Fruit and Seed Formation Without Fertilization

Fruit and Seed Formation Without Fertilization

Fruits and seeds are not only essential  in the life cycle of flowering plants; they are also utilized as sources of food. In a few species, a special mechanism has evolved to produce seed and fruit. This mechanism can prominently be seen in Asteraceae.  Read on to explore these special mechanisms.

Apomixis

Apomixis is a type of asexual reproduction that mimics sexual reproduction to produce seeds in flowering plants. Two types of apomixis are found in flowering plants. These are as follows:

1. An unfertilized diploid egg developing into the embryo through parthenogenesis. Example: Rosaceae
2. Embryo arising directly from the nucellar cells of the ovule. Example: Citrus

Polyembryony

Polyembryony may be defined as the phenomenon of more than one embryo developing from a single ovule. It was discovered by Leeuwenhoek. Polyembryony occurs commonly in many animals and plants, Example: Nine-banded armadillo. Polyembryony is classified into two types. These are as follows:

1. True polyembryony – More than one embryo develops from a single ovule. Example: Citrus
2. False polyembryony – More than one embryo develops from different ovules. Example: Mango

Parthenocarpy

Parthenocarpy may be defined as the production of fruit from an unfertilized egg. It can be achieved by naturally or artificially. Example: seedless watermelon.

Two types of parthenocarpy are found. These are as follows:

1. Stimulative parthenocarpy – In this process, pollination is required to produce fruits. Example: Seedless watermelons.
2. Vegetative parthenocarpy – In this process, pollination is not required to produce fruits. Example: Seedless cucumbers.

Hybrid cultivation of fruits by parthenocarpy is used to increase productivity. But, parthenocarpy process is expensive. As a result, hybrid seeds and fruits become quite expensive.

Frequently Asked Questions

1. What is Apomixis?

Apomixis is a type of asexual reproduction that mimics sexual reproduction to produce seeds in flowering plants.

2. What is Polyembryony?

Polyembryony is defined as the phenomenon of more than one embryo developing from a single ovule

3. What is Parthenocarpy?

Parthenocarpy is defined as the production of fruit from an unfertilized egg.