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5. ORIGIN OF SEEDLING...
5.3. RESULTS
5.3.1. Optimisation of seedling root fluorescence test
The major modification of seedling root fluorescence test i.e., the germination of seeds
in Petri dishes instead of glass plates proved to be very advantageous because all seedlings
were in the same stage of development after the 18-day long test and fluorescence could
be reliably read. The highest level of fluorescence was observed after six days of germination
(Table 5.1A) and this period was applied in all subsequent experiments. The durations
of germination could not be longer than seven days since after that time roots started to
fluoresce.
The level of fluorescence depended also on temperature and the highest number of
fluorescent seedlings were observed at 27 o C (Table 5.1B). Noteworthy, the light exposure
reduced strongly the level of fluorescence even though the boxes, where glass plates with
seedlings were put, were wrapped in aluminum foil (Table 5.1C). This is probably due to
decomposition of annuloline by light.
From the preliminary experiments it is obvious that the duration of seedling root fluorescence
tests should not exceed 14 days (Table 5.1.D) what is in agreement with the Association
of Official Seed Analysts Rules (IOA 2006) but in contrast to Niemyski and Budzyńska
(1972) recommendations and Polish standards PN-79/R-65950. The prolonged period of
seedling incubation resulted in loss of fluorescence mainly due to root death. This also
caused difficulties in seedling rescue.