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Group Title: Agronomy research report - University of Florida Department of Agronomy ; AY-95-04
Title: Growth and nutrient accumulation in tropical soda apple (Solanum viarum Dunal)
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 Material Information
Title: Growth and nutrient accumulation in tropical soda apple (Solanum viarum Dunal)
Physical Description: 27 leaves : ; 28 cm.
Language: English
Creator: Trenholm, Laurie Elizabeth, 1955-
University of Florida -- Agronomy Dept
Publisher: Department of Agronomy, Institute of Food and Agricultural Sciences, University of Florida
Place of Publication: Gainesville Fla
Publication Date: 1995?]
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Subject: Weeds -- Florida   ( lcsh )
Noxious weeds -- Florida   ( lcsh )
Genre: bibliography   ( marcgt )
non-fiction   ( marcgt )
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Statement of Responsibility: L.E. Trenholm ... et al..
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General Note: Agronomy research report - University of Florida Department of Agronomy ; AY-95-04
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Volume ID: VID00001
Source Institution: University of Florida
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    Historic note
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HISTORIC NOTE


The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
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(EDIS)

site maintained by the Florida
Cooperative Extension Service.






Copyright 2005, Board of Trustees, University
of Florida




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Agronomy Research Report AY-95-04


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Library


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GROWTH AND NUTRIENT


ACCUMULATION IN


TROPICAL SODA APPLE (Solanum


viarum Dunal)







L.E. Trenholm', A.K. Sturgis2, A. Nnaji3, R.N. Gallaher4,

R.U. Akanda5, and J.J. Mullaheys


Graduate Research Assistant1, Dept. of Environmental Horticulture; Graduate Research
Assistant2, Dept. of Agronomy; Graduate Fellow3, Dept. of Geography; and Professor
of Agronomy4, Dept. of Agronomy, Univ. of Florida, Gainesville, FL., respectively; and
Postdoc Research Associate5 and Associate Professor5, Southwest FL. Res. Educ.
Cent., Immokalee, FL, respectively.






Agronomy Research Report AY-95-04


GROWTH AND NUTRIENT


ACCUMULATION IN


TROPICAL SODA APPLE (Solanum


viarum Dunal)







L.E. Trenholm1, A.K. Sturgis2, A. Nnaji3, R.N. Gallaher4,

R.U. Akanda5, and J.J. Mullahey5


Graduate Research Assistant', Dept. of Environmental Horticulture; Graduate Research
Assistant2, Dept. of Agronomy; Graduate Fellow3, Dept. of Geography; and Professor
of Agronomy4, Dept. of Agronomy, Univ. of Florida, Gainesville, FL., respectively; and
Postdoc Research Associate5 and Associate Professor5, Southwest FL. Res. Educ.
Cent., Immokalee, FL, respectively.








Agronomy Research Report AY-95-04


GROWTH AND NUTRIENT ACCUMULATION IN

TROPICAL SODA APPLE (Solanum viarum Dunal)




L.E. Trenholm1, A.K. Sturgis2, A. Nnaji3, R.N. Gallaher4,

R.U. Akanda', and J.J. Mullahey6

Graduate Research Assistant1, Dept. of Environmental Horticulture; Graduate Research Assistant2, Dept.
of Agronomy; Graduate Fellow3, Dept. of Geography; and Professor of Agronomy4, Dept. of Agronomy,
Univ. of Florida, Gainesville, FL., respectively; and Postdoc Research Associate5 and Associate
Professor6, Southwest FL. Res. Educ. Cent., Immokalee, FL, respectively.

Keywords: broadleaf, macronutrient, micronutrient, nutrient concentration, nutrient content,
Solanaceae, weed, SOLVI
ABSTRACT
Tropical soda apple (Solanum viarum Dunal), an aggressive broadleaf weed, has been spreading
rapidly throughout some southeastern states. This plant proliferates in pasture lands, ditches, and citrus
groves, posing a threat to agriculture in the Southeast. The spread of TSA through Florida has been
associated with cattle movement across the state. The objective of this research was to evaluate
growth rates and nutrient accumulation in tropical soda apple (TSA) at various ages. Plants were
sampled from two different locations (hammock and pasture) in southwest Florida at 25, 50, 75, 100,
and 125 days after emergence. Dry matter production and nutrient concentration were determined for
all plant parts. Dry matter production was greater in pasture plants and increased over time for both
locations. Hammock plants produced the most dry matter in stems; pasture plants had greatest growth
in leaves and stems. Nutrient concentration differed due to main and sub effects (age and plant part)
for all nutrients except K, which had a significant interaction. Potassium was found in greatest
concentration in plant tissue. Most nutrients in most plant parts had a positive correlation with age; root
tissue contents of K, P, N, Cu, Fe, and Zn did not increase over time. In stem tissue of hammock
plants, Fe also did not increase over time. Tropical soda apple appears well suited for rapid growth in
long photoperiods, elevated temperatures, and sandy soils.
INTRODUCTION
Tropical soda apple (Solanum viarum Dunal) has been observed to be spreading
rapidly throughout the southeastern United States. A perennial broadleaf weed,
tropical soda apple (TSA) is native to Argentina and Brazil and has established itself
in India, Honduras, Mexico, and the West Indies (Mullahey et al. 1993b; Bryson and
Byrd, 1994). Tropical soda apple is a member of the Solanaceae family, belonging to
section Acanthophora and subgenus Leptostemonum (Nee, 1991). Tropical soda apple
was first observed in the US in Hendry County, Fl. in 1987 (Mullahey, et al. 1993b).
By 1990 it was classified as a serious weed problem; by 1995, it had infested
150,000 acres in south and central Florida (Mullahey and Colvin 1994). Florida cattle
ranchers estimate that TSA had cost the cattle industry 11 million dollars by 1993
(Mullahey et al. 1994). This northern spread has continued, extending through north








Florida, Georgia, Alabama, and Mississippi. In 1995 it was placed on the Federal
Noxious Weed List (Bryson, et al. 1995). Tropical soda apple is found predominantly
in improved pasture lands, ditches, citrus groves, sugar cane (Saccharum officinarum)
fields, oak (Quercus sp.) hammocks (Mullahey, et al. 1993a, 1993b), and sod fields
(Bryson, et al. 1995). It is commonly associated with soils of the Spodosol order,
which are typically poorly drained and fairly level (Mullahey and Colvin, 1994).
When mature, TSA stands from one to two meters tall. It has light colored
prickles on leaves, stems, petioles, and calyxes. Its leaves are lobular and pubescent,
ranging in size from 10 to 20 cm in length and 6 to 15 cm in width. Five-petaled white
corollas and yellow or cream colored stamens surround a single pistil. When immature,
fruits have mottled pigmentation similar to a watermelon (Citrullus lanatus) rind; at
maturity they are yellow, smooth, and globular. Seeds are somewhat flattened and
reddish-brown, with an average of 413 per fruit (Mullahey, et al. 1993b). In Florida,
flowering of TSA has been observed from early fall to late spring (Mullahey, et al.
1993b); other researchers define its flowering period as ranging from February through
August (Akanda, et al. 1995a).
Tropical soda apple seed production is estimated at 50,000 per season per plant
(Mullahey, et al. 1993b). These are readily disseminated by cattle, wildlife, and water
to new locations, primarily in grazing pastures. Seed germination is improved by
passage through digestive systems (Mullahey and Colvin, 1993). Dissemination of
seed through herbivory is a primary force in the rapid spread of TSA. Optimal seed
germination was reported with temperatures of 180C for 16 hours and 250C for 8
hours (Vincente, 1972). Akanda et al. (1995b) reported maximum germination at
300C. Germination responded to green (545 nm) and red (650 nm) light wavelengths
(Akanda, et al. 1995b). Maximum seed germination occurred at planting depths of 5.6
cm (Akanda, et al. 1995b). Mullahey and Cornell (1994) reported optimum placement
at 3.6 cm in depth for germination. Seed germination has been reported to be as high
as 93% in five month old seeds (Mullahey and Cornell, 1994).
Seedlings of TSA grew most rapidly from 60 to 80 days, increasing in height
during this time from 20 to 40 cm. At 60 days, there were an average of 20 leaves
per plant. Flowering occurred 75 days after planting, with fruiting at 108 days
(Mullahey and Cornell, 1994). Other research showed flower bud initiation occurred
at 35-40 days after planting, with flowers srt by 50-60 days (Patterson and
McGowan, 1996). Planting density of up to 49,000 plants ha' has been suggested
for maximum fruit production (Reddy, et al. 1991). Photoperiod has been shown to
influence seedling growth, with maximum vegetative development occurring in 12-16
hours of light. Decreasing photoperiod to eight hours delayed onset of reproductive
development approximately seven days (Patterson and McGowan, 1996).
Tropical soda apple is also spread vegetatively from an extensive and vigorous
root system, which may include roots extending up to six feet from the crown
(Mullahey and Colvin, 1994). Root systems up to 0.3 m deep with lateral roots of 1
m long and 2.5 cm in diameter have been reported (Bryson and Byrd, 1994). Depth
of root placement did not affect regeneration, but vegetative growth was affected by
size of root segment (Mullahey and Cornell, 1994). Horsenettle (S. carolinense L.) and








