The coconut odyssey - the bounteous possibilities of the ... - ACIAR

over during this concealed phase
of germination, as the direction
the roots and shoot would become
distorted and their growth would be
retarded. �e shoot tip requires two
to four weeks to elongate sufficiently
to appear through the husk,
depending on its vigour and on the
thickness of the husk. Slicing off a
section of husk immediately above
the soft eye hastens emergence.
In the purposeful management of
the seedling, the early phase is called
the ‘pre-nursery’. It is followed by the
planting of the developing seedling
into a large polybag, by which time
the roots have probably emerged
from the underside of the husk,
sometimes struggling to force their
tips through the thin, but rather
tough, outer layer. �is layer is best
sliced away to encourage rapid root
emergence. If the nut is large, more
of the husk might need to be sliced
off to fit it more readily into the
polybag, submerged to half its depth
in the potting soil.
�e seedling ‘sponges’
from the kernel
�e haustorium—the soft, spongy
internal organ expanding within
the nut—is often referred to as
the ‘egg’ or ‘apple’. Progressively, the
haustorium makes contact with the
entire inner surface of the kernel
(except in very large nuts), releasing
softening enzymes as it does so. It
rapidly absorbs the nut water, and
from the kernel it takes nutrients
at an increasing rate to provide
substance and energy for the growth
of the seedling.
In the three-month gap between
germination and the expansion
of the first green leaf, the seedling
depends solely on the kernel for its
energy supply. �ere follows a period
of gradual ‘weaning’ as the young
seedling expands a series of leaves,
46
each larger than the one before. Each
new leaf supplies a greater share of
the energy needs of the seedling,
which thereby becomes less and less
reliant on the diminishing kernel to
sustain its accelerating growth.
�e rich nutrient and energy
mixture derived from the kernel
is delivered by the haustorium to
the developing seedling for at least
12 months, although sooner or
later a proportion of seeds suffers
invasion by fungi or bacteria that
disable the haustorium. While the
seedling is able to survive this loss
of access to the kernel, it suffers a
Figure 3-4. Polybag seedlings in a large plantation nursery in Mozambique
(1992). �e seedlings will be transplanted to the field without any significant
setback after developing three or four more leaves.