नमस्कार विद्यार्थी मित्रांनो Study of plasmolysis in epidermal peels हे प्रॅक्टिकल Experiments to be performed - PART A मधील आहे. याचाच अर्थ तुम्हाला हे प्रॅक्टिकल Exam मध्ये Examinar ला Performe करून दाखवायचे आहे. म्हणूनच प्रॅक्टिकल Exam च्या दृष्टीने हे Experiment अतिशय महत्त्वाचे आहे. या ब्लॉग मध्ये आपण Practical Book मधील या Experiment Number - 2 ची उत्तरे पाहणारं आहोत. ही उत्तरे काळजीपूर्वक वाचून आपल्या Practical Book मध्ये लिहा किंवा तुमच्या कॉलेजमधील संबंधित विषय शिक्षकांची मदत घ्या.
2. Study of plasmolysis in epidermal peels.
Exosmosis in a living cell when placed in hypertonic solution, is called plasmolysis.
Aim :- To study plasmolysis in epidermal cells of Tradescantia leaf.
Requirements :- Fresh leaf of Tradescantia, concentrated sugar solution, distilled water, slides, cover slips, watch glass, blades, etc.
Principle :- Osmotic concentration of cell sap decides the movement of solvent molecules across the different types of membranes.
Figure :-
Procedure :- 1. Take a fresh Tradescantia leaf and peel off its lower coloured surface in such a way that epidermal cells can be observed.
2. Take a small piece of epidermal peels and place it in concentrated sugar solution for few minutes (hypertonic solution). Mount it on slide and put a cover slip.
3. Observe the slide under microscope and focus over few cells.
4. Take another small piece of peel from lower epidermis and place it in water (hypotonic solution) for few minutes, Mount it on a slide and put a cover slip.
5. Carefully observe this slide also under microscope.
Observations :- 1. The slide prepared using hypertonic solution shows shrinkage of cytoplasm (protoplast) cytoplasm moves (recedes) away from the cell wall and becomes concentrated to corner of the cell. This is known as plasmolysis.
2. The slide prepared using hypotonic solution or water shows that cell cytoplasm bulges or swells i.e. increases in size. This is due to endosmosis.
Inferences :- When plant cells are immersed in a concentrated salt solution, such as a 5% sodium chloride solution, plasmolysis occurs. During this process, 4 to 5 percent of the cell's water moves out through the cell membrane into the surrounding medium. This happens because the water concentration inside the cell is higher than outside. As a result, the protoplasm shrinks and assumes a spherical shape.
Questions
1. What does occupy the space between the cell wall and protoplast of a plasmolysed cell?
Ans :- In a plasmolysed cell, the hypertonic solution (i.e., a solution with high salt concentration) occupies the space between the cell wall and the shrunken protoplast.
2. Define incipient plasmolysis.
Ans :- Incipient plasmolysis is the initial phase of plasmolysis, where the protoplasm is just beginning to detach from the cell wall.
3. Where do we use plasmolysis at home?
Ans :- Plasmolysis is utilized at home for food preservation. Salting creates a hypertonic condition that kills fungi and bacteria through plasmolysis, which is why pickles, meat, and fish are preserved by salting. Similarly, jams and jellies are preserved by adding sugar, creating a hypertonic environment that prevents microbial growth.
4. It is possible to use plasmolysis in fish drying?
Ans :- Fish drying is an example of osmosis, not plasmolysis.
5. Give reasons of selecting the leaf peel from the lower surface of Tradescantia leaf.
Ans :- The epidermal peel is generally taken from the lower surface of the Tradescantia leaf because the lower surface has a higher number of stomata compared to the upper surface.
Multiple Choice Questions
1. When water enters the cell, the pressure exerted by its Swollen protoplast is...
a. Turgor pressure
b. D.P.D.
c. Osmotic pressure
d. Imbibition
Ans :- a. Turgor pressure
2. In a fully turgid cell, what will be zero?
a. WP
b. OP
c. TP
d. Water potential
Ans :- d. Water potential
3. In a turgid cell surrounded by pure water, the wall pressure...
a. Increases
b. Decrease
c. Fluctuate
d. Remain unchanged
Ans :- a. Increases
4. The osmotic pressure of cell sap is more in...
a. Mesophytes
b. Xerophytes
c. Hydrophytes
d. Halophytes
Ans :- b. Xerophytes
5. The protective cover of vacuole is called...
a. Cell wall
b. Leucoplast
c. Plasmalemma
d. Tonoplast
Ans :- d. Tonoplast
Observe the slide and draw the diagram.
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| Slide Diagram |
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