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Copyright 2005, Board of Trustees, University
of Florida
y c3 ?UNIVERSITY OF FLORIDA
3 1262 05611 3672
Agronomy Research Report, AY021990
Growth Relationships Among Plant Parts Of High Yield:rP'anut:
II. N And P F 2 0 9
D. L. Overman and R. N. Gallaher .
Graduate Student and Professor of Agronomy, Dept. of Agronomy
Inst. Food and Agr. Sci., University of FL., Gainesville 32611
ABSTRACT
Both N and P are needed for protein synthesis as well as
numerous other known functions associated with the rate of
photosynthesis and energy transformations in the plant. The
objective of this research was to evaluate growth and development
of 'Florunner' peanut (Arachis hypogaea L.) parts on the basis of
N and P uptake. Samples from a loamy sand soil (Grossarenic
Paleudult) were collected 11 times over the 140 day growth period.
Root, stem, leaf, seed and shell parts were analyzed for N and P
concentrations and contents using standard procedures. The uptake
of both elements in the stem and leaf tissues increased rapidly to
a maximum at about 77 days after planting (DAP). After 77 days,
the N and P contents in the seed and the plant as a whole increased
rapidly, while decreasing in other plant parts, due to
translocation to the seed. The whole plant total N and P contents
increased linearly, which indicates that uptake of these elements
continued until maturity. The P concentration of the seed was 0.40
dag kg1 at,140 DAP, while the N concentration was 5.33 dag kg.
INTRODUCTION
The nutrient element concentration of a plant varies with age
and stage of development as well as among its plant parts.
Nutrient uptake and internal mobility, as well as dry matter
changes, can affect the nutrient concentration in plant tissues.
A better understanding of the nutrient requirements of a crop can
be obtained by knowledge of total nutrient absorption by plants
throughout the season.
Nitrogen is essential to growth because it is a constituent of
amino acids, amides, nucleotides, and nucleoproteins, and is
essential to cell division and expansion. It is also a structural
unit of chlorophyll. Nitrate and ammonium are the major sources of
inorganic N taken up by the roots of higher plants. Most of the
ammonium has to be incorporated into organic compounds in the
roots; ammonium and ammonia are toxic at quite low concentrations.
Nitrate is mobile in the xylem and also can be stored in the
vacuoles of roots, shoots, and storage organs. Nitrate has to be
reduced to ammonia in order to be incorporated into organic
compounds and to fulfill its essential functions as a plant
nutrient. The form used by the plant depends in part on rainfall
and soil pH; NO3 uptake is greater in acid soils than NH+4 uptake.
Due to these factors, NO3 is the predominant ion absorbed by crop
plants other than rice (Oriza sativa L.) (Gardner et al., 1985).
Depending on the plant species, development stage, and organ,
the N concentration required for optimal growth varies between 2
and 5 dag kg1 of the plant dry weight. When the supply is
suboptimal, growth is retarded; N is mobilized in mature leaves and
retranslocated to areas of new growth (Marschner, 1986). There are
several important sources of N to developing fruit including
redistribution of vegetative N, root uptake of soil N, and
symbiotically fixed N (in the case of legumes). The percentage of
seed N coming from each source is dependent on the crop, its
environment, and the cultivar grown. Sinclair and deWit (1975)
separated 24 crops into four groups based on seed biochemical
composition and N requirements. Peanut (Arachis hypogaea L.) was
assigned to a group whose members should be able to sustain seed
growth with a relatively small rate of N uptake. They speculated
that the peanut and other members of this group would not exhibit
net N redistribution within the plant unless availability of soil
or nodule fixed N were restricted.
Nitrogen probably occurs in more compounds which are involved
in peanut metabolism than any other element with the exception of
C, H, and 0. Peanut, being a legume, can use atmospheric N after
it has been symbiotically fixed by Rhizobium spp. The question of
whether or not rhizobia can fix adequate N for peanut production is
not settled (Reid and Cox, 1973).
Phosphorus is involved in photosynthesis, respiration, and
other metabolic processes. It has a key role in energy metabolism
through the adenosine diphosphateadenosine triphosphate
transformation (ATP). It is an essential constituent of the
ribonucleic and desoxyribonucleic acids, cell membranes
phospholipidss), and phosphoproteins (Gardner et al., 1985).
Phosphorus regulates many enzymic processes which involve ATP. It
also acts as an activator of some enzymes (Epstein, 1972).
Phosphorus is absorbed primarily as the monovalent phosphate
anion (H2PO4) and less rapidly as the divalent anion (HP042). The
soil pH controls the relative abundance of these two forms, H2P04
being favored below pH 7 and HP042 above pH 7. Unlike N, P never
undergoes reduction in plants and remains as phosphate, either free
or bound in organic forms as esters (Salisbury and Ross, 1985).
