Practical 1
Invitro Pollen germination
Aim – To study the pollen germination of the given flower on a slide.
Requirements –
Apparatus – Fresh seasonal flowers, Slide, coverslip, forceps, needle, dropper, microscope
Chemicals – Sucrose, Boric acid, Magnesium sulphate, Potassium nitrate, water.
Diagram –
Comments –
a. The pollen grains will germinate in the nutrient-rich medium. The vegetative/tube cell
enlarges and emerges through
one of the germ pores, eventually forming a pollen tube.
b. The generative cell nucleus grows into the pollen tube and makes two male gametes (sperm
nuclei).
Precautions –
a. Flowers should be freshly plucked.
b. Weighing of chemicals must be done accurately.
c. Slide and coverslip must be clean and dry.
d. First observe the pollen grains under low power of the microscope and then under high
power.
Practical 2
Floral adaptations for pollination
Aim - To study the flowers adapted to pollination by different agents such as wind, insects and birds.
Material Required - Fresh flowers, Magnifying glass
Procedure - Observe the given flowers and note their features in your observation w.r.t. to the type of
pollination
Observations -
1. Flowers Pollinated By Wind
Flowers are small and inconspicuous, hence are produced in a cluster called inflorescence.
Pollen grains are light so they can easily travel by wind currents.
Flowers do not have any bright colour, nor fragrance or nectar
Anthers and stigma hang out of the flower. Stigma is hairy or feathery to trap the pollen which are
produced in large quantity by the flower.
2. Flowers Pollinated By Insects
Flowers are open and brightly coloured with good fragrance to attract the insects.
Pollen grains are spiky or sticky so as to attach to the body of the insects.
Stigmas are generally sticky for pollen deposition.
3. Flowers Pollinated By Birds
The flowers are tubular and curved that facilitates nectar-sucking by birds.
The flowers are odourless and bright-coloured that attracts the birds.
Practical 3
Exercise on controlled pollination
Aim - To study the exercise on controlled pollination through emasculation, bagging and tagging.
Materials Required - Plants with large bisexual flowers, Tweezers, Scissors, Brush, Alcohol, Rubber bands,
Paper bags, Paper clips, Tags, Magnifying Glass
Procedure
1. Select a bud of the flower and open it to remove the stamens. This is known as emasculation. Mark it
as the female parent plant.
2. The plant is then covered with a butter paper bag to prevent it from getting pollinated by any
undesired pollen. This step is known as bagging.
3. Bring it in contact with the anther of the male plant with desired characteristics. The pollen should be
dusted on the surface of the stigma.
4. Cover the pollinated flower immediately with the butter paper bag and label it with the name of the
seed parent. This step is known as tagging.
Observations -
1. The flower has been emasculated and tagged with the name of the plant and date of emasculation.
2. Cross pollination has been done with the desired pollen.
3. The bag also has a tag attached on it that indicates all details including the date of cross pollination.
Precautions -
1. The flower should be emasculated before dehisence of the anther to avoid the pollen coming in contact with the stigma.
2. Emasculation should be done with tweezers to avoid contact of human hands that may contain any pollen.
Emasculation
