Germ & dormancy - generic practical

Improving the identification, handling
and storage of “difficult” seeds
• Forceps
• Scalpel
Method/Procedure
Depending on time, species available and the particular dormancy issues you want to
better understand, the following treatments may be tried.
1. GA experiment
Draw three samples of 40 seeds each of a physiologically dormant species. Subdivide
each sample into four replicates of ten seeds. Sow the first, second and third set of
replicates on 1% water agar containing 0mM, 0.7mM and 10mM GA respectively (or
on paper wetted with GA solutions) and incubate at 25 o C. Score for germination after
7 – 8 days of incubation. Use protrusion of the radicle as measure of germination.
2. Requirement for alternating temperature
Draw two samples of 40 seeds each of a physiologically dormant species. Subdivide
each sample into four replicates of ten seeds. Sow the first and the second set of
replicates on appropriate media and incubate at 25 o C and 30/25 o C respectively. Score
for germination after 7 – 8 days of incubation. Use protrusion of the radicle as
measure of germination.
3. Surgical treatment
Draw three samples of 40 seeds each of a physiologically dormant species. Subdivide
each sample into four replicates of ten seeds. Surgically expose the embryo of the
seeds of the second set of replicates carefully to avoid damaging the embryo. Nip
away from embryo, the seed coat of the seeds of the third set of replicates Sow the
three sets of replicates on on appropriate media and incubate at 35/15 o C. Score for
germination after 7 – 8 days of incubation. Use protrusion of the radicle as measure of
germination.
4. Nipping experiment
Draw two samples of 40 seeds each of a physically dormant species. Subdivide each
sample into four replicates of ten seeds. Nip away from the embryo, the seed coat of
the seeds of the second set of replicates to avoid damaging the embryo. Sow both the
first and second set of replicates on on appropriate media and incubate at 25 o C. Score
for germination after 7 – 8 days of incubation. Use protrusion of the radicle as
measure of germination.
5. Potassium nitrate treatment
Draw two samples of 40 seeds each of a physiologically dormant species.. Subdivide
each sample into four replicates of ten seeds. Sow the first and second set of replicates
on 1% water agar containing 0% and 0.2% Potassium nitrate (or on paper wetted with
0.2% nitrate solution) respectively and incubate at 25 o C. Score for germination after 7
– 8 days of incubation. Use protrusion of the radicle as measure of germination.
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