Question

Mention two features by which the dicot leaf and monocot leaf can be distinguished in a vertical section.

Answer 1

Hint: Monocot is the term used for the flowering plants that contain only one cotyledon, the same like that the dicot refers to the flowering plants having two cotyledons. They differ from each other by various morphological features.

Complete answer: Monocot leaf and Dicot leaf can be distinguished from each other on the basis of the type of venation pattern and symmetry.
i. Venation pattern:- Monocot leaves show parallel venation which means that in these leaves, the veins strike parallel to each other. It has isobilateral symmetry means both the leaf surfaces are similar because it has an equal number of stomata distribution and undifferentiated mesophyll.
ii. Symmetry:- Dicot leaf shows reticulate venation which means that the veins are striking towards each other. It has dorsiventral symmetry means having both the different leaves surface, because it has stomata only in the lower epidermis and differentiated mesophyll. In dicot leaf, the mesophyll cells usually differentiated into two types of tissues named as palisade, spongy parenchyma while monocots have no such differentiation. There is also a difference in the vascular bundles in dicots which differ in size due to the presence of reticulate venation but in monocots, it is parallel venation. Also, the bulliform cells in dicot leaf are absent whereas, in monocots especially in grasses, it is present. The leaves of monocot plants are characteristically longer and slender while dicot plants have leaves that are relatively smaller and broader than monocot plants.

Note: Monocots are plants that produce seeds with a single cotyledon, whereas dicots are plants that give rise to seeds with two cotyledons. The cotyledons contain the stored food reserves of the seed. As these reserves are used up, the cotyledons may turn green and begin photosynthesis or may wither as the first true leaves take over food production for the seedling.