Difference Between Monocot and Dicot Embryo

The main difference between monocot and dicot embryo is that monocot contains a single cotyledon in its embryo whereas dicot contains two cotyledons in its embryo. Monocots and dicots are the two divisions of angiosperms, the flowering plants. They are the most successful and diversified groups of plants on earth. Monocots and dicots differ in their structure as well. They have different types of stem, roots, leaves, flowers, and seeds.

Key Areas Covered

1. What is a Monocot Embryo
     – Definition, Structure
2. What is a Dicot Embryo
     – Definition, Structure
3. What are the Similarities Between Monocot and Dicot Embryo
     – Outline of Common Features
4. What are the Difference Between Monocot and Dicot Embryo
    – Comparison of Key Differences

Key Terms: Cotyledon, Dicot Embryo, Monocot Embryo, Plumule, Primary Axis

What is a Monocot Embryo

Monocot embryo is a rudimentary stage of monocots that can develop into a new individual. It occurs inside the seed. Monocots contain one embryonic leaf or cotyledon in its embryo. The cotyledon of the monocot is narrow and long. It occurs at the tip of the primary axis. The plumule or the rudimentary shoot is present at the lateral side of the primary axis. A large endosperm is present in the monocot seed as well.

Figure 1: Monocot (left) and Dicot (right) Cotyledon

Some examples of monocots are grasses like sugar cane and bamboo, cereal grains like rice, wheat, and corn, crops like palm and banana, asparaguses like onion and garlic and horticultural plants like lilies, daffodils tulips, and orchids.

What is a Dicot Embryo

Dicot embryo is a rudimentary stage present inside the dicot seed. It consists of two cotyledons, which are broad. The two cotyledons occur on either side of the primary axis. The apical bud is present at the tip of the primary axis while the root tip is present at the base of the axis. The embryonic leaves do not resemble the true leaves in shape and are fatter than true leaves. However, dicots have a tiny endosperm.

Figure 2: Embryonic and True Leaves of Dicot

Most woody plants are the examples of dicots; oaks, roses, daisies, beans, peas, and tomatoes are some examples.

Similarities Between Monocot and Dicot Embryo

• Both monocot and dicot embryo are rudimentary stages of angiosperms developed from the zygote inside the embryo sac.
• Both embryos consist of cotyledons, primary axis, rudimentary shoot and root.
• Upon germination, both monocot and dicot embryos develop into a new individual.

Difference Between Monocot and Dicot Embryo

Definition

Monocot Embryo is a rudimentary stage of a monocot.

Dicot Embryo is a rudimentary stage of a dicot.

Number of Cotyledons

Monocot Embryo consists of one cotyledon.

Dicot Embryo consists of two cotyledons.

Position of Cotyledons

Monocot Embryo: A single monocot cotyledon occurs at the terminal position.

Dicot Embryo: Two dicot cotyledons occur laterally.

Plumule

Monocot Embryo: Plumule occurs laterally in monocot embryo.

Dicot Embryo: Plumulue occurs distally in dicot embryo.

Pulumule Envelope

Monocot Embryo: The envelope of the monocot plumule is called coleoptile.

Dicot Embryo: The dicot plumule doesn’t have an envelope.

Coleorhiza

Monocot Embryo: Coleorhiza is the protective sheath of the monocot radicle.

Dicot Embryo: Dicot embryo does not have a coleorhiza.

True Leaves

Monocot Embryo: Monocot cotyledon resembles the true leaves.

Dicot Embryo: Dicot cotyledons do not resemble the true leaves.

Conclusion

Both monocot and dicot embryos are rudimentary structures of angiosperms. Monocot and dicot embryo mainly differ by the number of cotyledons in the embryo. Monocot embryo consists of a single cotyledon while dicot embryo consists of two cotyledons.

Reference:

1. “Embryo in Flowering Plants: Structure, Types and Development.” Your Article Library, 22 Feb. 2014, Available here.

Image Courtesy:

1. “Monocot vs dicot Pengo” By w:User:Pengo (CC BY-SA 3.0) via Commons Wikimedia
2. “Young castor bean plant showing prominent cotyledons” By Rickjpelleg assumed – Own work assumed (based on copyright claims) (CC BY-SA 2.5) via Commons Wikimedia