Longitudinal Section of a Flower: Explanation & Sample Questions

Longitudinal section of a flower is the reproductive part of the flowers or plants. Flowers also reproduce through various parts present in the flower’s body. Flowers can be categorised based on the basis of existence of male and female reproductive parts: Bisexual flower is a flower that has both stamen and pistil (male and female). Unisexual is the flower is one which lacks one of the reproductive part (male or female). Based on the fact flower has various parts essential for the reproduction like Ovary, Style, Stigma, Pistil, Anther, Filament, Stamen. 

Also check: How Do Organisms Reproduce? Overview

Key takeaways: longitudinal section of a flower, flowers, types of flowe, reproduction in flower, bisexual and unisexual flower. 

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Definition of a Flower

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Flowers are the plant's reproductive organs. Pollination is the process by which flowers create new seeds. Flowers are one of the most important parts of a plant’s morphology.Flowers are borne by all plants in their young age of reproduction . It plays the most important role in the development of fruits and seeds. Flowers are the reproductive part of angiosperms, which reproduce by sexual reproduction. Flowers bear stamen (which produces male gametes) or carpel (which produces female gametes), or both. Flowers can thus be said as the plant’s primary reproductive organ. The below figure shows picture of reproductive parts of a flower.

Also read: How do Organisms Reproduce?

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Types of Flower

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1. Bisexual flower: A bisexual has both stamen and pistil that is both female and male part.
2. Unisexual flower: An unisexual flower is one which lacks one of the reproductive part either (male or female). For example Papaya and watermelon have unisexual flowers, Hibiscus, mustard plant have bisexual flowers.

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Longitudinal Section of Flower (Explanation)

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Flower is the reproductive organ of the plant. Its main work is to reproduce and keep the species of the plant alive. Apart from its beauty and aroma, its main work is to produce seeds to keep the generation of plants alive. The reproductive section of flower is often called as the Longitudinal Section of the flower. It contains female and male part of the flower in case the flower is bisexual. 

Longitudinal Section Of a Flower

• Sepals (Calyx): The outer part or layer of the flower is made up of leaf-like green structures called sepals. They serve as a foundation for the flower and also work as a support for the petals. Sepal can be found around the stalk base of the flower. 
• Petals (Corolla): The secondary whorl inside the sepals is made up of colorful, and usually big and aromatic parts that are petals.. Petals contain a strong perfume or odour to attract pollinators such as insects and bees.The non-essential floral organs are sepals and petals. stamen and carpels or Pistil are crucial floral organs as they are involved in Reproduction.
• Androecium: The androecium is made up of stamens, which are male reproductive organs in plants. The third whorl of the flower is formed by stamens, which are found inside the petals. Stamens are made up of two parts: a filament, which is a thin stalk, and an anther, which is the fertile component present at the filament’s tip ,anther contains male germ cells.
• Carpel: Carpel (also known as Pistil) is the female reproductive component of plants The 4th and deepest whorl of a flower is a carpel. Carpel is made up of three parts:
• Ovary: A flower’s reproductive gland, which is important in the development of seeds. As the name suggests this gland serves as a storage area for eggs and ovules inside the flower.
• Style: The pistil’s adapted section, that is a long, tube-like slender stalk. It connects the stigma to the ovary, which houses the female egg cells known as ovules.
• Stigma: This part of the flower is found in the female reproductive portion that is pistil of a flower .Its main work is to catch the male gametes and transport it towards the inner reproductive parts of the flower.
• Anther: A 4 lob sac-like structure that is responsible for pollen grain synthesis and storage.
• Filament: Connected to the anther, this thread-like structure's main work is to keep the anther in place.
• Stamen: Stamen is also known as Androecium, and it is the male reproductive portion of a flower. Anther and filament make up the majority part of it.

Also read:

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Reproduction in Flower

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The male germ-cell fuses with the female gamete present in the ovule and divides up with time and make up a seed this is the full reproduction process in the nut shell.This fusion of the germ-cells gives the zygote which is capable of growing into a new plant. Thus the germ cells or pollen needs to be transferred from the stamen (male reproductive part) to the stigma (female reproductive part). If this transfer of pollen occurs in the same flower, it is called self-pollination. 

On the other hand, if the pollen is transferred from one flower to another, it is known as crosspollination. This transfer of pollen from one flower to another is achieved by agents like wind, water or animals. After the pollen lands on a suitable stigma, it reaches the female germ-cells which are in the ovary. After fertilization, the zygote divides several times to form an embryo in the ovule, Then the ovule develops a tough coat and is gradually converted into a seed. The ovary grows rapidly and ripens to form a fruit.

Also read: Sexual reproduction

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Points To Remember

• A complete flower comprises four whorls: Calyx, Corolla, Stamens and Carpels.
• Calyx is the first and the outermost whorl of a flower, which comprises units called sepals.
• Petals of the flower help in reproduction by attracting bees and other insects for cross pollination.
• Stamen is also known as the third whorl of the flower and is the male reproductive part.
• The petals and sepals are called the vegetative part of a flower, whereas the stamen and pistil are called the reproductive parts of a flower.
• Unisexual flower reproduce through cross pollination.

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