Fertilization is an essential process in the life cycle of plants, as it allows for the production of seeds, fruit, and new growth. There are two main types of fertilization in plants: self-fertilization and cross-fertilization.
Self-fertilization, also known as selfing, occurs when a plant’s flowers are pollinated by pollen from the same plant. This type is common in plants with flowers that are not visibly attractive to pollinators, such as insects or birds.
On the other hand, cross-fertilization occurs when a plant’s flowers are pollinated by pollen from another plant of the same species. This type is more prevalent in plants with flowers that are attractive to pollinators.
Fertilization in plants involves four main steps:
Pollination: Pollination is the process of transferring pollen from the male reproductive organs (stamen) of a flower to the female reproductive organs (pistil) of the same or a different flower. Pollination can occur through self-fertilization, where the pollen is transferred within the same flower or plant, or through cross-fertilization, where the pollen is transferred from one plant to another. Pollination is usually facilitated by pollinators such as bees, butterflies, birds, and wind.
Germination of pollen grain: After pollination, the pollen grain germinates on the stigma, the receptive part of the pistil. The pollen grain produces a pollen tube, which grows down the style towards the ovary where the ovules are located.
Penetration of the ovule: The pollen tube grows until it reaches an ovule and penetrates it, releasing the sperm cells.
Fertilization: One of the sperm cells fertilizes the egg cell in the ovule, while the other sperm cell fertilizes the two polar nuclei to form the endosperm, a tissue that provides nutrients to the developing seed. The fertilized egg cell develops into an embryo, while the endosperm develops into the seed coat. The fertilized ovule develops into a seed, and the ovary develops into a fruit.
Difference between pollination and fertilization
Pollination and fertilization are two important processes that are necessary for plants to reproduce and produce seeds. Pollination is the transfer of pollen from the male reproductive organ of a flower to the female reproductive organ of the same or another flower. Pollen contains the male gametes (sperm cells) that are necessary for fertilization. Fertilization, on the other hand, is the fusion of the male and female gametes to form a zygote, which will develop into a seed.
Pollination occurs when pollen is transferred from the anthers (male reproductive structures) of one flower to the stigma (female reproductive structure) of another flower. This can be done by a variety of means, including wind, insects, birds, and other animals. Pollination is necessary for the plant to produce seeds, but it does not guarantee fertilization.
Fertilization occurs when the male gametes (contained in the pollen) are transferred to the female gametes (contained in the ovules) and they fuse to form a zygote. This process occurs within the ovary of the flower and is necessary for the plant to produce seeds. Without it, the plant will not be able to produce seeds and will not be able to reproduce.