Advertisements
Advertisements
प्रश्न
What causes the opening and closing of guard cells of stomata during transpiration?
Advertisements
उत्तर
The tiny pores present on the surfaces of leaves, called stomata, help in the exchange of gases. Each stoma consists of bean-shaped or dumbbell-shaped guard cells. The epidermal cells surrounding the guard cells are modified to form subsidiary cells. The opening and closing of the guard cells is caused by a change in their turgidity. The inner walls of the guard cells are thick and elastic, while the outer walls are thin. The numerous microfibrils present in the guard cells facilitate the opening and closing of the guard cells.
At the time of the opening of the stomata, the turgidity of the guard cells increases. As a result, the outer walls bulge and the inner walls become crescent-shaped. The stomatal opening is facilitated by the radial arrangement of the microfibrils.
At the time of the closing of the stomata, the guard cells lose their turgidity, the outer and inner walls retain their original shapes, and the microfibrils get arranged longitudinally.
APPEARS IN
संबंधित प्रश्न
State whether the following statement is true or false. Rewrite the false statement correctly.
Transpiration cools the plant when it is hot outside.
Fill in the blank:
Water is lost from the leaves by__________.
Define the termTranspiration
Define the term Transpiration stream
Name the process by which water loss takes place through the leaves.
The diagram given alongside is an apparatus used to study a particular phenomenon in plants.
(i) Name the apparatus.
(ii) What is it used for?
(iii) What is the role played by the air bubble in this experiment?
(iv) Of what use is the reservoir?
An apparatus as shown below was set up to investigate a physiological process in plants. The setup was kept in sunlight for two hours. Droplets of water were then seen inside the bell jar. Answer the questions that follow:
Why was the pot covered with a plastic sheet?
Boojho’s uncle was hospitalised and put on dialysis after a severe infection in both of his kidneys.
What is dialysis?
Which one is not related to transpiration?
Describe briefly the three physical properties of water which helps in ascent of water in xylem.
ABA (Abscisic acid) is called a stress hormone. From where does this hormone get released in leaves?
Observe the diagram and answer the following;
 (i) |
 (ii) |
- Are these types of guard cells found in monocots or dicots?
- Which of these shows a higher water content (i) or (ii)?
- Which element plays an important role in the opening and closing of stomata?
The radio labelled carbon in carbon dioxide supplied to potato plants in an experiment was seen in the tuber eventually. Trace the movement of the labelled carbon dioxide.
Why is transpiration less in the still wind?
Observe the following diagram and identify the process and its significance from the following options:
The process of evaporative loss of water from the aerial parts of a plant is ______.
(a) State whether the following statement are True or False.
(b) Rewrite the false statement in the correct form by changing either the first or the last word only.
Transpiration helps to cool the body of the plant.
