Materials Included In Kit

Additional Materials Required

Prelab Preparation

The Roundup herbicide is provided in concentrated form. Dilute the herbicide before use. Mix 1 mL of herbicide with 20 mL of distilled water. The 30 mL of concentrate in the kit can make 600 mL+ of herbicide. Place the diluted herbicide in small dropper bottles for ease of use during the laboratory. Label all containers appropriately.

Since soil-potting activities can be messy, you may want to set up several specific planting areas in your classroom with tables protected with plastic sheeting or newspapers. Confined work areas make lab cleanup much easier.

Approximately two hours before planting, soak the soybean seeds in water. Soak the two types of seeds in separate labeled containers so that the two types are not mixed up.

Safety Precautions

Caution should be taken when working with Roundup herbicide. Do not allow skin, eyes or mouth to contact the herbicide. Do not ingest the herbicide. Wear chemical splash goggles, chemical-resistant gloves and a chemical-resistant apron. Wash hands thoroughly after all laboratory work. Do not get Roundup on any plants outside of this experiment. Please review current Safety Data Sheets for additional safety, handling and disposal information.

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. All plant material and soil can be disposed of according to Flinn Suggested Disposal Method #26a.

Teacher Tips

• Enough materials are provided in this kit for 30 students working in pairs or for 15 groups of students. The initial setup will require a laboratory period. Partial class periods will be required for observations and treatments for several weeks following the initial setup class period.
• Soybean seeds should not be kept from year-to-year. The germination rate for all soybeans, and roundup ready seeds in particular, drops significantly after one year. Two years after harvest most roundup ready soybean seeds are not viable.
• This activity is an excellent stimulus for discussing selective breeding and genetic engineering. Be sure students understand the Roundup Ready concept and how Roundup Ready seeds are obtained. You might start the lab discussion by having students compare the two seeds and see if they look different. Genetically modified food is a hotly debated issue currently and might be an excellent topic for a class debate.
• The Roundup Ready soybeans will continue to grow after the herbicide treatment. All of the other plants in the experiment should wither and die. It is possible to transplant the Roundup Ready soybeans to a garden, grow them to maturity, harvest the next generation of seeds and determine if they are Roundup Ready.
• Suggest students do additional research on genetically modified food and conduct a class debate on the issues.

Introduction

Examine a few food items at the grocery store. The labels reveal the calories, fat and fiber content. But what about the ingredients that are not on the labels? Chances are good that the tortillas you pick up contain corn whose genes were manipulated to kill insects and the oil you buy is from soybeans that were genetically engineered to resist weed killer.

Background

Humans have been “genetically modifying” everything from corn to pigs for many centuries. The major tool in this process has been selective breeding. If a new breed of soybean was desired that was resistant to a certain fungus, then soybeans would be planted and individuals that fared well against the fungus were selected and bred with each other. Then seeds that fared well from the next generation were crossed with each other for many succeeding generations with the hope of creating a strain that was resistant to the fungus. Likewise, animals were bred over generations to create individuals with “desired” traits. Using selective breeding techniques, people have created variegated roses, giant pumpkins, cattle with more muscle mass, and horses that can run faster. We have even selectively bred chickens to produce eggs with lower cholesterol!

With the advent of the “genetic revolution” over the last 50 years, scientists have found ways to speed up the process of producing organisms with desirable genetic traits. Genetic engineering techniques allow scientists to insert specific genes into a plant or animal without having to go through the trial-and-error approach of selective breeding. Genetic engineering is therefore extremely rapid compared to selective breeding. With genetic engineering, it is also much easier to place specific traits into different species. A plant, for example, could be created containing the human insulin gene. The plant could then be grown in mass to harvest human insulin. This example, of course, would appear to be a good thing. Controversy, however, arises if a deleterious gene is transferred—either intentionally or by accident—into a different species.