A study of mineral accumulation in corn (Zea mays L.) followed
the growth and development of the corn plant in relation to the
accumulation and movement of N and P in the plant. The results
demonstrated that the various minerals are absorbed from the soil,
move throughout the plant into different tissues, or are lost from
the plant independently of one another (Sayre, 1948). The rate of
nutrient uptake in the corn plant is relatively slow early in the
season, but the rate increases as the plant grows and develops.
Uptake of N and P continues to near maturity (Hanway, 1963). The
influence of different soil fertility levels on N and P uptake by
corn plants and the distribution of these nutrients in different
parts of the plants at different times during the growing season
has been studied. Phosphorus accumulation in the plants was more
rapid than dry matter accumulation early in the season, but
accumulated at a nearly linear rate, similar to dry matter, during
the remainder of the season. Accumulation of N was more rapid
early in the season but the rate of accumulation decreased later
(Hanway, 1962).
Dry matter accumulation and nutrient uptake in sorghum
(Sorghum bicolor [L.] Moench) starts slowly, but the rate increases
as growth and development occur. On a relative basis, N is taken
up more rapidly than P (Vanderlip, 1979). In another study of
sorghum growth and nutrient uptake, it was found that N and P
accumulation proceeded almost linearly until maturity (Roy and
Wright, 1974). A study of winter wheat (Triticum aestivum L.)
compared the accumulation of N and P in the leaves, stem, head, and
grain at different growth stages. At maturity, most of the N and
P was found in the grain; there was a net loss of P from the aerial
parts of the plant as the grain filled (Waldren and Flowerday,
1979).
In studies conducted by Hanway and Weber (1971) to gain more
information about mineral nutrition of soybean (Glycine max [L]
Merrill) plants, a late season decrease in N and P was observed in
all plant parts, except in the seeds, regardless of whether N and
P fertilizer had been applied. It appeared that these nutrients
were translocated to the seeds as they developed and were lost from
other plant parts even though the nutrients were readily available
in the soil. Approximately half of the N and P in the mature seeds
was translocated from other plant parts, and the remaining half
taken up from the soil and nodules during seed development.
Fertilizer applications increased the amounts of N and P
accumulated by the plants. In studies of foliar fertilization of
soybean (Boote et al., 1978), the N and P concentration of upper
leaves and total canopy leaves of control soybean declined almost
linearly during seed filling.
The peanut plant normally uses symbiotically fixed N for
growth and development, but N deficiencies may result from
limitations in the symbiants or environment. The 'Florunner'
cultivar fixed more N than a nonnodulating line tested (Selamat and
Gardner, 1986). The studies suggest that the practice of N
fertilization of wellnodulated peanut does not increase pod or
seed yield. In another experiment (Kvien et al., 1986), it has
been demonstrated that N is mobilized from thevegetative tissue
into the developing pods, throughout the pod development period.
The objective of this research was to evaluate growth and
development of 'Florunner' peanut parts on the basis of N and P
uptake.
MATERIALS AND METHODS
The experiment was conducted with 'Florunner' peanut in Levy
County, Florida in 1978 (Gallaher, 1990). The plants were washed
in water within one hour of sampling, and separated into root,
leaf, stem, seed and shell parts. The plants were dried at 70 C in
a forced air oven, weighed, and then ground in a Wiley mill using
a stainless steel screen with 2 mm diameter holes. The plant
material was stored in air tight glass jars.
For Microkjeldahl N analysis, 100 mg of the ground sample of
each dried plant part was placed in a 100ml digestion tube. In
addition, 3.2 g of a salt/catalyst (90% anhydrous K2SO4, 10%
anhydrous CuS04), 10 ml of concentrated H2S04, and 2 boiling chips
were placed in each tube. The tubes were placed in an aluminum
block digester (Gallaher et al., 1976); 2 ml of H202 were added to
each sample. The samples were digested for 2.5 hours. After
cooling, each solution was brought up to volume (75 ml) with
deionized water and transferred to storage bottles. The N
concentration of each sample was determined on a Technicon
AutoAnalyzer II.
The plant material was prepared for mineral analysis by dry
ashing procedure. A 1 g sample of each plant part was placed in a
beaker and ashed in a muffle furnace for 4 hours at 480 C. After
removal from the furnace, deionized water (5 ml) was added to each
beaker. Two ml of HC1 were added to each beaker. The beakers were
placed on a hot plate and heated until the liquid had evaporated
and were allowed to dry. In the hood, 2 ml of HC1 were added to
each beaker; also 1520 ml of deionized water were added. Each
beaker was covered with a watch glass and heated until boiling
occurred (about 30 minutes). After cooling, all samples were
transferred to 100 ml volumetric flasks. The volume in each flask
was brought up to 100 ml with deionized water and mixed well. A
portion from each flask was transferred to 20 ml vials. Prepared
solutions were analyzed for P by colorimetry in the IFAS Soil
Testing Laboratory, University of Florida, Gainesville, Florida.
