Salt Tolerance Identification And Evaluation System Construction Of Common Garden Trees In North China

In saline-alkali area,soil salinization limits the growth of plants,and the species of garden plants are few,and the resources are poor,which makes it more difficult for garden greening.Therefore,the establishment of evaluation system of salt tolerance of garden plants,screening of saline-alkali tolerant garden plants and its application in landscape greening of saline-alkali land are very important,which can provide the basis for the selection of landscaping tree species in saline-alkali areas in order to maintain biodiversity and ecological stability.In this paper,18 kinds of common garden greening plants in northern China were selected to carry out salt and alkali stress at seedling stage of plants.The traditional experiments were carried out from the treatment mode and time of salt stress of garden plants,the evaluation index of plant salt tolerance and data analysis.The changes of 29 indexes related to plant growth morphology and physiology under saline-alkali stress were analyzed.The salt-alkali tolerance of plants was comprehensively evaluated by fuzzy membership function and cluster analysis.By using correlation analysis,principal component analysis and grey correlation analysis,the indexes with high correlation degree with salt-alkali tolerance were selected,and the evaluation system of salt-alkali tolerance was established.It provides theoretical support for the screening and application of landscaping plants in saline-alkali areas of northern China.The results show that:?1?In terms of growth and physiological indexes,the survival rate,plant height,ground diameter and other indexes of 18 species of plants showed obvious response with the increase of salt-alkali stress,but the degree of response varied with different plant species.It is not scientific to use a single index to evaluate salt-alkali tolerance and to rank salt-alkali tolerance,so the comprehensive evaluation method is adopted.?2?The salt-tolerant plants was evaluated by using the fuzzy membership function of 29indexes.The order of salt tolerance of plants was:Ulmus pumila>Platycladus orientalis>Wisteria sinensis>Robinia pseudoacacia>Chimonanthus praecox>Link Forsythia suspensaali>Ginkgo biloba>Pyracantha fortuneana.The sequence of plant alk tolerance was:Ulmus pumila>Ginkgo biloba>Robinia pseudoacacia>Chimonanthus praecox>Platycladus orientalis>Wisteria sinensis>Pyracantha fortuneana>Link Forsythia suspensa.Through cluster analysis,the classification of salt-tolerant plants showed that Ulmus pumila?Platycladus orientalis belonged to strong salt-tolerant plant grade,and Wisteria sinensis belonged to more salt-tolerant class.Robinia pseudoacacia belongs to salt-tolerant,Chimonanthus praecox belongs to slight salt-tolerance,Link Forsythia suspensaali?Ginkgo biloba?Pyracantha fortuneana belong to salt-tolerant plant grade;Ulmus pumila?Ginkgo biloba belongs to the class of alkali-resistant plants,Robinia pseudoacacia?Chimonanthus praecox belong to the more alkali-tolerant plants Grade,Platycladus orientalis belongs to slight alkali-resistant plant grade,Wisteria sinensis?Pyracantha fortuneana?Link Forsythia suspensa.belongs to alkali-resistant plant grade.?3?In the process of establishing the evaluation system,on the basis of fuzzy membership function,K⁺/Na⁺in leaves and Na⁺in leaves and in roots Cl^-,in roots were screened out from29 salt tolerance indexes of 8 species by correlation analysis,principal component analysis and grey correlation analysis.Proline,Mg²⁺in leaves,Ca²⁺in roots,Na⁺in stems,and succulence in leaves were highly correlated with the membership function values of salt tolerance indexes in plants.The fuzzy membership function was used for further verification,and it was found that the screening indexes could reflect the sequence of salt-alkali tolerance in plants in an all-round way,so these indexes constituted the evaluation system.