Question

What differentiates a dicot leaf from monocot leaf?
A. Stomata only on upper side
B. Differentiation of palisade and spongy parenchyma
C. Parallel venation
D. Stomata on upper and lower sides

Answer 1

Hint: Dicotyledon is a member of the flowering plants that has a pair of leaves and cotyledons, in the embryo of the seed. Most common examples are garden plants, shrubs and trees, and broad-leafed flowering plants such as magnolias and hollyhocks. Monocots have only one seed leaf. It is a thin leaf, because the endosperm to feed the new plant is not inside the seed leaf. They are usually rounded because they contain endosperm.

Complete answer:
A-Stomata only on upper side
Stomata on the upper surface helps in exchange of gases between them and atmosphere. While the land plants have stomata on their lower surface. This is in order to prevent excess loss of water.

B-Differentiation of palisade and spongy parenchyma
The palisade is usually directly beneath the epidermis of the upper surface of the leaf. The spongy parenchyma fills the space beneath palisade parenchyma. It is interspersed with a voluminous intercellular system.

C-Parallel venation
When the veins are arranged web-like all over the lamina, it is known as reticulate venation. When the veins are arranged parallel to one another, it is known as parallel venation.

D-Stomata on upper and lower sides
Botanists call the upper side the adaxial surface and the lower side abaxial surface. The epidermis aids in the regulation of gas exchange. It contains stomata, which are openings for exchange of gases.

Thus the correct answer is B - Stomata on upper and lower sides.

Note: Dicot leaf differs from monocot leaf in terms of presence of more number of stomata in the lower epidermis, presence of differentiated mesophyll and also vascular bundle.