Investigation On Native Ornamental Grasses In Fujian And Evaluation Of Ecological Functions Of Three Ornamental Grass Species

Our country pays more and more attention to the construction and protection of ecological environment and a series of related policies and regulations have been issued.Under the background of this era,sponge city came into being.The application of natural plants is one of the important ways to improve ecological environment in sponge cities.Ornamental grasses have aesthetic value,ecological value and humanistic value,which are very suitable for the construction of sponge city.At present,ornamental grasses have not been widely used in the south of China.If the resources of ornamental grasses in Fujian province are investigated and utilized,it will not only enrich modern urban landscape and improve ecological benefits,but also be of great help to promote the development of local ornamental grasses industry in Fujian province.Therefore,based on the investigation and understanding of the current situation of local ornamental grass resources in Fujian province,3 ornamental grass species of Eragrostis pilosa,Cymbopogon citratus and Jrundo were primarily selected.Starting from the requirements of sponge city,the ecological functional characteristics of those ornamental grasses above were investigated in terms of water absorption and storage,water resistance,water purification and water release.The main results are as follows:1.The water absorption and storage capacity were explored and were found that the capacity of water absorption and storage of the 3 ornamental grass species is:A.donax>E.pilosa>C.citratus.2.In terms of water resistance,the change regulation of morphological and physiological indexes of 3 ornamental grass species under different water stress were studied.It was found that the water resistance of the 3 ornamental grass species is:A.donax>E.pilosa>C.citratus.3.In terms of water purification capacity,the purification effects of 3 ornamental grass species which are in 3 kinds of planting mediums on the 5 materials of TOC,TN,Fe,Zn and P in water were studied.It was found that all 3 ornamental grass species were suitable for planting in the mediums of perlite and vermiculite.The purification rates for Fe and P in this kind of planting medium were higher with ranging from 60%to 95%than others.Among them,A.donax was the best for Fe and P,with the highest values reaching 94.27%and 86.74%respectively.4.In terms of water release capacity,the water use efficiency was mainly used to characterize the water release capacity of the 3 ornamental grass species.It was found that the daily variation of water use efficiency of the 3 ornamental grass species was not significant.Since the water use efficiency is mainly influenced by net photosynthetic rate,the maximum daily variation of net photosynthetic rate of A.donax(6.71 μmol·m-2·s-1)is higher than that of E.pilosa(5.08 μmol·m2·s-1)and C.citratus(3.05μmol·m2·s-1),so it is inferred that the water release capacity of the 3 ornamental grasses:A.donax>E.pilosa>C.citratus.The 3 ornamental grass species have different characteristics.All of those ornamental grasses above are suitable for the needs of sponge city construction under different conditions and have good prospects for development.