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Copyright 2005, Board of Trustees, University
A Review of Literature Involving the Use of Growth Regulators to Induce
Flowering of Tropical Foliage Plants
University of Florida, IFAS y-:
Central Florida Research and Education Center Apopka
CFREC-Apopka Research Report, RH-90-11 / ik.
Introduction: This report presents a summary of published literature
concerning the use of growth regulators to induce flowering of foliage
plants. The information in this report is intended to be a reference for
anyone interested in flowering foliage plants.
Two reasons for inducing flowering of foliage plants are: 1) to
increase the salability of a particular plant that has attractive flowers
(i.e. Bromeliads, Spathiphyllum and Zantedeschia); and 2) to obtain
flowers, that may or may not have any ornamental value, for breeding
purposes (i.e. Aglaonema, Dieffenbachia and others in this report).
Only two chemicals have been utilized to induce flowering of foliage
plants; they are gibberellic acid (GA3) and ethrel (ethephon). The
results of this literature review are summarized in Table 1.
Summary of Literature
Aglaonema (ref. #6) Aglaonema flowers have no ornamental value and become
a nuisance once they begin to die and decay on the plant. However, the use
of GA3 as a treatment for simultaneous flower induction is imperative for
breeding purposes. A single foliar spray with 250 ppm GA, has consistently
induced flowering and increased flower number in many species and
cultivars. The time from treatment to blooming is about 4-5 months.
Bromeliads (ref. #13) Studies with Aechmea, Guzmania and Vriesea showed
that 25 mg of ethephon applied to the vase of these bromeliads, 1.5 to 2
years old at the time of treatment, should induce flowering within 2 months
without damaging leaves.
Twenty-five mg of ethephon can be obtained by mixing one tablespoon
(15 ml) of 21.3% ethrel in one gallon (3.8 liters) of water and adding 2
tablespoons (30ml) of this solution to the vase of the bromeliads. In the
above study the vases contained water from overhead watering the day before
treatment, so it is not necessary to drain existing water from the vases
before applying the ethephon.
Caladium (ref. #3) Tubers, removed from storage, then soaked for 8 or 16
hours in 250 ppm GA, flowered approximately 65 days. These results are
important for breeding purposes.
1Professor of Plant Genetics, Central Florida Research and Education Center
Apopka, 2807 Binion Road, Apopka, Florida 32703
Cordyline (ref. #2) Terminal inflorescences of Cordyline terminalis
appeared 4-6 weeks after apical buds were treated with GA or GA .
Optimum flowering required application of 0.12-0.15 ml of 500 ppm A
applied to the apical bud. These results are mainly of value to breeders.
Dieffenbachia (ref. #4) The ability to routinely flower Dieffenbachia
species and cultivars simultaneously has made breeding much easier. This
is accomplished by a single foliar spray with 250 ppm GA3. Flowers
normally mature within 3-4 months following treatment.
(ref. #7) Tetraploid breeding lines have proven more difficult to
flower using GA3 sprays and require higher treatment rates than normal
diploid plants. Even at rates of 500 ppm only 30-80% of tetraploid plants
flowered compared to 100% of diploids.
Ficus (ref. #11 and #12) Application of 500 mg ethephon to Ficus
benjamina liners in 2-gallon pots stimulated flowering and fruiitset.
However, root and top growth was severely reduced and top growth became
prostrate rather than vertical. These results may be of value to someone
interested in breeding Ficus.
Homalomena (ref. #10) Homalomena lindenii plants were stimulated to
flower with a single foliar spray to runoff with 100, 200 or 400 ppm GA3.
Treated plants flowered within approximately 140 days. All treated plants
averaged 10-11 flowers while untreated plants did not bloom. In a second
test, plants sprayed with 25, 50, 75 or 100 ppm GA3 produced an average of
8-9 flowers per plant 4 months after treatment whereas those treated with 0
or 10 ppm did not flower. These results are of value for breeding purposes
only since the flowers have no ornamental merit.
Spathiphyllum (ref. #5) The ability to induce flowering of Spathiphyllum
with G was first reported in 1981. Spathiphyllum 'Mauna Loa' seedlings
flowered after receiving a single foliar spray of G at 250, 500 or 1000
ppm. Most treated plants had visible buds or open blooms within 12-14
weeks after treatment. In that study approximately 15% of the
inflorescences exhibited distortion consisting of either curved peduncles
or spathes with extra appendages.
