6-0-
FER 2 19f
Agronomy Research Report AY-89-08
Leaf and Stem Nutrient Status
Affected by Age and Ornamental Species
by
S. H. Angell, R. N. Gallaher, and T. H. Yeager
Crop Nutrition Class Student, Professor of Agronomy,
and Associate Professor of Ornamental Horticulture
Agronomy Department, Inst. of Food and Agri. Sciences,
University of Florida, Gainesville, Florida, 32611.
31 March 1989
Abstract
Relationships between soil and plant nutrient concentrations
are useful in determining the nutritional status of plants. The
objective of this study was to examine concentrations of
perennial woody ornamental leaf and stem tissue as affected by
age. Pittosporum tobira (Thunb.), Rhododendron Mrs. G. G.
Gerbing L., Podocarpus macrophyllus (Thinb.), Illicium
parviflorum Michx, and Buxus microphylla (Siebold & Zucc.) were
grown at the University of Florida on Typic Hyperthermic
Quartzisamments. With the exceptions of Ca and P, the nutrient
concentrations in the plant tissues were below normal levels as
reported in the literature. Plant nutrient levels increased and
decreased with age as predicted by the literature. With few
exceptions, plant nutrient ratios also appeared low. These
plants received sporadic fertilization and it is recommended that
more attention be given to the nutritional status of woody
ornamentals on the University of Florida campus.
Index words
Flush, Azalea, Boxwood, Anise, Pittosporum, Podocarpus, tissue,
concentration.
Introduction
Perennial woody ornamentals are used by institutions,
corporations, and individuals for asthetics as well as for
functional purposes such as buffers from temperature extremes.
Nutrient concentrations in plant tissues can influence the vigor
of woody perennials and the concentrations may change with time
(1, 2, 6, 7, 9, 10, 11, 12, 13, 14). Growth flushes are
associated with the increased concentrations of tissue N and K
over time (9), so it is important to maintain the proper
nutritional status of ornamentals to assure a vigorous plant (7,
9, 11).
The nutrient status of the uppermost mature leaves have
been used as a guideline for determining the optimal nutrient
concentrations for the plant (13). This is helpful to the
growers of woody ornamentals for establishing proper
fertilization practices. Examination of the interaction of the
nutritional status of leaves and stems over time will provide
insight as to how nutrient concentrations change with time.
Materials and Methods
Perennial woody ornamentals surrounding the ornamental
horticulture greenhouses at the University of Florida were
selected for sampling. The names of the perennial woody
ornamentals used in this study are as follows: Pittosporum
tobira, Variegatum Pittosporum; Rhododendron Mrs. G. G. Gerbing,
Azalea; Podocarpus macrophyllus, Podocarpus; Illicium
parviflorum, Anise; Buxus microphylla, Boxwood. From hereon,
these ornamentals will be reffered to by their common names.
Samples were collected on September 19, 1988 from healthy
plants exihbiting no visible signs of nutrient or water stress.
Three replications were taken of each species, each replication
being taken from individual plants. The stems and leaves were
removed with scissors. The stem and leaf material was removed
from two flushes, or episodic periods of growth. In this study,
flush 1 represents the newer growth, while flush 2 represents the
older material. Time elapsed between flushes is four to five
weeks (12).
Samples were separated according to species (Variegatum
Pittosporum, Azalea, Podocarpus, Anise, or Boxwood), tissue (stem
or leaf), and flush (one or two). The 60 samples were then
distilled water washed 1 hour after collection and dried in a
forced-air oven at 70 C for 24 hours. Following drying, the
plant tissue was ground through a 2mm stainless steel screen
using a Wiley mill. Ground plant samples were stored in air-
tight plastic bags at room temperature until they were analyzed.
