Treatment of Syngonium 'Maya Red' with Thidiazuron in Attempt to Induce Basal Branching

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University of Florida, IFAS
Central Florida Research and Education Center - Apopka
2807 Binion Road, Apopka, Florida 32703
CFREC-Apopka Research Report RH-91-1

R.J. Henny and W.C. Fooshee

Introduction: Syngonium 'Maya Red' is an attractive plant with pink juvenile leaves. However, Synqonium 'Maya Red' does not produce basal shoots and new leaves lose their pink coloration once mature foliage is produced, which is typically after 8-10 leaves develop and plants start to vine. Consequently 'Maya Red' has not become a major Syngonium cultivar. Hopefully, inducing basal shoot development would make a more aesthetic plant and perhaps delay foliar color loss by inhibiting vining.

In some instances plants with strong apical dominance have been stimulated to branch when treated with synthetic cytokinins. One such cytokinin, N6 -benzyladenine (BA) has been used successfully to increase branching in Anthurium (4), Dieffenbachia (2), Peperomia (1) and Spathiphyllum (3). However, in preliminary tests with syngonium 'Maya Red', BA treatment was not successful at rates up to 500 ppm (Henny, unpublished data). Some enlargement of axillary buds occurred following BA treatment but development soon ceased. Subsequent removal of the central leader failed to stimulate more than a single bud to grow out.

Thidiazuron is the active ingredient in Dropp® 50 WP (NOR-AM Chem Co., Wilmington, DE), a commercial cotton defoliant, Previous research by Mk. et al. (6) had shown that it possessed strong cytokinin activity when incorporated into the tissue culture medium used for beans. If effective in stimulating branching, thidiazuron, a 50% wettable powder, would be easier to mix and apply than BA.

Materials and Methods:

Sixty rooted liners, from a 72-celled plastic tray, were repotted into 4-inch pots filled with VerGro container mix (Verlite Co. Tampa, FL) June 8, 1989. The same day plants were treated with thidiazuron at rates of 0, 1, 5, 10, 50 or 100 ppm by applying 10 ml of test solution at the plant base; ten plants were treated at each rate of thidiazuron. This experiment was conducted in a shaded greenhouse under natural photoperiod with a maximum light level of 2000 fc and maximum air temperature of 95°F (35°C). Fertilization consisted of 2.5 grams ( teaspoon) of 19N-6P205-12K2O) Osmocote per pot.

Data, recorded twelve weeks after treatment, included plant height (vine length), length and width of the largest leaf, fresh weight of shoots and roots (with soil washed off) and number of basal buds longer than 1 cm.

Results and Discussion:

Syngonium 'Maya Red' was responsive to treatment with thidiazuron. Treated plants produced numerous elongated basal buds at and beneath the soil surface, but most did not continue to develop and produce new leaves. The average number of elongated basal buds was 0.0, 4.7, 7.8, 13.6, 18.1, and 10.7 at the 0, 1, 5, 10, 50, and 100 ppm treatments respectively (Table 1). Production of elongated buds at rates of 5 ppm and higher was accompanied by enlargement of stem tissues at the plant base including portions that were callus- or gall-like giving treated plants an abnormal appearance.

In addition, plants treated with thidiazuron were shorter, had smaller leaves and less shoot and root fresh weight than untreated controls (Table 1). Effects became greater as the level of thidiazuron increased. At high thidiazuron rates (50 and 100 ppm) almost no roots remained indicating root loss following treatment since all plants were well-rooted initially. A similar response was observed previously with Alocasia X Chantrieri (5).

Results from this experiment indicate that thidiazuron is a much more active compound than BA; in fact treatment rates of 5-10 ppm thidiazuron were injurious. Therefore, the sensitivity of Syngonium to thidiazuron levels requires precise methods of application to prevent disruption of normal plant growth.

Two major problems must be addressed for thidiazuron to be effective for induction of basal shoots in Syngonium. The first is to prevent the deleterious effects on root development, and second, methods must be found to stimulate continued growth and development of elongated basal buds. These aspects of treatment are currently being studied.


Table 1. Effect of thidiazuron (Dropp® 50 WP) on overall plant growth and production of elongated basal buds in Syngonium 'Maya Red'.

Thidiazuron
conc
(ppm)
Total no.
elongated
buds
Plant
height
(cm)
Leaf
length
(cm)
Leaf
width
(cm)
Fresh
Weight
shoots(g)
Fresh
Weight
roots(g)
0 0.0 131.4 22.5 6.6 42.6 29.8
1 4.7 101.1 20.2 5.9 35.8 24.9
5 7.8 79.8 19.4 5.4 35.2 15.3
10 13.6 58.0 17.8 5.1 32.3 14.8
50 18.1 16.6 9.4 4.7 17.9 2.3
100 10.7 13.0 7.8 4.1 10.1 1.4
LSD (5%) 5.0 42.6 3.4 0.6 7.7 5.4

Literature Cited:

1. Henny, R.J. 1985. BA induces lateral branching of Peperomia obtusifolia. HortScience 20(1):115-116.

2. Henny, R.J. 1986.- Increasing basal shoot production in a nonbranching Dieffenbachia hybrid with BA. HortScience 21(6):1386-1388.

3. Henny, R.J. and W.C. Fooshee. 1985. Induction of basal shoots in Spathiphyllum 'Tasson' following treatment with BA. HortScience 20(4):715-717.

4. Henny, R.J. and W.C. Fooshee. 1989. BA-treatment stimulates basal shoot production in Anthurium X 'Southern Blush'. CFREC-Apopka Research Report RH-89-16. 3pp.

5. Henny, R.J. and W.C. Fooshee. 1990. Thidiazuron stimulates basal bud and shoot formation in Alocasia X Chantriere Andre'. HortScience 25(1):124.

6. Mk., M.C., D.W.S. Mk., D.J. Armstrong, K. Shudo, Y. Isogai and T. Okamota. 1982. Cytokinin activity of N-phenyl-Nl-1, 2, 3-thiadiazol-5-ylurea (Thidiazuron). Phytochemistry 21:1509-1511.