Pollen Pistil Interaction: Mechanism & Outbreeding Devices

Ans. Pistil is the female reproductive organ of a flower. It typically consists of three parts: the stigma, style, and ovary. 

• Stigma is the sticky, receptive surface at the top of the pistil where pollen grains land.
• The style is the stem-like part of the pistil that connects the stigma to the ovary. 
• Ovary is the lower part of the pistil that contains one or more ovules, which are the female reproductive cells of the plant. 
• When an ovule is fertilized by a sperm cell from a pollen grain, it develops into a seed.
• The pistil is responsible for receiving pollen, transmitting it to the ovules, and eventually producing seeds.

Ans. Pollen Grains are small, microsporangia (microscopic male reproductive structures) that are produced by the anthers of flowers. 

• They contain the male gametophytes of seed plants, which are the microgametophytes (pollen grains) that produce male gametes (sperm cells) during sexual reproduction.
• Pollen grains are typically small, lightweight, and highly resistant to desiccation (drying out). 
• They are adapted for wind dispersal or for transport by insects, birds, or other animals.

When a pollen grain lands on the stigma of a pistil (the female reproductive organ of a flower), it germinates and sends a pollen tube down through the style to the ovary, where it fertilizes an ovule (a female reproductive cell) to form a seed.

Ans. Pollen Pistil interaction is the process by which pollen from the anther of a flower is transferred to the stigma of the same or another flower, resulting in fertilization and the production of seeds.

• The process begins when a pollinator, such as a bee or a hummingbird, lands on the flower and collects nectar from the nectary. 
• As the pollinator moves from flower to flower, it brushes against the anthers of the flowers and collects pollen on its body.
• When the pollinator lands on the stigma of another flower, some of the pollen grains are transferred to the sticky surface of the stigma. 
• The pollen grains germinate and produce a pollen tube, which grows down the style and into the ovary of the flower.
• Inside the ovary, the pollen tube releases its sperm cells, which fertilize the egg cells inside the ovules. 
• The process completes the fertilization of the ovules, leading to the production of seeds.

The fertilized ovules develop into seeds, and the ovary grows and matures into a fruit, which contains and protects the seeds. The seeds are eventually dispersed, either by animals, wind, or water and can germinate to grow into new plants.

Ans. Hermaphroditic Flowers are flowers that have both male and female reproductive organs. In these flowers, fertilization can occur through self-pollination or cross-pollination.

• Self-pollination occurs when pollen from the anther (male reproductive organ) of a flower is transferred to the stigma (female reproductive organ) of the same flower or another flower on the same plant.
• Cross-pollination occurs when pollen from one flower is transferred to the stigma of another flower on the same plant or on a different plant of the same species.

In hermaphroditic flowers, self-pollination may occur if the pollen from the anther is able to reach the stigma of the same flower before the flower has fully opened, or if the flower is self-fertile and able to fertilize itself. Cross-pollination may occur if the pollen from one flower is carried by wind, insects, or animals to the stigma of another flower on the same plant or on a different plant.

Ans. (D) Anther

Explanation: Anthers are the male reproductive organs of the flower. They are located on the stamen, which is the male reproductive organ of the flower. The anthers produce microsporangia (microscopic structures that contain microsporocytes) that give rise to pollen grains.

Ans. Pollen Pistil Interaction is necessary for plants because it is the means by which they reproduce sexually. 

• This interaction is necessary because it allows plants to produce offspring that have genetic material from both parent plants. 
• It increases genetic diversity within a population, which can be beneficial for the survival and adaptation of the species. 
• Without the interaction between pollen and the pistil, plants would be unable to reproduce sexually and would have to rely on other means of reproduction, such as vegetative reproduction.

Ans. Outbreeding refers to the transfer of pollen from one individual to the pistil of another individual that is not closely related to the pollen donor.

• It can occur through a variety of mechanisms, including cross-pollination by insects or other animals, or by the wind. 
• Outbreeding is important for the production of offspring with a greater genetic diversity, which can be beneficial for the long-term survival and adaptability of the species. 
• In some plant species, self-fertilization (mating with oneself) is also possible, but this can lead to a reduction in genetic diversity and can be disadvantageous in the long term.

Ans. In cross-pollination, pollen from one flower is transferred to the pistil of another flower on the same plant or on a different plant of the same species. This results in the production of seeds that contain genetic material from both parent plants. Cross-pollination is more common in plants that are not self-fertile and relies on external factors such as wind, insects, or animals to facilitate the transfer of pollen.

Self-pollination occurs when pollen from the anther of a flower is transferred to the pistil of the same flower or another flower on the same plant. This results in the production of seeds that contain genetic material from only one parent plant. Self-pollination is more common in plants that are self-fertile and do not require external factors to facilitate the transfer of pollen.

Ans. There are many mechanisms by which plants and animals have evolved to promote outbreeding and prevent inbreeding. Here are three examples of outbreeding devices:

• Dichogamy refers to the separation of the male and female reproductive organs in time or space, which prevents self-fertilization and promotes cross-fertilization between individuals. 
• Herkogamy is a type of outbreeding mechanism that refers to the physical separation of the male and female reproductive organs in a plant, which prevents self-fertilization and promotes cross-fertilization between individuals.
• Heterostyly is a type of outbreeding mechanism found in some plant species in which the flowers have two different types of stamen and pistil arrangements. It is thought to have evolved to increase genetic diversity and reduce inbreeding depression.

Ans. Pollen-Pistil interaction is the process by which pollen, produced by the anthers of a flower, is transferred to the stigma of the same or a different flower. The first step in this process is typically the release of pollen from the anthers. This can occur through a variety of mechanisms, including wind, water, or animal pollinators such as bees, butterflies, and hummingbirds. Once the pollen has been released, it must come into contact with the stigma of a flower in order for fertilization to occur.