;soluble protein content,soluble sugar content,and O2-production rate are less.2,With the decrease of the stress temperature,the activity of SOD enzyme of the branches of Fraxinus chinensis and Syringa oblata Lindl increased gragually and that of the other species increasd first and then decreased;the relative conductivity of each tree species showed a gradual increase trend.At the same time LT50 of the species is as follows: Weigela florida cv.Red Prince:-26.86??Ulmus pumila cv.jinye:-29.98??Prunus × cistena:-22.64??Ulmus pumila L.:-21.23??Populus simonii:-27.07??Lonicera maackii(Rupr.)Maxim.:-30.04??Salix matsudana Koidz.:-46.49??Fraxinus chinensis:-44.85??Syringa oblata Lindl.:-35.14?;MDA content in the branches of the species showed the same trend of gradual increase.3.Throuth the low temperature treatment,the amplification stages of soluble protein content of the branches of the species are different,Ulmus pumila cv.jinye,Prunus × cistena,Populus simonii,Lonicera maackii(Rupr.)Maxim.,Salix matsudana Koidz.,Fraxinus chinensis and Syringa oblata Lindl.branches gradually increased as the temperature decreased;Weigela florida cv.Red Prince and Ulmus pumila L.increased first and then decreased;the soluble sugar content of the branches of Weigela florida cv.Red Prince,Ulmus pumila cv.jinye,Prunus × cistena,Ulmus pumila L.,Populus simonii,Lonicera maackii(Rupr.)Maxim.,Fraxinus chinensis and Syringa oblata Lindl.increased first and then decreased,only that of Salix matsudana Koidz.branches increased gradually;O2-production rate of the branches of Lonicera maackii(Rupr.)Maxim.,Salix matsudana Koidz.,Fraxinus chinensis and Syringa oblata Lindl.increasd first and then decreased and that of the other species increased gradually.4.Through analying the physiological and biochemical indexes of relative conductivity,MDA content,soluble protein content,soluble sugar content,SOD activity and O2-production rate of the branches of each species with the principal component analysis method and evaluating the cold resistance with the membersh-ip function method,the result is as follows: Salix matsudana Koidz.> Fraxinus chinensis > Syringa oblata Lindl.> Lonicera maackii(Rupr.)Maxim.> Ulmus pumila cv.jinye > Populus simonii > Weigela florida cv.Red Prince> Prunus × cistena > Ulmus pumila L..5.The result of the comparison of the cold hardiness of each species is the same with the result of LT50 and comprehensive evaluation.