After weighing 100 mg of plant tissue for N analysis, 3.2 g
of catalyst (a 9:1 ratio of K2S04:CuSO4), 10 ml. of H2SO4, and 2
ml H202 were added in a test tube and digested for 6 hrs. on an
aluminum digestion block (3).' The following day the samples were
analyzed by a Technicon II Autoanalyser to determine N
concentrations. For analysis of other nutrients a dry ashing
procedure was used. A recorded amount of plant material was
weighed to 1.00 g and ashed at 470 C in a muffle furnace for 4
hrs. HC1 was added to precipitate Si and then the flask was
brought to volume and cooked until dry. The flask was brought up
to 100 ml. volume with 0.1 N HC1 and analyzed with a Perkin-Elmer
atomic absorbtion spectrophotometer model 630. Phosphorus was
determined colormetrically with a rapid flow analyzer, K by
atomic emission, while Ca, Mg, Cu, Fe, Mn, and Zn were determined
by atomic absorbtion (3).
Soil samples were taken at random in the top 15 cm. from the
base of each shrub for each replication. Samples were sieved to
pass a 2 mm. stainless steel screen. Nitrogen was determined
from a 2.00 g sample and analyzed as outlined for plant tissue.
Phosphorus, K, Ca, Mg, Cu, Fe, Mn, and Zn were extracted using
the double acid procedure (8) and concentrations determined as
outlined for plant tissue. Soil pH was determined for each
sample by using a Corning glass electrode potentiometer (10).
Soil organic matter was determined using the Walkley-Black
Potassium bicarbonate procedure.
Results and Discussion
Nitrogen, K, Mg, Fe, Mn, and Zn leaf and stem concentrations
in all 5 species for both flushes were generally low as compared
with the literature (Tables 1-9). Phosphorus concentrations
were within the sufficiency ranges as perscribed by Yeager (12),
while plant Ca and Cu levels were high. These plants were only
sporadically fertilized, but soil tests revealed that these soils
had high levels of Cu, very high levels of P, and extremely high
levels of Ca (Table 10). This may explain why tissue Ca, P, and
Cu were generally within or above the recommended sufficiency
ranges.
Nitrogen, P, K, Fe, Mn, and Zn tissue concentrations were
lower than reported by Wright et al.(13), and the nutrient
responses was similar for each flush (Fig. 1-3). Increasing
levels of Ca within a given tissue sample resulted in
corresponding decreases in the levels of K concentrations (Fig.
2). This indicates an interaction between these nutrients.
Absolute concentrations of nutrients are not the only
criteria upon which to base the vigor of a plant. Plant tissue
nutrient ratios are also important in assesing the condition of
an ornamental plant'(Yeager, personal communications). Average
ratios were low except those involving Ca (data not presented),
presumably because of the excessive Ca in the soil. These data
suggest that the ornamentals sampled have an imbalance in the
nutrients absorbed. Apparently this imbalance was not severe
enough to cause readily observable physiological stress, but this
information does have management implications.
Nutrient concentrations may vary with time and type of
tissue sampled (Tables 1-9). It was found that increases and
decreases of nutrients over time agreed with the literature (1,
7, 9, 11, 13, 14, 15) and with expected norms given which
nutrients are mobile and which are not. The exception to this
was Cu, which appeared to increase with time in every instance
except that it appeared to decrease in Pittosporum and Boxwood
stems. Further, all leaves contained a higher concentration of
N, P, Ca, Mg, Fe, and Mn than the stems, with some differences
being significant and highly significant.
Results indicate that while these ornamentals appeared
visibly healthy, there existed within the plants some nutrient
deficiencies and imbalances. Overall plant growth may have been
restricted by nutrient deficiencies and imbalances, although this
was not evident. It is important to realize that considerable
nutrient imbalances may be occurring within the plant despite the
lack of visual tell-tale signs such as necrosis.
Based on the results of this study, it is recommended that
appropriate fertilizer analysis and rates be applied on a timely
basis to enhance the vigor of woody ornamentals around the
greenhouse on the University of Florida campus. This management
should be administered so as to achieve sufficiency nutrient
levels in leaf tissue. Periodic tissue and soil testing should
be used to monitor fertility. Carrying out this recommendation
should enhance the beauty of the ornamentals.