Statistics were run using a TRS80 microcomputer. Standard
deviations and multiple regression analyses were conducted. Graphs
were prepared and plotted using a MC386 microcomputer and an LP
1000 Laser printer. The graph of concentration is a regression
fitted curve of concentration values. Content (yield of N and P)
was calculated by multiplying dry matter yield per square meter by
nutrient concentration. The percent of final content was
calculated by dividing the nutrient content of each plant part at
a specific sampling date by the final content of that part at
harvest. The cumulative content was calculated in the following
way: (1) root (nutrient content value for the root); (2) stem (sum
of the root and stem nutrient content values); (3) leaf (sum of the
root, stem and leaf nutrient content values); (4) shell (sum of the
root, stem, leaf, and shell nutrient content values); (5) seed (sum
of the root, stem, leaf, shell and seed nutrient content values).
RESULTS AND DISCUSSION
Nitrogen
The N concentration and content of the various peanut plant
parts at different ages are presented in Tables 1 and 2. The
concentration of N (Figure 1) in the leaf, stem, and shell
decreased while there was a linear increase in the seed N
concentration. In the root, the N concentration remained almost
constant. In Figure 2, the cumulative uptake of N by the various
plant parts at different ages is shown. The N content of the
peanut plant parts at different times during the growing season is
shown in Figure 3. Until about 7784 days after planting (DAP),
accumulation of N was in the vegetative tissues, with the leaf
accumulation about double the accumulation in the stem. At 77 DAP,
the accumulation of N in the leaf was 56% of the total N in the
plant; the seed, stem, shell, and root contained 11%, 21%, 9% and
3%, respectively. After 77 days, the reproductive tissues began to
accumulate N; at 140 DAP, the seed contained about 75% of the total
N in the plant, and the shell, 3%. The leaf, stem, and root
contained 14%, 7% and 1%, respectively. From 42 days to 77 days,
the leaf gained N at a rate of 180 mg per day; the stem gained
about 80 mg per day. The leaf lost 100 mg per day from 77 days to
126 days, while the stem lost about 30 mg per day. The total N
content (Figure 4) increased linearly throughout the 140 days. At
77 DAP, the plant had accumulated 44% of the total N. The plant as
a whole gained N at a rate of 380 mg per day from 42 to 140 days.
In Figure 5, the N content in the various peanut plant parts is
expressed as a percentage of the final content; the total content
is shown in Figure 6. This illustrates what is shown in Figures 2,
3, and 4.
The peanut is a legume and is able to obtain N through its
symbiotic association with Rhizobium spp. Whether the crop can
maintain an adequate N level during the entire season in this
manner is questionable. Crop variety, Rhizobium strain, and soil
and climatic conditions are factors related to efficiency of N
fixation and utilization (Cox et al., 1982). Jones (1974)
considers the sufficiency range of N for peanut to be 3.504.50 dag
Table 1. Nitrogen concentration in peanut plant parts affected by age.
Plant Part
Age Root Stem Leaf Seed Shell
Days dag kg1
42
50
57
62
70
77
91
107
120
135
140
2.13
2.34
2.33
2.41
2.59
2.65
2.51
2.74
2.58
2.33
2.17
(0.17)*
(0.23)
(0.19)
(0.16)
(0.51)
(0.22)
(0.35)
(0.32)
(0.41)
(0.23)
(0.25)
2.11
1.98
1.83
1.74
1.48
1.38
1.09
1.03
0.94
0.96
0.90
(0.10)
(0.17)
(0.11)
(0.03)
(0.12)
(0.08)
(0.09)
(0.06)
(0.15)
(0.09)
(0.08)
4.41
4.06
4.00
4.00
3.80
3.79
3.57
2.77
2.68
2.65
2.56
(0.19)
(0.14)
(0.21)
(0.15)
(0.17)
(0.11)
(0.13)
(0.11)
(0.22)
(0.20)
(0.17)
0.00
0.00
0.00
0.00
0.00
4.78
4.83
4.99
5.05
5.16
5.33
(0.00)
(0.00)
(0.00)
(0.00)
(0.00)
(0.08)
(0.11)
(0.11)
(0.14)
(0.08)
(0.13)
0.00
0.00
0.00
0.00
0.00
2.83
2.12
1.43
1.40
1.30
1.11
(0.00)
(0.00)
(0.00)
(0.00)
(0.00)
(0.15)
(0.23)
(0.08)
(0.27)
(0.14)
(0.14)
*Standard deviation
Each value is an average of 8 replications
Table 2. Nitrogen content in peanut plant parts affected by age.
