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PUMPA - SMART LEARNING
எங்கள் ஆசிரியர்களுடன் 1-ஆன்-1 ஆலோசனை நேரத்தைப் பெறுங்கள். டாப்பர் ஆவதற்கு நாங்கள் பயிற்சி அளிப்போம்
Book Free DemoThe four whorls:
Calyx and corolla are the two outermost whorls of a flower. As they do not directly take part in reproduction, they are also known as non-essential or accessory whorls.
As androecium (stamen) and gynoecium (carpel) take part directly in reproduction, they are known as essential whorls.
![stamens and pistils.jpg](https://resources.cdn.yaclass.in/b14f0a8c-62af-4d24-b131-46dcccdadbd9/stamensandpistilsw704.jpg)
Androecium and gynoecium
Androecium:
It is the male part of the flower that is composed of stamens. Each stamen is made up of a filament and a small pouch-like structure at the tip called the anther.
![YC Editorial - Divya (34).png](https://resources.cdn.yaclass.in/b319a4e1-f9a3-4ae1-8e58-7527fb408f96/YCEditorialDivya34w600.png)
Structure of stamen
The pollen grains are formed in the pollen sac's anther.
Pollen grain:
![Figure_32_01_06f (1).jpg](https://resources.cdn.yaclass.in/8fba5f9d-b7b2-4512-a873-e506702053ea/Figure320106f1.jpg)
Structure of a pollen grain
Pollen grains are typically spherical in shape. They have a two layered wall. Exine is the hard outermost layer. It has germpores, which are large openings. Intine refers to the thin inner layer. It's a cellulose and pectin-based thin and continuous layer. The vegetative and reproductive cells are the two cells found in mature pollen grains. The nucleus of a vegetative cell is a large one. The generative cell splits into two male gametes during mitosis.
Gynoecium:
The female part of the flower which is made up of carpels is known as gynoecium.
![1024px-Gynoecium_diagram_for_Simple_wikipedia.jpg](https://resources.cdn.yaclass.in/97043bd1-ca34-4748-991c-c8c38b9b8df6/1024pxGynoeciumdiagramforSimplewikipediaw425.jpg)
Gynoecium
It consists of three parts:
- Ovary
- Style
- Stigma
The ovary is a structure in which ovules are present.
![YC Editorial - Divya (35).png](https://resources.cdn.yaclass.in/d4b5813e-36de-4412-97c8-a4a19ea9631a/YCEditorialDivya35w400.png)
Structure of gynoecium
Reference:
https://www.flickr.com/photos/rayinmanila/20561557586
https://upload.wikimedia.org/wikipedia/commons/a/a2/Figure_32_01_06f.jpg
https://upload.wikimedia.org/wikipedia/commons/thumb/b/b8/Gynoecium_diagram_for_Simple_wikipedia.jpg/1024px-Gynoecium_diagram_for_Simple_wikipedia.jpg
https://upload.wikimedia.org/wikipedia/commons/1/1d/Figure_32_01_05.jpg
https://upload.wikimedia.org/wikipedia/commons/thumb/6/6e/ABC_Model.svg/512px-ABC_Model.svg.png