Growth is a characteristic of living things. Growth is de ned as the permanent increase in size. Growth happens through cell division or cells getting larger. In most owering plants, growth starts when the seed begins to germinate.
Investigating Conditions Necessary for Seed Germination
Seed germination is the development of a seed into a seedling. The changes that occur during seed germination include absorption of water through mi-cropyle, bursting of testa, and emerging and elongation of the radical. Then seed coat is discarded and cotyledons open out and begin to photosynthesize. Between the cotyledons, the plumule emerges and produces leaves. At this point, the young plant is called a seedling. The conditions necessary for seed germination include water, oxygen and optimum temperature.
To investigate conditions necessary for seed germination.
Bean seeds, water, cotton wool, rubber stopper*, 4 test tubes*, cooking oil, boiling water, ice water (if available)
1. Prepare 4 test tubes from syringes and label them 1, 2, 3, and 4.
2. Buy ice for ice water.
3. Boil water and let it cool to room temperature.
1. Place cotton wool at the bottom of each test tube.
2. Add a few seeds in each of the test tubes.
3. In test tube 1, add enough water to soak the cotton wool.
4. In test tube 2, add cool boiled water to ood the seeds; add small amount of oil to form a layer above the water.
5. In test tube 3, add ice water.
6. In test tube 4, do not add any water.
7. Keep the test tubes under these conditions for four days.
8. Record your observations every day and add water as needed to each tube, being sure to add only ice water to test tube 3.
Only test tube 1 will show proper germination. The other test tubes will show little or no growth because they do not have the conditions necessary for germination.
1. Collect all the used materials, cleaning and storing items that will be used later. No special waste disposal is required.
When planting seeds we must make sure that they receive oxygen, water, and proper temperature for germination. Boiling removes the oxygen dissolved in water and the layer of oil in test tube 2 prevents oxygen from re-entering the water.
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