robust horsenettle (S. dimidiatum Raf.), which are related to TSA, have been shown
to have very high regenerative capacity from root sections ranging in size from 1.0 to
6.0 cm. Root sections buried at up to 16 cm in depth had 100% regeneration in
horsenettle (Wehtje, et al. 1987).
Earlier research on TSA has focused on the content of solasodine, an alkaloid
substance found in TSA fruit (Reddy, et al. 1991; Krishnan, 1983; 1987). Tropical
soda apple is grown commercially in some Indian nations for this substance.
Total non structural carbohydrates (TNC) were higher in roots than stems
(Mullahey and Cornell, 1994). Concentrations were variable over time, averaging 20
to 35%. Concentrations were highest in roots during winter months; with the onset
of spring growth, these stores were depleted. This is correlated with the growth cycle
of TSA.
Nutrient uptake and growth of related crops has been studied. Tomato
(Lycopersicon esculentum L.) had maximum dry matter production in root zone
temperatures of 25C, and maximum nutrient uptake at 26.70C. Nutrient uptake was
reduced at both higher (> 25C) and lower (<250C) for all elements except B, Fe, and
Mo (Tindall, et al. 1990).
Control of TSA is difficult due to the vigorous regeneration exhibited by this
species. Repeated applications of herbicides are necessary to combat TSA; many of
the treatments effective against this species, however, are injurious to the pasture-
crops associated with TSA (Akanda, et al. 1995a). Recommendations currently include
broadcast treatments with triclopyr [(3,5,6-trichloro-2-pyrindinyl)oxy]acetic acid in
combination with spot treatments of dichlorprop (+-)-2-[[[[(4-methoxy-6-methyl-1,3,5-
triazin-2-yl)amino]-carbonyl]amino]sulfonyllbenzoic acid and 2,4-D (Mullahey, et al.
1993a).
While there currently is no literature concerning growth and nutrient
accumulation in TSA, work has been done on nutrient sufficiency levels of other crops
in this genus. These include eggplant (S. Melongena L.) and Irish potato (S. tuberosum
L.). In addition, research on tomato, which is also in the Solanaceae family, may be
considered valid for comparison. The purpose of this research was to evaluate growth
rates and nutrient concentrations in TSA at 25, 50, 75, 100, and 125 days after
emergence of TSA seedlings in pasture and hammock habitats.
MATERIALS AND METHODS
Tropical soda apple plants were collected from two sites (pasture and
hammock) at 25, 50, 75, 100, and 125 days of age from near the Southwest Florida
Education and Research Center, Immokalee, Fl. Criteria used to distinguish each age
is described as follows: 25-day old plants were about 0.20 m tall; 50-day old plants
were about 0.40 m tall; 75-day old plants were 0.60 to 0.70 m tall and just beginning
to flower; 100-day old plants were approaching 1.0 m tall and had lots of flowers and
some young fruit that were generally small and all were still green in color; 125-day
old plants were 1.0 m tall or more, was full fruiting which were mostly green with
some yellow fruit present. Four replications were collected in total; the first in early
Sept. 95, the other three on 26 Sept. 1995. Samples were taken at random for all
replications. Soil samples were also obtained from each site. Number of plants








collected was recorded, and plants were separated into root, stem, leaf, and fruit
tissue. Fresh weights were obtained and tissue was washed according to the following
procedure: samples were dipped and shaken for 30 seconds in a 0.1% Liqui-nox
detergent solution, rinsed in deionized water for 10 seconds, dipped and shaken for
45 seconds in a 3% by volume concentrated HCI solution, and thoroughly rinsed in
deionized water (Futch and Gallaher, 1994; Gallaher, 1995). Tissue was then drained,
placed in bags, and dried in a forced air oven at 70C until a stable weight was
reached. Tissue was chopped if needed, and ground in a Wiley mill to pass through
a 2 mm stainless steel screen and stored in air tight plastic bags. Prior to preparation
for nutrient analysis, tissue was redried at 700C for approximately 2 hours. Tissue
was prepared for both mineral and N analysis. For mineral analysis, 1.0 g of sample
was weighed into a 50 ml Pyrex beaker. Samples were ashed in a muffle furnace for
approximately six hours at 4800C. Once cooled, samples were transferred to the hood,
where 20 ml deionized water was added to beakers by slowly decanting liquid down
one side of beaker. Two ml concentrated HCI were added to this, and beakers were
heated on a hot plate until dry. Beakers were immediately removed from the hot plate,
and 20 ml deionized water and two ml HCI were again added to beakers. Beakers
were placed on hot plate again, covered with a watchglass, and allowed to boil
vigorously before cooling to room temperature. Beaker solutions were then transferred
to 100 ml volumetric flasks by washing beakers thoroughly with deionized water.
Samples were brought to volume, flasks covered with Parafilm, and gently shaken to
diffuse contents. After allowing samples to settle, solution was decanted from flask
into plastic storage bottles, and analyzed for mineral nutrient concentration (Ca, Mg,
Cu, Fe, Mn, and Zn) by AA Spectrophotometer. Potassium was analyzed for by atomic
flame emission spectrophotometer; P by colorimeter.
For N analysis, 0.100 g sample was weighed into 100 ml test tube. Two boiling
beads and 3.2 g of salt catalyst (9 parts K2SO4:1 part CuSO4) were added to each
tube. Tubes were placed in digestion block (Gallaher, et al. 1975) under the hood, and
10 ml concentrated sulfuric acid were added to each tube. Contents of tubes were
mixed using a vortex mixer. At that time, two 1 ml increments of H202 were added to
tubes. Pyrex funnels were placed over mouths of tubes, and samples were digested
for approximately 6 hours at 375C. After cooling, tubes were again mixed on vortex
mixer; 25 ml deionized water was added as tubes were mixed. Following further
cooling, tubes were brought to volume, boiling beads were removed, and solutions
were transferred to storage bottles. Bottles were gently shaken. For analysis, samples
were transferred to small test tubes in sample trays. Care was taken not to decant any
sand or organic particles into analysis tubes. Analysis was run on Technicon
Autoanalyzer II, which is connected to a graphics printout recorder which indicates N
levels.
Soil was analyzed for pH, organic matter, CEC, buffer capacity, nutrient levels
(including Na), and texture. For pH analysis, 20 ml soil and 40 ml deionized water
were combined in a plastic cup. A calibrated pH meter electrode was inserted to just
above the soil-water interface, and readings were taken when fluctuations ceased.
Organic matter was determined by placing 1.0 g soil into a 500 ml Erlenmeyer flask.








