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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.                     ...
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To demonstrate that chlorophyll is necessary for photosynthesis.

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 •  First of all take a potted plant, like croton, which has variegated leaves,  i.e partly green and partly non- green.  •  Now keep the plant in a dark place for about three days so that all starch gets used up.  Now keep the plant in bright sunshine for three to four days.  •  Pluck a leaf from the plant and mark the green area in it and trace them on a sheet of paper. Now the leaf is boiled in water and then immersed in warm 90% alcohol solution, so the green parts of the leaf get decolourised.                                                          •  After washing the leaf in water, pour some iodine solution over the colourless leaf and observe the change in colour of the leaf and compare this with the tracing of the leaf done in the beginning.              ...
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Sunlight necessary for photosynthesis

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  To show that sunlight is necessary                     for photosynthesis.        Let's we do a experiment.  We will now perform a activity that show  sunlight is  necessary for photosynthesis. By the end of this activity we will show that leaves finally make starch  as food by photosynthesis.  •  Take a potted plant with green leaves.  •  Place it in a dark room for 3 days, so that all the starch is used up by the leaves.  •  Cover a part of leaf of the plant with aluminum foil or black paper.  •  Now keep the plant in sunlight for about six hours.  •  Pluck the partially covered leaf from the plant and remove the foil.  •  Boil the leaf in water to denature the enzymes. Now boil the leaf in water until flaccid and then imersed it in warm 90% alcohol solution until decolourised. Thus leaf will become colurless.    ...
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