Theory : The word Photosynthesis is composed of the English word Photo meaning light and synthesis meaning synthesis. Photosynthesis means the combination of several substances to create a compound. The biochemical process in which green plants combine water and carbon dioxide with the help of chlorophyll in the presence of sunlight to produce sugary food and release oxygen as a by-product is called photosynthesis. Charles Barnes first used the term Photosynthesis in 1898.
Necessary Materials
1. A deciduous tree with long leaves.
2. Large mouth glass bottle- 1.
3. 20% caustic potash solution.
4. Petridis with water – 1.
5 Chopped oysters – 1.
6. Vaseline or wax.
7. 80% alcohol.
8. 1% iodine solution.
Procedure or course of action
1. Before the test, the plant with the tub was kept in a dark room for three days and sterilized.
2. Tilting the large-mouthed bottle on the table, I took some caustic potash solution inside the bottle.
3. I took a long leaf with pods from a tree kept in the dark. I inserted the tip of the sheet into the bottle through the cut hole.
4. I dipped the leaves in watery Petridis.
5. For airtightness, I coated the cut part with vaseline or beeswax to seal the gap well.
6. I left the test with the leaves in the sunlight.
7. After 3-4 hours the leaf was taken out of the bottle and boiled in 80% alcohol. The leaves became discolored due to chlorophyll loss.
8. The discolored leaf was thoroughly washed in water and soaked in 1% iodine solution for 1 minute.
9. The leaf was removed from the iodine solution, washed in distilled water and placed on a clean white paper.
observation
It was observed that the part of the leaf which was outside the bottle turned blue or black on contact with the iodine solution. But the leaf inside the bottle did not change color.
Decision
The part of the leaf inside the bottle received sunlight, water and oxygen, but no CO2. So no sugar or sugar is produced. CO2 is essential for photosynthesis.
warning
1. I kept the plant in the dark for a certain time.
2. I closed the mouth of the bottle well with vaseline so that there is no gap.
3. I boiled the leaf well.
4. I took care not to use chemicals in the body.
5. I observed well.