briefly explain the procendure to preare temporary slide of plant cell using onion peels
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AIM : To prepare stained temporary mount of onion peel , record
its observation and draw diagram
MATERIALS REQUIRED Onion, slide, coverslip, watchglass, forceps, blade, needle, brush, dropper, water, glycerine, knife, blotting paper, microscope.
THEORY The cells of onion peel consist of cell wall, cell membrane, nucleus and a large central vacuole. As the vacuole is very large and occupies most part of the cell, so the nucleus lies at the periphery in the cytoplasm. Other cell organelles like mitochondria, plastids, endoplasmic reticulum, ribosomes, etc., also lie in the cytoplasm but are not stained by the safranine stain so we cannot see them.
POCEDURE 1. Cut an onion into 5-6 pieces with a knife.
2. Take a thick scale leaf and fold it gently to break it. With the help of a forceps pull a thin transparent peel from its concave surface.
3. Put this thin transparent peel into a watch glass, full of water.
4. With the help of dropper, add 1-2 drops of safranine to stain the peel.
5. After two minutes, the peel turns red in colour.
6. Mount the stained peel on a clean slide in a drop of glycerine using a brush. Cut the peel in a proper rectangular shape with the help of a blade.
7. Cover it with coverslip.
8. Drain out excess glycerine from the slide with the help of blotting paper.
9. Focus the peel under low power of compound microscope and observe the cells.
10. Then observe the cells of onion peel under high power
OBSERVATIONS 1. The peel of onion leaf consists of a large number of regularly placed rectangular cells lying side by side without any inter cellular spaces.
2. Each cell has a distinct cell wall.
3. A darkly stained nucleus is present on the periphery of each cell.
4. Light stained cytoplasm is also seen.
RESULT 1. Onion peel has cell wall surrounding each cell.
2. Cells are rectangular and regularly , arranged.
3. There are no inter cellular spaces.
4. A dark stained nucleus lies on one side of the cell due to the presence of large vacuole in the center of the cell.
5. Cytoplasm is also towards the periphery in which nucleus lies. PRECAUTIONS 1. The peel is very delicate so do not hold it with fingers. Use brush.
2. Peel should not be over-stained or under-stained.
3. Peel should not become dry.
4. Peel should not get folded.
5. Hold the glass slide only by the edges.
6. The slide, coverslip and lens of the microscope should be cleaned before use.
7. The mounting of the peel should be done in the centre of the slide. 8. Always put the coverslip carefully so that no air bubbles enter the slide.
MATERIALS REQUIRED Onion, slide, coverslip, watchglass, forceps, blade, needle, brush, dropper, water, glycerine, knife, blotting paper, microscope.
THEORY The cells of onion peel consist of cell wall, cell membrane, nucleus and a large central vacuole. As the vacuole is very large and occupies most part of the cell, so the nucleus lies at the periphery in the cytoplasm. Other cell organelles like mitochondria, plastids, endoplasmic reticulum, ribosomes, etc., also lie in the cytoplasm but are not stained by the safranine stain so we cannot see them.
POCEDURE 1. Cut an onion into 5-6 pieces with a knife.
2. Take a thick scale leaf and fold it gently to break it. With the help of a forceps pull a thin transparent peel from its concave surface.
3. Put this thin transparent peel into a watch glass, full of water.
4. With the help of dropper, add 1-2 drops of safranine to stain the peel.
5. After two minutes, the peel turns red in colour.
6. Mount the stained peel on a clean slide in a drop of glycerine using a brush. Cut the peel in a proper rectangular shape with the help of a blade.
7. Cover it with coverslip.
8. Drain out excess glycerine from the slide with the help of blotting paper.
9. Focus the peel under low power of compound microscope and observe the cells.
10. Then observe the cells of onion peel under high power
OBSERVATIONS 1. The peel of onion leaf consists of a large number of regularly placed rectangular cells lying side by side without any inter cellular spaces.
2. Each cell has a distinct cell wall.
3. A darkly stained nucleus is present on the periphery of each cell.
4. Light stained cytoplasm is also seen.
RESULT 1. Onion peel has cell wall surrounding each cell.
2. Cells are rectangular and regularly , arranged.
3. There are no inter cellular spaces.
4. A dark stained nucleus lies on one side of the cell due to the presence of large vacuole in the center of the cell.
5. Cytoplasm is also towards the periphery in which nucleus lies. PRECAUTIONS 1. The peel is very delicate so do not hold it with fingers. Use brush.
2. Peel should not be over-stained or under-stained.
3. Peel should not become dry.
4. Peel should not get folded.
5. Hold the glass slide only by the edges.
6. The slide, coverslip and lens of the microscope should be cleaned before use.
7. The mounting of the peel should be done in the centre of the slide. 8. Always put the coverslip carefully so that no air bubbles enter the slide.
Answered by
1
Take an onion and remove its outermost peel.
2. Now cut a small part from an inner scale leaf with the help of a blade.
3. Separate a thin, transparent peel from the convex surface of the scale leaf with the help of forceps.
4. Keep this peel in a watch glass containing water?
5. Add two drops of safranin stain in the watch glass to stain the peel.
6. Take a clean slide and put a drop of glycerine in the centre of the slide.
7. With the help of a brush and needle transfer the peel on the slide. Glycerine prevents the peel from drying up.
8. Carefully cover it with a coverslip and avoid any air bubble from entering interring the coverslip.
9. Remove any excessive glycerine with a filter paper.
10. Observe the prepared mount of the peel under the low and high magnification of a compound microscope.
2. Now cut a small part from an inner scale leaf with the help of a blade.
3. Separate a thin, transparent peel from the convex surface of the scale leaf with the help of forceps.
4. Keep this peel in a watch glass containing water?
5. Add two drops of safranin stain in the watch glass to stain the peel.
6. Take a clean slide and put a drop of glycerine in the centre of the slide.
7. With the help of a brush and needle transfer the peel on the slide. Glycerine prevents the peel from drying up.
8. Carefully cover it with a coverslip and avoid any air bubble from entering interring the coverslip.
9. Remove any excessive glycerine with a filter paper.
10. Observe the prepared mount of the peel under the low and high magnification of a compound microscope.
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