Laboratory Exercise 3
Purpose: Techniques for Extraction of Nematodes from Soil and Plant Tissue: Qualitative and Quantitative Population Assessment
1. Videotape and discussion of separation practices.
2. Powerpoint presentation and slides on separation efficiency.
3. Demonstration of techniques for separating nematodes from soil and roots and population assessment.
a) Techniques requiring nematode movement.
1) Baermann funnel and modifications. 2) Mist chamber.
b) Flotation techniques.
1) Cobb's decanting and sieving. 2) Seinhorst two-flask method. 3) Single and multiple elutriators. 4) Sugar flotation/centrifugation.
4. Symptom evaluation and bioassay.
a) Root staining.
Observe developmental stages of root-knot nematode in stained roots.
b) Gall rating.
Rate the extent of root-knot nematode galling on a tomato roots on the four scales provided by
Barker, 1985, which are based on % galling. Also, determine the root-knot index using the
infection class method of Daulton and Nusbaum, 1961.
5. Examination of samples extracted in this laboratory period and of student samples:
a) Report to the class on the probable feeding habits and ecosystem functions of the nematodes present.
b) Determine characteristics of the female reproductive tract; indicate whether the arrangement of uteri is prodelphic, opisthodelphic, amphidelphic.
c) Draw representative male reproductive structures, including spicules and gubernaculum, caudal alae.
6. Homework Assignment:
Review sections of NEMAPLEX on the higher classification of the phylum Nematoda as follows:
Main Menu: Select...Biology and Taxonomy Select...Phylum Nematoda Select...Higher Classification of Nematodes Class Chromadorea Class Enoplea Main Menu: Select...General Nematology Select...Nematodes as Plant Parasites Select...Taxa containing Plant Parasites
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