Dicotyledonous and Monocotyledonous Seeds: Structure, Differences, Examples

What Is A Seed?

A seed is a fertilised ovule that contains an embryo, a supply of food, and a seed coat for its protection. Seeds are the simplest structures of reproduction in plants that provide them with a means to reproduce, disperse, and colonise new areas. They represent the main way by which plant species can survive through generations.

Seeds fall into two major groups: dicotyledonous (dicot) and monocotyledonous (monocot). Dicot seeds are those that have two cotyledons, as beans and sunflowers do; monocots are those with one cotyledon, as grasses and lilies do. The leaves also have different vein patterns: the veins form net-like patterns in dicots and parallel ones in monocots. The differences reflect separate lines of evolution and affect the overall development and structure of the plant.

Seed Structure

Seeds are complex organs that contain a miniature embryo and serve to provide nourishment for its development. A normal seed contains a few key components: the cotyledons, the first leaves of the plant; the embryo, which will become the new plant; the seed coat, which protects the seed from environmental damage; and the endosperm, inside the seed, which provides nutrients to the growing embryo.

Anatomy Of Seeds

Comparison of dicot and monocot seed structure

These are distinguished by the existence of two cotyledons and a more complex embryonic structure in dicot seeds, while monocot seeds bear a single cotyledon with less complex embryonic development.

Dicotyledonous Seeds

The details are given below:

Characteristics Of Dicotyledonous Seeds

Dicotyledonous seeds, or dicots, have two cotyledons that are typical storage organs of nutrients for the developing embryo. Some examples include beans, peas, and sunflowers—each of these examples has beans or seeds which come in many different shapes and constructions.

Examples: Beans, peas, sunflowers.

Germination Process

The most common kind of germination that occurs in a dicot seed is when the seed becomes imbibed, swells, and the coat cracks open. Quite often first, the cotyledons grow out, followed by the development of the true leaves. These three stages of germination—seed imbibition, radicle emergence, and cotyledon expansion—are all very essential in establishing the seedling.

Monocotyledonous Seeds

Monocotyledonous seeds, or monocots, are characterised by having a single cotyledon. This single cotyledon plays a role in nutrient absorption and seedling establishment.

Characteristics Of Monocotyledonous Seeds

Examples: Corn, wheat, rice.

Germination Process

The germination process of a Monocot seed, for example, Corn, involves the absorption of water and swelling. First to develop and grow downward was the radicle—or primary root—followed by growth upward of the shoot, composed of the cotyledon with its first true leaves.

Stages of monocot seed germination with illustrations

Stages of germination include imbibition, radicle elongation, and coleoptile growth, all processes necessary for the seedling to break free from the seed.

Comparative Analysis