Ten ml 1 N K2Cr207 was pipetted into the flask, followed by addition of 20 ml of
catalyst. This solution was then gently rotated for one minute, and allowed to stand
for 30 minutes. Two hundred ml deionized water were added to the flask, followed
by titration with 0.5 N ferrous sulfate solution. Color changes to a bright blue-green,
followed by a reddish-brown as endpoint is approached. At this point, titration is
complete, and amount of ferrous sulfate used is recorded and used to calculate
percent organic matter. Cation exchange capacity and buffer capacity were
determined by summation of cations in milliequivalents (as determined by nutrient
analysis). Mehlich I extractable nutrient concentrations (Mehlich, 1953) were
determined by ICAP 61E (Inductive Coupled Argon Plasma 61E). Mechanical analysis
(soil texture) was determined by weighing 100 g of dry screened soil into a beaker.
One hundred ml 5% Calgon solution was added to soil; mixture was stirred and
allowed to stand overnight. Two to three drops of oil was added, and solution was
transferred to dispersion cup and mixed for three minutes. This was then transferred
to 1000 ml graduated cylinder, and brought to 1120 ml with deionized water. Cylinder
was covered with Parafilm and gently inverted several times. A hydrometer was then
placed in slurry, and temperature and hydrometer reading recorded 40 seconds after
inversions. Cylinder was allowed to settle for two hours, at which time hydrometer
and temperature were read again.
Data were analyzed as two separate experiments (hammock and pasture), both
completely randomized design and utilizing the same variables. Analysis of variance
was run using MSTAT 4.0 (1985), with main treatments as age of plants and sub
treatments as plant parts. Means were separated using Duncan's new multiple range
test. Significance was determined at the 0.05 level or probability.
The document was prepared with a Packard Bell 406CD Pentium computer and
a Hewlett Packard LaserJet4 Printer. Additional software programs used included
WordPerfect 5.1 (1990) and Quattro Pro 4.0 (1987).
RESULTS AND DISCUSSION
Plant Dry Matter and Nutrient Content
Dry matter production and nutrient content had an interaction in both locations
(Table 1). Dry matter production of plants in both locations increased steadily over
time. Dry matter accumulation averaged 50% less in hammock than pasture plants.
This may be related to reduced light in the hammock, resulting in reduced rates of
photosynthesis. Increases in dry matter in both locations occurred at 125 and 100
days; 25, 50, and 75 days all had equal rates of growth. Fruit appeared between 75
and 100 days of age in some plants at both locations; in others, no fruit development
was observed until up to 125 days. This is slightly faster than observations of
Mullahey (Mullahey and Cornell, 1994), and about the same as observed by Patterson
(1995). Mullahey (1994), observed greatest increase in height between 60-80 days;
in this research, the largest percentage increase in dry matter production occurred
between 75 and 100 days. Hammock dry matter increased 400%, pasture 663%
during this time.
Nutrient content for all tissues (concentration x dry matter) increased over time
in relation to plant growth in both locations (Table 1). Potassium content exceeded all








other macronutrients at all ages, and the ratio of cations to N is high at all ages and
both locations. Average K ratios exceed those of N by 35%. For all macronutrients in
both locations, 125 day plants have highest nutrient contents, followed by 100 day
plants. The remaining plants were lowest in nutrient content, with no differences
between 25, 50, and 75 day plants. Micronutrients also increased over time in relation
to growth. All were greater at 125 days than 100 days. Iron content in pasture plants
at 25, 50, and 75 days did not differ from 100 day plants, while they did differ in
hammock plants. In both locations, Cu and Zn content at 25, 50, and 75 days was
equal, with differences between 100 and 125 day plants. Manganese, while steadily
increasing over time, had no differences between 25, 50, 75, and 100 days in
hammock plants, which were all less than 125 days. Manganese content in pasture
plants was lower at 25, 50, and 75 days than at the higher ages. Contents were lower
in hammock plants for all nutrients except Mn. Higher levels of Mn were observed
from hammock soil than from pasture (Table 4); TSA apparently takes up Mn as it
becomes available. For both locations, three of four reps had pH suitable for Mn
availability.
Nutrient Concentration
Nitrogen concentration did not vary by age, but was at highest levels at 25 days
for both locations (Table 2). This is indicative of N utilization by rapidly growing
plants. Levels remained higher in hammock plants, which had less dry matter
production. In addition, there were higher levels of organic matter in hammock soil
than pasture, and less competition for nutrients than in the pasture. Also, the
increased light quantity in the pasture may reduce N content. In hammock plants,
highest levels were in leaves, followed by fruit; stems and roots were equal. In pasture
plants, leaves and fruit had no differences in concentration, nor did stem and root
tissue. Nitrogen requirements may vary in related crops due to species or age. In trellis
tomato, N requirements decrease with successive blooms; requirements of Irish potato
also decrease over time. Levels recorded here in hammock plants are below
requirements for Irish potato at 30 cm, but similar to those required halfway through
tuber formation. Pasture plants have lower N concentration than that required by.Irish
potato, and are slightly below sufficiency levels for trellis tomato. Hammock plant
levels exceed those suggested for trellis tomato. Generally, N concentration greater
than 3.0% is typical of plants in the Solanaceae family (Jones, et al. 1991).
Concentration of P did not vary over time, although there was a slight reduction
in P levels in hammock plants (Table 2). In hammock plants, highest concentration
was in leaf tissue, followed by fruit. Stem and root tissue did not differ, and were
approximately half of leaf concentration. In pasture plants, leaf, stem, and fruit tissue
were all equal; root concentration averaged 40-50% less than other parts. Levels
declined slightly upon fruit formation. Phosphorous levels were slightly lower in
hammock plants, with the exception of 25 day plants; soil extractable P levels were
sharply lower in hammock plants. Phosphorous concentrations are within sufficiency
ranges for Irish potato and tomato cultivars, but less than recommended levels for
eggplant. Recommendations for P levels in Irish potato do not vary over time; those
for trellis tomato are initially higher than levels recorded here (Jones, et al. 1991).








