Sulfur Dioxide Absorption And Accumulation Research On Main Landscaping Plants In Yan’an, Shaanxi

This paper took main twenty-seven landscape plants included thirteen broad-leaved trees, six broad-leaved shrubs,five conifers and three lianas in Yan’an as studying objects. Through the methods of field survey and lab analysis, sulfur content in leaves, the leaf anatomical structures(thickness of leaves, thickness of upper epidermis, thickness of lower epidermis, cuticle thickness of upper epidermis, cuticle thickness of lower epidermis, thickness of palisade tissue, thickness of spongy tissue, thickness of vein, stoma length, stoma width, stoma density and so on), and physiological and biochemical characteristics(chlorophyll content MDA content and membrane permeability) were measured systematacially. The sulfur absorption and accumulation ability of different plants in different polluted areas were evaluated comprehensively by nephelometry and variance analysis, on the basis of the analysis, principal component analysis and membership function were used to screened the leaf anatomical structures indexes of the sulfur absorption ability, and analysed the seasonal trends of different plants’ physiological and biochemical characteristics in different sulfur pulluted areas. The results showed that:1. The sulfur absorption and accumulation ability of different greening plants were significantlt different, while the same kind of plant exist difference in in different polluted area. Among them, The sulfur absorption and accumulation ability of Salix babylonica and Salix matsudana is the strongest, while the sulfur absorption and accumulation ability of Picea asperata,Platycladus orientalis and Pinus bungeana is the lowest.2. After analysed the leaf anatomical structures of ten broad-leaved trees and nine shrubs & lianas, screened the leaf anatomical structures indexes of sulfur absorption ability by principal component analysis, combined with the order of average sulfur absorption ability and the membership function methods to validate. The thickness of leaves, thickness of palisade tissue,stoma density,thickness of upper epidermis those four indexes could be the indicators of broad-leaved trees’ sulfur absorption ability; thickness of leaves, thickness of palisade tissue, stoma size, thickness of vein, thickness of vascular bundle those five indexes could be the indicators of shrubs & lianas’ sulfur absorption ability.3. Combined the greening plant leaf physiological and biochemical characteristics in different pollution area and the order of average sulfur absorption capacity, the results showed that the weaker sulfur absorption capacity, the less stress form SO2, the more chlorophyll content, and vice versa, the less, which chlorophyll content can be the standard to determine sulfur absorption capacity of plants; the relationship between MDA content and sulfur absorption capacity is more complicate, therefore, MDA content cannot be the standard to determine sulfur absorption capacity of plants; plant cell membrane permeability has certain atmospheric SO2 concentration sensing range, and SO2 stress have impacts on plant membrane permeability. The relationship between cell membrane permeability and the sulfur absorb ability of plants needs further research.