The Effects of pH and Temperature on the Germination of Raphanus sativus Seeds

1. The Effects of pH and Temperature on the Germination of Raphanus sativus Seeds Keara Miley – Lake Shore Robin Smith – Lake Shore

2. Terminology • Two-Factor Design of Experiment • (DOE) • Raphanus sativus • (Radish) • Germination • When a seed starts to sprout • pH • How alkaline or acidic a substance is Miley -- Smith

3. How does pH affect germination? • pH affects germination because the acid breaks down the seed coat and allows more water to get absorbed Miley -- Smith

4. Temperature affecting Germination • If temperature is too high, moisture evaporates from the soil • If temperature is too low, water absorption slows Miley -- Smith

5. Why Do The Experiment? • More areas we can grow food, the more food we can grow • The purpose of the experiment was to find the pH level and temperature that would cause the most Raphanus sativus (radish) seeds to germinate Miley -- Smith

6. Problem • How do different levels of pH and temperature affect the germination of radish seeds? Miley -- Smith

7. Hypothesis • If the surrounding temperature is 35ºC and the pH level of the water sprayed on the seeds is 4.0, then the most radish seeds will germinate Miley -- Smith

8. Values Miley -- Smith

9. Materials • Source of tap water • Analytical balance • 100 mL spray bottles • Paper towels • Ziploc bags • Incubator (35°C) • Refrigerator • pH test strips • tweezers Miley -- Smith

10. Procedure • We mixed the water with either baking soda or citric acid to change the pH and get a high, a low, and a standard concentration • We sprayed the concentrations onto the radish seeds placed in Ziploc bags Miley -- Smith

11. Procedure • We then placed the bags into areas with the different temperature levels • After 3 days, we recorded the number of seeds that germinated in a table Miley -- Smith

12. Procedure Miley -- Smith

13. Data Analysis • The effect of pH on the germination of radish seeds was -0.17 units • On average, as pH increased, the number of seeds germinated decreased by 0.17 units Miley -- Smith

14. Data Analysis • The effect of temperature on the germination of radish seeds was 0.5 units • On average, as temperature increased, the number of seeds germinated increased by 0.5 units Miley -- Smith

15. Data Analysis • There may be an interaction between the two line segments because they are not parallel • The effect of the graph is 0.16 units Miley -- Smith

16. Observations Miley -- Smith

17. Hypothesis • Hypothesis was accepted • Most seeds germinated in 35°C temperature and pH level of 4.0 Miley -- Smith

18. Recap • Set out to find what pH level and temperature germinated the most seeds • We hypothesized that most seeds would germinate at 35ºC and a pH of 4.0 • Conducted experiment • Sprayed different pH levels on radish seeds Miley -- Smith

19. Recap • Set the seeds in areas of different temperatures • Recorded how many seeds germinated after three days • Found a temperature of 35°C and pH of 4.0 germinated the most Miley -- Smith

20. Design Flaws and Errors • Testing in an area of 22°C was too cold • Retested in an area of 28°C • Initially added too much citric acid and baking soda Miley -- Smith

21. Further Study • Different levels of pH • Wider ranges of temperatures • Different types of plants • Different soil types Miley -- Smith

22. Real Life Application • Retailers find best source to buy stock • Profits increase Miley -- Smith

23. Questions? Miley -- Smith

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