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Copyright 2005, Board of Trustees, University
9 Central Florida Research
FLORIDA and Education Center
Institute of Food and Agricultural Sciences Research Report
Angel-Wing Begonia Growth and Water Requirements Affected
by Paclobutrazol "sion Sci
t. Libr r'
SEP 3 0 19,94
CFREC-Apopka Research Report RH-94-4
University of Florida
Paclobutrazol, a plant growth regulator, has been shown to be effective in producing
foliage plants with attractive compact growth habits and in controlling the size of plants
maintained in interiorscapes (Cox and Whittington, 1988; Davis et al, 1985; LeCain et al, 1984;
Wang and Blessington, 1990). In earlier tests, paclobutrazol treated foliage plants growing in
a greenhouse or maintained under interiorscape conditions used less water and fertilizer than
untreated plants, even when plant growth was not noticeably affected (Poole and Conover 1992a;
Poole and Conover 1992b). Reducing water and fertilizer needs during production as well as
in interiors would save on labor and material costs and reduce risk of environmental pollution.
Angel-Wing begonias are attractive fibrous-rooted plants grown by the foliage plant
industry in a variety of pot and basket sizes. Plants have cane-like stems which sometimes
develop leggy, stretched growth. This experiment compared growth, quality and water
requirements of Angel-Wing begonia not treated with growth regulators to that of plants treated
On September 2, 1992, Begonia coccinea 'Pink' (Angel-Wing begonia) cuttings rooted
in 7.6-cm pots were transplanted into 15-cm standard pots using Fafard #4 growing medium.
The plants were grown in a greenhouse where light intensity was approximately 1600 ft-c and
air temperatures ranged from 70 to 900F. Plants were fertilized with 5 g/15-cm pot 19-6-12
Osmocote (Grace/Sierra Co., Milpitas, CA).
On September 3, 1992, the growing medium of plants was drenched with 100 ml water
or 100 ml solutions containing 0.12, 0.25, 0.38 or 0.50 ml BonziTM [BonziTM flowable emulsion,
0.4% active ingredient paclobutrazol, (ICI Americas, Inc., Goldsboro NC)]. Six replications
were provided for each drench treatment tested, with one plant as an experimental unit. Plants
'Professor of Environmental Horticulture and Center Director, Central Florida research and
Education Center, 2807 Binion Road, Apopka, FL 32703.
The Institute of Food and Agricultural Sciences is an Eq;al Employment Opportunity Affirmative Action Employer authorized to provide research, educational
information and other services only to individua, and institutions that function without regard to race, color, sex, age, handicap or national origin.
COOPERATIVE EXTENSION WORK IN AGRICULTURE, HOME ECONOMICS, STATE OF FLORIDA, IFAS, UNIVERSITY OF FLORIDA,
U.S. DEPARTMENT OF AGC CULTURE, AND BOARDS OF COUNTY COMMISSIONERS COOPERATING.
were watered one to three times per week as needed to maintain proper medium moisture levels.
Total water used by plants throughout the course of the experiment was determined by
the following method: 1) at every watering, a 2000 ml beaker was placed under each pot in
order to catch the leachate; 2) water was slowly applied to growing medium surface of each pot
in measured increments until leaching was observed; and 3) after one hour, the volume of
leachate in beakers was determined. Total water used by plants was defined as total water
applied to pots minus total leachate collected. (This method does not account for water
evaporation from medium surface between watering times).
Plants were graded on December 21, 1992, using a scale of 1 = dead, 2 = poor quality,
unsalable, 3 = fair quality, salable, 4 = good quality and 5 = excellent quality. On December
30, 1992, plant height and width (cm) were measured. Plant size was defined as the average
of plant height and width. Electrical conductivity (mmhos/cm) and pH of leachate were
determined initially on September 9, 1992 and again when research was concluded on January
Only BonziT treated plants were flowering when research was terminated. Plant height
and size were also affected by drench treatments (Table 1). Although plants were smaller as
BonziTM rate increased, more difference was observed in size of plants that did not receive
BonziTM and size of plants treated with the low BonziTM rate compared to the size differences
in plants getting 0.12 ml/15-cm pot BonziTM and plants drenched with 0.50 ml/15-cm pot.
Best quality plants received the lowest BonziTM rate tested, 0.12 ml/15-cm pot (Table 1).
As BonziTM rate increased, plant height and size decreased resulting in lower plant grades.
