Nematology 100
Name:
MID-TERM EXAM, 11/01/00
90 minutes
1. (25 points)
- You are provided with nematodes extracted from lawn soil on the UC
Davis campus.
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- a. Place an adult female plant-parasitic nematode of
any species on a microscope slide.
- Kill the nematode with gentle heat.
- Apply a coverslip.
- Seal the edge of the coverslip with fingernail polish
to prevent the slide from drying out.
- Place the slide on the compound microscope and adjust
the microscope to provide
Köhler illumination.
-
- b. Indicate on your exam sheet the Class and Order of
your nematode.
-
- c. Draw and label the component parts of the stylet
and esophagus for this type of nematode (either from your
specimen, or from your knowledge of anatomy and
morphology, or both).
-
- d. From the morphological and anatomical characteristics of the
specimen, indicate a probable feeding habit for this nematode and
explain why.
-
- e. Call the instructor for examination of your
nematode. If there is more than one nematode present in
the microscope field, indicate the specimen you wish to
have examined. Do not ask or expect the instructor to
make the selection.
- Only the nematode that you indicate initially will be
considered.
-
- Grading:
- adult female plant-parasite, good condition
10 pts
- juvenile, male or non-parasite, good condition
6 pts
- correct designation of Class and Order
2 pts
- reasonable justification of feeding habit designation
5 pts
- correct drawing and identification of stylet/esophagus
8 pts
- points off for damage, distortion, dry slides, etc.
2. (15 points)
a. Describe the feeding habits of the sheath nematode, Hemicycliophora arenaria.
b. How are the survival and reproduction of the nematode influenced by
environmental conditions?
3. (10 points)
In the table below, provide the following information
for each of the nematodes listed (answer by using the
appropriate letter).
(i) Order:
(ii) Esophagus type
(iii) Ovaries?
(iv) Virus vector?
(v) Adult female feeding habit?
(vi) Provide a recognized common name.
4. (10 points)
On the field trip you recovered the
ring nematode from an almond orchard. You also studied the nematode in the
laboratory.
Describe the observations and evidence (circumstantial and experimental)
that underlie our understanding of the effect of ring nematodes on the susceptibility of almond trees to bacterial canker.
5. (15 points)
(i) What are the functions of a plant
root?
(ii) List the ways in which
plant
roots may be damaged by, or respond to,
plant-parasitic nematodes.
6. (15
points)
a) Describe the processes of
acquisition, retention (retention sites, mechanism and retention period), and
transmission of plant viruses by plant-parasitic nematodes.
b) Which genera of nematodes
transmit Nepo viruses?
c) Indicate two virus
diseases, and the crops affected, that are vectored by species of Xiphinema.
7. (10 points)
Briefly describe a method of
separating nematodes from soil that does not require the nematodes to be motile.