Difference Between Somatic And Zygotic Embryogenesis

What is Embryogenesis?

Embryogenesis is the process by which an embryo arises from a fertilised egg or zygote. Embryogeny is composed of a well-coordinated series of stages, from cell division to differentiation and organ formation, until a mature embryo is formed. Hence, embryogenesis is very important in the development of multicellular organisms, since it lays the base for the construction of all tissues and organs.

It ensures the proper formation of a plant and animal body and its functioning. In plants, it makes sure that seeds are formed and thus leads to new plants, while in animals, it leads to the development of an entire living organism from a single cell.

Also Read:

• Different Parts of a Dicot Seed Embryo

• Difference Between Self-Pollination and Cross-Pollination

• Difference Between Pollination And Fertilisation

Zygotic Embryogenesis

Zygotic embryogenesis is a natural process. It initiates with the fertilisation of the egg by a sperm, which leads to the formation of a zygote.

Process of Zygotic Embryogenesis

• It is the process of embryonic development that takes place following fertilisation.

• It is the zygote that forms as a result of fertilisation.

• Cell division occurs following zygote formation.

• A cell differentiates into specific cells.

Stages of Zygotic Embryogenesis

• Fertilisation: Sperm and Egg are fertilised, which is called a zygote.

• Zygote Formation: Single-cell zygote is formed.

• Cell Division: Rapid mitosis occurs in the zygote.

• Differentiation: Division into specialised cells forming different tissues and organs.

Examples of Zygotic Embryogenesis

• In Plants, Zygotic embryogenesis relates to the development of seeds in flowering plants.

• In Animals, embryonic development in mammals.

• It provides genetic variability as it occurs sexually.

Applications of Zygotic Embryogenesis

Zygotic embryogenesis plays a significant role in natural processes and ecological balance.

• It guarantees diversity in the genome due to the sexual reproduction of species.

• Provides genetic variability within a population.

• Promotes evolutionary processes and adaptation to habitats.

Somatic Embryogenesis

Somatic embryogenesis is an artificial embryo development from somatic cells, which are non-reproductive cells.

Process of Somatic Embryogenesis

• Embryogenesis occurs due to the induction of somatic cells to form a zygote.

• It can also be done in vitro, i.e., in a laboratory.

Stages of Somatic Embryogenesis

• Initiation: Somatic cells are cultured

• Induction: Cells perform embryogenesis

• Proliferation: The Embryo starts to proliferate and differentiate.

• Maturation: The embryo develops and matures

• Germination: The mature embryo leads to the formation of a plant.

Significance Of Somatic Embryogenesis

• Important in plant biotechnology and agriculture

• Used in cloning and genetic engineering

• It is extensively used in tissue culture, particularly in orchid propagation.

Differences Between Somatic And Zygotic Embryogenesis

Zygotic embryogenesis occurs naturally from a fertilised egg cell and leads to genetically diverse offspring, while somatic embryogenesis is an artificial method where embryos develop from somatic (non-reproductive) cells, producing genetically identical plants.

MCQs on Differences Between Somatic And Zygotic Embryogenesis

Q1. Which of the following statements is true?

Statement 1: The growth and development of an embryo from a zygote in flowering plants is known as embryogenesis.

Statement 2: The phases of embryo development are the same in monocot and dicot plants.

Option 1: Statement 1 is correct but Statement 2 is incorrect

Option 2: Statement 2 is correct but Statement 1 is incorrect

Option 3: Both the statements are correct

Option 4: Both the statements are incorrect

Correct Answer: (3) Both the statements are correct

Explanation:

Statement 1: The growth and development of an embryo from a zygote in flowering plants is known as embryogenesis. Embryogenesis is a fundamental process in the life cycle of flowering plants, where a zygote formed through fertilization develops into a mature embryo within a seed. This process involves various stages and cellular changes, leading to the formation of different tissues and organs in the developing embryo.

Statement 2: The phases of embryo development are generally the same in monocot and dicot plants. Although there may be some variations and differences in timing, the overall sequence and major events of embryo development are conserved among flowering plants, regardless of whether they are monocots (e.g., grasses) or dicots (e.g., roses, beans). Both types of plants undergo processes such as the formation of the embryo proper, differentiation of cotyledons, and development of the embryonic root and shoot systems.

Hence, the correct answer is option 3) Both statements are true

Q2. Embryogeny correctly defined as

Option 1: Formation of embryo

Option 2: Development of embryo

Option 3: Also called embryogenesis

Option 4: All of these

Correct Answer: (4) All of these

Explanation:

Embryogeny is the formation and development of an embryo and also known as embryogenesis.

Hence, the correct answer is option (4) All of these

Q3. Select the correct order

Option 1: Zygote --> Globular embryo --> Mature embryo --> Heart shaped embryo

Option 2: Globular embryo --> Mature embryo --> Heart shaped embryo --> Zygote

Option 3: Zygote --> Globular embryo --> Heart shaped embryo --> Mature embryo

Option 4: Zygote --> Heart shaped embryo --> Globular embryo --> Mature embryo

Correct Answer: (3) Zygote --> Globular embryo --> Heart shaped embryo --> Mature embryo

Explanation:

In the process of fertilization in plants, the embryo develops at the micropylar end of the embryo sac, where the zygote is located. The zygote undergoes division only after a certain amount of endosperm is formed. This sequence is an important adaptation that ensures a sufficient supply of nutrients for the developing embryo. The endosperm, which forms after fertilization, acts as a source of stored food, providing energy and nutrients to the growing embryo. This mechanism helps the embryo receive the necessary resources for its growth and development, ensuring the survival of the plant's offspring.

Hence, the correct answer is option (3) Zygote --> Globular embryo --> Heart-shaped embryo --> Mature embryo

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