Effects of Smog on Photosynthetic Activity：对光合活性的烟雾的影响.pptVIP

Effects of Smog on  Photosynthesis Photosynthesis Plants convert carbon dioxide and water into carbohydrates using the energy of light, and release oxygen. Smog A smoky fog emitted by various industries, and released into the surrounding environment. Two types of smog: 1) Industrial and 2) Photochemical Industrial smog Produced by burning of carbon compounds or coal Made of sulfur oxides and particulate matter Photochemical smog Produced by auto emissions: Nitric oxide (NO), carbon dioxide (CO2), and hydrocarbons (HC) Reactions of these chemicals in the atmosphere produce: Nitric acid or acid rain (HNO3), formaldehyde, and ozone (O3) Ozone reacts with other pollutants to form secondary pollutants,such as peroxyacyl nitrates (i.e. PANs) The Problem with SMOG Not limited to large cities Smog travels halfway around the globe! Did you know? Smog alert for Statesboro (1999). Photochemical Smog and Photosynthesis Causes two main problems for plants: 1) Ozone destroys the leaves of plants because it acts as an oxidizing agent 2) Filtered sunlight limits amount of photosynthesis, which is crucial for plants Photosynthesis in chloroplasts Our Goals To replicate the effects of smog on photosynthetic activity To test the relationship between different levels of light intensity, and the rate of photosynthetic activity. Methods Plants (in the form of chlorophyll) Light source Filters (to simulate smog) How do we measure photosynthetic rate? Dichlorophenol-indophenol (DCPIP) DCPIP reduced (electrons) = colorless = NADPH DCPIP oxidized (no electrons) = blue = NADP Procedure To measure the change in concentration of the blue dye using a spectrophotometer This change in color will allow us to quantify the amount of photosynthesis taking place. See procedure in lab manual Continued Each lab bench will have progressively highly filtered light sources (to simulate higher rates of smog). Light intensity is already defined for each bench. The Spectrop