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

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

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

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

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

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

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

Values pH Temperature (°C) - + 4.0 6.0 8.0 28 30 35 Standard Miley -- Smith

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

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

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

Procedure Miley -- Smith

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

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

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

Observations Date Observation March 29 April 1 April 2 April 5 Bags and seeds are set up April 1 All standards have germinated and quite a few of the ones in the incubator. No germination in the refrigerator April 2 More have germinated in the incubator. Still no germination in the refrigerator April 5 Still no germination in the refrigerator. We will retry this part in warmer area of 28°C April 11 Seeds germinated in the warmer temperature Miley -- Smith

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

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

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

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

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

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

Questions? Miley -- Smith

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