Multiple Choice Questions on Internal Anatomy of Root and Leaf

The internal structure of a leaf includes the epidermis, mesophyll, and vascular bundles.

• Upper epidermis protects the leaf and may contain a cuticle.
• Palisade mesophyll contains tightly packed cells rich in chloroplasts for photosynthesis.
• Spongy mesophyll has loosely arranged cells for gas exchange.
• Vascular bundles contain xylem (water transport) and phloem (food transport).

This layered arrangement supports photosynthesis and transpiration.

The endodermis controls the movement of water and minerals into the vascular tissues of the root.

• It is the innermost layer of the cortex.
• Its cells contain Casparian strips, made of suberin.
• Casparian strips block passive flow and force water through living cells.

This selective barrier ensures regulated absorption into the xylem.

The main difference between dicot and monocot root internal structure lies in the arrangement of vascular tissues and presence of pith.

• Dicot root: Xylem is star-shaped with phloem between arms; pith is small or absent.
• Monocot root: Xylem and phloem are arranged in a ring; large central pith is present.
• Dicot roots usually have fewer xylem bundles (2–6), while monocots have many (polyarch).

These differences help in identifying plant types in anatomy studies.

The difference between dicot and monocot leaf internal structure is mainly in mesophyll differentiation and vascular bundle arrangement.

• Dicot leaf: Distinct palisade and spongy mesophyll; reticulate venation.
• Monocot leaf: Mesophyll not clearly differentiated; parallel venation.
• Monocot leaves often have bulliform cells for leaf rolling.

These anatomical features reflect their adaptation and classification.

The pericycle is responsible for the formation of lateral roots in plants.

• It is a layer of cells located just inside the endodermis.
• It retains the ability to divide actively.
• In dicots, it also contributes to secondary growth by forming part of the vascular cambium.

This makes the pericycle essential for root branching and growth.

In roots, xylem and phloem are arranged radially on different radii.

• Xylem forms a central core, often star-shaped in dicots.
• Phloem is located between the arms of xylem.
• This arrangement is called radial vascular arrangement.

It differs from stems, where vascular bundles are conjoint.

The mesophyll is the photosynthetic tissue located between the upper and lower epidermis of a leaf.

• It consists of palisade mesophyll for maximum photosynthesis.
• Spongy mesophyll facilitates gas exchange through air spaces.
• Contains numerous chloroplasts.

Mesophyll plays a central role in photosynthesis and gaseous exchange.

Root hairs are unicellular extensions of epidermal cells that increase the surface area for absorption.

• They arise from the epidermis of young roots.
• They absorb water and dissolved minerals from soil.
• They significantly increase absorptive capacity.

Root hairs are essential for efficient nutrient uptake in plants.

The vascular bundles in a leaf transport water, minerals, and food throughout the plant.

• Xylem carries water and minerals from roots to leaves.
• Phloem transports prepared food from leaves to other parts.
• They form the veins and midrib of the leaf.

This vascular system maintains conduction and structural support in the leaf.