SummaryThe morphology of the fruit and difficulties with fruit processing impose major limitations to germination of Persoonia sericea and P. virgata. The mesocarp must be removed without harming the embryo. Fermentation of fruit or manual removal of the mesocarp was effective but digestion in 32% hydrochloric acid (HCl) completely inhibited germination. The endocarp is extremely hard and therefore very difficult and time consuming to remove without damaging the seeds. The most efficient method was cracking the endocarp with pliers, followed by manual removal of seeds.Germination was completely inhibited unless at least half of the endocarp was removed. Microbial contamination of the fruit and seeds was controlled by disinfestation and germination of the seed under aseptic conditions. The results suggest that dormancy in these species is primarily due to physical restriction of the embryo by the hard endocarp.
Persoonia virgata R.Br. is harvested from the wild in
both its vegetative and flowering stages. There has been no systematic study
published on the annual growth cycle and anecdotal reports are conflicting.
The growth pattern, flowering and fruit development of
P. virgata in its natural habitat was recorded monthly
for two consecutive years. The main growth period occurred in late
spring–mid-autumn (November–May) when the shrubs were producing
little or no fruit. Very few open flowers were observed at the site over the 2
years, with only 6.7 and 12.7% of stems bearing open flowers in January
and February 1996, respectively. A second study of flowering on
container-grown shrubs showed that individual flowers were open for only
2–5 days, with individual stems taking 3–8.5 weeks to complete
flowering. The main fruit growth period occurred from May to September, and in
June and July 1996 the total fruit set per stem was 41.6 and 36.1%,
respectively. The fruit took at least 6 months to develop during which
vegetative growth was minimal. The harvesting of plants in the flowering or
fruiting stages removes the annual seed crop, which may reduce regeneration of
this obligate seed regenerator and threaten its survival after fire.
Summary. Persoonia virgata is an
endemic shrub of Australia that is being bush-harvested for its foliage and
sold on the domestic and export flower markets. The limiting factor to the
cultivation of many desirable Persoonia species has been
the extreme difficulty in developing a reliable propagation system. This study
investigated the effects of cutting type, maturity of the stock plant, and
genotype, on the rooting of P. virgata cuttings. It was
found that juvenile cuttings rooted significantly better than mature cuttings.
Some juvenile seedling genotypes yielded no rooted cuttings, whereas others
produced up to 90% rooting. No anatomical barrier to root formation was
discovered. High performance liquid chromatography showed differences in the
abundance of unidentified compounds in cuttings, related to season and to
genotypic differences in rooting abilities. A possible seasonal rooting
inhibitor was present in some genotypes. The potential for selection of
genotypes with improved rooting ability has been demonstrated.
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