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Pistil is the female reproductive part of a flower that is located at the center of the bloom. It's developed or adapted for pollination, followed by fertilization. The primary parts are a swelling base, the ovary, ovules, a stalk, a pollen-receptive tip, and stigma. It has a variety of shapes and is frequently sticky.
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Key Terms: Pistil, Carpel, Stigma, Style, Ovary, Pollen Grain, Ovary, stalk, pollen-receptive tip, ovules
What is a Pistil?
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The pistil or gynoecium represents the female reproductive component of the flower. A flower can be monocarpellary (just one pistil) or multicarpellary (having multiple pistils). Pistils can be syncarpous (joined) or apocarpous (separated).
Pistil
The stigma, style, and ovary are the three sections of each pistil. Pollen grains land on the stigma as a landing place. The long slender section underneath the stigma is called the style. The ovary is the bulged portion of the pistil at its base. The ovarian cavity contains the placenta. The placenta produces Megasporangia, also known as ovules.
| Pistil is the female reproductive organ in flowers. It comprises of three parts:
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Also Read: Sexual Reproduction in Flowering Plants
Function of Pistil
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Functions of a Pistil are as follows:
- The pistil is primarily developed for the pollination process, followed by fertilization.
- A suitable pollen grain settles on the stigma and germinates, generating a pollen tube during the pollination process.
- The pollen tube develops downward (style tissues) to deposit sperm for fertilization with ovules in the ovary.
- The pistil is a collective sense of the female reproductive system that collects male gametes from the androecium, the male reproductive portion.
Methods of Reproduction
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Reproduction in flowers occurs when pollen from one flower is transferred to the stigma of another flower. A pollen tube forms as soon as the pollen grain is trapped on the stigma. A sperm nucleus from a male gamete and an egg nucleus unites in the pollen tube to form a zygote. Ovules that have been fertilized become seeds.
Checkout: Pollen Germination on Stigma Through a Permanent Slide
Interaction Between Pollen and Pistils
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Pollen that lands on the pistil stigma may be compatible or incompatible with it. As a result, the compatibility determines whether the pollen is accepted or rejected by the stigma.
If the pollen and the pistil are compatible, the following events will occur:
- The pistil accepts pollen.
- Pollen tube formation
- The pollen tube makes its way to the ovary.
- Pollen grains make their way into the pollen tube.
- Through the micropyle, the pollen tube penetrates the ovule.
- Filiform apparatus allows pollen tubes to enter a synergid.
- Fertilization takes place.
Interaction Between Pollen and Pistil
If the pollen and pistil, on the other hand, are incompatible, the following events will occur:
- The pistil rejects pollen
- Pollen tube growth is inhibited
- Fertilization is not possible
As a result, the Pollen-Pistil interaction can be characterized as the pollen-pistil interaction is a dynamic pollen recognition mechanism.
Difference Between Carpel and Pistil [Click Here For Sample Questions]
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The difference between Carpel and Pistil are,
| Elements | Carpel | Pistil |
|---|---|---|
| Definition | Carpel refers to a flower's female reproductive organ, consisting of an ovary, a stigma, and frequently a style, and can be found alone or in groups. | Pistil refers to a flower's ovule-bearing or seed-bearing female organs. This clarifies the primary distinction between carpel and pistil. |
| Components | A carpel has an ovary, stigma, and style. | A pistil can have one or more carpels. |
| Significance | The number of carpels can be determined by counting the number of distinct styles. | The number of pistils can be determined by counting the number of distinct ovaries in a flower. |
| Function | Carpels are in charge of producing egg cells, fertilization, seed production, and dispersal. | The pistil is the female part of the flower and acts as a reproductive component. |
| Fertilization | Fertilization occurs | No fertilization |
| Egg cells | Egg cells are produced | Egg cells are not produced |
| Seeds | Production of seeds | No production of seeds |
Read More:
| Important Chapter Related Topics | ||
|---|---|---|
| Gemmule Formation | Double Fertilization | Fragmentation in Plants and Animals |
| Asexual Reproduction | Budding | Artificial Pollination |
| Binary Fission | Apomixis | Sporulation |
Structure of Pistil
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The pistil, which is positioned in the center of the flower, is the female reproductive portion of the flower. The primary components include,
- The swelling base
- Ovary (with prospective seeds or ovules)
- A stalk or style coming from the ovary
- The stigma
Pistil Structure
Each pistil is made up of one to many leaf-like structures, and its primary role is to protect the ovules.
Read More: Vegetative Propagation in Plants
Things to Remember
- The female reproductive component of a flower is the pistil. It comprises three parts: stigma, style, and ovary.
