Question

List the stepwise manner leading to formation of a plant embryo.

Answer 1

Answer:

Plant fertilization is the union of male and female gametes (reproductive cells) to produce a zygote (fertilized egg). So, how does fertilization occur? It's a pretty straight-forward process that's similar for both flowering plants (angiosperms) and seed-bearing plants (gymnosperms). Let's break the fertilization process down into four generalized steps.

Step 1: Pollination

In general, male gametes are contained in pollen, which is carried by wind, water, or wildlife (both insects and animals) to reach female gametes. The pollen is deposited on a plant's stigma, which is part of the pistil (the elongated part of a flower extending from the ovary). This process is called pollination.

Step 2: Germination

Within a few minutes, pollen tubes begin growing, or germinating, toward the egg cell. These tubes will provide a path for the sperm carried in the pollen to reach the egg.

Step 3: Penetration of the Ovule

The pollen tubes penetrate the ovule, which contains the female gametes.

Step 4: Fertilization

Sperm travel down the pollen tubes and fertilize an egg. Most angiosperms undergo double fertilization, where both an egg and the polar nuclei in the embryonic sac are fertilized.