The Effects of Airborne Pollutants and Climatic Factors of Different Sections of Tehran Areas on Leaf Characteristics of Oriental Plane (Platanus orientalis L.) Trees

Aims This study was carried out to determine the effects of urban gaseous pollutants (sulfur dioxide [SO2], nitrogen dioxide [NO2], and ozone [O3]) and climatic factors (temperature and precipitation) on the morphological and anatomical reaction of Platanus orientalis L. in Tehran. Materials & Methods Seven districts of this city with a wide spectrum of climatic conditions and diversity of elevation were selected, and gas concentration of SO2, NO2, and O3 was determined. Then, morphological and anatomical parameters of this plant including leaf area, specific leaf area (SLA), wet and dry weight, leaf toughness and thickness, water content, lamina, and main vein were measured and the analysis of their correlations with environmental (climatic and pollutant) factors along with their t-tests were evaluated. Findings The results showed that the climatic factors made significant (P < 0.05) changes on SLA, water content, wet and dry weight of green leaves of this plant. In addition, different levels of pollutant gases had significant (P < 0.05) effects on natural toughness, thickness, wet weight, number of spongy parenchyma layers, and the ratio of lamina mesophyll to subvein of leaves. Conclusion The results explain that anatomical and morphological characteristics of P. orientalis leaves have been influenced by environmental stresses and changes in these factors show the resistance of the plant to the environmental conditions.