hUNGARiAN AGRicUltURAl RESEARch

Figure 2. Conidia germinated on the petal’s surface and penetrate across the cuticle
and also stops the pathogen in
other flower parts. According to
Holb (2003) all parts of the Prunus
flowers are sensitive but the
sensitivity of the stigmata was not
emphasised.
Results of the infections carried
out at the Department of Genetics
and Plant Breeding under natural
and artificial (in vitro) conditions
indicate that penetration of the
pathogen has never occurred
through the stigmata. Moreover,
stigmata of the totally destroyed
flowers remain alive for the
longest time. Artificially infected
stigmata of the emasculated and
hand pollinated flowers also
showed fully resistance in the
experiments. According to the
Figure 3. Destroyed petal tissue shows the way of the mycelium
growth
results obtained from the natural
and artificial infection study it was
established that the start point of
infection are petals. Furthermore,
the germinated conidia easily
could penetrate through the cuticle
of the petals (Figure 2, 3, 4). This
assumption was partly confirmed
by the tissue structure of floral
organs. The resistance of the
emasculated and forced pollinated
flowers may be due to the removal
of petals and anthers.
Study on the mechanism of
infection was completed by the
investigation of the flower of Prunus
salicina, P. cerasifera, P. dasycarpa
and P. mume. All of the tested
Prunus flowers were destroyed by
the fungus but stigmata survived for
the longest time.
In case of the resistant
genotypes inoculation of the
flowers on twigs wasn’t succeed
by the injuring of twig’s phloem.
Contrary to that spreading of the
disease in the twigs tissue of
sensitive cultivars were very
quick. For further testing of the
resistance the artificial infection
was carried out on the shoots. .
Hungarian Agricultural Research 2009/3–4 19