- The stigma is the portion of the female reproductive system that serves as a landing platform for pollen grains.
- Because of the sweet component present, the stigma moves chemotropically. The ovary is the swelling base of the pistil.
- The placenta is a cushion-like structure found inside the ovarian cavity, where the ovules are found.
- The Pollen-Pistil interaction can be characterized as the pollen-pistil interaction is a dynamic pollen recognition mechanism.
- Pollen from one flower is transported to the stigma of another flower during flower reproduction.
Sample Questions
Ques. A flower's pistil will not take pollen from any plant other than its species. What causes this to happen? [2 Marks]
Ans. Self-fertilization is the term for this process. Blooms trade dust with the same bloom or another on a similar plant in self-fertilization. Any dust from an alternate bloom that lands on a blossom is discarded. Self-fertilization does not always guarantee genetic variation because hereditary material between plants is swapped.
Ques. What exactly is a pollen basket? [1 Mark]
Ans. The pollen basket is a pollen-gathering device seen in some honey bee species. It can be found in the tibia region of the hind legs, surrounded by stiff hairs. Honeybees visit multiple blooms in a single day, and the pollen they collect is stored in pollen baskets.
Ques. What is the pollen tube's method of entry into the ovule? [3 Marks]
Ans. The pollen tube penetrates the ovule through the micropylar end after reaching the ovary. It subsequently passes via the filiform apparatus at the micropylar end and into one of the synergids. Synergids secrete chemical substances that control the growth of pollen tubes. The pollen tube's tip penetrates one synergid, and the penetrated synergid begins to degenerate. The end of the pollen tube increases in size and ruptures after penetration, releasing the contents, including the two male gametes and the vegetative nucleus.
Ques. What is Pollen-Pistil interaction? [2 Marks]
Ans. Pollen-pistil interaction is a series of events between the time pollen is deposited on the stigma and the time the pollen tube is inserted into the ovule. Several points in the process are checked to see if pollen growth is being promoted or inhibited.
Ques. Explain the benefits of pollen-pistil interaction. [5 Marks]
Ans. The benefits of pollen-pistil interaction are:
- Plant breeders can use it to manipulate pollen development even in problematic situations.
- It's a precautionary measure to prevent unauthorized crossings.
- Unique proteins determine the pollen-compatibility pistil and incompatibility.
- Compatible pollens take in water and nutrients from the stigma's surface, germinate, and form pollen tubes.
- Pollen tube develops into a style whose growth and chemicals control course.
Ques. Describe how flowers reproduce sexually. [2 Marks]
Ans. The process of sexual reproduction involves the union of male and female gametes, which results in the formation of a diploid zygote, which then grows into a new organism. Sexual reproduction is seen in all blooming plants. Flowers are where blooming plants' sexual reproduction takes place. The parts of a typical angiosperm flower are organized in four whorls. Calyx, Corolla, Androecium, and Gynoecium are their names.
Ques. Identify the several sections of the pistil and their functions. [2 Marks]
Ans. The stigma, style, and ovary are the three sections of each pistil—pollen grains land on the stigma as a landing place. The long slender section underneath the stigma is called the style. The ovary is the bulged portion of the pistil at its base. The ovarian cavity contains the placenta. The placenta produces Megasporangia, also known as ovules.
Ques. Define the term "siphonogamy." [2 Marks]
Ans. The pistil can recognize and reject pollen grains incompatible with the same species or with other species. Pistil stimulates post-pollen activities that lead to fertilization when it recognizes the correct pollen. Fertilization combines the male and female gametes to generate a diploid zygote within the embryo sac. Male gametes are delivered to the egg through the pollen tube in angiosperms, known as siphonogamy.
Ques. Name the component or organism that usually does pollination on plants with ovaries having only one or a few ovules. [2 Marks]
(a) Bird
(b) Butterfly
(c) Bees
(d) Wind
Ans. (d) Wind.
Explanation: Anemophilous flowers are small, discreet, colorless, odorless, and nectarless. Non-essential elements of the flower are either missing or diminished. Male flowers are more plentiful than female blooms in unisexual flowers. The stamens of bisexual buds are usually numerous. The majority of pistils are uniovular.
Ques. Describe in detail the pollen-pistil interaction. [2 Marks]
Ans. A pollen grain on the stigma does not imply that fertilization will occur. Within a species, there is intraspecific incompatibility. If the pollen and the stigma are compatible, the pollen takes the water from the stigma (hydrates), and the pollen tube emerges. The pollen tube extends through the carpel's style to the micropyle, where the male gametes travel to the egg cell.
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