Effects of Dust on Morpho-physiological Responses of Fraxinus rotundifolia Mill. Seedling

The aim of this study was to evaluate the impacts of dust on the morpho-physiologial traits of Fraxinus rotundifolia Mill. seedling, a useful species in urban green space. In a greenhouse, a dust stress was applied using dust simulator with concentrations of 0, 750 and 1500 μg m-3. Experiment was conducted by a completely randomized design with 5 replicates (9 seedlings in each replicate) within 45 days with one-week interval.) . Dust deposition with 1500 µg m-3 concentration caused the appearance of symptoms of chlorosis and necrosis on leaves. This concentration decreased the amount of survival (29%), increment diameter (38%) and height (33%), average leaf area (19%), photosynthesis rate (45%), transpiration (60%), stomatal conductance (46%), mesophyll conductance (55%), spad index (23%), Fm (22%), Fv/Fm (22%), T1/2 (14%)increased intercellular CO2 concentration (22%), water use efficiency (40%), leaf temperature (2.34 oC) and Fo (30%).  For afforestation and tree planting initiatives in dust-polluted areas of urban and suburban regions of Iran,  F. rotundifolia seedling can be usefully used in areas where dust concentration is less than 750 μg m-3.