Agriculture Reference
In-Depth Information
Although self-contained germinators are convenient and do not require large designated areas, most
laboratories which test large numbers of samples of one or more species with the same temperature require-
ments should consider installing walk-in germination rooms. These can be as large as necessary, and can be
controlled with a single compressor that can be located outside to avoid excessive heat and noise. Multiple
germination trays are placed on mobile carts enclosed in Plexiglas, with tight-itting doors and can be
wheeled into the walk-in germinator to remain throughout the incubation period. The tight-itting door,
along with the moistened germination media, helps maintain excellent relative humidity. Following incuba-
tion, the carts are rolled back into the work area where the tests are evaluated. Such carts are useful for
germination in sand or soil as well as on different kinds of artiicial media such as blotters and paper towels.
An alternate method that some laboratories use is to line the walk-in germination chambers with shelving
on which germination boxes with covers to maintain the desired level of moisture throughout the test period
may be placed during incubation. This may provide a more eficient use of space and does not require as
much space to maneuver as wheeled carts.
Some laboratories prefer sand as germination media for large-seeded species such as corn and soy-
beans. When germinated in the light, sand tests produce seedlings which may appear more similar to those
under ield conditions than tests on artiicial media. The seedlings in sand tests have good natural color and
do not become etiolated like those between rolled towels. However, cleanliness may become a problem
and the tests require considerable germination space. Sand tests also require space for storing sand, as
well as its disposal after use. Because of these concerns, the sand test is not as prevalent as in earlier years.
Germinators or cold rooms with temperatures of 5°C to 10°C are also required for pre-chilling treatments
to break dormancy before germination in some crop species. A dark room with UV light may be needed for
laboratories that perform luorescence tests for ryegrass and hard or red fescue. If the lab performs grow
out tests (for varietal identiication), a controlled environment including light and temperature, such as
growth chambers or a greenhouse, may be needed.
It is important to have large storage areas with convenient access to the germination preparation area
for storing germination supplies such as planting trays, plastic containers and various kinds of germination
media, including sand and soil. Media such as blotters, paper toweling and creped cellulose paper may be
needed. Other facilities needed in close proximity to the germination preparation area include a darkroom
with UV light for evaluating luorescence tests, X-ray analysis and photographic ilm development. Finally,
adequate sinks and counter space will be necessary for preparation and evaluation of each of the different
types of seed tested. Some laboratories have dishwashers for cleaning germination trays and boxes. Safety
precautions such as wearing gloves and masks have to be followed whenever indicated. Some chemicals
such as KNO3 and GA3 acid may be needed for some germination tests. Seed testing rules and handbooks
and other references relevant to germination testing are needed in the germination area. Record keeping of
temperature, equipment maintenance, and tests conducted is needed for quality assurance purposes.
Special Tests
“Special tests” is a term that is generally used to refer to a group of tests other than purity and germination
tests. Some laboratories may have a separate section where special tests are conducted. Examples of special
tests include tests for viability by tetrazolium, vigor tests, chromosome counts, ploidy by cytometry, X-ray,
seed moisture content, electrophoresis, pathological, genetic traits, and other tests that generally provide
useful information about the quality of the seeds in question. Each laboratory may evolve a somewhat
unique special testing area, depending on the tests offered. In addition to suitable work area for each test,
considerations should include cabinet space for safe chemical storage, exhaust hoods for analyst safety and
chemically resistant sink and counter tops. It should include the equipment needed to conduct the various
tests offered. One common area may be provided for all special tests or a different area for each.