Summary
Nutrient levels in plants studied were low with the
exception of Ca and Cu (figs. 1-3). The high levels of these
nutrients are explained by the correspondingly high levels of
soil Ca and Cu (Table 10). The high levels of Ca in the plant
tissue suppressed the K levels in the same tissue (Fig. 2).
Potassium levels increased with time, thus Ca and Mg
concentrations decreased over time (fig. 2). Nutrient
concentrations in the leaves exceeded nutrient concentrations in
the stems for N, P, Ca, Mg, Fe, and Mn (Tables 1, 3, 4, 5, 7, and
8). It is recommended that tissue samples be taken from youngest
mature stems or leaves.
Fig. 1.
Issue of
24-4
N i t rogen and Phosphorus concentrations in leaf flush
'woody ornamrentrals on the Univers ity of+ Florida c campus
vs public shed values from healthy plants.
Publ ished
Flush Two
Experimental
/ Flush Two
Pub I shed
Flush One
/ Experimental
Flush One
Nitrogen Phosphorus
Macronutrient
Fig. 2. Calciu, rM, Magnesium ur, ,and Potassium c oncent rat tions in leaf flush
tissue o'f woody ornamental s on the Un i vers i ty of F Iorida campus
vs pub I shed values from, healthy plants.
15.0--
13.1 ]
G Published
11.3-- Flush Two
01
1 9.40--
s Experimental
K Flush Two
K -- ,. LJ
o 5.6 Published
SFlush One
a 3.80--
SEx
S.-..- n Flush One
Ca I u Magnesium Potassium
Macronutrient
F i g. 3. Z incr, ananese, Ir-on, and Copper c onc en t rc t i ons in lea f f ush
ti issue of woody ornamental I on the Un i v.ers i ty. o f F Iorida campus
vs pub I i shed values from healthy plants.
200--
/
175--
Pub Ii shed
I 150-- ; F Flush Two
r 125--
1a 5 Exper imenta I
,, FIush Two
S100-- C
075-- Published
F I ush One
o 050 -
S/ Experimental
f 0-- l5 Flush One
a /
Zinc Manganese Iron Copper
Micronutrient
Table 1: Nitrogen concentration in leaf and stem tissue of five
ornamental species on the University of Florida campus.
Flush
species /
tissue
PODOCARPUS I
Leaf
Stem
Average
PITTOSPORUM
Leaf
Stem
Average
ANISE
Leaf
Stem
Average
BOXWOOD
Leaf
Stem
Average
AZALEA
Leaf
Stem
Average
One Two Average
---------------------/kg-----------------------
- - - - - g- /k g - - - - - -_
14.4 a
11.0 a
12.7
18.5
11.5
15.0
17.6
9.1
13.4
23.7
19.7
21.7
12.7
7.5
10.1
14.9 a ns
9.2' b ns
14.7
10.1
12.1
10.1
8.4
14.3 a
10.0 b
9.3 :t:
17.8
8.8
17.7 c
8.9 d
13.3 ns
17.9
15.3
20.8 a
17.5 b
16.6 *
11.2
4.8
12.0 c
6.2 d
8.0 *::
Flush one and two are summer and spring growth of leaf and stem,
respectively, in 1988. Values in columns between leaf and stem
not followed by the same letter are significantly different at
the 0.05 level of probability for a vs. b and at the 0.01 level
for c vs. d. Values in rows between flush one and two are
significantly different at the 0.05 level of probability
with an or at the 0.01 level of probability with a **.
NS = no significant differences .' I = interaction between
tissues and flushes.
Table 2: Potassium concentration in leaf and stem tissue of five
ornamental species on the University of Florida campus.
