Agriculture Reference
In-Depth Information
Fig. 6.3
Different type of shoots in
Citrus
according to the number of leaves and flowers
In
Citrus
, flower induction has been reported to occur late in autumn, whereas
differentiation occurs afterwards (Fig.
6.3
). Recent molecular approaches support
this scheme, distinguishing between genes that regulate flowering induction and
those that regulate the floral differentiation processes. As for other species, it has
been shown for
Citrus
that flowering ability is influenced by the integration of
environmental signals from the photoperiod and vernalization pathway, mainly
modulated by two floral integrators, the
FLOWERING LOCUS T
(
CiFT
) and the
SUPRESSOR OF OVEREXPRESSION OF CONSTANS 1
(
SOC1
) genes. Accord-
ingly, an increased FT protein constitutes a signal
per se
that is exported from leaf
to the shoot apical meristem, where floral differentiation takes place. Once the bud
is induced, the increased
CiFT
expression found in both buds and leaves is respon-
sible for a continuous flux of FT protein to the developing meristems up until the
floral morphogenetic phase is initiated.
SOC1
induces early flowering and delays
senescence of floral organ.
