Study of Pollen germination on a slide

Exercise: Study of Pollen germination on a slide

NOTE: Pollen germination can be studied by dusting some pollens from common flowers like Crotalaria, Hibiscus, Pisum, etc. on a glass slide containing a drop of 10% sugar solution or tender coconut water or any nutrient medium.

Observe the slide after about 10 – 15 minutes under the low power of compound microscope.

You will be able to observe the pollen tubes coming out of the pollen grains.

Aim:

To study the pollen germination on a slide.

Requirements:

Fresh seasonal flowers, cavity slide, cover slip, compound microscope, sucrose, boric acid, distilled water, beakers, etc.

Procedure:

·        Prepare a nutrient solution by dissolving 1 gm. of sucrose / 1 gm. of boric acid in 100 ml. of distilled water.

·        Take a clean cavity slide and put a few drops of nutrient solution in the cavity of the slide.

·        Dust a few pollen grains from the stamen of a mature flower on it.

·        View the slide in the microscope after 5 minutes and then observe it regularly for about half an hour.

Observation:

In nutrient medium, the pollen grains germinate. The tube cell enlarges and comes out of the pollen grain through one of the germ pores to form a pollen tube. The tube nucleus descends to the tip of the pollen tube. The generative cell also passes into it. It soon divides into two male gametes.

Inference: Different stages of germinating pollens are observed. Some pollens are in their initial stage of germination while others have quite long pollen tube containing tube nucleus and two male gametes.

Precautions:

·        Flowers should be freshly plucked.

·        Use clean cavity slide to observe the pollen grains.

·        The slides should not be disturbed, otherwise position of pollen grains will get changed.