Plant Part
Age Root Stem Leaf Seed Shell Total
Days mg sq m
42 174( 32)* 709(152) 3405( 711) 0( 0) 0( 0) 4289( 838)
50 254( 34) 1368(236) 5034( 543) 0( 0) 0( 0) 6657( 760)
57 273( 53) 2209(629) 6509(1508) 0( 0) 0( 0) 8992(2138)
62 329( 67) 2460(431) 7793(2384) 0( 0) 0( 0) 10583(2252)
70 433(128) 3591(679) 9172(2344) 0( 0) 0( 0) 13196(2906)
77 477( 62) 3777(495) 10057( 460) 1964( 300) 1704(202) 17981(1313)
91 460( 76) 3068(378) 8863( 797) 6939( 717) 1903(331) 21235(1761)
107 427(104) 2531(359) 5458( 340) 15976(1492) 1274(174) 25668(2049)
120 553(117) 2274(586) 5339(1226) 19845(2337) 1359(296) 29372(3736)
135 644(105) 2719(689) 5769(1057) 27225(4201) 1716(349) 38074(5676)
140 484( 81) 2680(513) 5710( 951) 30519(3037) 1433(216) 40828(3097)
*Standard deviation
Each value is an average of 8 replications
6.0
5.5
5.0
4.5
'N
0 4.0 
, 3.5 
o
G
S3.0
O 2.5 
2.0
z 2.0
1.5
1.0
0.5
0.0
Nitrogen concentration in peanut plant parts affected by age.
U
Root
+
Stem
Leaf
Seed
Shell
I I I I I I I i I I I I I
42 49 56 63 70 77 84 91 98 105112119126133140
Days After Planting
Figure 1 .
45
40 Seed
35 Shell
30 Leaf
TO: 25 Stem
cF 20. Root
o 15
'7"
10
5
0
42 49 56 63 70 77 84 91 98 105112119126 133140
Days After Planting
Figure 2. Cumulative nitrogen content in peanut parts affected by age.
25
o20
15
I
42 49 56 63 70 77 84 91 98 105112119126 133140
Days After Planting
Figure 3. Nitrogen content in peanut plant parts affected by age.
45
40
35
' 30
S25
S20
1 15
z
10
5
0
42 49 56 63 70 77 84 91 98 105112119126133140
Days After Planting
Total nitrogen content in peanut affected by age.
Figure 4.
180
160
140
 120
aU
C.
( 100
) 80
1
z 60
40
20
42 49 56 63 70 77 84 91 98 105112119126133140
Days After Planting
Figure 5. Nitrogen content in peanut plant parts expressed as a
percentage of final content affected by age.
100
90
80
70
S60
(U
a)
S50
S40
S30
20
10
0
42 49 56 63 70 77 84 91 98 105112119126133140
Days After Planting
Figure 6. Total nitrogen content in peanut expressed as a percentage
of final content affected by age.
kg' in leaves approximately 40 days old for the soils and
conditions he had analyzed. The N concentration in the leaf at 42
DAP was 4.41 dag kg1 (Table 1).
Nitrogen requirements of peanut plants are affected by the
amounts of other elements available. Some studies have found that
N applications reduced the response obtained from P fertilization.
Others have shown that P fertilization can cause increased uptake
of N and P. Recommendations from another study for optimum
production call for peanut to be fertilized to provide levels of N
and P in the leaves such that when N is at 2.5 dag kg', P is at
0.15 dag kg"1, for example, or when N is 4.0 dag kg1, P is 0.25 dag
kg" (Reid and Cox, 1973). Comparison with the results of this
experiment show some agreement (Tables 1 and 3).
The concentration of N has been shown to decrease linearly
during the growing season in peanut foliage and leaflets (Cox et
al., 1982). By labeling the vegetative tissue of the peanut plant
with 15N prior to pod set, it has been shown that N is continually
mobilized from the vegetative tissue to the pods. It was concluded
that a portion of the 15N moved out of the main stem as well as out
of all lateral branches. Total 15N in the vegetative portion of
'Florunner' continually declined after initial fruit set. The
decline was matched by a continuous increase in 15N in the
developing fruit (Kvien et al., 1986). This agrees with the
results of this experiment.
For the period 77 to 140 DAP, the sum of the loss of N from
the stem, leaf, and shell, and the increase in the root N and in
the total N account for the N moving into the seed. Translocation
of N from the other plant parts to the seeds occurred as long as
the seeds were developing, and there was continual uptake of N
during the same period. This corresponds to what Sayre (1948)
found in corn.
Phosphorus
The P concentration of the various plant parts is shown in
Table 3 and Figure 7. As seen for N, the concentration values show
that P was being translocated from the vegetative tissues to the
seeds as the peanut aged. In Figure 8, the cumulative uptake of P
by the different plant parts as affected by age is presented. The
distribution of P into the plant parts at different times during
the growing season is shown in Table 4 and Figure 9. Nitrogen
accumulation in the leaf and stem was greater than P accumulation.
Until about 77 DAP, accumulation of P was greater in the vegetative
tissues. AT 77 DAP, the accumulation of P in the leaf was about
48% of the total P in the plant; the seed, stem, shell, and root
contained 13%, 27%, 9% and 2%, respectively. After 77 days, the
seed began to accumulate P; at 140 DAP, the seed contained about
80% of the total P in the plant, and the shell, 2%. The leaf,
stem, and root contained 11%, 6%, and 1%, respectively. Phosphorus
Table 3. Phosphorus concentration in peanut plant parts affected by age.
