- Sexual reproduction occurs in all flowering plants, i.e., angiosperms. It is the process of fusion of haploid gametes, resulting in the production of a diploid zygote. Which ultimately develops into new organism.
- Different types of adaptations are shown in angiosperms by the diversified structures of the inflorescences, flowers and floral parts, to ensure the formation of the end products of sexual reproduction, i.e., the fruits and seeds.
Flower
- It is the modified condensed shoot arising on the axil of small leaf-like structure called bract and consists of four whorls or floral appendages, attached on the receptacle.
- Of these, the two lower whorls, i.e., calyx and corolla are sterile and considered as non-essential/accessory/helping whorls and the two upper whorls, i.e., androecium and gynoecium are fertile and are considered as essential or reproductive whorls.
Structure
Parts of Flower
- In a flower, four different sets of whorls or floral members are attached to a central axis called thalamus.
- The outermost and the first accessory whorl is of sepals and is called calyx.
- The second accessory whorl is of petals and is called corolla.
- Next to the corolla, is the male reproductive whorl of stamens called androecium.
- The female reproductive whorl is of carpels and is called gynoecium or pistil.
- Calyx and corolla are the non-essential whorls while androecium and gynoecium are the essential whorls.
Function
- Calyx
(i) Its main function is to protect the flower in bud condition. It is smaller than the petals in size.(ii) When green, it is photosynthetic in nature.(iii) When colored, it attracts insects for pollination.
- Corolla
(i) It provides color and scent to attract pollinators.(ii) Sometimes the base of corolla bears some secretory glands and secretes nectar.(iii) They also provide protection to the plant.
- Androecium
Its main function is the production of microspores, i.e.,pollen grains containing male gametes within the anther lobe.
- Gynoecium
The function of gynoecium is the production of megaspores eggs, fruits and seeds.
FAQ
What is the structure of a flower?
A flower typically consists of several parts, including the petals, sepals, stamen (male reproductive organ), pistil (female reproductive organ), ovary, style, and stigma.
What is the function of petals?
The petals of a flower are often brightly colored to attract pollinators such as bees, butterflies, and birds. They also protect the reproductive organs of the flower.
What is the function of sepals?
Sepals are usually green and protect the flower bud before it opens. They also support the petals and help in attracting pollinators.
What is the function of the stamen?
The stamen is the male reproductive organ of a flower, consisting of the filament and anther. The anther produces pollen, which contains the male gametes.
What is the function of the pistil?
The pistil is the female reproductive organ of a flower, consisting of the ovary, style, and stigma. The ovary contains ovules, which develop into seeds upon fertilization.
How does pollination occur in flowers?
Pollination is the process by which pollen is transferred from the anther (male part) to the stigma (female part) of a flower. This can occur through various agents such as wind, water, insects, birds, or animals.
What is the role of nectar in flowers?
Nectar is a sugary liquid produced by flowers to attract pollinators. Pollinators such as bees and butterflies feed on nectar while inadvertently transferring pollen from one flower to another, aiding in pollination.
How do flowers develop into fruits?
After successful pollination and fertilization, the ovary of the flower develops into a fruit, which encloses and protects the seeds. The fruit matures and eventually disperses the seeds, allowing for the growth of new plants.
