[Biology Class Notes] on Study of Pollen Germination on a Slide Pdf for Exam

In this article, students will learn about the germination of pollen on a slide in the form of an experiment but first, let’s understand the concept of pollen germination. Pollination is the method by which pollen grains are transferred from the anther of a flower which is the male part to the stigma of the same or different flower which is the female part of the flower. Pollination is mostly carried out by abiotic components of the environment such as the wind and the water. 

Pollen grains germinate when they absorb nutrients and water and grow a pollen tube from the style to the ovary part through one of the germ pores. Then the nucleus moves down to the pollen tube as well as the generative cells, which in turn develop into two male gametes. One of the two sperm fuses with the egg cell present in the ovule and develops into the embryo, while the other combines with another nucleus from the ovule and forms the endosperm. This is called double fertilisation. This is what happens during pollen germination. Now let’s study the process of pollen germination when studied in a slide.

Aim

The experiment aims to observe pollen germination on a slide. 

Materials Required

• Freshly plucked flower from grass or china rose,

• 10 mg boric acid

• Beaker

• Microscope

• Sucrose (10 g)

• Coverslips

• Slide

• Dropper

• Magnesium sulphate (20 mg)

• Calcium nitrate (30 mg)

Procedure

The first step is to prepare the nutrient solution by dissolving the sucrose and boric acid in water. Then this mixture has to be dropped using a dropped on the cavity slip. Then using a brush or simply by fingers, brush off a few pollen grains and let the slide for 15 minutes. Then the microscope has to be used to observe the slide at intervals of 30 minutes.

Observations

It can be observed that by enlargement of the vegetative cells, the pollen grains are germinating when submerged in the nutrient medium. A pollen tube is formed when the nucleus grows and emerges from one of the germ pores and forms two male gametes which can be either spherical or lenticular in shape. These pollen grains that germinate are called viable pollen grains. These gametes are called sperm nuclei. There will also be some pollen grains that will not form pollen tubes, hence, they are called non-viable pollen grains.

Precautions

There are precautions to be observed while performing this experiment:

• Dirty or previously used slides should not be used for dusting pollen grains. Slides should be clean and dry for use.

• Only a few drops of the nutrient medium is required for germination. 2-3 drops of the solution are enough, more than that may hinder the process of pollen germination.

• Only freshly plucked flowers should be used and the experiment should be conducted within some time of plucking.

• The cavity slide used for observation should have depression at the centre so that the solution can be held in that cavity and does not flow.

Conclusion

Pollen germination can be carried out in a nutrient medium and studied under a microscope when proper environmental conditions are given.