Agriculture Reference
In-Depth Information
exhausting chemical fumes from treated seed or dust from other seed samples. Some laboratories are also
tending to move away from routine use of hand lenses to binocular microscopes or desk magniiers with
appropriate light source. Some modern laboratories have Ergovision purity stations with advanced optics
and mechanical seed conveyors which provide eficiency and ergonomics. They contribute to ergonomics
and eficiency, especially in testing small-seeded kinds such as bentgrass and Kentucky bluegrass.
Purity areas should also be equipped with compressed air to allow rapid, thorough and easy clean-up
as well as vacuum systems which can remove dust and fumes from chemically treated seeds to protect ana-
lyst health. A hood may be needed for mixing and subdividing treated seeds. Some laboratories no longer
test treated seed because of health concerns and dificulty with seed identiication. Others have established
special rooms with exhaust systems for testing treated seed without endangering analyst health.
The purity area should be equipped with a seed reference collection or herbarium containing seed
samples of all weed and crop species that might be expected to occur in any sample. This should be accom-
panied by identiication plates, drawings and anatomical descriptions to help with identiication problems.
The collection should also be supplemented by seed and plant mounts and taxonomy books. It is important
that the seed reference collection or herbarium should be veriied by someone who has good expertise in
seed and plant identiication. There is some thought among quality assurance specialists that the seed refer-
ence collection is a “reference standard” and should be veriied for authenticity just like a thermometer or
a check weight.
Germination Testing
Germination areas should be equipped with desks or tables for preparing and interpreting germination tests
in close proximity to self-contained germinators. When germinators are located in adjacent rooms, they
should be readily accessible to the main work area. Larger laboratories have walk-in germinators located
in special germination rooms (where temperature and light can be controlled) with convenient access to
analyst workstations and tests transported on carts back and forth as needed. Such isolated germination
rooms help avoid both noise and heat from compressor motors plus noise from solenoids, fans and various
electronic controls that can otherwise interfere with analyst concentration and comfort. This also allows
repair or regular maintenance of germinators, central air compressors, and vacuum pumps with minimal
disruption of the analytical routine.
Vacuum lines should run to every planting station to allow vacuum planting of seeds. It is best to use
large capacity central vacuum units that are designed for continuous operation. The main unit should be
located away from the analysts to avoid noise and problems from objectionable exhaust fumes.
Most seed laboratories depend on cabinet-type germinators to provide optimum germination condi-
tions. These are self-contained and provide sensitive temperature control, along with supplemental lighting
for light-sensitive seeds. They are relatively inexpensive and most laboratories can afford several such units
to provide optimum conditions for different species tested. They are relatively small, mobile and can also be
spaced conveniently throughout the working area as needed. However, because they generate considerable
heat and sound levels, in larger laboratories with multiple units, it may be preferable to place them in a
separate room away from the testing area.
While self-contained germinators are versatile and easily controlled, they have limited capacity and
require relatively high maintenance. Furthermore, humidity control is dificult, except for those which
employ a water curtain or some other means for maintaining humidity. Although some types provide good
humidity control, they require softened water for best maintenance-free performance. Otherwise, the water
system tends to become clogged and ineficient, requiring frequent maintenance. Other germinators utilize
misters and atomizers to maintain humidity, although distribution of humidity throughout the germination
chamber is usually a problem. Because of such problems, most germinators now do not have humidity
control, but depend on humidity control within the individual test container.
