We have uncovered plasticity in a Passiflora species (P. edulis)
that is well studied and documented due to its commercial
importance. The rare occurrence of a second flower flanking
the tendril of P. edulis was observed a long time ago (Cusset,
1968 and the references therein). Nonetheless, the ontogenetic
nature of plasticity was not reported before. It might
be that the chance combination of specific alleles present in
the ‘Passion Dream’ genotype is unique in allowing this plasticity
Two flowers flanking a tendril were formed by adding
Cytokinin to the existing genotype, and without any addition
of hormones by a novel combination of the same alleles in an
F2 progeny. Therefore, both genetic and environmental cues
might modulate the developmental plasticity underlying the
number of flowers a P. edulis plant is able to produce. The ability
to modulate the numbers of fruits a plant is able to produce
is of enormous economic importance.
In Israel, short photoperiods in winter are accompanied by
low temperatures so that the combination of short photoperiods
and extreme day/night temperature shifts are not common
under field conditions. It would be of interest to study
P. edulis germplasm in regions where such environmental
conditions occur, and observe if this transformation of the
tendril/flower producing axillarymeristem into a leaf-producing
meristem could be observed in other genotypes, and if it
does, would such a change in program have any adaptive
advantages.