TheImprovement ofTropical and Subtropical Rangelands

172 IMPROVEMDIT OF TROP/GAL AND SUBTROP/GAL RANGELANDS
to one seedling per cell. The IlUCceu of the direct seeding method depends
upon the accuracy of the seed information. Germination tests
vary from laboratory to laboratory, and no standardised tests are
available for many shrub, and forbs. Since laboratory germination
tests are run under controlled conditions, test results may differ from
greenhouse germination. Sometimes the seed is obtained just before
the lOWing date and 80 there is not enough time for seed testing.
Germinant Technique The "germinant technique" is the lOwing
of pregerminated seed into the growth container. This propagation
method is best for plants with simple dormancy requirements and
species with seeds too large to handle mechanically. It is particularly
suitable for seed lots of variable or unknown quality, because
only good seed is IOWIl in the growth container. Cell occupancy is
maximized with this method as there are few blank cells and no
subsequent thinning is needed.
The germinant procedure requires clean seed, 80 seed lots should
be sterilized with chlorine bleach to reduce molding during stratification.
The seeds are usually hydrated with a 24- to 48-hour soak
and then prepared for the stratification chamber.
Seed can be germinated in "naked" stratification, where bare
seeds are kept in a plastic bag or mixed with a moisture-holding
material such as peat mou. The acidity of the peat m088 helps
retard seed molds during the lengthy stratification period, which can
last up to eight months. Seeds are ready to transfer to the growth
container when a white radicle becomes visible, but before the radicle
becomes 80 long that it is easily damaged.
The planting operations consist of pouring the stratified seed out
in a tray and picking out the germinants by hand or with tweezers.
The germinants are placed in a depreuion or small hole in the potting
80il in the growth container and covered with grit or perlite. Seeds
should be placed with the radicle oriented downwardj if the radicle
is pointed upward it will reveree itself in response to gravity, which
may result in a stem crook in the young seedling.
Trauplant. Transplants are a third propagation method.
Transplants are seedlings grown to the cotyledon state in trays and
then transplanted into growth containers. This propagation method
is best for woody plants with complex dormancy requirements, or
for species whose small seeds would be almost imp088ible to plant
by hand. This technique is ideal for seed lots of variable or unknown
quality.