The key difference between carpel and pistil is that carpel is a reproductive part of a flower and contains an ovary, stigma, and style, whereas pistil is made of several carpels or can be made of a single carpel.
A flower is a highly specialized reproductive shoot. A typical flower has 4 whorls, one after the other, on a stalk. The stalk can be short or long. The two lower whorls are not directly involved in reproduction. Therefore, they are called accessory whorls. The upper two whorls are directly involved in reproduction. Therefore, they are called reproductive whorls. The reproductive whorl is made up of microsporophylls and megasporophylls. Microsporophylls are called stamens, and megasporophylls are called carpels in anthophytes/ angiosperms. Some flowers have both stamens and carpels in the same flower, and some flowers possess either carpels or stamens. The third whorl is known as the androecium, which is the male whorl. The fourth whorl is known as the gynoecium, which is the female part of the flower.
CONTENTS
1. Overview and Key Difference
2. What is a Carpel
3. What is a Pistil
4. Carpel vs Pistil in Tabular Form
5. Summary – Carpel vs Pistil
What is a Carpel?
Carpels are megasporophylls. Megasporophylls are modified leaves that bear ovules. Depending on the number of carpels present, the pistil can be either simple or compound. When the pistil carries only one carpel, it is said to be a simple pistil, and when the pistil carries two or more, the pistil is said to be a compound pistil. In compound pistils, the carpels may remain free, or they may remain fused. Each carpel possesses three parts: stigma, style, and ovary.
Stigma is at the upper end of the style, and it is the structure that receives the pollen grains. Structurally, the stigma is like a knob, and it is sticky in order to receive pollen grains. Style is like an extension of the ovary and is like a very thin and narrow tube. It bears the stigma at the top. The surface of the style may be very smooth and hairy in order to trap pollen grains. At the bottom of the style is a swollen-looking structure, which is the ovary. The ovary can be single-chambered or multiple-chambered. The ovary contains ovules. Each ovule has an embryo sac inside. After fertilization, the ovary gives rise to the fruit, and the ovules give rise to seeds.
What is a Pistil?
The female reproductive whorl of the flower is the gynoecium, which is also known as the pistil. This is the fourth whorl of the flower. The pistil contains one or more carpels. It may contain one or more carpels.
Depending on the number of carpels present, the pistil can be either simple or compound. When the pistil carries only one carpel, it is said to be a simple pistil, and when the pistil carries two or more, the pistil is said to be a compound pistil. In compound pistils, the carpels may remain free, or they may remain fused.
What is the Difference Between Carpel and Pistil?
Carpels are the basic units of pistils, which may be free or fused. In certain situations, the two words can be used interchangeably, but in certain situations, they cannot be used. For example, the words are used interchangeably when a flower has three free carpels and three simple pistils. However, the two words cannot be used interchangeably when a flower has 3 fused carpels because then it contains only one compound pistil. This is the key difference between carpel and pistil.
Summary – Carpel vs Pistil
The key difference between carpel and pistil is that carpel is a reproductive part of a flower and contains an ovary, stigma, and style, whereas pistil is made of several carpels or a single carpel.
Image Courtesy:
1. “ABC flower development” By Laura Aškelovičiūtė – Student work dedicated to Wikipedia (CC BY-SA 4.0) via Commons Wikimedia
2. “Mature flower diagram” By Mariana Ruiz LadyofHats – Own work (Public Domain) via Commons Wikimedia