Macadamia Nuts in Hawaii: History and Production - ctahr ...

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Figure 47. Germinating seeds with micropyle, stem end, and suture
to the side, showing the straight-line orientation of stem
and roots. The properorientation can be accomplished by
pushing seeds into place on the firm medium before
covering with a layer of planting medium.
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(Counesy of Ralph H. Molo:aul
I
macadamia nuts. Moltzau's illustration shows that
when the micropyle and stem-end orientation of
the seeds are aligned horizontally, with the suture
to the side, the hypocotyl with its shoot and root
emerges from the seed in a straight up and down
orientation.
On the other hand, Fig. 48 illustrates malformations
of seedling root systems when the seeds, at
planting, are improperly handled with the micropyle
in either an up or down position, or when
obstructive materials are in the planting medium.
The result can be trees as shown in Fig. 49 with
gross embedment of bark as they developed in a
twisted fashion. The "creases" are very harmful
and can result in total loss of a tree aftera profitable
period of growth and production.
Figure 50 illustrates another bad situation
when the taproots of young seedlings are cut to
accommodate the size of containers, or when the
taproots instead develop as laterals in structure
and in function. Note that the many laterals are
emerging on the stem, which is no more than 2 to 3
inches long and, morphologically, has already
Figure 48. Malformed seedlings. Left to right, (I) roots growing into
a half-shell remnant in the planting medium, causing
cupping and short upward growth; (2) curved stem
growth from seeds with micropyle at the bottom; (3)
seedling with micropyle at the top; (4) curved root growth
caused by a large obstruction in the seedling root area.