Laboratory Exercise 4
Purpose: Quantitative population assessment; effects of plant residues and defense compounds on nematode survival; nematode morphology and anatomy.
1. Powerpoint presentation and slides of nematode damage to plants.
2. Experiment: Effect of substances of plant origin on nematode survival and activity. The following materials are some examples:
- cellulose powder, high C:N ratio, not considered a source of toxic metabolites.
- milled mustard (Brassica juncea), source of the glucosinolate sinigrin which is metabolized to allyl isothiocyanate.
- yellow mustard seed, Sinapis hirta, source of the glucosinolate sinalbin which is metabolized to 4-hydroxybenzyl isothiocyanate
- garlic powder, a source of allicin which is oxidized to S-allylcysteine and other sulfur-containing compounds.
some of the compounds, for example the isothiocyanates, are unstable, some with a half-life of only a few hours.
3. Note differences in the nematode communities extracted from soil samples in the last lab period and in other samples provided..
4. Practice basic skills: hand-picking nematodes, heat-killing with flame or slide-warmer device, and making temporary mounts. You need to be able to see internal structures clearly.
5. Use the keys provided in Nemaplex to identify the nematodes to the level of family (in Nemapex Select Biology and Taxonomy then Nematode Characteristics and Taxonomic Keys then Families of Plant and Soil Nematodes.
6. Complete observations on stoma
and esophagus structures of nematodes with different feeding habits:
plant parasites, bacteria feeders, fungus feeders, predators.
7. Complete observations of reproductive systems.
8. Extract nematodes from your own samples as assigned
9. Homework Assignment:
Review areas of NEMAPLEX dealing with nematodes as plant parasites and nematode damage to plants.
Select...Introduction to Nematodes
Select...Nematodes as Plant Parasites
Select...General Concepts of Disease
How Nematodes Damage Plants
Taxa Containing Plant Parasites
Back to previous menu
Select...Characteristics of Nematodes
Select...Reproductive Strategies of Nematodes
Select...In the News - review current and recent news issues regarding nematodes. Note issues regarding pesticides and volatile organic compounds (VOCs).
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