Plant Part
Age Root Stem Leaf Seed Shell
Days dag kg
42 0.20 (0.02)* 0.22 (0.02) 0.29 (0.02) 0.00 (0.00) 0.00 (0.00)
50 0.21 (0.02) 0.21 (0.03) 0.28 (0.02) 0.00 (0.00) 0.00 (0.00)
57 0.21 (0.02) 0.20 (0.02) 0.28 (0.02) 0.00 (0.00) 0.00 (0.00)
62 0.20 (0.02) 0.19 (0.02) 0.26 (0.01) 0.00 (0.00) 0.00 (0.00)
70 0.19 (0.03) 0.15 (0.02) 0.24 (0.01) 0.00(0.00) 0.00 (0.00)
77 0.19 (0.02) 0.13 (0.02) 0.25 (0.01) 0.43 (0.03) 0.21 (0.01)
91 0.18 (0.03) 0.10 (0.01) 0.21 (0.01) 0.36 (0.02) 0.16 (0.02)
107 0.18 (0.04) 0.07 (0.01) 0.14 (0.01) 0.37 (0.03) 0.10 (0.02)
120 0.18 (0.04) 0.07 (0.02) 0.15 (0.02) 0.38 (0.02) 0.08 (0.02)
135 0.16 (0.04) 0.06 (0.02) 0.14 (0.01) 0.39 (0.03) 0.07 (0.02)
140 0.15 (0.02) 0.06 (0.03) 0.14 (0.02) 0.40 (0.02) 0.05 (0.01)
* Standard deviation
Each value is an average of 8 replications
0.40
U
0.35 Root
0.30 Stem
Leaf
6 0.25 e
SShell
0.20
o Seed
0.15
0.10
0.05
0 .0 0 I i I i ,
42 49 56 63 70 77 84 91 98 105112119126133140
Days After Planting
Figure 7. Phosphorus concentration in peanut plant parts affected
by age.
3000
Seed
2500 
Shell
(D R
E 2000 Leaf
C,
Stem
E 1500 
Root
Ca
L.
1000
.C
0
13_
500
0
42 49 56 63 70 77 84 91 98 105112119126133140
Days After Planting
Figure 8. Cumulative phosphorus content in peanut plant parts
affected by age.
Table 4. Phosphorus content in peanut plant parts affected by age.
Plant Part
Age Root Stem Leaf Seed Shell Total
1
Daysmg sq m
42 16.1 ( 2.0)* 74 (10) 225 ( 41) 0 ( 0) 0 ( 0) 315 ( 49)
50 22.5 ( 4.2) 144 (38) 349 ( 43) 0 ( 0) 0 ( 0) 516 ( 81)
57 24.7 ( 4.8) 241 (70) 449 ( 88) 0 ( 0) 0 ( 0) 714 (159)
62 27.4 ( 5.0) 268 (62) 501 (136) 0 ( 0) 0 ( 0) 797 (123)
70 31.5 ( 5.4) 352 (73) 585 (153) 0 ( 0) 0 ( 0) 968 (208)
77 33.3 ( 4.2) 362 (65) 652 ( 25) 176 ( 26) 126 (14) 1349 ( 63)
91 32.2 ( 5.7) 281 (43) 513 ( 48) 511 ( 65) 146 (22) 1483 (128)
107 27.5 ( 7.2) 174 (44) 279 ( 37) 1183 (117) 85 (22) 1749 (190)
120 37.8 (10.2) 170 (65) 300 ( 94) 1506 (175) 77 (25) 2090 (310)
135 42.9 (12.7) 173 (66) 308 ( 65) 2048 (356) 97 (34) 2669 (460)
140 32.8 ( 5.7) 172 (98) 310 ( 62) 2268 (245) 61 (15) 2845 (286)
* Standard deviation
Each value is an average of 8 replications
2500
Root
+
2000 Stem
4
E Leaf
0
S1500 e
Shell
1000
C
C
 500
42 49 56 63 70 77 84 91 98 105112119126133140
Days After Planting
Figure 9. Phosphorus content in peanut plant parts affected by age.
content in the leaf was greater than in the stem; the same was true
for N. Nitrogen content in the leaf was greater than P content in
the leaf. From 42 to 77 DAP, the leaf gained P at a rate of 11 mg
day', while the stem gained 8 mg day'. The leaf lost 7 mg day'
from 77 to 126 DAP, while the stem lost about 3 mg day1. The total
P content (Figure 10) increased linearly throughout the 140 days.
The plant as a whole gained 26 mg day1' from 42 to 140 DAP. At 77
days, the plant as a whole had taken up 47% of the total P
accumulated. In Figure 11, the P content in the peanut plant parts
at different ages is expressed as a percentage of the final
content; the total P content is shown in Figure 12. This
illustrates what is shown in Figure 8, 9, and 10.