Flush
species /
tissue
PODOCARPUS
Leaf
Stem
Average
PITTOSPORUM I
Leaf
Stem
Average
ANISE
Leaf
Stem
Average
BOXWOOD
Leaf
Stem
Average
AZALEA
Leaf
Stem
Average
One Two Average
---------------------/kg------------------------
-------------- g/Kg --- -------------
11.0
10.0
10.5
16.1 a
8.1 b
8.5
8.2
11.3
9.8
10.6
5.7
8.2
3.4
4.7
4.1
7.2-
8.8
14.7 a
10.1 a
8.0 ns
14.0 a ns
11 .1 a :*::*
15.1
6.0
12.6
5.1
7.5
6.7 a
9.4 a
6.3 **$
8.2
3.9
6.1 ns
2.3
2.9
2.6 *::
9.4 a
4.8 b
2.9 a
3.8 b
Flush one and two are summer and spring growth of leaf and stem,
respectively, in 1988. Values in columns between leaf and stem
not followed by the same letter are significantly different at
the 0.05 level of probability for a vs. b and at the 0.01 level
for c vs. d. Values in rows between flush one and two are
significantly different at the 0.05 level of probability
with an :: or at the 0.01 level of probability with a **.
NS = no significant differences I = interaction between
tissues and flushes.
TABLE 3: Phosphorus concentration in leaf and stem tissue of five
ornamental species on the University of Florida campus.
Fl-ush
species /
tissue
PODOCARPUS
Leaf
Stem
Average
PITTOSPORUM
Leaf
Stem
Average
ANISE
Leaf
Stem
Average
BOXWOOD
Leaf
Stem
Average
AZALEA I
Leaf
Stem
Average
One Two Average
---------------------g/kg -------------------
2.8
2.3
3.2 a
2.3 a
3.
2.2
2.9 ns
3.2
1.5
2.4
2.3
2.3
2.3
1.6
1.6
1.6
1.1 a
1.4 a
1.3
5.3
2.9
4.3 a
2.2 b
4 1 :*::
2.3
2.3
2.3 a
2.3 a
2.3 ns
1.2
0.9
1.4 a
1.3 a
1.1 ns
1.5 a ns
0.6 b ns
1 .1
1.3
1.6
Flush one and two are summer and spring growth of leaf and stem,
respectively, in 1988. Values in columns between leaf and stem
not followed by the same letter are significantly different at
the 0.05 level of probability for a vs. b and at the 0.01 level
for c vs. d. Values in rows between flush one and two are
significantly different at the 0.05 level of probability
with an or at the 0.01 level of probability with a **.
NS = no significant differences I = interaction between
tissues and flushes.
TABLE 4: Calcium concentration in leaf and stem tissue of five
ornamental species on the University of Florida campus.
--------------------------------------------
Flush
species /
tissue One Two Average
---------------- /k---------------------
PODOCARPUS
Leaf 9.7 16.3 13.0 a
Stem 7.4 11.8 9.6 a
Average 8.6 14.1 :
PITTOSPORUM
Leaf 7.7 18.8 13.3 a
Stem 5.7 16.6 11.2 a
Average 6.7 17.7 **
ANISE I
Leaf 2.0 a 3.3 a ns 2.7
Stem 2.4 a 2.2 b ns 2.3
Average 2.2 2.7
BOXWOOD
Leaf 9.9 15.8 12.9 c
Stem 6.6 5.0 5.8 d
Average 8.3 10.4 ns
AZALEA I
Leaf 16.4 a 17.7 a ns 17.1
Stem 8.3 a 2.1 b ns 5.2
Average 12.4 9.9
Flush one and two are summer and spring growth of leaf and stem,
respectively, in 1988. Values in columns between leaf and stem
not followed by the same letter are significantly different at
the 0.05 level of probability for a vs. b and at the 0.01 level
for c vs. d. Values in rows between flush one and two are
significantly different at the 0.05 level of probability
with an or at the 0.01 level of probability with a **.
NS = no significant differences I = interaction between
tissues and flushes.
TABLE 5: Magnesium concentration in leaf and stem tissue of five
ornamental species on the University of Florida campus.
