EXPERIMENT TO SHOW THAT CO2 IS ESSENTIAL FOR PHOTOSYNTHESIS.

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 •  Take two healthy potted plants, almost of the same size. 

•  Keep them in a dark room for three days. 

•  Now, place each plant on separate glass plates. 

•  Cover both plants with separate bell-jars as shown in. 



















• Keep petri dish containing potassium hydroxide and place it in inside one of the jars. Potassium hydroxide is used to absorb CO2. 

•  Make the set up airtight by applying molten wax at the point of the bell jars meeting the glass plates. 

•  Place the plant in sunlight for two hours. 

• After 3-4 hours, remove a leaf from each plant and check for the presence of starch as in the above activities. 

•  Conclusion-  The leaf which had no carbon does not turn blue . The leaf containing CO2 does turn blue ad starch was produced in those leaves only. This suggest that carbon dioxide gas is necessary for photosynthesis. 


                    THANKS

•  Question-  Do both the leaves show the presence of the same amount of starch.? 


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