Question

The characteristic feature of the stomata in gymnosperms is that,

(a) they are deeply sunken in pits

(b) there are subsidiary cells

(c) the walls of the guard cells are completely free of lignin.

(d) the walls of the guard cells and subsidiary cells are partly free
of lignin.
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Answer 1

$\huge\bf{Answer :}$

• They are deeply sunken in pits (Option A)

The characteristics feature of the stomata in gymnosperms it that, they are deeply sunken. They are also named as sunken stomata.

$\huge\bf{Extra\:Information :}$

Stomata - Stomata are the tiny pores present in the lower epidermis of the leaf.

• The meaning of stomata is Stoma - mouth.

• It is responsible for exchanging of gases.

• It regulates the water loss through transpiration process.

• The tiny pores of stomata maintain the moisture balance in the leaf.

• It allows the exchange of carbon dioxide and give out oxygen during the process of photosynthesis.

$\bf{Gymnosperms :}$

• The seed in gymnosperm is naked as no fruit formation.

• The reproductive organs of gymnosperms are sporophylls form cones.

• Xylem tissue found incomplete in gymnosperms.

• Only tracheids are present and vessels are absent.

• Companion cells of phloem are also absent.

• Example - Cycas, ephedra, Gnetum and pinus.

Answer 2

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$\pink\bigstar\:\bf{\red{\overbrace{\underbrace{\purple{(a)\:They\:are\:deeply\:shunken\:in\:pits\:.}}}}}$

$\bf{\gray{\underbrace{\blue{REASON:-}}}}$

• In Gymnosperm, the stomata is also known as Sunken stomata .

• Sunken stomata are characteristic of Cycas , Pinus and Taxus .

• A sunken stomata is a stomata in a small pit, which protects the escaping water vapour from air currents, decreasing water loss from the leaf .

• In Gymnosperms, the leaves are needle like, heavily cuticularized epidermis and exhibits sunken stomata, scattered on the lower surface only .

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$\bf{\underline{\underline{Characteristics\:of\:Gymnosperm:-}}}$

1. They do not produce flowers .
2. Seeds are not formed inside a fruit . They are naked .
3. They are found in colder regions where snowfall occurs .
4. They develop needle-like leaves .
5. They are perennial or woody, forming trees or bushes .
6. They are not differentiated into ovary, style and stigma .
7. Since stigma is absent, they are pollinated directly by the wind .
8. The male gametophytes produce two gametes, but only one of them is functional .
9. They form cones with reproductive structures .
10. The seeds contain endosperm that stores food for the growth and development of the plant .
11. These plants have vascular tissues which help in the transportation of nutrients and water .
12. Xylem does not have vessels, and the phloem has no companion cells and sieve tubes .

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