Question

The common material used in demonstrating plasmolysis in the laboratory is
(a) Garden Nasturtium
(b) Baisum
(c) Banya
(d) Tradescantia

Answer 1

Hint: This is a herbaceous wildflower which belongs to the genus which is also known as spiderwort or Indian paint. The flower unfolds in the morning and closes when sunlight falls on it.

Complete answer:
The common procedure used in demonstrating plasmolysis in the laboratory is:
- Peel off a small segment from the lower surface of the leaf by tearing the leaf obliquely with a single jerk by scraping it with a safety blade.
- Mounted the peel in a drop of water on a slide and then placed a coverslip and observed under a microscope.
- Make different molar concentrations of sugar solution such as 2.0M, 4.0M, 6.0M, etc.
- Take the other peel and similarly mount the peel of Tradescantia in a drop of sugar solution of different concentration on different slides. - After 30 minutes each preparation under a microscope.
Observation of the experiment-
- The withdrawn of cell content is due to the loss of water from the cell causing vacuole to shrink. The small space between cell wall and cell content indicate the beginning of plasmolysis.
- With increasing the concentration of sugar solution the space between cell wall and cell contents widens.
- Finally cell contents collected on one side and the cell is called plasmolysed.
So, the correct answer is, ‘tradescantia.’

Additional Information:
- Osmosis: Osmosis is the phenomenon of movement of solvent molecules from their higher contraction to lower concentration or from a solution of low concentration to high concentration through semipermeable membrane.

Note:
- Plasmolysis is defined as the shrinkage of protoplasm of the cell from the cell wall when the cell emerges in the solution which has a higher solute concentration than the cell sap.
- Osmotic potential: It is defined as the excessive hydrostatic pressure which must be applied to it in order to make its water potential equal to that of pure water.