Teacher Material - Advanced Preparation (continued)

What's Wrong with the Plants?

Activity 1

Plant Observation

The best plants to use for observation are cucumber, tomato, or egg plants because they are quick-growing and will exhibit obvious, characteristic symptoms of nematode infection.
Let seedlings get at least 5" tall before you inoculate. You can mix eggs with water and pour on the soil of the plant. Start these initial plants about two months before the lab. If possible have growing plants available for students to observe. Then when you introduce the plants they will know that you treated all plants the same.
Every team does not need to have a whole plant to observe. The plants can be shared if you do not have enough for all teams.

Egg Extraction

Students will use the microcentrifuge tubes to extract eggs. Small test tubes can be used. They should wear goggles and aprons. Even a small amount of bleach can be harmful to the eyes and will discolor clothing.
Leaving the eggs in the bleach too long or not rinsing the roots can destroy the eggs. Have students time the shaking of the roots carefully.
Bleach solution is 1 part bleach to 4 parts water.

Soil Extraction

The extraction filter dishes can be made from almost anything. You just need to make sure that the soil pouch is screened from the bottom of the dish. I suggest ä Tupperware-like sandwich boxes with lid. The screen needs to be pliable enough to make a free-standing filter that fits into the container. Stainless steel is recommended if available and affordable but do not use copper window screen. Copper is harmful to nematodes. The first set of students to do the lab should construct the dishes. (See Diagram) The screen will serve as a ‘basket’ for the soil pouch.

Scotties brand tissues are selected specifically because the spaces between the fibers are large enough for the nematodes to fit through and the tissues do not tear easily when soaked. Make sure the water covers about 1/2 of the tissue with soil.