Tag: structure of a leaf

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Questions Related to structure of a leaf

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

Epistomatic stomata are mostly found in 

  1. Aquatic plants

  2. Terrestrial plants

  3. Xerophytic plant

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Epistomatic stomata is having stomata on the upper surface of the leaf. This type of stomata is mostly found in aquatic plants. Aquatic plants float on the surface of the water and therefore stomata are not found in the lower epidermis. Stomata are found on the upper epidermis because for direct exchange of gases between the leaf and the atmosphere. 

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

The cells which contain the crystal of calcium carbonate is known as 

  1. Guard cell

  2. Silica cell

  3. Idioblast

  4. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Idioblasts are the crystal containing isolated plant cell. It is secretory in nature. the crystal is formed by the deposition of the inorganic materials like calcium salts. It is involved in the storage of reserve food, pigments, minerals, latex, gum, resin, tannin etc. So, the correct answer is option 'Idioblast'.
Multiple choice botany leaf - external morphology morphology of leaf structure of a leaf the leaf

The air spaces in the leaf is created by 

  1. Chlorenchyma

  2. Aerenchyma

  3. Palisade parenchyma

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
The spongy tissue that forms air spaces between the cells of leaves, stems and roots of some plants are called aerenchyma cells. It helps in the gaseous exchange between the shoot and the root and also provides buoyancy to the aquatic plants. So, the correct option is 'Aerenchyma'.
Multiple choice botany leaf - external morphology morphology of leaf structure of a leaf the leaf

Which of the following cells helps in the rolling of leaves in dry weather?

  1. Bulliform cells

  2. Guard cell

  3. Parenchyma cell

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Bulliform cells are found in the axial or upper surface of the epidermis of monocots. These are large, colourless, bubble-shaped (empty) cells found in clusters near the mid vein. In the presence of insufficient water, these cells loose water and become flaccid. In response to this condition, the leaf rolls inward (to expose the minimum part of the leaf) to minimise the water loss. So, the correct 'Bulliform cells'.

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

The cuticle present above the epidermis is helpful in reducing 

  1. Transpiration

  2. Respiration

  3. Photosynthesis

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The cuticle is comprised of polymers of wax. This layer is present on the surface of the epidermis of leaf and stem. This is the waxy and waterproof layer. This layer prevents the loss of water from the leaves and stem. This protective layer allows the retention of the water. This helps to reduce the loss of water in the form of water vapour by transpiration. 

Thus, the correct answer is option A. 

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

A Leaf of $20 \,cm^2$ grows $5 \,cm^2$ per hour and $B$ Leaf of $25 \,cm^2$ grows $5 \,cm^2$ per hour
The relative growth rate of leaf $A$ and $B$ respectively is

  1. $25\%$ and $20\%$
  2. $20\%$ and $25\%$
  3. $50\%$ and $100\%$
  4. $25\%$ and $50\%$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Relative growth is the increase in size relative to the size of the plant leaf present at the start of a given time interval. It can be also expressed as percentage increase.

Hence, for leaf A, relative growth = 5/20 × 100 = 25
For leaf B, relative growth = 5/25 × 100 = 20.
So, the correct option is '25 and 20'.

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

A modification of petiole is

  1. Phyllode

  2. Phylloclade

  3. Cladode

  4. Corm
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Phyllode is a green, expanded structure formed by the modification of petiole or rachis of the leaf. In most of the xerophytes, leaves are reduced to prevent water loss in such plants phyllodes develop to carry out photosynthesis.

An example is Acacia.
So the correct option is 'Phyllode'

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

Swollen lower end of leaf stalk is

  1. Petiole

  2. Pulvinus

  3. Thalamus

  4. Disc
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A swelling at the base of a petiole is known as pulvinus. It is a joint-like thickening at the base of a plant leaf or leaflet that facilitates growth-independent movement. For example, mango, pea and gram.
Therefore, the correct answer is option B.

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

Leaves develop from

  1. Nodes

  2. Internodes

  3. Epidermis

  4. Endodermis
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Leaves develop from nodes. Apart from leaves, branches and aerial roots also develop from nodes from the stem. It also holds buds. Adventitious roots may also develop from it. Internodes are the intervals between the nodes. 

Thus, the correct answer is 'Nodes.'

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

Sometimes a few epidermal cells in the vicinity of guard cells become specialized in their shape and size are known as 

  1. Stomatal aperture

  2. Trichomal cell

  3. Subsidiary cells

  4. Stomata
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The few epidermal cells surrounding the guard cells are modified to act as subsidiary cells. They lack chloroplasts and help in functioning of the guard cells by maintaining the water and solute balance with the guard cells.

A. Stomatal aperture is the opening of the stomata. It is also called stomatal pore.
B. Trichome cells give rise to the hair-like outgrowth called the trichomes.
C. Subsidiary cells are the modified epidermal cells near the guard cells.
D. Stomata are surrounded by the guard cells.
Hence, the correct answer is 'Subsidiary cells'