Flush
species /
tissue
PODOCARPUS
Leaf
Stem
Average
PITTOSPORUM I
Leaf
Stem
Average
ANISE
Leaf
Stem
Average
BOXWOOD
Leaf
Stem
Average
AZALEA I
Leaf
Stem
Average
One Two Average
--------------- /k-------------------------------
- - - - - a / i. - - - - --_.
2.6
1.0
1.8
2.0 a
1.4 a
1.7
1.6
1.6
1.6
1.6 a
1.5 a
1.6
3.4 a
2.3 a
2.9
2.5
0.9
2.6 a
1.0 a
1.7 ns
4.3 a ns
1.8 b ns
3.2
1.7
3.1
1.7
1.9
1.7 a
1 .8 a
1.8 ns
2.5 a ns
1.0 b ns
1.8
4.7 a ns
1.5 b ns
2.1
1.3
4.1
1.9
3.1
Flush one and two are summer and spring growth of leaf and stem,
respectively, in 1988. Values in columns between leaf and stem
not followed by the same letter are significantly different at
the 0.05 level of probability for a vs. b and at the 0.01 level
for c vs. d. Values in rows between flush one and two are
significantly different at the 0.05 level of probability
with an : or at the 0.01 level of probability with a *.
NS = no significant differences I = interaction between
tissues and flushes.
TABLE 6: Copper concentration in leaf and stem tissue of five
ornamental species on the University of Florida campus.
Flush
species /
tissue
PODOCARPUS
Leaf
Stem
Average
PITTOSPORUM I
Leaf
Stem
One Two Average
--------------------mg/kg--------------------
7.0
8.3
7.7
11.3 a
7.7 a
6.3
8.0
7.2 ns
6.7 b ns
12.3 a ns
6.7 b
8.2 a
9.0
10.0
9.5
ANISE
Leaf
Stem
9.7
13.0
11 .4
Average
BOXWOOD
Leaf
Stem
Average
AZALEA I
Leaf
Stem
Average
10.3
11.3
10.8
11.7 a
16.7 b
14.2
7.7
8.7
8.2 :*
6.7
13.0
9.9 ns
6.3 b ns
9.0 a ns
7.7
Flush one and two are summer and spring growth of leaf and stem,
respectively, in 1988. Values in columns between leaf and stem
not followed by the same letter are significantly different at
the 0.05 level of probability for a vs. b and at the 0.01 level
for c vs. d. Values in rows between flush one and two are
significantly different at the 0.05 level of probability
with an or at the 0.01 level of probability with a **.
NS = no significant differences I = interaction between
tissues and flushes.
Average
8.7 ns
10.9 ns
8.5 a
12.2 a
9.0
12.9
TABLE 7: Iron concentration in leaf and stem tissue of five
ornamental species on the University of Florida campus.
Fl ush
species /
tissue
PODOCARPUS
Leaf
Stem
Average
PITTOSPORUM
Leaf
Stem
Average
ANISE
Leaf
Stem
Average
BOXWOOD
Leaf
Stem
Average
AZALEA
Leaf
Stem
Average
One Two Average
----------------------mg/kg------------------------
----------------- mg/kg ~~-----------------
j
40.3
43.3
41 .8
55.5
35.3
45.5
42.3
45.3
43.8
53.3
49.7
51.5
87.3
66.3
76.8
56.7
35.7
48.5 a
39.5 a
46.2 ns
73.3
62.0
67.7 ns
63.7
40.7
52.2 ns
84.7
68.7
76.7 ns
126.7
65.7
96.2 ns
64.5 a
48.7 a
53.0 a
43.0 a
69.0 a
59.2 a
107.0 a
66.0 b
~ -7 - ---- - - - - --- -
Flush one and two are summer and spring growth of leaf and stem,
respectively, in 1988. Values in columns between leaf and stem
not followed by the same letter are significantly different at
the 0.05 level of probability for a vs. b and at the 0.01 level
for c vs. d. Values in rows between flush one and two are
significantly different at the 0.05 level of probability
with an or at the 0.01 level of probability with a **.'
