Question

Mesophyll is differentiated into palisade and spongy tissues in
(a) Extremely xerophytic leaves
(b) Hydrophytic leaves
(c) Monocot leaves
(d) Dicot leaves

Answer 1

The leaves are members of the flowering plants or angiosperms consisting of a lower and upper epidermis with stomata for the exchange of gases. The lower epidermis is less thick and more stomata than the upper epidermis.

Complete answer:
The mesophyll has many chloroplasts and is present between the two epidermal layers. It is usually differentiated into two regions which are the upper palisade parenchyma and the lower spongy parenchyma in dicot leaves or dorsiventral leaves. In monocot leaves or isobilateral leaves, undifferentiated mesophyll is present that shows spongy parenchyma.
So, the correct answer is ‘Dicot leaves’.

Additional information:
- Stems of dicot plants have a well- defined epidermis with a cuticle, a layer of dermis along with multicellular stem hair. Examples are sunflower and Cucurbita.
- In a dicot stem, vascular bundles are arranged in a ring around the pith and the pith is concentrated at the core of the stem.
- Xylem is described as an endarch and is used when there is more than one strand of primary xylem in a stem or root. The xylem develops from the inside towards the periphery, i.e., centrifugally. The protoxylem is closest to the center of the stem or root and the metaxylem closest to the periphery of the stem. The stems of dicot plants typically have endarch development and the roots are normally considered to have exarch development.
- The dicot plants have the cambium tissue which is a meristematic tissue and is present in the vascular bundles of the plant. This tissue has a regeneration capacity because of which it can form new tissue at the time of grafting.
- Closed vascular bundles are present in monocots as they lack cambium. In monocot stems vascular bundles are closed, collateral, and endarch.

Note: In flowering plants, the seeds of which typically contain only one embryonic leaf, or cotyledon are known as monocots, whereas dicot plants contain two cotyledons in its embryo. Examples of dicot plants are roses, magnolias, hollyhocks, and geraniums.