Observe buds blooming in Reproduction in Plants – Class 7 Science Experiment

Chapter Name: Reproduction in Plants

Activity Name: Observe buds blooming in Reproduction in Plants

Activity Description:

The experiment aims to observe the process of pollination and its effect on the development of fruits in a bottle gourd plant. It involves observing the blooming of female buds, collecting pollen from male flowers, and manually pollinating some female flowers while covering others to prevent natural pollination.

Required Items:

1. Bottle gourd plant in a garden with unisexual (male and female) flowers
2. Polythene bags
3. Pin
4. Sheet of paper
5. Cotton wool
6. Matchstick

Step by Step Procedure:

1. Select 10 closed female buds of the bottle gourd plant.
2. Loosely cover the selected female buds with polythene bags, tying the bags to the stalk of each bud.
3. Make tiny holes in the polythene bags using a pin to allow some airflow.
4. Wait for two days to observe the blooming of the buds.
5. Collect pollen grains from a male flower of the bottle gourd plant by plucking the stamens and shaking them over a sheet of paper.
6. Prepare a brush by twisting cotton wool over the tip of a matchstick.
7. Uncover five of the ten female flowers and apply the collected pollen grains onto their stigmas using the brush. The pollen grains will stick to the stigma.
8. Cover the pollinated female flowers again with the polythene bags.
9. Remove all male flowers from the plant to prevent pollen from reaching the remaining female flowers.

Experiment Observations:

1. After one week, observe both the pollinated and non-pollinated flowers.
2. Pollinated flowers should have developed into fruits, while non-pollinated flowers should not.

Precautions:

1. Ensure that the selected female buds are closed (petals not open) at the beginning of the experiment to avoid any prior pollination.
2. Cover the buds with polythene bags to protect them from external pollination sources and to prevent pollen grains from escaping.
3. Cover the non-pollinated flowers as well to serve as a control group and compare the effects of pollination.

Lesson Learnt from Experiment:

The experiment demonstrates the process of pollination in plants and its role in fruit development. Pollination is essential for the transfer of pollen from the male flower to the stigma of the female flower, leading to fertilization and subsequent fruit formation.