Question
ICSEENIBI10003240

The diagram below represents a structure found in a leaf. Study the same and answer the questions which follow:

(i) Name the parts labelled A and B.
(ii) What is the biological term for the above structure? 
(iii) What is the function of the part lallelled A?
(iv) Mention two structural features of A which help in the function mentioned in (iii) above.
(v) Where is this structure likely to be found in leaf?
(vi) The above structure helps In the process of transpiration. Explaln the term transpiration.
(vii) How many other cells are found surrounding this structure as seen in the diagram?

Solution

(i)
A - Guard cell
B- Stoma

(ii) Stomatal apparatus

(iii) Guard cells regulate the opening and closing of the stomata.

(iv) Guard cells have thick inner walls and thin outer walls. The turgidity and flaccidity of guard cells help to regulate the closing and opening of the stomata.

(v) The stomata are found on the upper and lower epidermis of the leaf.

(vi) Transpiration: It is the loss of water as water vapour from the aerial parts of the plant. Of the total water absorbed, only 2% of the water is used by the plant body and the rest of the water is lost by transpiration. Transpiration helps to cool the plant body. It also helps maintain the temperature of the surrounding region.

(vii) Five epidermal cells which are also known as accessory cells.

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