Tag: structure of a leaf

Questions Related to structure of a leaf

Evaporation in plants is restricted by

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

  1. Chloroplast

  2. Epidermis

  3. Cuticle

  4. Guard cell

  5. Sweat gland

Show answer
Correct Option: C
Explanation:

Leaf cuticle is protective covering on leaf epidermis and is composed of cutin, an insoluble heterogenous lipid polymer of long chain substituted aliphatic acids. Hence, it serves as water impervious layer to prevent water loos through transpiration. Stomata are the organs of transpiration which are present in the epidermis and their opening and closing are regulated by the change in turgidity of guard cells. Thus, the correct answer is C.

Identify the plant, if veins are appearing parallel on leaves.

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

  1. The plant is a dicot

  2. The plant is a monocot

  3. The plant is a gymnosperm

  4. The plant is an angiosperm

  5. The plant is a bryophyte

Show answer
Correct Option: B
Explanation:

If the veins on the the leaf run parallel to each other throughout the leaf, it is known as parallel venation. It is a feature of monocotyledonous plant. This type of veins are found in grasses.

Ground tissue gives rise to

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

  1. Cuticle

  2. Epidermis

  3. Mesophyll

  4. Phloem

  5. Xylem

Show answer
Correct Option: C
Explanation:

Ground tissue system comprises of simple permanent tissues like parenchyma, collenchyma and sclerenchyma. In leaves, the ground tissue consists of thin-walled chloroplast containing cells known as palisade mesophyll cells. 

So, the correct answer is 'Mesophyll cells'.

Trichomes present on the roots are used for

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

  1. Absorption

  2. Secretion

  3. Transpiration

  4. None of the above

Show answer
Correct Option: A
Explanation:

The unicellular hair-like structures present on the surface of the root are known as trichomes. These are finger-like projections of the cells in the regions of the root. The trichomes act like the root hairs. They are involved in the process of absorption of water and minerals from the soil. They also help to increase the surface area for absorption. 

Thus, the correct answer is option A. 

Monocot leaf can be distinguished from the dicot

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

  1. Stomata is equally distributed on both lower and upper epidermis

  2. Palisade cells on both upper and lower sides

  3. Several veins of nearly uniform size

  4. All of the above

Show answer
Correct Option: D
Explanation:
 Monocot leaf  Dicot leaf
 (i) The monocot leaf is of isobilateral symmetry.  The dicot leaf is of dorsiventral  symmetry.
 (ii) The bullifom cells are present on the upper epidermis.   The bulliform cells are absent.
 (iii) Stomata are equally distributed on both surfaces.   Stomata are present more in lower  surface and few on upper surface.
 (iv) In mesophyll cells, only spongy parenchyma is present with small intercellular spaces.  Mesophyll cells are made up of  palisade parenchyma and spongy  parenchyma with large intercellular  spaces.
 (v) Bundle sheath is made up of parenchyma and just above and below sclerenchymatous cells are found.  Bundle sheath is made up of  parenchyma and just above and below  the parenchymatous or  collenchymatous cells are found.

 Cuticle is made up of 

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

  1. Glycerol and hydrocarbon polymers impregnated with wax

  2. Lipid and hydrocarbon polymers impregnated with wax

  3. Fatty acid and hydrocarbon polymers impregnated with wax

  4. None of the above

Show answer
Correct Option: B
Explanation:
The protective and waxy covering around the epidermis of leaves, young shoots and other aerial parts of a plant is called a cuticle. it is made up of lipid and hydrocarbon polymers integrated with wax. It is formed by the epidermal cells. It acts as the permeability barrier for water soluble substances and water molecules and checks the evaporation of water from the epidermis. So, the correct option is B.

A mature angiosperm that bears only one leaf is

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

  1. Welwitschia

  2. Monophyllea

  3. Raffiesta

  4. Betula

Show answer
Correct Option: B
Explanation:

Plant with single leaf, Monophyllea (angiosperm) plant with two leaves only Welwitschia (gymnosperm).

Presence of sheathing leaf base and ligule are characteristic of

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

  1. Cycas leaf

  2. Fern leaf

  3. Banana leaf

  4. Grass leaf

Show answer
Correct Option: D
Explanation:

A ligule is an outgrowth present at the junction of leaf sheath and lamina in grass leaf. It occurs at the end of petiole at the leaf base. It is a strap-shaped extension of the corolla. It is a membranous appendages. Grass leaf also has sheathing leaf base. 

Thus, the correct answer is 'Grass leaf.'

A leaf without petiole is

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

  1. Sessile

  2. Subsessile

  3. Subpetiolate

  4. Simple

Show answer
Correct Option: A
Explanation:

Petiole is a stalk that attaches a leaf to the stem of a plant. A leaf without petiole is called as sessile leaf. It is a transition between the stem and the lamina.

Thus, the correct answer is 'Sessile.'

Smallest leaf occurs in

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

  1. Victoria

  2. Wolffia

  3. Cycas

  4. Spiraea

Show answer
Correct Option: B
Explanation:

The smallest leaf occurs in Wolffia. In Wolffia, the leaf is fused with the stem to form minute flat thallus. Thus, the correct answer is 'Wolffia.'