Quality of plants not treated with growth regulators was comparable to plants getting 0.25 ml/15-
cm pot BonziTM. However, Angel-Wing begonia plants drenched with BonziTM solutions
required less water during production than untreated plants. Differences in water use by plants
receiving growth regulators showed a trend toward decreasing water use as BonziTM application
rates increased. Height and size differences between treated and untreated plants probably
accounted for some, but not all, of the differences in water use.
Leachate pH was unaffected by treatments and dropped slightly over time (Table 2).
Leachate initial umhos/cm showed a linear increase with treatment number but final umhos/cm
were over twice as high for BonziT drenched plants compared to plants drenched with water.
This would indicate fertilizer uptake decreased as growth regulator rate increased.
Angel-Wing begonias drenched with BonziM used less than half the amount of water used
by plants not receiving growth regulators and water use generally decreased as BonziT
application rate increased. However, benefits from reduced water and fertilizer needs would
be meaningless if crop quality were not equal to or higher than quality of untreated plants. In
this test, best quality Angel-Wing begonias received 0.12 ml/15-cm pot BonziT, the lowest rate
tested. Although plants drenched with 0.25 ml/15-cm pot BonziTM were of comparable quality
to untreated plants, untreated plants needed more water and fertilizer during production
compared to treated plants and were not flowering when research was terminated.
Cox, C.A. and F.F. Whittington. 1988. Effects of paclobutrazol on height and performance
of aluminum plant in a simulated interior environment. HortScience 23:222.
Davis, T.D., K. Emino, W.Shurtieff and N. Sankhla. 1985. The promise of paclobutrazol.
Interior Landscape Industry 2(11):36-41.
LeCain, D.R., K.A. Schekel and R.L. Wample. 1984. The effect of paclobutrazol on
acclimatization of Ficus benjamin. HortScience 19:587 (abstract).
Poole, R.T. and C.A. Conover. 1992a. Paclobutrazol and indoor light intensity influence water
use of some foliage plants. Proc. Fla. State Hort. Soc. 105:178-180.
Poole, R.T. and C.A. Conover. 1992b. Water use and growth of eight foliage plants
influenced by paclobutrazol. Foliage Digest (15)12:1-3.
Wang, Y.T. and T.M. Blessington. 1990. Growth of four tropical foliage species treated with
paclobutrazol or uniconazole. HortScience 25:202-204.
quality and water consumption of Angel-Wing begonia affected by
BonziT, ml/15-cm Final htY Growth Plant gradew Water used
potz (cm) (cm)x (ml)v
0.00 68.8 81.6 4.0 5957.5
0.12 43.1 53.2 4.9 2463.5
0.25 39.2 43.5 4.1 2014.2
0.38 33.2 38.5 3.5 2234.8
0.50 24.7 30.1 2.2 1918.5
linear ** ** ** **
quadratic ** ** ** **
TPlants were drenched with 100 ml water or 100 ml solutions containing 0.12, 0.25, 0.38 or
0.50 ml BonziT on September 3, 1992.
YFinal height (cm) was measured on December 30, 1992.
xPlant size was determined as the average of final height and final width (cm), both measured
on December 30, 1992.
Plants were graded based on a scale of 1 = dead, 2 = poor quality, unsalable, 3 = fair
quality, salable, 4 = good quality and 5 = excellent quality.
'Water used = Total water applied total leachate collected.
"ns, **; Results nonsignificant or significant at P = 0.01, respectively.
Initial and final pH and electrical conductivity of leachate collected from
containers of Angel-Wing begonia drenched with 100 ml water or a 100 ml
solution containing 0.12, 0.25, 0.38 or 0.50 ml BonziM on September 3, 1992.
BonziTM, ml/15-cm Initial Final
potz Initial pHW Final pH pmhos/cm pmhos/cm
0.00 6.3 5.7 3513 475
0.12 6.3 5.5 3363 3368
0.25 6.3 5.6 3292 1712
0.38 6.2 5.6 3810 1234
0.50 6.3 5.7 3908 2122
linear ns ns **
quadratic ns ns ns ns
zPlants were drenched with 100 ml water or 100 ml solutions containing 0.12, 0.25, 0.38 or
0.50 ml BonziTM on September 3, 1992.
'Initial pH and /mhos/cm were measured from leachate collected after BonziTM was applied on
September 3, 1992. Final pH and C/mhos/cm were measured from leachate collected on January
xns, *, **; Results nonsignificant, significant at P = 0.05 and significant at P = 0.01,