PRODUCTION OF THE STUNTED OLEANDER

A trial was consummated at Orman Botanical Garden, Giza,
Egypt throughout 2005/06 and 2006/07 seasons to find out the effects
of foliar spraying with either 0, 50, 100 and 150 ppm of paclobutrazol
(PP-333) or 0, 1000, 2000 and 3000 ppm of cycocel (ccc) for three
times with three weeks interval, pinching treatment and their
interaction on growth, flowering and chemical composition of 6-
months-old Nerium oleander L. transplants grown in 30-cm-diameter
black polyethylene bags.
The obtained results exhibited that plant height (cm), stem
diameter (cm), branch and leaf No./plant, leaf area (cm2), root length
(cm), as well as the fresh and dry weights of aerial parts and shoots (g)
were significantly decreased in both non pinched and pinched plants
as a result of spraying with the various levels of either PP-333 or ccc
in the two seasons. The best dwarfing result was found due to
spraying with 100 ppm of PP-333 and 2000 ppm of ccc, as such two
treatments declined the size of treated plants to the optimum size
suitable for commercial marketing. Likely, pinching treatment
significantly reduced all vegetative and root growth parameters with
the exception of branch No./plant character, that was increased in
pinched plants with significant differences when compared to the non-
pinched ones in both seasons. Moreover, all concentrations of both
retardants, as well as pinching treatment delayed flowering and
significantly reduced all flowering measurements in both non-pinched
and pinched plants except for inflorescence No./plant trait, which was
PRODUCTION OF THE STUNTED OLEANDER244
in the same rank for non-pinched and pinched plants. However, the
low level of both PP-333 and ccc (50 and 1000 ppm, respectively)
significantly increased number of florets/inflorescence in the two
seasons. So, the plants under these two treatments were more
attractive.
The content of chlorophyll a, b, carotenoids and indoles (mg/g
F.W.) was progressively decreased in the leaves of both non-pinched
and pinched plants with elevating of either PP-333 or ccc levels, while
phenols content was gradually increased. Paclobutrazol at the rate of
50 ppm, on the other hand, raised the content of chlorophyll a and b in
the leaves of non-pinched and pinched plants. However, pinching
treatment induced a significant reduction in all previous constituents.
In brief, to obtain a good display of flowering pot Nerium
oleander L. plants with optimum vegetative and flowering
characteristics from the commercial point of view, it is recommended
to spray the foliage of non-pinched transplants with either low or
medium concentrations of PP-333 (50 and 100 ppm, respectively) or
ccc (1000 and 2000 ppm, respectively), and the pinched ones with the
only low concentration of either PP-333 (50 ppm) or ccc (1000 ppm),
for 3 times with 3 weeks interval.