Research On The Physiological Characteristics Of Four Shrubs Species And The Property Of Soil In Nanning

With the increasingly boosting of town building and the rapid increase of the number of automobiles, effects of traffic pollution has become the important portion in our country cities' pollution and imperiled the safe of entironment. It is important to study the effect of traffic pollution on the greening trees pecies and soils for the building of the city environment. This thesis selects samples of soil and the leaf blade of four greening shrubs, namely, Ficus microcarpa, Hibiscu rosasinensis, Schefflera octophylla, Duranta repens cv. goldenleaves from three traffic areas and one clean comparative region for study. Its content included that the study on the change of the physico-chemical properties of the soil and the bio-chemical indexes of the blade samples including net photosynthetic rate, transpiretion rate, chlorophyll content, fluorescent nature of chlorophyll, relative conductivity rate and S,Pb content etc. Besides, profound exploration is conducted in the study of plant's physiological reaction to its growth environment, the physico-chemical properties of the soil and its reaction to traffic exhaust. The result is as following:1. Compared with the comparative experiment area in Heibei plant nursery, the net photosynthetic rate, transpiration rate, chlorophyll content of the four shrub samples in three traffic areas have varying degrees of reduction respectively while the relative conductivity rate rises differently and the fluorescent parameter of chlorophyll is largely influenced by traffic pollution. Among them, the net photosynthetic rate of F. microcarpa fluctuates greatly and its resistance ability is weak. The transpiration rate of H. rosasinensis changes most sharply, that is, it is the most sensitive. With the strongest resistance ability, D. repens cv. goldenleaves has the slightest variations with the least increase of relative conductivity rate. As for the chlorophyll fluorescence parameter, H. rosasinensis has the largest changing rate, followed by S. octophylla, F. microcarpa, D. repens cv. goldenleaves respectively. Therefore, D. repens cv. goldenleaves enjoys the best resistance ability.2. Mostly composed of deep insufficiently cultivated and barren soil unearthed in the process of construction, the green soil subjects to different degrees of influence by the traffic environment. Compared with comparative area, the soil porosity rises, bulk density and pH falls, organic matter content stays at a low level in three main experiment traffic lines. Among them, the effective N and K content of the soil in You'ai Overpass, effective P and total P content in University Road, total N and K content in Minzu Avenue are the lowest.3. The S,Pb content of both the soil and the leaf blade in traffic areas have increased substantially in comparison with that of the comparative area. However, there is no significant correlation between the two. Therefore, it can be suggested that the S,Pb content of the shrub leaf blade mainly does not come from the soil around the root, but from the air, or more specifically, from the sulphur oxide compound or particulate matters containing lead of the automobile exhaust.