Double fertilization, class 12 Botany LearnQuest
Channel: LearnQuest
Date: 2023-12-06

Double fertilization is a unique reproductive process found in flowering plants (angiosperms). It involves two separate fertilization events, both occurring within the female reproductive organ, the ovary.

Here's a breakdown of the process:

Step 1: Pollination

Pollen grains are transferred from the male reproductive organ, the stamen, to the stigma, the receptive surface of the female carpel.

Step 2: Pollen tube growth

A pollen tube grows down the style of the carpel towards the ovule.

This tube carries two sperm cells.

Step 3: Double fertilization

One sperm cell enters the egg cell, resulting in fertilization and the formation of a diploid (2n) zygote. This is the embryo of the future plant.

The second sperm cell fuses with two polar nuclei in the large central cell of the ovule. This fusion creates a triploid (3n) primary endosperm nucleus (PEN).

Step 4: Seed development

The PEN divides repeatedly to form the endosperm, a nutrient-rich tissue that nourishes the developing embryo.

The zygote undergoes cell division and differentiation to form the various tissues of the embryo, including the root, stem, and leaves.

Significance of double fertilization:

Double fertilization ensures a direct link between the male and female gametes, leading to genetic diversity in the offspring.

The triploid endosperm provides a rich source of nutrients for the developing embryo, increasing its chances of survival and successful germination.

This complex process is essential for the reproductive success of flowering plants and their dominance in diverse terrestrial environments.

For further understanding, you can:

Explore diagrams of double fertilization online.

Watch educational videos illustrating the process.

Consult biology textbooks or online resources for detailed information.