(ref. #8) In this study four Spathiphyllum cultivars were given a
single foliar spray with 250 ppm GA3 during August. The cultivars tested
included Tasson, Wallisii, Queen Amazonica and Bennett. All four cultivars
flowered readily in response to GA3 treatment. Treated 'Bennett' and
'Wallisii' plants had open blooms within 9 weeks of treatment. 'Tasson'
and 'Queen Amazonica' required approximately 2 weeks longer to flower.
Overall flower quality was good for 'Bennett' and moderate for 'Tasson' and
'Queen Amazonica'. 'Wallisii' produced poor quality flowers.
(ref. #9) Spathiphyllum 'Starlight' was treated with a single foliar
spray of GA3 at 0, 125, 250 or 375 ppm in March. All treated plants had
good quality flowers at 15 weeks after treatment while no untreated plants
bloomed. GA3-treated plants were slightly taller and had new leaves that
were narrower than untreated plants. It was concluded that Spathiphyllum
'Starlight' would be a good cultivate for GA3-treatment.
Zantedeschia (ref. #1) GA3 was applied to calla lily at 0, 50, 100, 500
or 1000 ppm as a 10-minute preplant rhizome soak or as a foliar spray.
Soaking rhizomes in 500 ppm GA3 prior to planting increased number of
flowering shoots and flowers per shoot. Leaf width was narrower on treated
plants but length was not affected. Foliar sprays were applied when the
first leaf was unfolded on one-half of the plants. However, they were
generally not effective.
Table 1. A summary of growth regulators used to induce flowering of
Botanical Growth Treatment Method of
genus regulator rate application
Aglaonema GA` 250 ppm a single foliar spray to runoff
Aechmea Ethrel 25 mg poured into plant's vase
Caladium GA3 250 ppm tuber soak for 8 or 16 hours
Cordyline GA3 500 ppm 3 drops on 3 consecutive days to
the newest unrolled leaf
Dieffenbachia GA3 250 ppm a single foliar spray to runoff
Ficus Ethrel 500 mg soil drench
Guzmania Ethrel 25 mg poured into plant's vase
Homalomena GA3 100 ppm a single foliar spray to runoff
Spathiphyllum GA, 250 ppm a single foliar spray to runoff
Vriesea Ethrel 25 mg poured into plant's vase
Zantedeschia GA, 500 ppm 10-minute rhizome soak
1. Corr, B.E. and R.E. Widmer. 1987.
number in Zantedeschia elliottiana
and Z. rehmannii.
2. Fisher, J.B.
1980. Gibberellin-induced flowering in Cordyline
Journal of Experimental Botany 31(122):731-735.
3. Harbaugh, B.K. and G.J. Wilfret. 1979. Gibberellic
stimulates flowering in Caladium hortulanum Birdsey.
4. Henny, R.J. 1980. Gibberellic acid (GA3) induces flowering in
Dieffenbachia maculata 'Perfection'. HortScience 15:613.
5. Henny, R.J. 1981. Promotion of flowering in Spathiphyllum 'Mauna Loa'
with gibberellic acid. HortScience 16:554-555.
6. Henny, R.J. 1983. Flowering of Aglaonema commutatum 'Treubii'
following treatment with gibberellic acid. HortScience 18:374.
7. Henny, R.J. 1989. Floral induction in 2n and 4n Dieffenbachia
maculata 'Perfection' after treatment witI gibbe-ellic acid.
8. Henny, R.J. and W.C. Fooshee. 1985. Inducing flowering of four
Spathiphyllum cultivars with gibberellic acid (GA3). CFREC-Apopka
Research Report RH-85-3.
9. Henny, R.J. and W.C. Fooshee. 1988. Floral induction in Spathiphyllum
'Starlight' with gibberellic acid treatment. CFREC-Apopka Research
10. Henny, R.J. 1988. Inducing flowering of Homalomena lindenii (Rodigas)
Ridley with gibberellic acid. HortScience 23:711-712.
11. Johnson, C.R. 1979. Influence of growth regulators on Ficus benjamin
L. Nurserymen's Digest. 13(5):88.
12. Johnson, C.R. and J.N. Joiner. 1978. Influence of ancymidol and
ethephon growth of Ficus benjamina L. Proc. Fla. State Hort. Soc.
13. Poole, R.T. and C.A. Conover. 1975. Flowering of bromeliads. Florida
Foliage Grower 12(6):1-2.