Tag: structure of a leaf

Questions Related to structure of a leaf

Go through the following matches.

(i) China rose Twisted aestivation
(ii) Calotropis Valvate aestivation
(iii) Gulmohur Ascending imbricate aestivation
(iv) Pea Descending imbricate aestivation

Which of these are correct?

botany leaf - external morphology morphology of leaf structure of a leaf the leaf

  1. (i), (ii) and (iii)

  2. (ii), (iii) and (iv)

  3. ii), (iii), (iv)

  4. All are correct

Show answer
Correct Option: A
Explanation:
i) China rose - One margin of the appendage overlaps that of the next one (Twisted aestivation).
ii)Twisted aestivation -  The sepals or petals in whorl just touch one another at the margin (Valvate aestivation).
iii) Gulmohar botanical name is Delonix - Ascending imbricate aestivation.
iv) Tephrosia is a genus of flowering plants in the pea family - Descending imbricate aestivation.
So, the correct option is 'All are correct'. 

Leaf is _________ in origin.

botany leaf - external morphology morphology of leaf structure of a leaf the leaf

  1. Endogenous

  2. Exogenous

  3. Axillary

  4. Indefinite

Show answer
Correct Option: B
Explanation:

Leaves are exogenous (develop away from the plant body) in origin and develops from the swollen leaf primordium of the growing apex.

So, the correct option is 'Exogenous'.

A distinct endodermis is a constant feature of

botany leaf - external morphology morphology of leaf structure of a leaf the leaf

  1. Dicot leaves

  2. Monocot stems

  3. Monocot leaves

  4. Dicot stema

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Correct Option: A
Explanation:
The cells of the endodermis typically have their primary cell walls thickened on four sides radial and transverse with suberin, a water-impermeable waxy substance which in young endodermal cells is deposited in distinctive bands called Casparian strips.
So the correct option is 'Dicot leaves'.

Guard cells are kidney shaped in 

botany leaf - external morphology morphology of leaf structure of a leaf the leaf

  1. Rice

  2. Beans

  3. Grasses

  4. Maize

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Correct Option: A
Explanation:
  • Guard cells are specialized epidermal cells present on the surface of leaves and stems of plants that control the gaseous exchange in plants.
  • The guard cells form stomatal pores through which gaseous exchange and transpiration take place.
  • In monocots, the guard cells are dumbbell shape.
  • In dicots, they are kidney or bean shaped.
  • So, the correct answer is 'Beans'.

Stomata are  present on the underside of the __________

botany leaf - external morphology morphology of leaf structure of a leaf the leaf

  1. Flower

  2. Fruit

  3. Seed

  4. Leaf

Show answer
Correct Option: D
Explanation:

Stomata are the openings surrounded by the guard cells that are specialized epidermal cells. These are present on the underside of the leaves and perform the functions of exchange of gases and transpiration.

Hence, the correct answer is 'Leaf' 

Midrib is observed in which part of leaf?

botany leaf - external morphology morphology of leaf structure of a leaf the leaf

  1. Leaf base

  2. Lamina

  3. Petiole

  4. Stipule

Show answer
Correct Option: B
Explanation:
  • The leaf consists of the following parts-
1) Leaf blade (lamina) is the broad and flat part of the leaf where photosynthesis occurs is also known as epipodium.
  • The midrib is the central prominent vein on the lamina which helps to transport water, minerals to different cells of the leaf.
2) Leaf base is the lowermost part of the leaf and is also known as hypopodium
3) The petiole is the stalk-like part of the leaf which connects the leaf blade to the stem.
  • Stipule is a small flap-like structure which grows at the base of the petioles and protects the growing petioles or falls off.
  • So, the correct answer is 'Lamina'.

Broad part of a leaf is

botany leaf - external morphology morphology of leaf structure of a leaf the leaf

  1. Leaf base

  2. Petiole

  3. Lamina

  4. All of the above

Show answer
Correct Option: C
Explanation:

Broad part of leaf is lamina. The lamina is the expanded portion of a leaf and it is specialized for photosynthesis. For this purpose, a leaf is typically flat and thin, to expose the chlorenchyma to light over a broad area and to allow light to penetrate fully into the tissues. 
Thus, the correct answer is option C.

A leaf is

botany leaf - external morphology morphology of leaf structure of a leaf the leaf

  1. Differentiated into nodes and internodes

  2. A lateral outgrowth of stem

  3. Endogenus in origin

  4. All of the above

Show answer
Correct Option: B
Explanation:

Exogenous, flattened, green, lateral appendages arising from nodes of the stem or branches in acropetal succession are called as leaves. Leaves arise from shoot apical meristem and bear buds in their axils and help in assimilation of food, exchange of gases and transpiration. So, leaf is a lateral outgrowth of stem.  

Thus, the correct answer is option B.

In Funaria, archegonia attracts antherozoids by

botany leaf - external morphology morphology of leaf structure of a leaf the leaf

  1. Sucrose / Sugar

  2. Malic acid

  3. Maleic acid

  4. Citric acid

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Correct Option: A
Explanation:
  • During fertilization of Funaria, the ventral canal cell and the neck canal cells of the archegonium dis­integrate forming a mucilaginous substance. This mucilaginous substance absorbs water accu­mulated as rain or dew water, then swells up and the resultant pressure breaks apart the terminal cover cell. Now sugar containing mucilaginous substances ooze out through the opening of the archegonial neck.
  • The liberated antherozoids are now attrac­ted chemotactically towards the archegonia. Large numbers of antherozoids enter the neck, but only one of them fuses with the egg nucleus to form the diploid zygote.
  • Hence In Funaria, archegonia attract antherozoids by 'Sucrose / Sugar '.
  • So, the correct answer is 'Sucrose / Sugar '.

The leaf arises at the __________ on the stem.

botany leaf - external morphology morphology of leaf structure of a leaf the leaf

  1. Internode

  2. Axil

  3. Node

  4. Petiole

Show answer
Correct Option: C
Explanation:

  • Node: The leaves arise in the regions of the plant known as the plant nodes and are therefore the point of attachment of the leaves. 
  • The region of the plant between two nodes is known as the internode.
  •  The angle between the upper surface of the leaf and the stem from which it arises is known as the axil. 
  • The petiole is the stalk which attaches the leaf to the stem. 
So, the correct option is 'Node'.