A variety of techniques are used to modify plants and animals through genetic engineering. For example, there is a widely used herbicide call Roundup^®, made by Monsanto. Roundup kills nearly any plant that it touches. Monsanto has genetically modified soybeans and other crop plants to create “Roundup Ready” strains that are not affected by Roundup. By planting Roundup Ready^® seeds, a farmer can control weeds by spraying Roundup right over the crop. The Roundup Ready crop is unaffected by the herbicide, but the weeds are eliminated. Roundup Ready seeds reduce production costs and increase yield, so food becomes less expensive.

It is not just the major grain crops that are being engineered. Genetically engineered strains of apples, asparagus, bananas, broccoli, coffee, corn, cotton, grapes, lettuce, papayas, potatoes, raspberries, soybeans, squash, sugar beets, radishes, tomatoes and wheat are all being commercially grown. Many other food plants are at the experimental stage at this time. However, only two crops are truly significant in the food industry at this time. More than half of the U.S. soybean crop and one-third the corn crop are genetically engineered. Corn and soybean products are used in snacks, cereals, oils, soft drinks and many other food items. The potential impact that eating these genetically modified foods might have on humans is virtually unknown. No long-term studies are underway and there are many questions with few answers. Genetically engineered crops are very pervasive and there is no system in place at the moment to separate them from other crops. This somewhat controversial issue will be in the news for years to come.

Materials

Safety Precautions

Caution should be taken when working with Roundup herbicide. Do not allow skin, eyes or mouth to contact the herbicide. Do not ingest the herbicide. Wear chemical splash goggles, chemical-resistant gloves and a chemical-resistant apron. Wash hands thoroughly with soap and water before leaving the laboratory. Do not get Roundup on any plants outside of this experiment.

Procedure

1. Obtain two plant pots, potting soil, pot marker stakes, five presoaked regular soybean seeds and five presoaked Roundup Ready soybeans.
2. Make marker labels for each pot. Label with your name, date, and soybean treatment. Use the following abbreviations for the soybean treatments—RRS (Roundup Ready Soybeans) and NS (Normal Soybeans).
3. Fill each pot with potting soil and pack the soil gently but firmly into the pot until it is nearly full.
4. Place one marker in each pot by pushing it down into the soil.
5. Plant five soybean seeds of each type in its appropriately labeled pot. Spread the seeds evenly on top of the soil. Then gently press each seed just below the top level of the soil about 1 cm deep with the eraser end of a pencil or other blunt object.
6. Place the pots into a shared watering tray and water the soil thoroughly in the two pots. Be sure there is extra water in the water trays and that water can soak up into each pot from the bottom.
7. Place the watering tray in a well-lit area as directed by your instructor and let the soybeans sprout and grow for 5–7 days.
8. Observe the plants daily and record your observations on the Soybean Worksheet. Be sure the plant soil stays moist.
9. After approximately five days or as directed by your instructor, secure 20 “weed” seeds. Spread 10 weed seeds over the surface of each soybean pot, being careful not to disturb the soybean plants. Sprinkle a small amount of topsoil over the top of the weed seeds, water the pots, and return the pots to the watering tray.
10. After 14 total days have elapsed (or as directed by your instructor) treat all of the plants in both pots with Roundup Ready herbicide. Do this by dripping 2–3 drops of the herbicide onto the growing tip of each of the plants in the pots. Drip the herbicide carefully onto the plants. Use the droppers or pipets provided by your instructor. Do not allow the herbicide to contact your skin, clothing or any other items.
11. Observe the plants for the next 3–4 days. What happens to the various plants? Record your observations on the Soybean Worksheet.
12. Hold a class seminar on genetically modified food and answer these questions as a class:

1. What happened to the weeds after treatment with the Roundup herbicide?
2. What happened to the two types of soybeans after treatment with the herbicide?
3. Discuss the advantages and disadvantages of using Roundup Ready soybean seeds.

13. Consult your instructor for appropriate disposal procedures.

Student Worksheet PDF

10452_Student1.pdf