Pollen Pistil Interaction

Pollen pistil interaction is the process of transfer of pollen grains of one plant to the pistil/stigma of the same or different plant, which can be either self or cross-pollination. The pistil is the female reproductive part of a flowering plant, while pollen grains are the male reproductive part of a plant. Pollination is the first step of pollen pistil interaction, followed by the pollen adhesion to the stigma. Now, we'll be heading towards our next section, which is a pretty interesting one: the concept of outbreeding devices in plants. 

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Relation Between Pollen Pistil Interaction and Outbreeding Devices

The section is related to the concept of outbreeding devices and the relationship between pollen pistil interaction and outbreeding devices. Before proceeding to the types of outbreeding devices, let’s understand what outbreeding devices are.

What is The Meaning of Outbreeding Devices?
Outbreeding devices are the mechanisms/processes which the plants adapt to prevent self-pollination.  But why do plants use such devices? The important reasons are mentioned below. 

• Inbreeding Depression: The reason behind the adoption of such techniques by plants is that due to continued inbreeding, plants can develop a condition called inbreeding depression, leading to unhealthy offspring.

• No Genetic Variations: in self-pollination, due to the same genes of males and females, there are no genetic variations.  

• Unisexuality: If the plant is unisexual, Outbreeding is the only alternative.

• Unsynchronized Pollen Release: The release of pollen grains and receptivity of stigma should be synchronized for the breeding to happen. This prevents self-pollination.

Now, let’s get into the prime topic of the section- the types of outbreeding devices. 

Outbreeding Devices 

There are several devices that the plants adapt to promote cross-pollination, which are enumerated below:

Unisexuality: Unisexuality is an outbreeding device in which the plant bears, either male or female flowers. Besides, the flower is also not hermaphrodite. This is also known as Dioecism.

Dichogamy: In this outbreeding device, the stigma and the anther have different maturity times. Thus, depending upon the maturity, Dichogamy can be classified into two types:

• Protandry: The androecium matures before the gynoecium. For example, maize plants.

• Protogyny: The gynoecium matures before the androecium.    

Herkogamy: Herkogamy is a naturally occurring condition where there is a natural physical barrier to the entry of pollen grains into the ovaries.

Self-Sterility: In this outbreeding device, the plant possesses a gene to recognize similar genes and doesn’t allow the pollen grain to germinate. The self-sterile gene is present in the ovule and the grain.

Heterostyly: In this outbreeding device, the stigma and the anther differ in levels, preventing the pollen grain to reach the stigma and pollinating it. 

Pollen Prepotency: In pollen prepotency, a different flower's pollen matures faster than that of the same flower, thus helping in preventing autogamy.  

These are the outbreeding devices in plants. Now, if the question comes- Explain pollen pistil interaction and Outbreeding devices, one will be able to answer easily. The next section is the final section of the discussion and enumerates the steps of pollen pistil interaction.

Steps of Pollen Pistil Interaction

Pollination doesn’t always mean fertilization. For pollination to occur, the pistil needs to recognize the pollen grain of the same species. Pollen pistil interaction is not a small process. Thus, we need to understand the complete process of pollen pistil interaction, which results in successful fertilization. Enumerated below are the steps of pollen pistil interaction:

• The male plant releases pollen grains.

• The pollen grain lands on the pistil of the female plant.

• If the pollen is compatible, the pistil accepts it, while incompatible ones are rejected.

• If the pollen grain is accepted by the female plant, the grain forms pollen tubes and releases its contents and chemicals.

• The pollen tubes head towards the ovary through style.

• As the pollen tube reaches the ovary, the male gamete enters the ovary and is then synergic.

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This is the complete process of the pollen pistil interaction process that is required for successful fertilization.

We hope that all the concepts related to pollen pistil interactions and outbreeding devices in plants are pretty much clear. We have learned about both the steps of pollen pistil interaction as well as the different outbreeding devices.