Class 12 notes on Structure of Pollen Grains and function

-

                                    Pollen Grains 




 What is Pollen Grain -

A very minute spherical structure present on the flower representing male gametophyte is known as Pollen Grains.  Pollen Grains are the medium for fertilization i.e., the tiny body is swirling in the air and attach to the female part and promote pollination. Pollen  Grains are approximately  25-50 micrometers in diameter.

Structure  - 

 Pollen has the outstanding feature of two-layered walls made in such a way that it shows a variety of patterns and at the same time also represents consistency in organization and chemistry.  The outer layer is known as Exine,  divided into two subparts, exine sexine, and exine nexin while  The inner layer is thin and made up of cellulose and pectin known as Intine. 

 Some chemicals are present on the outer wall of the pollen grains called  Sporopollenin which is one of the most resistant organic material and is thought to be responsible for the preservation of pollen in fossil plants deposit. The sporopollenin is absent in one place where some pores are present through this pollen tube emerge out during germination on stigma.

 The cell wall of the pollen grain is surrounded by a thin plasma membrane having distinct cytoplasm. After maturity, the cell of pollen contains two types of cell - vegetative and generative. The vegetative cell is having a  big size with an irregular nucleus. Their function is to provide food to the Generative cell and nourish them.

The Generative cell has a dense cytoplasm with a distinct nucleus. Coming to this stage some species of the Angiosperms  (60 to 70 percent)  ' pollen is shed off and this process is known as 2 -cell stage. The remaining species generative cells develop and divide mitotically and give rise to two male gamete cells and hence the 3 - cell stage.

Uses of Pollen -   

  • They are rich in nutrition supplements.
  •  They are also used in the form of medicine
  •   Store pollen can be used as a pollen bank just like a seed bank. 

We will cover the next part in our next blog, please subscribe to my blog for not missing any updates 

Comments

Post a Comment

Popular posts from this blog

Sycon Canal System With Diagram

-
Image
                                     Canal system in Sycon  A sea creature called a sycon, or scypha , is usually found clinging to rocks or other surfaces. These creatures have tube-shaped bodies that open outward with the help of a hole called an Osculum . They have tiny openings called Spiracles and Ostia all over their bodies to let water in. This water flows through canals inside their bodies and comes out through the Osculum, which is a larger opening used for breathing. We'll observe the shape of this canal system, why it is essential for those animals, type of canal system , and  its significance. The Sycon Type Canal system is the unique feature of the phylum Porifera . This system is also known as the  aquiferous canal system . This system supports the significant function of the body like nutrition, respiration, excretion, etc. History Overview -  Grant, a scientist from Scotland, spent a lot of time studying sponges. He was one of the first to really explain how t
Read more

How Many Types of Eggs In Animals

-
Image
                                             Types of Egg Hello guys! We'll examine a crucial area of zoology in this blog: different varieties of eggs. So let's define reproduction first before moving on to the subject. Reproduction is the biological process in which a parent is responsible to produce their offsprings which may be of their own kind. Reproduction is a must process for every individual for the continuing existence of the species. As we all know, there are many different species on the planet, and each of them has a unique method of egg production and inside the egg they contain yolk . The yolk is composed of proteins, fats, vitamins, and minerals, which are vital for the growth and development of the embryo.  Eggs can be classified into different types based on the amount of yolk they contain. l.  On the basis of the amount of Yolk - Depending on the quantity of yolks, eggs can be  Alecithal / Microlecithal / oligolecithal - The amount of yolk pr
Read more

Aurelia Aurita Life Cycle: Characterstics, Classification

-
Image
                                             Aurelia  Aurelia aurita is a type of zooplankton found all over the world. They are see-through and don't have eyes, brains, or hearts. They're usually between 2 to 15 inches wide. Even though they prefer being alone, they get carried together in groups called Blooms by wind and water currents. At night, they look like they're moving through the water like jellyfish, which is why they're sometimes called " jellyfish ".  They have four reproductive organs surrounded by tentacles in their top part. Their body color changes based on what they eat, so they can be blue, pink, or other colors. Let's learn more about Aurelia in detail. Details Of Aurelia Diagram -  Body : The center of the diagram would display the jellyfish's bell-shaped body, often called the " umbrella. " Tentacles : Below the bell, you'd see long, hair-like tentacles extending outward. Oral Arms : The oral arms are  used for
Read more