The uptake of P by the roots and movement in the plant parts
correlates with the functions of P in plant metabolism. In spite
of the great number of metabolic functions which require P, the
total amount taken up by the peanut plant is small. Jones (1974)
considers the sufficiency range of P for peanut to be 0.25 0.50
dag kg"1 in leaves approximately 40 days old. Phosphorus
concentration in the leaf at 42 DAP was 0.29 dag kg1 (Table 3).
In the report by Reid and Cox (1973), a study was quoted which
showed that the percent of P decreased in peanut plants as the
plant aged. Another study showed that P moved rapidly from the
foliar portions of the plant to the developing fruit late in the
season. This agrees with the results of this experiment. The
pattern of N and P accumulation in corn, sorghum, wheat and soybean
was similar to this experiment (Hanway, 1962, 1963; Hanway and
Weber, 1971; Roy and Wright, 1974; Waldren and Flowerday, 1979).
Reports of the approximate P concentration in the stems, shells,
and seeds of peanut at harvest are 0.07, 0.03, and 0.36 dag kg1,
respectively (Nelson, 1980) which are very similar to these data
(Table 3).
For the period 77 to 140 DAP, the sum of the loss of P from
the root, stem, leaf, and shell, and the increase in the total P
account for the P moving into the seed. As noted for N,
translocation of P from the other plant parts to the seeds occurred
as long as the seeds were developing, and there was continual
uptake of P during the same period. This corresponds to what Sayre
(1948) found in corn.
The rapid uptake of N and P during the time dry matter was
accumulating in the leaves and stems would be expected, due to
photosynthesis and other metabolic processes. As the seed and
shell began to develop, the N and P content increased in the seed
and shell to meet the energy demands. The N and P content in the
leaf and stem decreased. The total N and total P content increased
linearly throughout the sampling period indicating there was
continual uptake of N and P. The N and P accumulation exhibited
the same pattern as shown by dry matter accumulation and energy
content.
In Figures 13 and 14, the N to P content ratio in peanut plant
3000
2500
L
(D
E 2000
S1500
E 1500
1000
500
0
42 49 56 63 70 77 84 91 98 105112119126133140
Days After Planting
Figure 10. Total phosphorus content in peanut affected by age.
250
200
C
a)
a
Q_
cn
L
O
' 100
_C
0
a
50
0
Figure 1 1.
Phosphorus content in peanut plant parts expressed as a
percentage of final content affected by age.
I I I t I i I I i i I i I
42 49 56 63 70 77 84 91 98 105112119126133140
Days After Planting
U
Root
_
Stem
Leaf
8
Shell
Seed
110
100
90
80
70
60
50
40
30
20
10
0
I I I I I I I I I I I t I I I
42 49 56 63 70 77 84 91 98 105112119126 133140
Days After Planting
2. Total phosphorus content in peanut expressed as a
percentage of final content affected by age.
Figure 1
24
U
22 Root
+
20 Stem
8 Leaf
18
6 Shell
16
z14
12
10
42 49 56 63 70 77 84 91 98 105112119126133140
Days After Planting
Figure 13. Nitrogen to phosphorus content ratio in peanut plant parts
affected by age.
I I I I I i i i
42 49 56 63 70 77 84 91
Days After
98 105
Planting
112 119 126 1 I
112119 126 133 140
Figure 14. Total nitrogen to total phosphorus content ratio in peanut
affected by age.
20
16
^mm
12
8
parts and the whole plant is shown. The ratio of N to P in the
seed remained almost constant from 77 to 140 DAP; at 77 DAP, the
ratio was 11, and at 140 DAP, the ratio was 13. The ratio of N to
P in the stem increased from 11 to 18 after 77 DAP; in the leaf the
ratio of N to P varied from 15 to 19, with the highest ratio at
about 140 DAP. The ratio in the root increased from 10 at 42 DAP
to 15 at 91 DAP and remained almost constant until 140 DAP. The
total N to P ratio was almost constant; at 42 DAP, it was 13 and at
140 DAP, 14.5. This indicates that a steady uptake of N and P is
required.
In many plant species, there is close interaction between P
and N concerning maturity, excess N delaying and abundant P
speeding maturity. If excess P is provided, root growth is often
increased relative to shoot growth. In contrast to effects with
excess N, this causes low shoottoroot ratios (Salisbury and Ross,
1985). Nitrogen requirements of peanut plants are affected by the
amounts of other elements available (Reid and Cox, 1973). It has
been found that N applications reduced the response obtained from
P fertilization. In another study, a positive response was found
to N when P was applied but a reduction in yield when N was applied
without P.
