What Is the Difference Between Carpel and Pistil in Plants?
A modified and condensed shoot useful for reproduction in angiosperms is called a flower. Flowers are often described as a modified stem. The gynoecium is an essential part of the flower as it contains the female reproductive organisms.
Carpel and pistil are the two female reproductive organism units in flower, the part which you see from outside. Carpel is a long stick-like structural part in the flower that comprises a mixture of three essential parts; stigma, style, and ovary - the female parts of a flower. There can be one or more carpels present in a flower.
The pistil consists of stigma, ovary, and style, and is generally fused along with the female reproductive parts.
Let’s peer inside the structure of the carpel. The ovary is the basal, swollen part inside the bud, which is a fertile part in the carpel. If there is only one carpel, the ovary is called unilocular, which means chamber. If there are two, three, or five carpels fused with each other, that is, a polycarpellary syncarpous condition, then the ovary is bilocular, trilocular, or pentalocular. Each chamber of the ovary contains one to many small globular structures called ovules or megasporangia. Ovules are produced on a soft fertile tissue called the placenta. Different modes of arrangement are exhibited within the ovary.
Style is a narrow elongated threadlike tubular structure that connects the ovary with the stigma. The terminal part of the carpel which receives pollen grains during the process of pollination is called stigma. Pollen germination happens during that specific time. Stigma is generally rough and sticky in nature. When all three parts of a carpel are fused together, it is called pistil. Therefore, the collection of fused carpels is called pistils in the case of syncarpous.
What is a Carpel
Carpels are composed of the stigma, style, and ovary, the female parts of a flower. Flowers can have one or more carpels. It can also be defined as the fourth whorl of the flower present in the centre.
What is a Pistil
The word pistol is derived from the Latin term pistillum, pestle. It can either be the same as an individual carpel as it comprises stigma, style, ovary, or a carpel fused together. This means a pistil can have lots of carpels.
The major difference between the carpel and pistil is that the carpel is a single reproductive unit (bisexual organism), while the pistil is the collection of fused ovaries. Carpel has seed production, while pistils do not. The ultimate goal of the carpel is to disperse the seed, while the pistil works as the female reproductive system of the flower. Carpel produce eggs, while pistils do not. Fertilisation happens for carpels but not for pistils.
Important Facts Regarding Flower
1. Gynobasic style is a characteristic feature of the family labiate (Ocimum), where style arises from the depression or cavity in the center of the ovary or directly from the thalamus.
2. Feather-like stigma is called the plumose stigma, as in grasses (Gramineae).
3. Receptacle is the modified, flattened pendulous on which flowers lie in a specific manner.
4. An additional whorl of bract is called an involucre.
5. Gynoecium is considered a modified leaf (megasporophyll).
6. Rafflesia arnoldii has the largest flower.
7. Long filamentous threads protruding at the end of a young cob of maize are style.
8. The colored sepals other than green color are called sepaloid. Example: Garden nasturation.
9. The term staminode is given to reduced or non-functional stamens. Example: Saliva.
10. If only one carpel is present in the gynoecium, then this condition is called the monocarpellary condition.
11. If more than one carpel is present in the gynoecium, then this condition is known as polycarpellary.
12. When all carpels are fused, this condition is called syncarpous. Example: mustard and tomato.
FAQs on Carpel and Pistil Explained: Differences, Structure & Role
1. What is a carpel in a flower?
A carpel is the fundamental female reproductive unit of a flower, often considered a modified leaf that encloses and bears ovules. The entire female reproductive organ of a flower, known as the gynoecium, is composed of one or more carpels. Each carpel structurally consists of three main parts: the stigma, style, and ovary.
2. What are the main parts that make up a carpel?
A carpel is comprised of three distinct parts, each with a specific function for reproduction:
Stigma: This is the receptive tip of the carpel. Its surface is often sticky or feathery to effectively trap pollen grains during pollination.
Style: A stalk-like structure that connects the stigma to the ovary. It serves as a pathway for the pollen tube to grow from the stigma down to the ovules.
Ovary: The enlarged, basal portion of the carpel that contains and protects the ovules. After fertilisation, the ovary develops into the fruit.
3. What is the main difference between a carpel and a pistil?
While related, carpel and pistil refer to different levels of organisation. A carpel is the individual, fundamental unit containing an ovary, style, and stigma. A pistil is the entire female reproductive structure, which can be composed of one or more carpels.
- If a flower has a single carpel, that structure is both a carpel and a simple pistil.
- If a flower has multiple carpels that are fused together, they form one compound pistil.
- If the carpels are separate, the flower has multiple pistils.
4. How are the terms 'gynoecium', 'pistil', and 'carpel' related in flower morphology?
These terms describe the female reproductive parts of a flower in a hierarchical way. The gynoecium is the collective term for all female parts in a single flower, forming the innermost whorl. The gynoecium itself is composed of one or more pistils. Each pistil, in turn, is made up of one or more carpels. Therefore, the carpel is the basic building block, which forms the pistil, and the pistil(s) collectively form the gynoecium.
5. What is the primary role of the carpel in plant reproduction?
The primary role of the carpel is to ensure successful sexual reproduction. It achieves this by protecting the ovules (which contain the female gamete) within the ovary, providing a receptive surface (stigma) for pollen, and guiding the pollen tube to the ovule via the style. Following fertilisation, the carpel's ovary matures into the fruit, and the ovules become seeds, facilitating dispersal and the creation of a new generation.
6. Why is the stigma's structure often sticky or feathery?
The physical structure of the stigma is a specific adaptation to maximise the chances of successful pollination. A sticky surface ensures that pollen grains from visiting insects or other animals adhere firmly and are not easily dislodged. A feathery structure increases the surface area, making it highly efficient at trapping wind-borne pollen. This structural specialisation is crucial for capturing compatible pollen, which is the first critical step for fertilisation to occur.
7. Can a flower have a single pistil but multiple carpels? Explain this condition.
Yes, this is a very common arrangement in flowering plants. This condition is called a syncarpous gynoecium. In a syncarpous flower, two or more carpels are fused together to form a single, compound pistil. While it appears as one structure externally, a cross-section of the ovary often reveals multiple chambers (locules), with each chamber corresponding to one of the original fused carpels. A classic example is a tomato or a bell pepper, which has one pistil formed from the fusion of multiple carpels.
