नमस्कार विद्यार्थी मित्रांनो, Study of structure and distribution of stomata on upper and lower surfaces of leaf 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 - 3 ची उत्तरे पाहणारं आहोत. ही उत्तरे काळजीपूर्वक वाचून आपल्या Practical Book मध्ये लिहा किंवा तुमच्या कॉलेजमधील संबंधित विषय शिक्षकांची मदत घ्या.
3. Study of structure and distribution of stomata on upper and lower surfaces of leaf.
Stomata minute, elliptical pores present on the epidermis of young stem, leaves and fruit wall.
Aim :- To study structure and distribution of stomata in upper and lower epidermis of leaf.
Requirements :- Fresh leaf of Betel (dicot plant) and grass or maize (monocot leaf), grass slides, cover slips, watch glass, blades, glycerine, etc.
Principle :- Loss of excess water in the form of vapour from aerial parts of the plant body, is known as transpiration. The main plant organ involved, is leaf and it carries out this process with stomata present on both of its epidermal layers. Dicot leaf shows the difference in the number of stomata on it's upper and lower epidermal surfaces whereas monocot leaf shows equal number of stomata on both surfaces.
Figure :-
Procedure :- 1. Take a betel leaf and a maize or grass leaf, fold these leaves and peel off them on both surfaces.
2. Using a blade, cut the peel on both the surfaces of leaf.
3. Mount these peels on slide, add a drop of glycerine over it and put a cover slip.
4. Observe both the slides under microscope.
Observations :- 1. The peel of betel (dicot leaf) shows presence of kidney shaped guard cells surrounded by scattered, irregularly shaped subsidiary cells. The number of stomata on upper epidermis is less than those on lower epidermis.
2. The peel of maize or grass leaf (monocot leaf) shows presence of dumb-bell shape guard cells surrounded by two subsidiary cells which are triangular and show parallel arrangement. The number of stomata on upper epidermis and lower epidermis generally equal.
Inferences :- In a dicot leaf, the lower surface has a greater number of stomata than the upper surface. In a monocot leaf, the number of stomata is roughly equal on both surfaces. In most floating plants, stomata are found only on the upper epidermis.
Questions
1. Which type of leaf you will use to study comparative rates of transpiration? Why?
Ans :- To study comparative rates of transpiration, monocot and dicot leaves are used. This is because the number of stomata differs on both surfaces in these plants. In monocot leaves, some plants have an equal number of stomata on both surfaces, while in dicot leaves, there are more stomata on the lower surface than the upper surface.
2. What are stomata?.
Ans :- Stomata are small pores located on the epidermis of leaves and young shoots of plants. They facilitate the exchange of gases and are surrounded by a pair of specialized cells called guard cells, which regulate the size of the openings.
3. What are the functions of stomata?
Ans :- Stomata facilitate the release of water vapor into the atmosphere through a process called transpiration. They also enable the exchange of oxygen and carbon dioxide between the leaf and the environment.
4. What is guttation?
Ans :- Guttation is the process by which excess water is secreted as droplets from the pores of some vascular plants, typically during the night.
5. Which structures are known as 'water stomata' and where are they located?
Ans :- Hydathodes, also known as water stomata, are specialized pores found mainly on the leaf margins.
6. Why is that there is differential number of stomata on the leaf surfaces in betel leaf?
Ans :- The number of stomata on leaf surfaces differs to optimize gas exchange and minimize water loss. In dicot leaves, if stomata are more numerous on the upper surface, it can lead to greater water loss during the day, especially under high temperatures. Stomata typically open during daylight to facilitate gas exchange, which is why their distribution affects water retention.
Multiple Choice Questions
1. Stomata open due to...
a. Influx of calcium ions
b. Influx of potassium ions
c. Efflux of potassium ions
d. Influx of hydrogen ions
Ans :- b. Influx of potassium ions
2. Loss of water in early morning from tips of leaves, is called...
a. Guttation
b. Transpiration
c. Respiration
d. Bleeding
Ans :- a. Guttation
3. Maximum water loss occurs through...
a. Stomata
b. Lenticels
c. Hydathodes
d. Cuticle
Ans :- a. Stomata
4. In a free floating hydrophyte, stomata are...
a. Absent
b. Present on upper surface
c. Present on lower surface
d. Present on both surfaces
Ans :- b. Present on upper surface
5. Which of the following is Not an isobilateral leaf?
a. Rice
b. Wheat
c. Sugarcane
d. Mango
Ans :- d. Mango
6. The leaf showing stomata on both the surfaces is known as...
a. Astomatic leaf
b. Epistomatic leaf
c. Hypostomatic leaf
d. Amphistomatic leaf
Ans :- d. Amphistomatic leaf
Observe the slide and draw the diagram.
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