Experiments of photosynthesis

Conditions necessary for photosynthesis:

Sunlight Chlorophyll Carbon Dioxide Water

Basis of Experiments:

Plants make starch as their food. Starch gives a blue black colour with iodine We destarch the leaves by keeping it in a dark room for about 3 days.

Sunlight necessity experiment

Importance Of Light Photosynthesis Experiment (image/jpeg)

Destarch the leaf. Cover the centre part of leaf with aluminium foil or black paper. (seal tightly so that sunlight can not enter) Keep for 3 - 4 days then pluck out the leaf and remove the foil. Boil the leaf in water to break the cell membrane and make it permeable. Keep it in alcohol and give a water bath. (since alcohol is flammable and can not be heated directly.) Wash with warm water and keep in a petri dish. Pour iodine solution.

Observation & Conclusion

Observation The uncovered part of leaf turns blue black but the covered part remains the same.

Result Sunlight is necessary for photosynthesis. Leaves make starch as a food by photosynthesis

VARIEGATED LEAVES

Geranium Leaves 2 Opt (image/jpeg)

A variegated leaf is a leaf which has both green and non-green parts.

croton(left) & coleus(right)

Croton Poster (image/jpeg)

Coleus 1 (image/jpeg)

Chlorophyll necessity experiment

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Destarch a plant with variegated leaves (like croton) . Keep in bright sunshine  for 3 - 4 days. Mark the boundries of non green parts (so as to differentiate between green and non green parts after leaf loses its colour) Boil the leaf in water. Keep in alcohol and give a water bath. Wash it in hot water. Dip in iodine solution. Observation: Only the area which was earlier green, turned blue black in colour. Result: Chlorophyll is important for photosynthesis.

29.04.08 Shivangi Biology 10.2.6.1.1 Sg Ss Html 46c68129 (image/png)

CO2 Necessity experiment

Take two healthy potted pots of nearly same size. Destarch them and place each of them on glass plates. Keep a watch glass containing potassium hydroxide (KOH) near one plant. KOH will absorb the CO2 Cover each plant with separate bell jars and seal them using vaseline. Keep in sunlight for around 2 hours and then pluck a leaf from both plants. Pour iodine to do the starch test. Observation: The leaf which had no CO2 around it didn't turn blue-black while the other did Result: Carbon Dioxide is necessary for photosynthesis.