A Thesis Presented To Basic Ecological Benefits And Photosynthetic Characteristics Of Main Vertical Greening Tree Species In Nanjing Area

Landscaping plants,especially woody plants,play an important role in improving the ecological environment of the city.In this paper,thirteen kinds of vertical tree species commonly used in Nanjing were selected.The net photosynthetic rate,transpiration rate,and light response curve were used to determine the differences in photosynthetic physiology characteristics,and the amount of carbon fixation and oxygen release,and the temperature and humidity were calculated.Quantitative data on basic ecological benefits such as quantity and water use efficiency.It can provide theoretical and practical basis for the planning and configuration of vertical greening tree species in Nanjing and the construction of ecological gardens.The main results are as follows:1.The net photosynthetic rate of the tested tree species varied greatly.Most of them showed obvious midday depression in summer.The other three seasons differed according to plant species.Most tree species have the highest transpiration rates in summer and the lowest in winter.2.The daily average carbon fixation and oxygen release ability of the tested tree species was as follows:Evergreen was Changchun linseed vine>Euonymus fortunei>honeysuckle>Yunnan Huangxin>Manchun>Ivy>Collateral stone;defoliation was wisteria>Mutong>climbing tiger>Roses of the Chinese vine>The American flag of the United States>Multi-flowered roses.The annual ranking of evergreen vertical greening tree species is Changchun Younpengtan>Euonymus fortunei>Honeysuckle>Yunnan Huangxin>Ivy>Manchunchun>Collaterals;The annual ranking of deciduous vertical greening tree species is Mouton>Wisteria>Parthenocissus>Rumex>American Lingxiao>Multi-flowered rose.The total amount of fixed carbon released by the year is roughly that of evergreen tree species that perform better than deciduous tree species.3.The overall cooling and humidification capacity of the tested tree species can be divided into three categories:honeysuckle and manchun are strong in evergreen tree species;Changchun Youmaitun,Yunnan Huangxin and collateral stones are the most capable tree species;Such as ivy.The deciduous tree species have strong ability of the United States Ling Xiao,Ivy creeper;medium-capacity species of trees are rattan rose,wisteria;weaker species are wisteria,more flower roses.The water use efficiency of evergreen vertical greening tree species was highest in winter and lowest in summer;the water use efficiency of deciduous tree species was mostly highest in autumn.5.The LCP,LSP,and AQY values of the measured objects were calculated based on the light response curves of the tested vertical planting tree species.It was found that the utilization efficiency of light energy of the leaves of Changchun lianashua and rattan rose is relatively high,and the ability to use weak light is also relatively high.Strong,the rest of the tree speeies are relatively weak in the use of weak light.6.Based on the extraction of leaf samples for determination of photosynthetic pigment content,combined with the comparison of net photosynthetic rate,it was found that the higher the chlorophyll content,the more beneficial the tree species can effectively absorb light energy in the low light environment and have stronger photosynthetic capacity.