Potassium occurred in highest concentration of any element in both locations
(Table 2). There was an interaction between age and plant part for both hammock and
pasture plants. Highest K concentrations were at 25 days when averaged across plant
parts. A reduction in K concentration over time is typical (Jones, et al. 1991).
Concentration in leaves did not vary over time in either location. In hammock plants,
stems had very elevated K levels at 25 days. There was some variation in stem K
concentration over time in both locations. Roots did not decline steadily over time in
either location. Leaf and stem tissue had the same average K concentration over time.
Potassium levels were generally greater in leaf tissue, with the exception of 25 days,
which had sharply higher stem concentration. The decrease in K concentration over
time may be correlated with the rapid plant growth and mobility of K; it is readily
translocated from old to young tissue, where it regulates many cellular activities and
functions in translocation of photoassimilates. Potassium levels declined with onset
of fruiting. Potassium requirements for the Solanaceae family are generally high; levels
recorded here are below sufficiency levels for early blooms in trellis tomato, well
below recommendations for Irish potato, but similar to sufficiency levels for eggplant
(Jones, et al. 1991). Hammock plants had higher K concentration than pasture plants,
which is correlated with soil K content. In addition, as K is involved in turgor
regulation in cells, this may be due to less need to control transpiration in hammock
plants, which may have more available water and lower rates of transpiration than
pasture plants.
Concentration of Ca had no differences due to plant age in either location (Table
2). There were differences in concentration between plant parts in both locations.
Calcium levels increase over time in trellis tomato and Irish potato (Jones, et al. 1991).
Levels here in both locations were less than those required by tomato and potato,
especially in hammock plants, but were similar to sufficiency levels for eggplant.
Levels are less than those typically characteristic of plants in the Solanaceae family
(Jones, et al. 1991). Calcium is not readily translocated to growing fruits (Jones, et
al. 1991), therefore Ca fruit levels recorded here are somewhat elevated. There is only
a slight reduction of stem tissue Ca levels at time of fruit formation. Calcium levels are
lower in hammock than pasture plants; extractable Ca in the soil also is lower in the
hammock location.
Magnesium had no differences in concentration due to plant age; there were
differences in hammock plants between all parts, however (Table 2). In pasture plants,
leaf, stem, and fruit are all equal in concentration; root tissue is lower. Levels are on
the low end of sufficiency ranges for eggplant and tomato, and less than those
required by Irish potato (Jones, et al. 1991). Magnesium levels are below those of Ca,
which may be restricting uptake of this cation. Magnesium decreased slightly over
time in both locations. Soil Mg levels were similar for both locations.
Copper concentration (Table 2) was within recommended levels for related
plants, which show no variation in sufficiency levels over time (Jones, et al. 1991).
Higher levels were recorded in 25 day hammock plants; all other ages were equal.
There were no differences due to age in pasture plants, although there was a decrease
over time. In hammock plants, highest concentrations were found in leaves and fruit,








followed by roots, then stems. Pasture plants had highest concentration in leaves.
Concentrations were greater in pasture plants, with the exception of fruit. This may
be related to organic matter of the soil, which was higher in hammock soil. Organic
matter may complex Cu, making it less available for plant uptake.
Iron concentration did not differ by age in either location (Table 2).
Concentrations were highest in leaves in hammock plants; all other parts were equal.
In pasture plants, highest concentration was in roots. Levels were within
recommended ranges for related plants, which have constant requirements over time
(Jones, et al. 1991). Levels were generally lower in pasture plants, although soil levels
were slightly higher in pasture soils.
Manganese concentration did not vary overtime, although there was a decrease
in tissue levels (Table 2). Manganese requirements of related plants also do not vary
over time (Jones, et al. 1991). Hammock plants had highest levels in leaf and stem
tissue, followed by root. Fruit Mn concentration was lower than other parts. Pasture
plants had no differences due to part. Manganese exhibits a wide range of sufficiency
values, and tissue sampled here is well within that range (Jones, et al. 1991).
Hammock tissue levels were substantially higher than pasture levels; which was also
true of soil samples.
Zinc concentration (Table 2) did not differ by age. In hammock plants, highest
concentrations were found in stem, followed by root and fruit. Lower levels were
recorded in leaves. Pasture plants also had highest levels in stem tissue, followed by
root, followed by leaf and fruit. Average Zn levels were higher in pasture plants, which
is similar to findings of Tindall, et al. (1990) for tomato, where Zn uptake increased
in response to temperature. Zinc levels were higher in hammock soil than pasture.
Trellis tomato requirements for Zn also do not vary over time; those of Irish potato
decrease slightly (Jones, et al. 1991). Concentrations here are within
recommendations for related plants.
Dry Matter and Nutrient Content By Age and Plant Part
Both locations had interactions between age and plant part for dry matter
production (Table 3). Averages of plant parts for content of each nutrient increased
over time in relation to increased dry matter production. Hammock leaf tissue did not
differ between 100 and 125 days; stem, root, and fruit all increased in size between
these sampling dates. At 25, 50, and 75 days there were no differences in size
between plant parts in either location. By 100 and 125 days, hammock stem tissue
was larger; in pasture plants, leaf and stem tissue remained equal in size. Increases
in growth were greater in pasture plants, particularly after onset of fruit development.
Root tissue varied the least between 125 day plants of the two locations. Pasture
plants are photosynthesizing at higher rates, and may partition less dry matter to roots
than hammock plants. Hammock plants instead expand their root system at a greater
rate to obtain mineral nutrients. All nutrient contents except for hammock plant Cu
had interactions of age and plant part.
Nitrogen content (Table 3) had its largest percentage increase between 100 and
125 days in hammock plants, largely due to increases in fruit growth at this time.
Largest percentage increase in pasture plants occurred between 75 and 100 days. In








both locations, highest content of N was in leaf tissue at 125 days, lowest in root
tissue. This is in response to demands of photosynthesis, indicating sinks for N
products. Concentration was higher in pasture plants in leaf and fruit tissue, and equal
in root and stem tissue. In pasture plants, there was no change in N content over time
in root tissue. Photosynthetic tissue and developing fruit were the stronger sinks for
N in the plants.
Phosphorous content (Table 3) remained constant over time in roots of plants
in both locations, while increasing in other parts. As roots were continuing to grow
at this time, it appears that P was translocated out to other locations rather than
accumulating in root tissue. All plant parts had equal P contents until fruiting.
Phosphorous appears to be translocated to fruit at this time; by 125 days, roots were
lower in P than other plant parts.
Potassium content likewise did not increase over time in roots of either location
(Table 3). In both locations, there were no differences in content between parts on the
first three sampling dates; by 125 days leaf and stem had highest contents in pasture
plants. In hammock plants, however, stems accumulated greater amounts of K than
leaves. Calcium content increased in plant parts over time, except in fruit from
hammock plants, which was constant over the two sampling periods (Table 3).
Calcium content did not differ among parts for either location for the first three
sampling dates. In hammock plants, highest content was in stem tissue; while leaf
tissue was highest in pasture plants. Lowest content was in fruit at 125 days. This
may contribute to making fruit palatable to grazing animals, as Ca levels in plant tissue
is highly correlated with oxalic acid levels (Calcium oxalate) and hardened cell walls
(Gallaher, 1975).
Copper content did not vary due to the interaction of age and plant part (Table
3). It did increase over time in the average of the parts, while there were no
differences in Cu content between parts. In pasture plants, Cu increased over time in
all parts except roots, which remained constant. Roots also had the lowest content
of any part.
Iron increased in time in all parts, except for stems of pasture plants, which
remained constant (Table 3). For both locations, highest content was in leaves, where
it is used in photosynthesis. In addition, both locations had equal content in stems,
roots, and fruit.
Content of Mn increased over time in all parts except fruit, which remained
constant, for both locations (Table 3). Hammock plants had large increases in stem
content, while in pasture plants, leaf tissue was greatest. Manganese functions
primarily in photosynthesis and as an enzyme co-factor, and highest content would
be expected in leaf tissue.
Zinc content (Table 3) increased over time except for pasture root and fruit
tissue. Higher content was found in stem tissue for both locations.
SUMMARY AND CONCLUSIONS
Dry matter production was at least twice as great in pasture plants on three of
five sampling dates. In spite of heightened competition for water and nutrients from
grass and other rapidly growing weeds in pasture areas, much greater rates of growth








