The key difference between pollination and fertilization is that Pollination is the transfer of pollen from the male to the female reproductive organs in plants, while fertilization is the fusion of the male and female gametes resulting in the formation of a zygote.
What is Pollination?
Pollen grains are transferred from the stamens, the parts of a flower that produce them, to the ovules (seed precursors) either directly or through a pistil in flowering plants. In certain plants like conifers and cycads, where the ovules are exposed, pollen is caught in a fluid droplet secreted by the ovule.
However, in flowering plants, the ovules are enclosed within a hollow organ called the pistil. Pollen is deposited on the receptive surface of the pistil known as the stigma. Upon landing on the stigma, the pollen germinates, forming a pollen tube that grows through the pistil towards one of the ovules at the base.
During double fertilization in flowering plants, one of the sperm cells within the pollen tube fuses with the ovule’s egg cell, leading to embryo development. Simultaneously, the other cell combines with two subsidiary sexual nuclei of the ovule, initiating the formation of a nutrient-rich tissue called the endosperm. As the ovule develops, it undergoes a transformation into a seed.
What is Fertilization?
Fertilization is the process where a sperm nucleus, originating from the father, combines with an egg nucleus, originating from the mother, resulting in the primary nucleus of an embryo. This critical biological process involves the merging of genetic material from two distinct sex cells, or gametes, each carrying half the usual number of chromosomes for the species.
The most basic form of fertilization, seen in microorganisms and protozoans, involves an exchange of genetic material between two cells. The initial important event in fertilization is the fusion of the membranes of the two gametes, creating a channel that allows the transfer of materials between the cells.
In advanced plants, fertilization follows pollination, wherein pollen is transferred to and establishes contact with the female gamete or macrospore.
Pollination vs Fertilization
The major difference between pollination and fertilization is given below:
| Basis of Comparison | Pollination | Fertilization |
| Meaning | The internal process inside the flowers. | The pollen tube enters the ovule. |
| Mechanism | External process on the flower’s outer part. | Forms to facilitate male gamete transfer to the ovule. |
| Pollen Tube | Does not form. | The genetic and biochemical process. |
| Sequence | Occurs before fertilization. | Occurs after pollination. |
| process | Physical process. | The genetic and biochemical process. |
| Occurrence | Occurs in flowering plants only. | Occurs in almost every plant and living being. |
| External factors | Required. | Not required. |
| Types | Self-pollination and cross-pollination. | No specific types. |
| Result | Leads to fertilization. | Results in the formation of seeds. |
| Agents | Wind, water, birds, insects, animals. | Pollen tube enters the ovule. |