| Material Information
||Effect of temperature and Daminozide on germination and growth of China Doll seedlings
||CFREC-Apopka research report
||4 p. : ill. ; 28 cm.
||Chase, A. R ( Ann Renee )
Robinson, C. A
Conover, Charles Albert, 1934-
Central Florida Research and Education Center--Apopka
||University of Florida, Institute of Food and Agricultural Sciences, Central Florida Research and Education Center
||Place of Publication:
||Evergreens -- Effect of temperature on -- Florida ( lcsh )
Evergreens -- Effect of pesticides on -- Florida ( lcsh )
Seedlings -- Growth -- Florida ( lcsh )
Germination -- Experiments -- Florida ( lcsh )
||government publication (state, provincial, terriorial, dependent) ( marcgt )
bibliography ( marcgt )
non-fiction ( marcgt )
||Includes bibliographical references (p. 2).
||Statement of Responsibility:
||A.R. Chase, C.A. Robinson, and C.A. Conover.
| Record Information
||University of Florida
||All rights reserved by the source institution and holding location.
||oclc - 70208820
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Effect of Temperature and Daminozide on Germination ; SC ,, i
and Growth of China Doll Seedlings L i br '
A. R. Chase, C. A. Robinson and C. A. Conover' SEP 3 01994
CFREC-Apopka Research Report RH-94-1
University of Florida
China Doll, Radermachera sinica, is an evergreen tree that was introduced from southeast
Asia for use as an indoor houseplant. It is sometimes called Radermachera or Radar plant, but
China Doll appears to be the name most commonly used in the foliage industry. China Doll
grows rapidly and becomes leggy and unsalable unless treated with growth regulators. Several
research reports have been published since 1986 regarding growth of China Doll as affected by
temperature and fertilizer level (1, 2, 3). In 1990, Wang and Dunlap reported on the effect of
ethylene on leaf abscission of China Doll (4). Very little other written information is available
about producing this crop.
In late 1992, a research project was started to evaluate growth of China Doll under
different temperature conditions to determine the potential for an interaction between temperature
and the growth regulator, daminozide. Seeds were obtained from a local producer and planted
at a rate of 100 per 6 inch standard pot containing Vergro potting medium. They were placed
in temperature control chambers which were set to soil temperatures of 68, 77, 86, or 95F.
Twelve pots per temperature were used. Percent germination was determined weekly for 1
month, and at the end of the test period, pots were evaluated for overall appearance which took
into account seedling density and size as well as color. This test was performed three times
between November 1992 and August 1993.
A second series of experiments was performed using seedlings from a commercial
producer. Plants were about 3 inches tall and had not been treated with any growth regulators.
They were planted in 6 inch standard pots again containing Vergro and top-dressed with 5 g of
Sierra 19:6:12 slow release fertilizer at test initiation. Soil temperatures were the same as those
described above and again used 12 pots per temperature. Half of the pots in each temperature
'Professor of Plant Pathology, Biological Scientist, and Professor of Environmental
Horticulture and Center Director, Central Florida Research and Education Center -Apopka, 2807
Binion Road, Apopka, FL 32703, respectively.
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COOPERATIVE EXTENSION WORK IN AGRICULTURE, HOME ECONOMICS, STATE OF FLORIDA, IFAS, UNIVERSITY OF FLORIDA,
U.S. DEPARTMENT OF AGRICULTURE, AND BOARDS OF COUNTY COMMISSIONERS COOPERATING.
/ Central Florida Research
FLORIDA and Education Center
Institute of Food and Agricultural Sciences Research Report
were treated with daminozide at the recommended rate (1 g/360 ml water) by spraying them to
runoff. Plant height was determined after one month and percent difference in height of water-
treated controls and daminozide-treated plants at each temperature was calculated. This test was
performed three times between December 1992 and July 1993.
Soil temperature significantly affected both germination percentage and overall top grade
of the China Doll seedlings in all three tests (Fig. 1). Best germination and top grade were
consistently found in pots with a soil temperature maintained at 86F. Plants in these pots were
more vigorous, had better green color and as a result had best top grades. Plants produced at
the other three temperatures had poorer germination and were of lower quality; with those
growth at 95F lowest in all three tests.
Height was significantly affected by both soil temperature and daminozide treatment with
greatest height suppression occurring at 860F (Fig. 2). There was a significant interaction
between soil temperature and daminozide treatment on plant height in only one of the three tests
(Table 1). Daminozide suppressed height at all temperatures from about 24 to 34%. The
percent height suppression was similar regardless of time of year although plants grew tallest
in the test conducted during the spring (Test 2). Plants produced at 95F were consistently
shorter than those in the other three temperatures.
Soil temperature can significantly affect germination and growth of China Doll seedlings.
Optimal germination and growth occurred with a soil temperature of 860F. During the spring,
plants may grow too rapidly and become unsalable necessitating applications of growth
regulators such as daminozide. The percent of height reduction which was achieved with the
daminozide treatment was consistent regardless of time of year in our tests, making adjustments
in rate of application apparently unnecessary. It is clear that a production schedule for China
Doll seedlings must take temperature into account since the plants grew twice as fast during the
spring test as they did during the winter or summer tests.
1. Chase, A. R. and R. T. Poole. 1989. Nutrition of Radermachera sinica. CFREC-Apopka
Research Report RH-89-10.
2. Poole, R. T., A. R. Chase and L. S. Osborne. 1991. China Doll. CFREC-A Foliage Plant
Research Note RH-91-11.
3. Poole, R. T. and C. A. Conover. 1986. Response of foliage plants to minimum
temperatures and fertilizer levels. AREC-Apopka Research Report RH-86-18.
4. Wang, Yin-Tung and J. R. Dunlap. 1990. Leaf abscission in Radermachera sinica in
response to ethylene and silver thiosulfate. HortScience 25(2):233.
Table 1. Effect of soil temperature and daminozide treatment on height of China Doll seedlings
in three tests.
Growth Regulator 21 Jan
95 F water
95 F daminozide
Growth Regulator (G)
zSignificance is denoted as ns =
significant at the 1% level.
not significant, = significant at
Mean plant height (in)
5 May 1993
the 5% level, ** =
21 July 1993
Figure 1. Effect of soil temperature on germination and top grade of China Doll seedlings. Top
grade was arated on a scale from 1 (dead) to 5 (excellent). Data presented are
the mean of three tests.
Soil Temperature (F)
S Average germination M Average grade
Figure 2. Effect of soil temperature on percent height suppression for China Doll treated with
daminozide. Data presented are the mean of three tests.
Percent Height Suppression
Soil Temperature (F)