occurred. Tropical soda apple has been shown to be highly responsive to light and
photoperiod for germination of seedlings and subsequent growth. Maximum vegetative
development occurs in 12-16 hour photoperiods (Patterson, 1995), similar to
daylengths occurring during growth of plants sampled here.
Content of all nutrients, averaged across all plant parts, increased over time in
relation to plant growth. Content of K was high in both locations, exceeding N content
in all instances except 25 day pasture plants. This may aid in keeping TSA free of
drought stress, due to K functioning in stomatal regulation.
There were no interactions of age and plant part for nutrient concentration,
except for K in both locations. The only variations due to age were reductions in N
concentration in pasture plants, and Cu concentration in hammock plants. Reductions
in N concentration are not uncommon over time; the pasture plants would be more
likely to show this due to their increased rate of growth over hammock plants.
Concentrations of Ca, P, and Cu were greater in pasture plants; N, K, Mg, Fe, Mn, and
Zn were all higher in hammock plants. This may be related to direct functioning of
these latter elements in photosynthesis and growth, both of which were reduced in
hammock plants. Leaf tissue had higher or equal concentrations of all nutrients except
Fe in pasture plants and Zn in both locations. Iron concentration in pasture plants was
highest in root tissue, Zn concentration was greatest in stem tissue.
There was an interaction of dry matter and age by plant part. In hammock
plants, stems had greater dry matter production than other plant parts. This is most
likely caused by the tendency of shaded plants to have longer internodes, resulting in
longer stems. In pasture plants, leaves and stems had equal amounts of dry matter.
Nutrient content did not increase over time in all plant parts. In root tissue, K
and P in both locations, as well as N, Cu, Fe, and Zn in pasture plants did not vary
over time in relation to plant growth. Additionally, Fe in hammock plants did not vary
in stem tissue over time. In growing tissue, this is equivalent to a depletion of this
nutrient, as content would increase automatically as a function of growth. For root
tissue, this would indicate that these elements are being utilized faster than roots are
growing, or that these nutrients are being rapidly translocated from roots to more
demanding sinks, without being continually replaced.
Tropical soda apple appears to be well suited for growth in conditions of long
days, warm temperatures, and sandy soils. Potassium deficiency, sometimes seen in
sandy soils, is not evident in TSA. Competition from other plants does not appear to
inhibit growth of TSA; the extensive root system of TSA appears capable of supplying
rapid growth with sufficient nutrients.
ACKNOWLEDGMENTS
Technical support provided by Jim Chichester, Howard Palmer, and Walt Davis is greatly appreciated.
This research paper resulted from a practical problem (to be solved by soil and plant analysis and with
the support of the scientific literature) assigned to students in the Agronomy Department course
"AGR6422 Crop Nutrition," Dr. Raymond N. Gallaher, Instructor. Problems are designed to not only
give students experience and knowledge of collecting, handling, treating, and analyzing plant and soil
samples in "Crop Nutrition-Plant Nutrition," but also to provide real-world experience working with
fellow students and experienced professors in the art and science of playing the role of "Plant Nutrition
Doctors .








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control of tropical soda apple (Solanum viarum Dunal). Florida Agric. Bp: Sn
J. Ser. No. R-04658. In Review.
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affecting germination of tropical soda apple (Solanum viarum Dunal). Florida
Agric. Exp. Stn. J. Ser. No. R-04609. In Review.
Bryson, C.T., and J.D. Byrd, Jr. 1994. Solanum viarum (Solanaceae), new to -
Mississippi. Sida 16(2):382-385.
Bryson, C.T., J.D. Byrd, Jr., and R.G. Westbrooks. 1995. Tropical soda apple
(Solanum viarum Dunal) in the United States. Miss. Dept Agric and
Commerce, Bureau of Plant Industry, Information Sheet, 2 pp.
Futch, S.H., and R.N. Gallaher. 1994. Citrus leaf wash comparison of zinc
nutritional and nutrient uptake analysis. Agronomy Research Report AY-94-06.
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Gallaher, R.N. 1975. The occurrence of calcium in plant tissue as crystals o f
calcium oxalate. Commun. in Soil Sci. and Plant Anal. 6(3):315-330.
Gallaher, R.N. 1995. Comparison of Zn nutritional spray treatments for citrus leaf
adsorption and absorption. Agronomy Research Report AY-95-02. Agronomy
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Gallaher, R.N., C.O. Weldon, and J.G. Futral. 1975. An aluminum block digester for
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Jones, J.B., B. Wolf, and H.A. Mills. 1991. Plant Analysis Handbook. Micro-Macro
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Krishnan, R. 1983. Review of multilocational varietal evaluation trials on Sb2mun
viarum Dunal. Proc. V Workshop of All India Coordinated Improvement Project
on Medicinal and Aromatic Plants. pp 24-25.
Krishnan, R. 1987. Performance of selections in Solanum viarum. Proc. VII
Workshop of All India Coordinated Improvement Project on Med. and Arom. PI.
pp. 134-141.
Mehlich, A. 1953. Determination of P, Ca, Mg, K, Na, and NH4. Mimeo, North
Carolina Soil Test Div. North Carolina State University, Raleigh, NC.
MSTAT 4.0 1985. Users Guide to MSTAT, Version 4.0. Michigan State
University, Lansing.
Mullahey, J.J., and D.L. Colvin. 1993. Tropical soda apple: a new noxious weed in
Florida. Univ. of Florida, Florida Cooperative Extension Service, Fact Sheet
WRS-7, 3pp.
Mullahey, J.J., J.A. Cornell, and D.L. Colvin. 1993a. Tropical soda apple (Solanum
viarum) control. Weed Technology 7:723-727.
Mullahey, J.J., M. Nee, R.P. Wunderlin, and K.R. Delaney. 1993b. Tropical soda apple
(Solanum viarum): a new weed threat in subtropical regions. Weed Technology
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Mullahey, J.J., and D.L. Colvin. 1994. Tropical soda apple in Florida (Solanum
viarum Dunal). SS-AGR-50. Inst. Food & Agric. Sci., Univ. of Florida,
Gainesville.
Mullahey, J.J., and J.A. Cornell. 1994. Biology of tropical soda apple (Solanum
viarum) an introduced weed in Florida. Weed Technology 8:465-469.
Mullahey, J.J., P. Hogue, K.U. Hill, S. Sumner, and S. Nifong. 1994. Tropical
soda apple census. The Florida Cattleman. June:69-75.
Nee, M. 1991. Synopsis of Solanum section Acanthophora: A revision of interest for
glycoalkaloids. p.258-266 In J.G. Hawkes, R.N. Lester, M.Nee, and N. Estrada,
eds. Solanaceae II1.
Patterson, D.T. 1995. Final report on tropical soda apple. F.D.A.C.S. contract 2522.
ARS.USDA South Atlantic Area.
Patterson, D.T., and M. McGowan 1996. Environmental limits to the distribution of
tropical soda apple (Solanum viarum Dunal) in the United States. In Weed
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Reddy, G.S., R. Krishnan, and M.V. Chandravadana. 1991. Planting density and
arrangement for higher berry and solasodine yields in Solanum viarum;
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temperature on nutrient uptake of tomato. Journal of Plant Nutrition
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Table 1.
tronical


Plant
Age


Plant dry matter and nutrient content in whole plant of variable age
soda apple from two environments in Florida, 1995
Variable
Dry Matter Ca Mg K P N Cu WF Mn -


Days ---------- g per 100 plants ---------- -- mg per 100 plants -------

----------------------------Hammock----------------

25 25 c 0.2c 0.08c Ic 0.09c 0.7c 0.4c 5c 6b 2c

50 288 c 3.0c 0.95c 8c 1.13c 5.5c 3.6bc 27c 29b 25c

75 619 c 6.0c 1.48c 15c 1.62c 12.5c 5.0bc 55c 78b 53c

100 2476 b 21.5b 5.74b 57b 6.90b 34.8b 17.8b 172b 282b 183b

125 5633 a 44.0a 10.8a 133a 12.3a 85.4a 38.5a 457a 830a 485a

Average 1808 14.9 3.82 43 4.41 27.8 13.0 143 245 150

** ** ** ** ** ** ** ** ** **
CV (%) 37 57 57 34 68 37 76 50 89 49
---------------------------Pasture---------------------

25 73 c 0.6c 0.22c 1.2c 0.27c 1.5c 1.9c 36b 9c 6c

50 300 c 3.3c 0.77c 7.1c 1.12c 4.3c 3.8c 39b 14c 27c

75 743 c 8.4c 2.12c 17.5c 2.81c 10.5c 9.7c 90b 39c 68c

100 4927 b 51.8b 13.4b 105 b 18.1b 61.2b 61.2b 392b 204b 410b

125 11906 a 122.5a 28.5a 234 a 41.6a 148 a 123 a 1460a 352a 710a

Average 3590 37.3 9.0 73.1 12.8 45.1 39.9 403 124 244


CV (%) 39 38 41 22 32 46 49 104 71 27

Values among plant age treatments within dry matter or a nutrient not followed
by the same letter are significantly different at the 0.05 level of probability
according to Duncan's new multiple range test.

