Agriculture Reference
In-Depth Information
When fl ower production ceases, the apical meristem again reverts to the 5/l3
phyllotaxy, with a transition area of short leafy bracts, followed by the growth
and development of the crown (Fig. 12.1).
Fruit
The fruit, more precisely defi ned as a coenocarpium (a multiple fruit derived from
ovaries, fl oral parts and receptacles of many coalesced fl owers), also commonly
referred to as a sorosis (a syncarp of fused fruitlets from inferior ovaries), is
topped by a leafy stem referred to as the crown (Fig. 12.5). The fruit 'shell' is
composed mainly of sepal and bract tissues and the apices of the ovaries, while
the edible fl esh is primarily composed of ovaries, the bases of sepals and bracts,
and the cortex of the axis, which is an extension of the peduncle.
Fruitlets develop from fl owers that do not abscise (Fig. 12.1). The style,
stamens and petals wither, with remaining fl oral parts developing into the
fruitlet (Okimoto, 1948). Yeast and bacteria can enter through the nectary
gland, and mature fruit is not sterile (Rohrbach and Apt, 1986). In the
normal fruit there are 8 gently sloping rows and 13 shorter, steeper rows of
fl owers. The number of fruitlets can be estimated by counting the fruitlets on
the long, gently sloping spiral and multiplying by eight, the number of spirals
(Bartholomew and Paull, 1986). It takes approximately 4 months from the
end of the last open fl ower to fruit maturity, and the total time from fl oral
initiation to harvest takes between 6 and 7 months (Figs 12.6 and 12.7).
Temperature signifi cantly accelerates or delays development.
Fig. 12.6.
Pineapple fruit growth and development in Hawaii.
