Pulsatilla vulgaris (L.) Mill. - Plantlife

1.3 Genetic implications
The chromosome base-number of the genus is 8. Pulsatilla vulgaris is tetraploid (2n = 32) and
may have arisen following hybridization between P. patens (2n = 16) and P. pratensis (2n = 16)
(Böcher, 1934). Spontaneous hybrids between subsp. vulgaris and P. pratensis and P. patens
are known from Northern Europe (Akeroyd, 1993) and work on Swedish populations has
indicated that hybridization barriers are weak between subspecies of Pulsatilla vulgaris, and
between P. vulgaris and P. halleri (Lindell, 1998).
Bailey (1996) found a low percentage of polymorphic loci in five sites across the geographic
range of Pulsatilla vulgaris in England (Barton Hills, Knocking Hoe, Rodborough Common,
Devils Dyke, Therfield Heath), suggesting that overall genetic variation is low, although there
were significant differences for individual primers between some of the sites examined.
Further work is needed to more fully assess these differences, and in relation to overall
fitness, population size and degrees of geographical isolation.
Similar work has been undertaken in Germany on 11 populations ranging from 50 plants to
7300 plants (Hensen et al., 2005) and found a significant positive relationship between genetic
diversity and both population size and seed mass (per population). Genetic diversity was
significantly lower in smaller populations than in larger ones, suggesting that genetic drift
(random change of allele frequency within a population) has been the main cause of the loss
of diversity as populations have become smaller and fragmented following rapid land-use
change (i.e. the chance of alleles being lost from one generation to another has been greater
in smaller populations).
Hensen et al. (2005) also found a high level of within population variability which was
attributed to life-history traits likely to preserve variability, namely allogamous pollination, a
long life span and vegetative reproduction. Interestingly there was only weak, albeit
significant differentiation between populations which was correlated to the geographical
distance. This suggests that genetic drift has been the major force driving differentiation
between German populations as the former larger population became fragmented. The
weakness of this relationship suggests that the loss of genetic variability through drift has
been, to some extent, balanced by gene flow between closer populations. Since seed dispersal
in Pulsatilla vulgaris is limited it was concluded that the foraging radius of pollinators,
currently thought to be in the order of several kilometres for honeybees (Steffan-Dewenter &
Kuhn, 2003) and bumblebees (Osborne et al., 2008), is critical in offsetting genetic drift as
populations become smaller and more isolated. However, even if pollinators forage over
several kilometres it seems very unlikely that they would travel between English populations
given their small size and degree of isolation.
1.4 Medicinal properties
Pulsatilla vulgaris is unpalatable and poisonous to humans and animals due to the presence of
the glycoside ranunculin in the leaves and roots which is converted to anemonine when the
plant is dried (Plants for a Future, 2010). Small doses are taken internally in the treatment of
pre-menstrual syndrome, inflammations of the reproductive organs, tension headaches,
neuralgia, insomnia, hyperactivity, bacterial skin infections, septicaemia, spasmodic coughs in
asthma, whooping cough and bronchitis. Externally, it is also used to treat eye conditions such
as diseases of the retina, senile cataract and glaucoma. In homeopathy, extracts are used to
treat measles as well as minor complaints such as nettle rash, toothache, earache and bilious
indigestion (Plants for a Future, 2010).
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