** = Significant at the 0.01 level of probability according to F test. CV
coefficient of variation.


I










Table 2. Plant nutrient concentration in plant parts of variable age tropical
soda apple from two environments in Florida, 1995
Plant Variable
Age Leaf Stem Root Fruit Average
Days


25

50

75

100

125

Average

CV parts =


25

50

75

100

125

Average

CV parts




25

50

75

100

125

Average

CV parts


----------------------------- Ca, % --------------------------------
---------------------------Hammock--------------------------------

0.78 0.76 0.88 0.81 a

1.03 0.80 0.86 0.90 a

1.00 0.86 0.80 0.88 a

1.08 0.66 0.83 0.58 0.79 a

1.01 0.75 0.83 0.54 0.78 a

0.98 w 0.76 x 0.84 x 0.56 y

18%; Significance main = NS, Sub = **, interaction = NS

-----------------------------Ca, %------------------------------
---------------------------Pasture------------------------------


1.06 0.76 0.80 0.87 a

1.24 0.98 0.99 1.07 a

1.20 1.02 1.33 1.18 a

1.33 0.89 0.99 0.56 0.94 a

1.33 0.96 1.23 0.61 1.03 a

1.23 w 0.92 wx 1.07 w 0.59 x

= 18%; Significance main = NS, Sub = **, interaction = NS

----------------------------- Mg, % -------------------------------
-----------------------------Hammock-------------------------------

0.45 0.29 0.21 0.32 a

0.42 0.23 0.14 0.26 a

0.36 0.19 0.14 0.23 a

0.38 0.17 0.15 0.37 0.26 a

0.29 0.17 0.13 0.25 0.21 a

0.38 w 0.21 y 0.15 z 0.31 x

= 20%; Significance main = NS, Sub = **, interaction = NS










Table 2. Continued--


25

50

75

100

125

Average

CV parts




25

50

75

100

125

Average


CV parts




25

50

75

100

125

Average


24%; Significance main = **, Sub = **, interaction = **

------------------------------K, %--------------------------------
---------------------------Pasture-----------------------------

2.72a w 2.55a wx 1.59a x 2.29

2.78a w 2.60a x 1.23a y 2.21

2.81a w 2.53a w 1.50a x 2.28

2.49a wx 1.83a xy 1.23a y 3.15a w 2.17

2.11a wx 1.69a x 1.22a x 3.07a w 2.02

2.58 2.24 1.35 3.11


CV parts = 33%; Significance main = *, Sub = **, interaction = *.


----------------------------- Mg, % ---------------------
---------------------------Pasture----------------

0.35 0.35 0.18 0.29 a

0.30 0.29 0.16 0.25 a

0.30 0.35 0.19 0.28 a

0.28 0.29 0.16 0.26 0.24 a

0.23 0.26 0.18 0.28 0.24 a

0.29 w 0.31 w 0.17 x 0.27 w

= 26%; Significance main = NS, Sub = **, interaction = NS.

------------------------------ K, % ------------------------------
---------------------------Hammock-------------------------

3.83a x 6.38a w 2.59a y 4.62

3.53a w 3.50b w 1.58b x 2.87

3.61a w 2.71bc w 1.45b x 2.59

3.22a wx 2.43c x 1.27b y 3.87a w 2.70

3.06a wx 2.25c x l.llb y 3.32a w 2.43

3.45 3.45 1.60 3.60










Table 2. Continued--


25

50

75

100

125

Average

CV parts


------------------------------- ---P, % ------------------
---------------------------Hammock-------------

0.44 0.35 0.33 0.37 a

0.43 0.28 0.19 0.30 a

0.37 0.20 0.16 0.24 a

0.39 0.20 0.18 0.43 0.30 a

0.35 0.16 0.13 0.35 0.25 a

0.40 w 0.23 y 0.20 y 0.39 x

= 25%; Significance main = NS, Sub = **, interaction = NS.

------------------------- P, %---------- -----------------
---------------------------Pasture------ ----------

0.42 0.30 0.21 0.31 a

0.46 0.36 0.20 0.34 a

0.49 0.39 0.25 0.38 a

0.44 0.35 0.19 0.41 0.35 a

0.40 0.33 0.20 0.45 0.34 a

0.44 w 0.35 w 0.21 x 0.43 w

= 29%; Significance main = NS, Sub = **, interaction = NS.

--------------------------------N, % --------------------------------
---------------------------Hammock-------------------------------

4.51 1.38 1.65 2.51 a

3.91 1.07 0.98 1.99 a

3.91 1.24 0.96 2.04 a

3.66 1.00 0.94 2.01 1.90 a

3.78 0.88 0.86 1.82 1.83 a

3.95 w 1.12 y 1.08 y 1.91 x

= 31%; Significance main = NS, Sub = **, interaction = NS.


25

50

75

100

125

Average

CV parts




25

50

75

100

125

Average

CV parts










Table 2. Continued--


25

50

75

100

125

Average

CV parts




25

50

75

100

125

Average


CV parts




25

50

75

100

125

Average


33%; Significance main = *, Sub = **, interaction = NS.

--------------------------- Cu ppm ----------------------------
------------------------Pasture------------------

21.8 7.3 27.7 18.9 a

18.8 7.0 9.3 11.7 a

21.3 8.0 10.8 13.3 a

20.5 6.0 8.3 10.0 11.2 a

16.0 4.8 8.5 12.3 10.4 a

19.7 w 6.6 y 12.9 x 11.1 xy


CV parts = 65%; Significance main = NS, Sub = **, interaction = NS.


------------------------------ ------------,
---------------------------Pasture-----------------

2.54 1.96 1.30 1.94 a

2.14 0.84 0.93 1.30 b

2.25 0.84 0.87 1.32 b

1.93 0.55 0.67 1.92 1.27 b

1.89 0.56 0.77 1.80 1.26 b

2.15 w 0.95 x 0.91 x 1.86 w

= 40%; Significance main = **, Sub = **, interaction = NS.

---------------------------- Cu, ppm ------------------------------
---------------------------Hammock---------------------------

18.3 14.0 15.3 15.8 a

15.0 5.3 7.8 9.3 b

11.0 4.5 6.0 7.2 b

9.8 3.8 7.0 17.0 9.4 b

10.0 4.8 6.8 8.3 7.4 b

12.8 w 6.5 y 8.6 x 12.6 w


6










Table 2. Continued--


25

50

75

100

125

Average


CV parts =




25

50

75

100

125

Average


CV parts =




25

50

75

100

125

Average

CV parts =


----------------------------- Fe, ppm -----------------
---------------------------Hammock- -------------------

430 50 126 202 a

148 55 88 97 a

165 30 95 97 a

145 25 85 141 99 a

225 38 65 80 102 a

223 w 40 x 92 x 110 x


120%; Significance main =NS, Sub = **, interaction = NS.

