Common In Small Trees And Shrubs Broadleaf Photosynthetic Characteristics Of Garden Trees In Nanjing And The Related Ecological Functions

Taking Nanjing city common 22 kinds of broadleaf trees and small garden shrub species for the study,the use of LI-6400XT photosynthesis measurement system,measuring the test species in the net photosynthetic rate and transpiration rate,based on the analysis of photosynthetic species properties;combined with leaf area index,calculated and analyzed their oxygen capacity of carbon fixation and cooling humidification capacity,divided according to the level of classification of species and ecological functions,in order to select for the garden construction and configuration of Nanjing trees provide a scientific basis.The main results of the study are as follows:1.leaf area index for the test species vary greatly;index based on the size of the sort can be divided into third gear,the leaf area index greater than 4.50 mosquito species are female,Pittosporum,Elaeagnus,gardenia;leaf area index 3.00-4.49 there are sweet-scented osmanthus,Bauhinia,Photinia,privet,Euonymus,sea Xianhua,bloom,heather,wood hydrangeas,pomegranate,apricot,loquat,bayberry,coral tree,rubrum,Euonymus;LAI there are less than 2.99 Zhuahuai,smiling.From the green point of view,the total leaf area was significantly higher than small trees shrubs.2.The test trees net photosynthetic rate,diurnal variation of transpiration rate are unimodal and bimodal curve curved type;and both are oriented in a single peak.Summer net photosynthetic rate,transpiration rate was higher than the number of bimodal species other seasons.Seasonal changes in the test species in the photosynthetic rate,showed more spring than in other seasons,the lowest in winter;spring is the description most productive period for the test species photosynthesis.Seasonal variation in transpiration rate,showing more summer than other seasons,winter transpiration rate lowest in spring and autumn,the trees closer.Carbon Fixation and Oxygen Release 3.The ability of the test species generally showed the highest spring;carbon sequestration and oxygen release capacity of the lowest in winter.Of course,there are six kinds of high autumn trees release carbon fixation and oxygen capacity.Comprehensive test species in the growing season of carbon fixation and oxygen release capacity size,clustering can be divided into three files,carbon sequestration and oxygen release ability of the deciduous trees have Zhuahuai,pomegranate,Bauhinia;evergreen species loquat,heather,Elaeagnus,smiling,Photinia.Moderate deciduous trees have bloom,apricot,wood hydrangeas;evergreen species are privet,mosquito mother,coral trees,Pittosporum,rubrum,Euonymus.Deciduous tree species are less able Euonymus,sea Xianhua;evergreen species are red bayberry,sweet-scented osmanthus,gardenia.4.In addition to the sea Xianhua,the other 21 kinds of tree species for ecological effect showed up in summer;the lowest in winter.Summer on single-species comparative analysis of the ability to cool humidifiers available:small evergreen tree in the cooling capacity humidifier strong performance has heather,loquat,privet;evergreen shrubs,there is a strong Elaeagnus,Pittosporum.Small deciduous tree in strong humidification cooling capacity is Zhuahuai;deciduous shrub,the stronger is the Bauhinia.Comprehensive test species in the growing season humidification cooling capacity size,clustering can be divided into three files,cooling humidification ability of deciduous tree species Bauhinia,Zhuahuai,apricot,Euonymus;evergreen species are Elaeagnus son,Pittosporum.Moderate deciduous trees have wood hydrangeas,pomegranate,bloom,sea Xianhua;evergreen species loquat,heather,mosquito mother,privet,loquat,Photinia,Euonymus,rubrum.The ability to lower species are evergreen species are osmanthus,gardenia,smiling,coral tree,bayberry.5.The test species summer water use efficiency was the lowest.Most evergreen trees in winter maximum water use efficiency;the basic performance of deciduous trees in spring water maximum utilization.Water use efficiency is generally higher than evergreen species of deciduous trees.Tree water use efficiency based on the level,you can cluster analysis three categories:one species have higher water use efficiency bayberny,Euonymus japonicus,sweet-scented osmanthus,mosquito mother,heather,coral tree;there are two types of tree species Pittosporum medium WUE Photinia,privet,Elaeagnus,loquat,pomegranate,smiling;the rest are three species,water use efficiency is low,mostly deciduous trees.