Effects Of Soil Compaction On The Eco-physiological Characteristics Of Urban Greening Trees

In this thesis, three saplings such as Michelia chapensis, Michelia maudiae and Ilex latifola, or three seedlings such as Cinnamomum camphora,Photinia serrulata and Magnolia denudate were taken as reseach materials, to study the effects of soil compaction on eco-physiological characteristics of these saplings and seedlings through different soil compaction gradient simulation, for providing theoretical basis for urban greening trees selection, which is of great practical significance.The main results showed as followings:(1)The leave chlorophyll contents of three saplings and three seedlings decreased as the increasing of the soil compaction level, and the chlorophyll content of three seedlings in middle growth period was higher than that in early and late growth period.(2)The photosynthetic physiological characteristics of six tree species decreased as the increasing of the soil compaction level, and the occuring time and value of diurnal maximum of photosynthetic physiological characteristics varied under different soil compaction levels.(3)The values of hydraulic architecture parameters decreased, while the soil compaction intensity increased, and the values in middle growth period were higher than those in early and late growth period.(4)The content of proline and malondiadehyde showed an increasing trend with the soil compaction intensity increased.(5)The biomass and morphological structures of seedlings'root system including root length, root surfarea, root volume et al were negatively related to soil compaction.(6)By the method of subordinate function, soil compaction resistance ability of saplings and seedlings was analysed, in which soil compaction resistance of saplings and seedlings ranked as Michelia maudiae>Michelia chapensis>Ilex latifola and Cinnamomum camphora >Magnolia denudata>Photinia serrulata respectively.(7)Key indices for soil compaction resistance of saplings and seedlings were ordinated using the grey relation method, showed as net photosynthetic rate>hydraulic architecture parameters>chlorophyll content>malondiadehyde content >proline content, and biomass>net photosynthetic rate>chlorophyll content>the length of roots>hydraulic architecture parameters respectively.