In Figure 15, the percent of total uptake at different times
is shown for N, P, dry matter, and energy. At 42 DAP, the percent
of total uptake of N, P, dry matter, and energy is 11, 11, 10, and
7% respectively. In comparison, at 77 DAP, the percent of total
uptake of N, P, dry matter, and energy is 44, 47, 53, and 40%,
respectively. For each unit of dry matter, a constant ratio of N
and P is required.
SUMMARY
The peanut plant first accumulated N and P in vegetative
tissues when a high rate of photosynthesis was occurring, and
reached a peak at about 77 DAP, after which N and P in the leaf and
stem began to decrease. Nitrogen and P were translocated from the
leaf and stem to the seed; both nutrients are essential in
metabolic processes that occur in the development of the seed. The
total N and P uptake increased linearly, which indicates that N and
P uptake continued until maturity. The N concentration of the seed
was 5.33 dag kg1 at 140 DAP, while the P concentration was 0.40 dag
kg"1. The total N uptake was 380 mg m2 per day while the P uptake
was 30 mg m2 per day. At 42 DAP, the total N accumulated and the
total P accumulated was 11%. At 77 DAP, the total N accumulation
was 44% of the total and total P accumulation was 47% of the total.
110
100
42 49 56 63 70 77 84 91 98105112119126133140
Days After Planting
Figure 15. Percent of total uptake of dry matter, energy, N,
and P affected by age.
U
Dry Matter
+
Energy
Nitrogen
Phosphorus
90
80
70
60
50
40
30
APPENDIX
APPENDIX
Table 1. Regression equations for N concentration in Figure 1.
Variable Intercept Coeff 1 Coeff 2 Coeff 3 Coeff 4 Coeff 5 r2 P
Seed NCN 4.11 A + 8.15 E03 T .73 4.01E08
Stem NCN 0.79 A + 0.10 T 2.45 E03 T2 1.97 E05 T3 5.30 E08 T4 .95 1.26E12
Leaf NCN 9.19 A 0.25 T + 4.75 E03 T2 4.02 E05 T3 + 1.20 E07 T4 .92 3.23E12
Shell NCN 10.16 A 0.13 T + 5.00 E04 T2 .91 6.14E10
Root NCN 0.86 A + 0.86 T 2.06 E04 T2 .27 2.06E05
NCN
= N concentration, Coeff. = Regression coefficient, T = Days after planting.
Table 2. Regression equations for N content in Figure 3.
Variable Intercept Coeff 1 Coeff 2 Coeff 3 Coeff 4 Coeff 5 r2 P
Seed NCT 2865.23 A 119.05 T + 1.41 T2 3.94 E03 T3 .97 2.37E13
Stem NCT 561.10 A + 8.23 T + 0.35 T2 5.54 E03 T3 + 2.11 E05 T4 .70 1.39E09
Leaf NCT 671.48 A 6.38 T + 1.33 T2 0.02 T3 + 6.32 E05 T4 .66 3.45E09
Shell NCT 1187.09 A 51.60 T + 0.49 T2 + 4.76 E03 T3 8.49 E05 4 + 3.01 E07 5 .77 3.32E10
Root NCT 17.06 A 2.66 T + 0.17 T2 3.04 E03 T3 + 2.19 E05 T4 5.70 E08 T5 .66 5.33E09
NCT = N content, Coeff. = Regression coefficient, T = Days after planting.
Table 3. Regression equations for N content in Figure 4.
Variable Intercept Coeff 1 Coeff 2 Coeff 3 Coeff 4 Coeff 5 r2 P
Total NCT 2433 A + 92.30 T 0.74 T2 + 2.96 E03 T3 .95 8.93E13
NCT = N content, Coeff = Regression coefficient, T = Days after planting.
APPENDIX CONTINUED
Table 4. Regression equations for N content expressed as a percentage of final content in Figure 5.
Variable Intercept Coeff 1 Coeff 2 Coeff 3 Coeff 4 Coeff 5 r2 P
Seed %NCT = 108.90 A + 1.48 T .94 1.50E10
Stem %NCT = 188.15 A + 1.90 T + 0.15 T2 2.24 E03 T3 + 8.31 E06 T4 .69 1.86E09
Leaf %NCT = 159.39 A + 0.83 T + 0.20 T2 2.88 E03 + 1.06 E05 T4 .57 2.99E08
Shell %NCT = 307.75 A 3.46 T + 0.01 T2 .11 0.08
Root %NCT = 51.11 A + 2.59 T 0.01 T2 .53 3.64E08
% NCT = Percent of final nitrogen content, Coeff = Regression coefficient, T = Days after planting.
Table 5. Regression equation for total N content expressed as a percentage of final content in Figure 6.
Variable Intercept Coeff 1 Coeff 2 Coeff 3 Coeff 4 Coeff 5 r2 P
Seed %NCT = 58.61 A + 2.22 T 0.02 T2 + 7.02 E05 T3 .93 1.89E12
%NCT = Percent of final nitrogen content, Coeff = Regression coefficient, T = Days after planting.