-- ------ ------------ Fe, ppm ------------------------------
------------------------- Pasture---------------------------------

168 30 662 287 a

167 63 198 143 a

188 50 168 135 a

110 40 113 60 81 a

203 40 215 40 124 a

167 wx 45 x 271 w 50 x


163%; Significance main =NS, Sub = *, interaction = NS.

----------------------------- Mn, ppm ----------------------------
-------------------------- Hammock--------------------- ---

223 202 254 226 a

189 164 129 161 a

208 170 123 167 a

223 178 85 123 152 a

166 172 115 77 133 a

202 w 177 wx 141 x 99 y

33%; Significance main = NS, Sub = **, interaction = NS.


Table 2. Continued--


---









Table 2. Continued---
---------------------------- Mn, ppm ------------------------------
------------------ Pastu-------------- -----e

25 90 50 99 80 a

50 54 36 35 42 a

75 60 40 54 52 a

100 51 34 78 41 51 a

125 40 27 32 25 31 a

Average 59 w 37 w 59 w 33 w

CV parts = 66%; Significance main = NS, Sub = +, interaction = NS.

----------------------------Zn, ppm -----------------------------
---------------------------Hammock-------------------------------

25 73 115 109 99 a

50 60 111 78 83 a

75 56 110 82 83 a

100 54 101 65 65 71 a

125 48 100 67 116 83 a

Average 58 y 108 w 80 x 91 x

CV parts = 25%; Significance main = NS, Sub = **, interaction = NS.

----------------------------- Zn, ppm -----------------------------
---------------------------Pasture-------------------------------

25 54 111 87 84 a

50 59 130 82 90 a

75 51 130 89 90 a

100 46 142 61 34 70 a

125 33 107 42 30 53 a

Average 49 y 124 w 72 x 32 y

CV parts = 28%; Significance main = +, Sub = **, interaction = NS.

Values among plant age treatments within a nutrient not followed by the
same letter (a,b,c,d) are significantly different at the 0.05 level of
probability according to Duncan's new multiple range test.
Values among plant parts within a plant age treatment not followed by the
same letter (w,x,y,z) are significantly different at the 0.05 level of
probability according to Duncan's new multiple range test.
CV = Coefficient of variation; NS = F test non significant at 0.05 level
of probability (p); + = F test significant at the 0.10 level of p; = F test
significant at the 0.05 level of p; ** = F test significant at 0.01 level of p.









Table 3. Dry matter and nutrient content in plant parts of variable age tropical
soda apple from two environments in Florida, 1995
Plant Variable
Age Leaf Stem Root Fruit Average
Days
----------------- Dry weight, g dry matter per 100 plants -----------

---------------------------Hammock-------------------------------

25 12 c w 7c w 6c w 8

50 115bc w 99c w 74c w 96

75 198bc w 25c w 169c w 206

100 528b xy 1088b w 656b x 204b y 619

125 1026a x 2786a w 1009a x 812a x 1408

Average 376 846 383 508

CV parts = 44%; Significance main = **, Sub = **, interaction = **

---------------- Dry weight, g dry matter per 100 plants -----------
---------------------------Pasture----------------------------

25 34c w 19c w 21b w 25

50 126c w 103c w 70b w 100

75 285c w 263c w 196b w 248

100 1864b w 1876b w 678ab x 509b x 1232

125 4137a w 4510a w 1278a y 1980a x 2976

Average 1289 1354 449 1245

CV parts = 42%; Significance main = **, Sub = **, interaction = **

------------------------ Ca, g per 100 plants----------------------
---------------------------Hammock-------------------------------

25 0.10c w 0.05c w 0.05b w 0.07

50 1.39c w 0.29c w 0.72b w 1.00

75 2.23c w 2.43c w 1.34b w 2.00

100 6.60b w 7.81b w 5.79a w 1.29a x 5.37

125 11.08a x 20.25a w 8.28a x 4.42a y 11.01

Average 4.28 6.29 3.24 2.86

CV parts = 55%; Significance main = **, Sub = **, interaction = **









Table 3. Continued--


25

50

75

100

125

Average

CV parts




25

50

75

100

125

Average


CV parts




25

50

75

100

125

Average


49%; Significance main = **, Sub = **, interaction = **.

------------------------ Mg, g per 100 plants ----------------------
---------------------------Pasture--------------------------------

0.13c w 0.06c w 0.03b w 0.07

0.37c w 0.28c w 0.12b w 0.26

0.85c w 0.90c w 0.38b w 0.71

5.28b w 5.69b w 1.15ab x 1.32b x 3.36

9.39a x 11.39a w 2.24a z 5.46a y 7.12

3.20 3.67 0.78 3.39


CV parts = 44%; Significance main = **, Sub = **, interaction = **


------------------------ Ca, g per 100 plants ----------------------
---------------------------Pasture--------------------------------

0.31c w 0.14c w 0.15c w 0.20

1.56c w 1.00c w 0.72c w 1.09

3.30c w 2.56c w 2.54c w 2.80

25.08b w 16.73b x 7.17b y 2.82b y 12.95

53.53a w 42.05a x 15.84a y 11.23a y 30.66

16.75 12.49 5.28 7.03

= 37%; Significance main = **, Sub = **, interaction = **

------------------------ Mg, g per 100 plants ----------------------
---------------------------Hammock--------------------------------

0.05c w 0.02c w 0.01b w 0.03

0.53c w 0.30c w 0.12ab w 0.32

0.68c w 0.56c w 0.23ab w 0.49

2.00b w 2.04b w 1.Olab x 0.69b x 1.44

3.07a x 4.38a w 1.33a y 2.07a y 2.71

1.27 1.46 0.54 1.38









Table 3. Continued--

------------------------ K, g per 100 plants------------------------
---------------------------Hammock--------------------------------

25 0.5c w 0.4c w O.la w 0.3

50 4.3c w 2.6c w 1.3a w 2.7

75 6.7bc w 5.9c w 2.4a w 5.0

100 17.7b wx 23.7b w 8.4a x 7.2b x 14.3

125 32.6a x 61.7a w 11.la y 27.1a x 33.1

Average 12.4 18.9 4.7 17.2

CV parts = 70%; Significance main = **, Sub = **, interaction = **.

------------------------ K, g per 100 plants ----------------------
---------------------------Pasture----------------Pa----s

25 l.lc w 0.5c w 0.4a w 0.7

50 3.6c w 2.6c w 0.9a w 2.4

75 7.8c w 6.8c w 2.9a w 5.8

100 46.2b w 34.7b w 7.9a x 15.8b x 26.1

125 84.0a w 75.1a w 15.7a y 59.6a x 58.6

Average 28.5 23.9 5.6 37.7

CV parts = 53%; Significance main = **, Sub = **, interaction =

------------------------ P, g per 100 plants ----------------------
---------------------------Hammock-------------------------------

25 0.05c w 0.02c w 0.01a w 0.03

50 0.64c w 0.33c w 0.17a w 0.38

75 0.74c w 0.62c w 0.26a w 0.57

100 2.35b wx 2.53b w 1.18a xy 0.86b y 1.73

125 3.88a wx 4.26a w 1.28a y 2.86a x 3.07

Average 1.53 1.55 0.58 1.86

CV parts = 70%; Significance main = **, Sub = **, interaction =









Table 3. Continued


25

50

75

100

125

Average

CV parts




25

50

75

100

125

Average


CV parts




25

50

75

100

125

Average


46%; Significance main = **, Sub = **, interaction = **.

