Materials Included In Kit

Additional Materials Required

Safety Precautions

Alcohol solution is very flammable and should not be used near open flames. Seeds are routinely treated with mold-inhibiting chemicals to help preserve them. Once seeds are brought into the laboratory, they are considered chemicals and should not be consumed. Be sure to wash hands and work areas thoroughly upon completion of the laboratory work. Wear chemical splash goggles and chemical-resistant gloves. Please follow all laboratory safety guidelines.

Disposal

Please consult your current Flinn Scientific Catalog/Reference Manual for general guidelines and specific procedures, and review all federal, state and local regulations that may apply, before proceeding. Materials from this lab can be disposed of according to Flinn Suggested Disposal Method #26a and #26b.

Teacher Tips

• Enough materials are provided in this kit for 30 students working in pairs or for 15 groups of students. The initial setup may reasonably be completed in a partial class period and observations and discussion completed the next day.

• Germination results are very dramatic for this very simple experiment. Only seeds in the Petri dish with plain water are likely to germinate at all, thus, indicating the sensitivity of seeds to their surroundings. The results dramatically illustrate how simple imbalances can kill seeds or prevent them from germinating.
• Almost any concentrations of alcohol or soap solution will be effective for this exercise (5–10% solutions are recommended).
• A logical extension of this laboratory would be to determine the lower threshold of the sensitivity of radish seeds to alcohol, soap or vinegar by repeating the experiment with diluted solutions. This activity could be conducted as a class activity with different groups doing various dilutions of the solutions in order to determine the critical points of sensitivity with the various solutions.

Sample Data

Answers to Questions

1. Which treatment resulted in the greatest rate of germination? Explain.
   

   The plain water resulted in the greatest germination rate. All other treatments produced no germination.
   

2. Is there water in all the dishes? Is water needed for germination? Support your answer from the data.
   No, there is only water in one of the dishes. Yes, water is needed for germination as the only seeds that germinated were grown on water-soaked filter paper.
   
3. Suggest an explanation for the lack of germination in those dishes with 0% germination.
   

   Seeds need moisture to germinate so obviously the dry paper would not cause seeds to germinate. Alcohol dries much faster than water, therefore seeds would not germinate there either. It seems a natural pH is also helpful in order to increase germination.
   

4. Do any of the dishes suggest possible analogies to the effects of acid rain? Other environmental pollutants? Explain your answer.
   

   Based on the results, it seems a natural pH is best to yield optimal germination rates. Therefore, one would predict acid rain would not yield a high germination rate.

Introduction

Seeds must have moisture in order to sprout and grow. Is pure water required, or will any liquid do?

Concepts

• Germination

• Environmental pollution

Background

A seed is viable if its embryo is alive and, therefore, the seed is capable of germination. Germination (sprouting and growth) of a seed depends on the interplay of a number of internal seed and environmental factors. A seed that is viable will not necessarily germinate. Moisture is one variable that is critical for seed germination. How critical is it and what form must it take?

Materials

Safety Precautions

Alcohol solution is very flammable and should not be used near open flames. Seeds are routinely treated with mold-inhibiting chemicals to help preserve them. Once seeds are brought into the laboratory, they are considered chemicals and should not be consumed. Be sure to wash hands and work areas thoroughly upon completion of the laboratory work. Wear chemical splash goggles and chemical-resistant gloves. Please follow all laboratory safety guidelines.

Procedure

1. Place a layer of filter paper into the bottom of five Petri dishes.
2. Set up the five Petri dishes as outlined in Table 1. Pour specified liquids on the filter paper until the paper is completely wet. Evenly space ten radish seeds on the soaked filter paper. Cover the seeds with another piece of filter paper soaked in the same solution. Label the Petri dishes and set them aside for three days.

3. After three days or when instructed by your teacher, open the dishes and examine the seeds in each of the dishes. Record the number of germinated (sprouted) seeds in each dish on the Germination Worksheet.

Student Worksheet PDF

10446_Student1.pdf