12th Biology Practical ~ (Part B) 1. comparative study of rates of transpiration in the upper and lower surface of leaf using four leaf experiment.

12th Biology practical book answers pdf Maharashtra board 

~ Comparative study of rates of transpiration in the upper and lower surface of leaf using four leaf experiment.

Observation table:

Sr. no	Type of leaf	Observation
1	Leaf A	Remain fresh
2	Leaf B	Show little wilting
3	Leaf C	Shows more wilting
4	Leaf D	Shows complete wilting

 

 

 

Conclusion:

1.       Leaf A remain fresh because all the stomata are blocked by Vaseline, no transpiration.

2.      Leaf B shows little wilting as transpiration take place from upper surface of leaf.

3.      Leaf C shows more wilting as transpiration occurred from lower surface of leaf; stomata are in more no. compared to upper surface.

4.      Leaf D shows complete wilting as transpiration could take place from both surfaces.

 

Questions:

1)      Define transpiration

Loss of excess water in form of vapour through the aerial parts (specially leaves) of the plant body called as transpiration.

 

2)     What are stomata?

Stomata is minute, elliptical pore or aperture formed of two guard cells and accessory cells.

 

3)     Enlist different types of transpiration.

a.      Cuticular transpiration

b.      Lenticular transpiration

c.       Stomatal transpiration

 

4)    How lenticels are different from typical stomata?

Stomata	Lenticels
Opening of stomata is based on the requirement of plant	Lenticels remain open
Kidney shaped guard cells are present	Lenticels do not contain guard cells
Stomata occur during primary growth of plant	Lenticels occur during secondary growth of plant
Mainly occur the lower epidermis of leaf	Occur in the peridermis of the woody trunk or the stem

 

5)     Explain guttation

Loss of water in the form of liquid or water droplets from small pores called as guttation. These pores are called as water stomata or hydathodes. Plants have hydathodes at the end of veins on the leaf margin.

 

 

Multiple choice questions

 

1.       Maximum loss of water in form of water vapour takes place through _______

Ans: b) stomata

 

2.      Which of the following is involved in guttation?

Ans: c) Hydathode

 

3.      Thick cuticle reduces loss of water through_______

Ans: b) epidermal cells

 

4.      The entry of water from subsidiary cells into guard cells is affected by________

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_______

Ans: c) guttation

 

6.     Stoma widens when the guard cells become_______

Ans: d) turgid

Fin :)