नमस्कार मित्रांनो इयत्ता बारावी Biology या Subject च्या Practical मध्ये PART - B: Demonstration Experiments (Spotting) हा भाग Practical Exam च्या दृष्टीने फार महत्त्वाचा आहे. या Blog Post मध्ये आपण Spotting Practical Number 1: Comparative study of rates of transpiration in the upper and lower surfaces of leaf, using four-leaf experiment. ह्या Practical Experiment चे Answer पाहणार आहोत. खाली दिलेल्या उत्तरांमध्ये काही अडचण असल्यास आम्हाला comment करा किंवा तुमच्या संबंधीत विषय शिक्षकांशी चर्चा करा.
B. DEMONSTRATION EXPERIMENTS (Spotting)
1. Comparative study of rates of transpiration in the upper and lower surfaces of leaf, using four-leaf experiment.
Loss of excess water in the form of vapour through the aerial parts of the plant is called transpiration.
Aim :- To study comparative rote of transpiration in upper and lower surfaces of leaf by conducting four leaf experiments.
Requirements :- Two stands, thread, four leaves of Calotropis/ banyan tree, Vaseline (petroleum jelly), etc.
Figure :-
Procedure :- The leaves selected should be healthy preferably of the same size and showing the same stage of growth. Tie the different leaves of the same plant with thread in such a way that they will be equidistant and surfaces will be properly exposed to the sunlight.
Tie the thread to the stand at both ends.
Apply Vaseline to the leaf surface in the following manner,
1. Leaf A: - Petroleum jelly is applied on both the surfaces
2. Leaf B: - Petroleum jelly is applied on the lower surface only
3. Leaf C: - Petroleum jelly is applied on the upper surface only
4. Leaf D: - Petroleum jelly is not applied
Observe the order of drying of these leaves, 2-3 days after setting the apparatus and then prepare the observation table.
Observation Table :-
| Sr. no. | Type of leaf | Observation |
|---|---|---|
| 1 | Leaf A | Fresh & green |
| 2 | Leaf B | Partially shrivilled |
| 3 | Leaf C | Fresh than Leaf B |
| 4 | Leaf D | Wilts Completely |
Questions
1. Define transpiration.
Ans :- Transpiration is the process by which water is lost from the aerial parts of plants in the form of vapor.
2. What is stomata?
Ans :- Stomata are tiny, elliptical openings found in the epidermis of leaves and young stems.
3. Enlist different types of transpiration.
Ans :- There are three types of transpiration:
1. Cuticular transpiration (8-10%)
2. Lenticular transpiration (0.1-1%)
3. Stomatal transpiration (83-90%)
4. How lenticels are different from typical stomata?
Ans :- Lenticels are pores made up of loosely arranged cells and are found in the bark of woody stems in dicot plants; they are absent in leaves. In contrast, stomata are small openings in the epidermis of leaves and young stems.
5. Explain guttation.
Ans :- Guttation is the loss of water in liquid form, which occurs through specialized structures called hydathodes located along the leaf margins at the ends of veins.
Multiple Choice Questions
1. Maximum loss of water in the form of water vapours takes place through...
a. hydathode
b. stomata
c. cuticle
d. leticel
Ans :- b. stomata
2. Which of the following is involved in guttation?
a. Stomata
b. Guard cell
c. Hydathode
d. leticel
Ans :- c. Hydathode
3. The thick cuticle reduces the loss of water through...
a. mesophyll cells
b. epidermal cells
c. passage cells
d. sclerenchyma cells
Ans :- b. epidermal cells
4. The entry of water from subsidiary cells into guard cells is affected by...
a. auxin
b. K+
c. Ch
d. ABA
Ans :- b. K+
5. Loss of excess water in the form of liquid, occurring along the margins of leaves of certain plants is known as...
a. transpiration
b. respiration
c. guttation
d. photosynthesis
Ans :- c. guttation
6. Stoma widens when the guard cells become...
a. flaccid
b. rigid
c. cupid
d. turgid
Ans :- d. turgid
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