NS = no significant differences I = interaction between
tissues and flushes.
TABLE 8: Manganese concentration in leaf and stem tissue of five
ornamental species on the University of Florida campus.
Flush
species /
tissue
PODOCARPUS
Leaf
Stem
Average
PITTOSPORUM I
Leaf
Stem
Average
ANISE
Leaf
Stem
Average
BOXWOOD
Leaf
Stem
Average
AZALEA
Leaf
Stem
Average
One Two Average
----- ------------mg/kg------------------------
23.0
7.7
15.4
57.0 a
18.0 b
37.5
47.3
35.3
41 .3
5.0
5.0
5.0
115.0
118.0
116.5
23.0
8. C
23.0 a
7.9 b
15.5 ns
130.0 a ns
34.3 b ns
93.5
26.2
82.2
68.7
31.3
50.0 *
7.3
5.0
6.2 ns
136.6
112.0
58.0 a
33.8 b
6.2 a
5.0 a
125.8 a
115.0 a
124.3 ns
- -7 - - - - - - --- -
Flush one and two are summer and spring growth of leaf and stem,
respectively, in 1988. Values in columns between leaf and stem
not followed by the same letter are significantly different at
the 0.05 level of probability for a vs. b and at the 0.01 level
for c vs. d. Values in rows between flush one and two are
significantly different at the 0.05 level of probability
with an : or at the 0.01 level of probability with a **.
NS = no significant differences .I = interaction between.
tissues and flushes.
TABLE 9: Zinc concentration in leaf and stem tissue of five
ornamental species on the University of Florida campus.
Flush
species /
tissue
PODOCARPUS
Leaf
Stem
Average
PITTOSPORUM I
Leaf
Stem
Average
ANISE
Leaf
Stem
Average
One Two Average
20.3
22.0
21.2
85.7 a
27.3 b
56.5
18.7
23.3
21.0
16.7
19.d
18.5 a
20.5 a
17.6 ns
193.3 a ns
62.3 b ns
139.5
44.8
127.8
15.7
17.3
17.2 a
20.3 a
16.5 ns
11.7
16.7
14.2
BOXWOOD
Leaf
Stem
Average
AZALEA I
Leaf
Stem
Average
56.3 a
34.3 a
45.3
13.3
14.3
13.8 ns
67.7 a ns
31.0 b ns
49.4
Flush one and two are summer and spring growth of leaf and stem,
respectively, in 1988. Values in columns between leaf and stem
not followed by the same letter are significantly different at
the 0.05 level of probability for a vs. b and at the 0.01 level
for c vs. d. Values in rows between flush one and two are
significantly different at the 0.05 level of probability
with an or at the 0.01 level of probability with a **.
NS = no significant differences I = interaction between
tissues and flushes.
12.5 a
15.5 a
62.0
32.7
Table 10: Status of soils at the base of five ornamental
species at the University of Florida campus.
Ornamental Species
Soil Podocarpus Pittosporum Anise Boxwood Azalea
Variable
__-------------------------------------------------------------------
N g/kg 1.30 1.02 0.95 1.50 1.08
P g/kg 0.13 0.24 0.12 0.29 0.09
K g/kg 0.03 0.02 0.05 0.04 0.02
Ca g/kg 2.90 2.10 2.20 3.00 0.92
Mg g/kg 0.08 0.09 0.10 0.15 0.06
Cu mg/kg 0.24 0.99 0.32 0.47 0.64
Fe mg/kg 7.80 20.30 7.30 14.10 12.40
Mn mg/kg 7.70 13.60 9.60 16.80 7.10
Zn mg/kg 6.96 39.20 43.20 47.70 28.80
Al mg/kg 4.40 226.50 261.20 207.30 260.40
O.M. % 2.57 3.28 2.04 3.63 3.07
pH 6.5 7.0 6.9 7.1 6.1
All values are an average of three replications
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