Cleistogamy – Features, Advantages and Types

Cleistogamy is a phenomenon that describes self-pollination in certain types of flowers. Plants exhibit mainly two types of reproduction and these are the sexual mode of reproduction by producing seeds and the asexual mode of reproduction through budding, vegetative propagation, etc. Cleistogamous flowers remain closed throughout their lives and exhibit self-pollination. In this article, we will learn what is cleistogamy, the characteristics of cleistogamy, advantages, and disadvantages of cleistogamy.

What is Cleistogamy?

The word “cleistogamy” means “closed or hidden marriage”. The flower that exhibits cleistogamy remains closed throughout its life and performs self-pollination (transferring of pollen from the anther to the stigma of the same flower). These flowers are also known as ‘Cleistogamous flowers”.

What is Cleistogamy Pollination?

The “cleistogamy pollination” means self-pollination. It is a type of autogamy (fusion of gametes of a single individual). These flowers are not dependent on any external factors for their pollination and they produce a specialized set of seeds. The anther and the stigma are relatively small in such flowers.

The cleistogamy pollination is mainly shown by plants that belong to the grass family such as pansy, peas, peanuts etc. The major drawback of cleistogamous pollination is that it can not produce genetically diverse seeds because the anther and stigma of the same flower contain the same genetic combination. So, pollination in such cases reduces the genetic variability of the seeds.

Cleistogamous Flowers

Cleistogamous flowers are the flowers that remain closed throughout their life and they mainly perform self-pollination. These flowers are usually bisexual. Cleistogamous flowers are invariably autogamous because the flower remains closed so there ois no chance of another pollen entering the stigma. Instead the pollen grain of cleistogamous flowers transfers to the stigma without the help of any pollinating agent. Cleistogamous flowers examples are flowers of peas, peanuts etc.

Cleistogamy and its Types

Cleistogamy or “hidden marriage” can be of various types. The types are described below:

• Parenthesis Cleistogamy: In this type, the flowers undergo self pollination in their bud stage. After this, the flower opens itself at the later stage of its life. Example- Cuscuta.
• Pseudo Cleistogamy: This type of cleistogamy is seen in plants that contain both the closed flower and open flowers. The closed flowers only exhibit the cleistogamy pollination.
• Complete Cleistogamy: The plants that contain only closed flowers exhibit complete cleistogamy. Here, closed flowers undergo self pollination or cleistogamy pollination for their reproduction.
• True Cleistogamy: In this case, the plants are morphologically different, which means large open flowers and small closed flowers. The closed flowers exhibit cleistogamy or self pollination.

Characters of Cleistogamy

Cleistogamy is a natural phenomenon that is exhibited by some specialised flowers of the grass family. Some features of cleistogamy is mentioned below:

• Cleistogamy pollination is a type of autogamy. Here, pollen grains from another are transferred to the stigma of the same flower.
• Cleistogamy is exhibited by closed flowers.
• The petals of the cleistogamous flowers are not attractive or gaudy. Because, the flowers do not need any pollinators for their reproduction.
• These flowers possess both the male reproductive organ or the anther and the female reproductive organ or the stigma within themselves.

Cleistogamy Examples

Some plants which show cleisotgamy have been given below:

1. Peanuts
2. Pea
3. Pansies

Advantages of Cleistogamy

Advantages of cleistogamy is given below:

• Plants with cleistogamous flowers do not need to spend resources on making gaudy petals. Gaudy petals are essential to attract pollinators that will carry the pollen from the anther of a flower. But, as the cleistogamous flowers exhibit self pollination, they are not dependent on the pollinators for their reproduction. So, the cleistogamous flowers do not make their petals attractive or gaudy.
• Cleistogamy enables a plant to reproduce in adverse environmental conditions. Because, such flowers perform self pollination and they are not dependent on any external factors for their reproduction. So, in adverse environmental conditions, they can safely perform their fertilisation within closed flowers. Thus, they can maintain their population in adverse conditions also.
• In cleistogamy or self pollination, chances of loss of pollen grains is minimal. So such flowers do not need to produce pollen grains in large quantities.

Disadvantage of Cleistogamy

In spite of having numerous advantages, cleistogamy exhibits certain drawbacks also:

• Sexual reproduction can not be seen in cleistogamous flowers. These flowers exhibit self-pollination and as a result of it, genetically diverse seeds are not produced. Because the anther and the stigma of the same flower contain the same genetic combination. So, genetic variation in seeds does not appear due to such self-pollination
• As there is no genetic variation in seeds, genetic diversity in cleistogamous plant populations is also absent.
• The chances of inbreeding depression and the appearance of harmful alleles are also high in cleistogamous plants.

Conclusion – Cleistogamy

Cleistogamy or hidden marriage is a phenomenon of self pollination which is exhibited by certain closed flowers. This is a type of autogamy. Cleistogamy pollination enables these plants to reproduce in adverse environmental conditions because they are not dependent on external pollinators for their reproduction. But, self pollination also reduces their genetic variability of seeds.

FAQs on Cleistogamy

What do you mean by Cleistogamous Flowers?

Cleistogamous flowers are the closed flowers which means they remain closed throughout their life. Such flowers exhibit self pollination.

What are the Advantages of Cleistogamy?

Cleistogamy enables a plant to reproduce in adverse environmental conditions. Such plants are not dependent on external pollinators for their reproduction.

Does Cleistogamy Exhibit Self Pollination?

Yes, cleistogamy is a type of self pollination. Here, the pollen grains from the anther are transferred to the stigma of the same flower and thus it facilitates fertilisation.

Write a Disadvantage of Cleistogamy.

Cleistogamy does not exhibit cross pollination. So, the genetic variability of seeds is very low in such modes of reproduction.

Give an Example of a Plant that exhibits Cleistogamy.

Cleistogamy is mainly exhibited by the plants that belong to the grass family. Such plants are peas, peanuts etc.

What is Cleistogamy Class 12?

Cleistogamy is a special reproductive strategy employed by flowers to ensure self-pollination. It is the ability to reproduce without opening. This means that even if the flower does not bloom, the plant can still produce seeds, ensuring survival in challenging environments.

What is the Difference Between Cleistogamy and Chasmogamy?

Cleistogamy is a type of reproduction where flowers do not open, ensuring self-pollination, while chasmogamy involves flowers that open for pollination and here cross-pollination occurs.

What are the Two Types of Cleistogamy?

The two types of cleistogamy are complete cleistogamy, where flowers are truly cleistogamous, and pseudo-cleistogamy, where flowers involves both chasmogamous and cleistogamous flowers.

Why Cleistogamous Flowers are Invariably Autogamous?

The cleistogamous flowers are invariably autogamous because they do not open leaving little scope for cross-pollination.

What is Cleistogamy and Dichogamy?

Cleistogamy is a self-pollinating reproductive technique where flowers remain closed, while dichogamy refers to the different maturation time of androecium and gynoecium within the same flower.