Agriculture Reference
In-Depth Information
Pleated Paper
Pleated paper (Fig. 5.7) has come into prominence in recent years as a medium for certain species. It is
similar to ilter paper that is pre-folded into 50 accordion-like pleats into which the seeds are placed for
germination This provides an advantage for germination of species such as sugar beet and New Zealand
spinach, in that it provides greater contact area for seeds throughout the critical early stages of imbibition
and germination. It is also useful for coated seeds which can be pre-softened, revealing multiple seeds from
one unit as well as avoiding erroneous multiple counts in multigerm seed units like beet seeds. Its primary
disadvantage is that it must be hand planted without the aid of counter heads that expedite planting on other
media. Another disadvantage is its relatively high cost compared to other media (Ashton 2001).
Figure 5.7. Germination of pelleted sugar beet seeds in pleated paper.
Sand or Soil
Sand or soil germination tests (Fig. 5.8) enjoyed great popularity in the past because of their close associa-
tion with ield conditions. However, because of problems associated with storage and disposal, soil vari-
ability, pathogens, and cleanliness of the workplace, soil is no longer allowed as a primary germination test
medium, although it may be used in certain retest situations. The AOSA rules recognize two sand substrata
conditions: S = sand in which the seeds are planted directly to depths ranging from approximately 1/4-inch
for seeds the size of clovers, and 1/2 to 3/4-inch for seeds the size of corn and beans and TS = top of sand
in which the seeds are planted directly on the surface.
There are no uniformly accepted speciications for the kinds of sand and soil to use in a germination
test. However, a clean, sharp quartz or builders sand (not too ine) is suggested. The sand should be not less
than 99.5% SiO
2
with a particle size of 0.05 to 0.8 mm and should be washed and free of organic mate-
rial and salts. If reused, the remaining organic matter must be removed and the sand sterilized to kill any
remaining microorganisms. For soil, a sandy loam with a moderately high water holding capacity is suitable
