Root Structure: Dicot and Monocot

Root Structure - Dicot and Monocot

• Roots are the important underground part of vascular plants, responsible for anchoring, absorbing water and nutrients, and sometimes storing food.
• Some plants have aerial roots, which grow above ground, like banyan trees.
• Roots perform anchoring, absorption, storage, and reproduction.
• Roots have an integral system for these functions.

Primary Structure of Dicot Root

• Epiblema (Epidermis): Outermost layer of densely arranged cells with thin walls. Root hairs protrude from some epidermal cells.
• Cortex: Layer under the epidermis, composed of several layers of thin-walled parenchyma cells. Usually narrower than the monocot cortex.
• Endodermis: Innermost layer of the cortex, barrel-shaped cells with thickened walls forming a Casparian strip.
• Pericycle: Thin-walled layer of cells under the endodermis; involved in lateral root formation.
• Vascular Bundles: Consisting of alternating xylem and phloem with the xylem arranged in a central position (exarch). Monocot roots sometimes have more than six vascular bundles.
• Pith: Central region of the root, usually absent or small in dicot roots.

Primary Structure of Monocot Root

• Epiblema (Epidermis): Outermost layer with densely packed cells, single layer, no cuticle; root hairs may be present.
• Cortex: Broad layer underneath the epidermis; composed of multiple layers of parenchyma cells.
• Endodermis: Innermost layer in the cortex; barrel-shaped cells forming a ring; may have less prominent Casparian strips.
• Pericycle: Layer under the endodermis; single layer of parenchyma cells, crucial for lateral root formation.
• Vascular Bundles: Radial arrangement of xylem and phloem with multiple (usually 8 or more) bundles. The xylem is arranged in a ring (exarch).
• Pith: Well-developed and prominent central region of parenchyma cells.

Salient Features of Dicot and Monocot Roots

• Dicot Roots: Absence of hypodermis; epidermis has unicellular hairs; radial vascular bundles limited in number (typically less than 6); xylem arranged centrally (exarch); pith may be absent or small; presence of cambium enabling secondary growth.
• Monocot Roots: Absence of hypodermis; epidermis has unicellular hairs; radial vascular bundles plentiful (typically 8 or more); xylem in a central ring (exarch) but radiate into a polyarch arrangement; prominent pith; absence of cambium, preventing secondary growth.

Explore the intricate root structures of dicot and monocot plants in this quiz. Learn about the primary structures of dicot roots, including epiblema, cortex, endodermis, pericycle, and vascular bundles. Test your understanding of their functions and characteristics.