To Study the Pollen Germination on a Slide (Class 12 Biology Practical File)
Studying pollen germination on a slide is an important experiment in Class 12 Biology. This practical helps students observe how pollen grains develop pollen tubes, essential for fertilization in flowering plants. Fresh pollen is placed on a slide containing a sucrose solution, which acts as a nutrient source. Under suitable conditions, pollen grains absorb water and germinate, forming visible pollen tubes. These tubes carry male gametes for fertilization. Using a microscope, students can clearly observe the growth pattern and structure of pollen tubes. This experiment helps understand plant reproduction and strengthens practical learning for board examinations.
AIM: To study the pollen germination on a slide.
REQUIREMENTS
Fresh seasonal flowers, slide, coverslip, microscope, sucrose, boric acid, magnesium sulphate, potassium nitrate, beakers etc.
PROCEDURE
1. Prepare a nutrient solution by dissolving 10g sucrose, 10g boric acid, 30 mg magnesium sulphate and 20 mg potassium nitrate in 100 ml of water.
2. Take a few drops of this solution on a clean slide, and dust few pollen grains from the stamen a of a mature flower on it.
3. Observe the slide in the microscope after 5 minutes and then observe it regularly for about half an hour.
OBSERVATION
In nutrient medium, the pollen grain germinates. 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. Each male gamete is lenticular to spherical in outline.
PRECAUTIONS
1. Flowers should be freshly plucked.
2. Use clean slide to observe the pollen grains.
Class 12 Biology Lab Manual – Final Practicals | Complete Lab Experiment File
A. List of Experiments
1. Prepare a temporary mount to observe pollen germination.
2. Study the plant population density by quadrat method.
3. Study the plant population frequency by quadrat method.
4. Prepare a temporary mount of onion root tip to study mitosis.
5. Isolate DNA from available plant material such as spinach, green
pea seeds, papaya, banana etc.
B. Study and observe the following (Spotting):
1. Flowers adapted to pollination by different agencies (wind, insects, birds).
2. Pollen germination on stigma through a permanent slide or scanning electron
3. Identification of stages of gamete development, i.e., T.S. of testis and T.S. of
ovary through permanent slides (from grasshopper/mice).
4. Meiosis in onion bud cell or grasshopper testis through permanent slides.
5. T.S. of blastula through permanent slides (Mammalian).
6. Mendelian inheritance using seeds of different colour/sizes of any plant.
7. Prepared pedigree charts of any one of the genetic traits such as rolling of tongue,
blood groups, ear lobes, widow's peak and colour blindness.
8. Controlled pollination - emasculation, tagging and bagging.
9. Common disease causing organisms like Ascaris, Entamoeba, Plasmodium, any
fungus causing ringworm through permanent slides, models or virtual images or
specimens. Comment on symptoms of diseases that they cause.
10. Models specimens showing symbiotic association in lichens, root nodules of
leguminous plants, and parasitic mode of nutrition shown by Cuscuta on host.
11. Flash cards / models showing examples of homologous and analogous organs.
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