------------------------ N, g per 100 plants--------------------
---------------------------Pasture------------------------------

0.9c w 0.3b w 0.3a w 0.5

2.8c w 0.9b w 0.7a w 1.4

6.4c w 2.3b w 1.7a w 3.5

36.7b w 10.6b x 4.2a x 9.7b x 15.3

77.5a w 25.8a x 10.3a y 34.8a x 37.1

24.9 8.0 3.4 22.2


CV parts = 62%; Significance main = **, Sub = **, interaction = **


----------------------- P, g per 100 plants -----------------------
---------------------------Pasture--------------------------------

0.16c w 0.05c w 0.05a w 0.09

0.61c w 0.39c w 0.14a w 0.38

1.30c w 1.01c w 0.49a w 0.93

8.06b w 6.58b w 1.37a x 2.08b x 4.52

16.26a w 14.48a w 2.49a y 8.39a x 10.40

5.28 4.50 0.91 5.23

= 53%; Significance main = **, Sub = **, interaction = **

------------------------ N, g per 100 plants--------------------
---------------------------Hammock--------------------------------

0.5d w 0.1c w 0.1c w 0.2

3.9c w 0.9b w 0.8bc w 1.8

6.6c w 4.3bc w 1.6bc w 4.2

16.3b w 9.2b x 6.lab xy 3.2b y 8.7

37.0a w 27.7a x 8.6a z 15.3a y 21.4

12.9 7.8 3.4 9.2










Table 3. Continued--


25

50

75

100

125

Average


CV parts =




25

50

75

100

125

Average


CV parts




25

50

75

100

125

Average


------ ---------------- Cu, mg per 100 plants ---------------------
-------------------------- Hammock--------------------------------

0.21 0.09 0.08 0.12c

2.02 0.62 0.72 1.18bc

2.58 1.40 0.99 1.66bc

6.01 4.75 4.79 2.19 4.44b

11.95 12.95 6.66 6.90 9.61a

4.59 w 3.91 w 2.65 w 4.54 w


86%; Significance main =**, Sub = +, interaction = NS.

---------------- Cu, mg per 100 plants ---- --------
------------------------- Pasture------ -----------------

0.76c w 0.13b w 1.02a w 0.63

2.38c w 0.75b w 0.65a w 1.26

5.59c w 2.18b w 1.96a w 3.24

38.60b w 11.41ab x 5.87a x 5.34b x 15.30

67.08a w 21.70a x 10.81a y 23.10a x 30.67

22 88 7.23 4.06 14.22


68%; Significance main =**, Sub =**, interaction = **

----------------------- Fe, mg per 100 plants ----------------------
-------------------------- Hammock-------------------- ----

4.4c w 0.3b w 0.6b w 1.8

14.1c w 4.7b w 8.3b w 9.0

31.6bc w 8.2b w 15.8b w 18.5

69.7b w 29.8b wx 57.7a w 14.4b x 42.9

219.8a w 102.2a x 64.0a x 71.0a x 114.2

67.9 29.0 29.3 42.7


CV parts = 68%; Significance main =NS, Sub = **, interaction = **


.- -









Table 3. Continued---

----------------------- Fe, mg per 100 plants ----------------------
---------------------------Pasture--------------------------------

25 7.3b w 0.6a w 27.7a w 11.8

50 19.9b w 7.0a w 12.la w 13.0

75 46.1b w 14.5a w 29.3a w 30.0

100 201.0b w 81.2a w 79.4a w 29.9a w 97.9

125 937.3a w 174.3a x 271.la x 77.5a x 365.0

Average 242.3 55.5 83.9 53.7

CV parts = 175%; Significance main =**, Sub = *, interaction = **

----------------------- Mn, mg per 100 plants ----------------------
---------------------------Hammock--------------------------------

25 3.1b w 1.5c w 1.4b w 2.0

50 13.0b w 8.6c w 7.0b w 9.5

75 28.0b w 28.8c w 21.5ab w 26.1

100 86.0ab wx 135.5b w 46.3ab w 14.8a x 70.6

125 152.0a x 498.0a w 115.0a x 65.9a x 207.7

Average 56.4 134.5 38.2 40.3

CV parts = 87%; Significance main = **, Sub = **, interaction = **

----------------------- Mn, mg per 100 plants ----------------------
---------------------------Pasture--------------------------------

25 3.9c w 1.0c w 3.6b w 2.8

50 7.0c w 4.0c w 2.4b w 4.4

75 17.3c w 11.3c w 10.8ab w 13.1

100 90.5b w 62.3b wx 33.2ab x 18.9a y 51.1

125 151.3a w 115.8a x 39.5a y 45.9a y 88.1

Average 54.0 38.9 17.9 32.4

CV parts = 58%; Significance main = **, Sub = **, interaction = **









Table 3. Continued----

----------------------- Zn, mg per 100 plants-------------------
---------------------------Hammock-----------------

25 0.9b w 0.9c w 0.7c w 0.8

50 7.2b w 12.6c w 5.3c w 8.4

75 10.lb w 28.8c w 14.4bc w 17.7

100 27.8ab xy 103.0b w 42.0ab x 9.8b y 45.6

125 51.0a y 272.0a w 68.0a xy 93.5a x 121.1

Average 19.4 83.4 26.1 51.6

CV parts = 49%; Significance main = **, Sub = **, interaction = **

----------------------- Zn, mg per 100 plants-------------------

---------------------------Pasture...----------------------

25 1.8b w 2.0c w 1.9a w 1.9

50 6.9b w 14.2c w 6.0a w 9.0

75 14.4b w 34.8c w 19.1a w 22.7

100 85.3a x 271.3b w 36.0a xy 17.5a y 102.5

125 135.8a x 462.8a w 53.5a y 58.0a y 177.5

Average 48.8 157.0 23.3 37.8

CV parts = 52%; Significance main = **, Sub = **, interaction = **

Values among plant age treatments within a nutrient not followed by the same
letter (a,b,c,d) are significantly different at the 0.05 level of probability
according to Duncan's new multiple range test.

Values among plant parts within a plant age treatment not followed by the same
letter (w,x,y,z) are significantly different at the 0.05 level of probability
according to Duncan's new multiple range test.

CV = Coefficient of variation; NS = F test non significant at 0.05 level of
probability (p); + = F test significant at the 0.10 level of p; = F test
significant at the 0.05 level of p; ** = F test significant at the 0.01 level of
p.










Table 4. Soil characteristics of hammock and pasture soils where tropical soda apple plants were collected.

Location Rep pH BpH CEC OM N Ca Mg K P Cu Fe Mn Zn Na

meq/
100g ------- ---- --------------------------- mg/kg -------------------

Hammock 1 7.6 7.91 29.2 4.4 0.20 5280 196 77 52 0.16 2.4 83.4 16.4 50.4

2 5.0 7.39 8.50 4.4 0.16 560 72 68 5 0.12 6.0 9.6 4.8 10.4

3 4.7 7.38 7.96 5.1 0.28 444 64 75 6 0.08 8.4 10.1 4.4 12.4

4 4.8 7.35 9.54 4.2 0.18 632 122 80 7 0.12 19.6 3.7 3.9 10.8

Pasture 1 8.2 7.94 27.3 1.3 0.08 5240 56 42 160 0.16 7.6 4.3 5.0 18.4

2 5.3 7.48 9.52 3.4 0.18 808 132 62 9 0.20 4.0 2.3 2.1 13.2

3 4.9 7.49 9.69 5.6 0.17 784 176 68 12 0.28 19.6 3.7 1.6 10.8

4 5.0 7.49 7.52 4.0 0.15 560 60 42 5 0.28 6.4 2.0 3.1 8.2


Rep = replications; pH and OM are the averages of three researchers.




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