Table 6. Regression equations for P concentration in Figure 7.
Variable Intercept Coeff 1 Coeff 2 Coeff 3 Coeff 4 Coeff 5 r2 P8
Seed PCN = 3.19 A 0.08 T + 6.70 E04 T2 1.92 E06 T3 .44 5.38E05
Stem PCN = 0.09 A + 0.02 T 4.12 E04 T2 + 3.12 E06 T3 8.12 E09 T4 .91 5.60E12
Leaf PCN = 0.18 A + 6.45 E03 T 1.06 E04 T2 + 4.19 E07 T3 .92 3.66E12
Shell PCN = 0.77 A 9.79 E03 T + 3.37 E05 T2 .90 6.21E10
Root PCN = 0.21 A 2.54 E05 T 2.84 E06 2 .32 4.81E06
PCN = Phosphorus concentration, Coeff = Regression coefficient, T = Days after planting.
APPENDIX CONTINUED
Table 7. Regression equations for P content in Figure 9.
Variable Intercept Coeff 1 Coeff 2 Coeff 3 Coeff 4 Coeff 5 r2 P
Seed PCT = 214.65 A 8.94 T + 0.11 T2 2.99 E04 T3 .97 2.91E13
Stem PCT = 170.36 A + 6.76 T 0.07 T2 + 2.37 E04 T3 .63 5.41E09
Leaf PCT = 117.94 A + 3.55 T + 0.02 T2 6.24 E04 T3 + 2.78 E06 T4 .68 2.15E09
Shell PCT = 93.79 A 4.08 T + 0.04 T2 + 3.73 E04 T3 6.71 E06 T4 + 2.38 E08 T5 .69 2.39E09
Root PCT = 4.57 A 8.51 E03 T + 9.96 E03 T2 2.14 E04 T3 + 1.69 E06 T4 4.60 E09 T5 .48 3.80E07
PCT = Phosphorus content, Coeff = Regression coefficient, T = Days after planting.
Table 8. Regression equation for total P content in Figure 10.
Variable Intercept Coeff 1 Coeff 2 Coeff 3 Coeff 4 Coeff 5 r2 P
Total PCT = 212.00 A + 8.31 T 0.07 T2 + 2.88 E04 T3 .93 1.85E12
PCT = Phosphorus content, Coeff = Regression coefficient, T = Days after planting.
Table 9. Regression equations for percent of final P content in Figure 11.
Variable Intercept Coeff 1 Coeff 2 Coeff 3 Coeff 4 Coeff 5 r2 P
Seed %PCT = 108 A + 1.48 T .94 1.30E10
Stem %PCT = 1105 A +43.69 T 0.46 T2 + 1.48 E03 T3 .47 2.29E07
Leaf %PCT = 841 A +35.32 T 0.38 T2 + 1.28 E03 T3 .57 2.19E08
Shell %PCT = 371 A 1.81 T .30 1.94E04
Root %PCT = 133 A 0.60 T + 0.31 T2 6.58 E03 T3 + 5.15 E05 T4 1.40 E07 T5 .46 6.63E07
%PCT = Percent of final P content, Coeff = Regression coefficient, T = Days after planting.
APPENDIX CONTINUED
Table 10. Regression equation for total P content expressed as a percentage of final content in Figure 12.
Variable Intercept Coeff 1 Coeff 2 Coeff 3 Coeff 4 Coeff 5 r2 P
Total %PCT = 73.28 A + 2.87 T 0.03 T2 + 9.79 E05 T3 .94 1.72E12
%PCT = Percent of final P content, Coeff = Regression coefficient, T = Days after planting.
Table 11. Regression equations for the N to P content ratio in Figure 13.
Variable Intercept Coeff 1 Coeff 2 Coeff 3 Coeff 4 Coeff 5 r2 P
Seed N/P = 83.39 A + 2.63 T 0.02 T2 + 6.77 E05 T3 .48 2.28E05
Stem N/P = 10.51 A 0.06 T + 8.15 E04 T2 .61 7.07E09
Leaf N/P = 24.45 A 0.45 T + 6.22 E03 T2 2.39 E05 T3 .67 2.11E09
Shell N/P = 33.13 A 0.48 T + 2.94 E03 T2 .45 1.99E05
Root N/P = 3.47 A + 0.20 T 8.11 E04 2 .43 3.39E07
N/P = Ratio of Nitrogen to Phosphorus content, Coeff = Regression coefficient, T = Days after planting.
Table 12. Regression equation for the N to P content ratio in Figure 14.
Variable Intercept Coeff 1 Coeff 2 Coeff 3 Coeff 4 Coeff 5 r2 P
Total N/P = 34.55 A 1.09 T + 0.02 T2 1.39 E04 T3 + 3.57 E07 T4 .29 5.21E05
N/P = Ratio of Nitrogen to Phosphorus content, Coeff = Regression coefficient, T = Days after planting.
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