EXPERIMENT 4 Objective. To demonstrate plasmolysis and deplasmolysis in peels of Tradescantia/Rhoeo in hypotonic and hypertonic solutions using sodium chloride and potassium chloride.

                                                                  EXPERIMENT 4

Objective. To demonstrate plasmolysis and deplasmolysis in peels of Tradescantia/Rhoeo in hypotonic and hypertonic solutions using sodium chloride and potassium chloride.

REQUIREMENTS

Tradescantia/Rhoeo leaf, blade, forceps, glass slides, cover slips, measuring cylinder, beakers, balance, microscope, blotting paper, dropper, sodium chloride, potassium chloride, water, etc.

PROCEDURE

1.Prepare 0.1% and 5% solutions of each of sodium chloride and potassium chloride in separate beakers.

2. Peel off a small segment from the lower surface of Tradescantia leaf. This can be done by tearing the leaf obliquely with a single jerk or scraping it with blade.

3. Mount a piece of the peel in dilute solution (0.1%) of sodium chloride on a glass slide and then place a cover slip over the peel. Observe it under the microscope and draw its cells.

4. Take another piece of the peel and mount it in concentrated solution (5%) of sodium chloride. After sometime,observe it under the microscope and draw the boundaries of the protoplast. The protoplast will appear shrinked in one corner of the cell.

5. Now replace the concentrated solution of sodium chloride with water by sucking it with blotting paper from one side of the cover slip and pouring a drop of water with the help of a dropper from another side of the slide Observe the peel under the microscope and draw the cells. The protoplast of the cell will appear at its original position.

6. Repeat the experiment using potassium chloride solution also.

OBSERVATION

The cells in dilute (hypotonic) solution appears turgid due to endosmosis, while the cells in concentrated(hypertonic) solution shows plasmolysis due to exosmosis. When the concentrated solution is replaced with water,the protoplast of the cells aquire its original shape.

CONCLUSION

The cells show plasmolysis when placed in hypertonic solution due to exosmosis. The plasmolysed cells when placed in dilute solution or water show deplasmolysis due to endosmosis.

PRECAUTIONS

1. The peel should not be exposed or dried.

2. Slide should be kept dried by removing extra solution with blotting paper.