- Email: [email protected]
Energy state of wheat leaves in ammonium nitrate-treated plants
Pergamon Press
Life Sciences Vol. 16, pp. 603-610 Printed in the U.S.A.
ENERGY STATE OF WHEAT LEAVES IN AMMONIUM NITRATE-TREATED PLANTS Te May Ching, Saundra Hedtke and Adriel E. Garay Crop Science Department Oregon State University Corvallis, Oregon 97331 (Received in final form January 16, 1975)
Summary Energy state, as indicated by content of ATP and total adenosine phosphates and energy charge, is higher in leaves of the fertilizertreated plants of wheat {Triticum aestivum L. var. Yamhill) than those without fertilizer. Structural components and amino acid pool are also larger, but sucrose, total sugars and stanch content are smaller, indicating efficient biosynthesis and facilitated transport of photosynthetic products in leaves of fertilized plants. Technical Paper number 3958, Oregon Agricultural Experiment Station. Nitrogen-containing fertilizers are generally used to increase plant productivity.
It is commonly accepted that the fertilizer provides the sub-
strate for enzymic and structural nitrogenous compounds which in turn stimulate growth and yield.
The increased ribosomal RNA genes in the large genotroph of
flax by successive applications of nitrogen fertilizer {1) is one of the mechanisms by which fertilizer exerts its effect on growth. however, have not been explored extensively.
Other mechanisms,
This paper reports for the first
time the influence of ammonium nitrate on adenylate energy state of wheat leaves. Materials and Methods High quality seeds of wheat {Triticum aestivum L. var. Yamhill) were planted at a rate of 80 kg/ha in October, 1973, on Woodburn silt loam with 35 kg/ha of N as urea at planting time in Corvallis, Oregon. An additional 150 kg/ha of N as ammonium nitrate was applied on March 16, 1974, on one-haif of the wheat field.
On May 30, when the plants were at heading, two replications
of 10 leaves each from 4 positions (lst leaf being the flag leaf) on the plant 603
604
Energy State of Wheat Leaves
were collected at 9:00a.m. in liquid nitrogen.
Vol. 16, No. 4
Approximately two grams of
frozen leaves were hand ground with 10 ml of 0.25 N perchloric acid in a supercooled mortar with pestle.
The slurry was centrifuged at 10,000 g for 10 min
and the supernatant collected. combined.
The extraction was repeated twice and extracts
The combined extracts were neutralized with potassium hydroxide and
the precipitate was removed.
The neutralized extract was diluted 100 times with
0.025 M HEPES containing 0.025 M Mg acetate, pH 7.5.
ATP was determined in the
diluted extract by the luciferin-luciferase system with an Aminco Chem-glow photometer {2).
ADP was converted to ATP by phosphoenol-pyruvate and pyruvate
Kinase {EC 2.7.1. 40) and then assayed.
AMP was converted to ADP with endogenous
ATP by adenylate kinase {EC 2.7.4.3) and the resulting ADP was converted to ATP and assayed (3).
Energy charge {EC) was calculated according to Atkinson {4):
EC =([ATP]+l/2[ADP]}A[ATP]+[ADP]+[AMP]).
Extraction was conducted at 0 to 3C
and extracts were kept fn an ice bath to prevent deterioration. For estimation of metabolites in the extract. glucose plus glucose-6phosphate and sucrose were determined in the neutralized extracts.
Glucose was
assayed by a modification of the "Glucose stat pack" of the Cal Biochem.
In
this procedure, 50JUl of the extract were added to 2 ml reaction mixture containing buffer, hexokinase (EC 2.7.1.1), glucose-6-phosphate dehydrogenase {EC 1.1.1.49) and NAD.
The 0 time absorbence at 340 nm was read immediately in order
to correct for absorbence of the extracts.
The absorbence was read again after
15 min incubation at 30C, and the increment from 0 time was calculated as glucose plus glucose-6-phosphate.
Sucrose in extract was hydrolyzed by invertase
(EC 3.2.1.26) in acetate buffer (pH 5.0, 0.1 M) at 30C for 15 min then assayed as glucose.
The difference of glucose content in original extract and inver-
tase-hydrolyzed-extract was multiplied by a factor of 1.9 and considered as sucrose.
Total sugars were estimated in diluted extracts by the anthrone
method ( ).
Insoluble polysaccharides in the residue were hydrolyzed by 0.2N
H2S04 (6) and assayed by the anthrone method with a correction factor of 0.9. Another two sets of comparable samples were collected in polyethylene bags
Vol. 16, No. 4
605
Energy State of Wheat Leaves
and packed in ice-chest.
One set was for the determination of fresh weight,
dry weight (24 hrs at 85C), water content, leaf area and specific leaf weight (SLW, mg/cm2).
The other set was for the analyses of chlorophylls (7) and free
amino acids in the ethanol extract by ninhydrin method (5). Results and Discussion The application of 150 kg/ha of N as ammonium nitrate to young wheat plants increased the total leaf fresh weight, dry weight, water content and area (Table 1) to 174, 150, 111 and 192% of control plants, respectively.
The
specific leaf weight, however, was reduced by the fertilizer to 76% of the control.
This decrease probably is caused by more water content in fertilized
material.
The fertilizer-induced increases are not equal in leaves at differ-
ent positions of the plant.
For instance, the number one leaf from the top
(flag leaf) was always the most stimulated one among the four viable leaves. Usually five or six leaves were found on each tiller, but the fifth and sixth leaves were generally senescent and yellowish.
These effects of fertilizer
prevail in all plant species and have already been reported (8). The contents of ATP, ADP and total adenosine phosphates (AP) per gram of leaf fresh weight averaged 25% higher in plants with fertilizer than without. AMP content, however. was 40% lower in fertilized plants (Table 2). When the contents were compared on per-leaf basis, the fertilizer-stimulated total increases reached 32 to 281% of the control on all three nucleotides and the total.
These increases in pool size of nucleotides indicate that not only the
phosphorylation of ADP to ATP via photosynthesis is more efficient in fertilized plants but also the synthesis of nucleotides are more.
Based on the increase of
50% in total leaf dry weight (Table 1) and 300% in chlorophyll content (Table 3 and 4) in fertilized plants. the total synthesis of ATP and AP must be more than 3-fold of the control. One more interesting aspect is the effect of leaf position on the pool size of the nucleotfdes.
The flag leaf had 0 to 7 %more ATP, ADP and total
AP per unit weight than that of the control, whereas the 4th leaf had 10 to
%
606
Vol. 16, No. 4
Energy State of Wheat Leaves
less than the control (Table 2).
The ratio of all the criteria measured in leaf
1 to leaf 4 of fertilized plants further indicates the effect of NH4N03, because leaf 4 was completely formed before the application of fertilizer while the flag leaf was developed after the application.
This position effect is also
evident in control material and it is probably related to light availability and water content (Table 1). TABLE 1.
Fresh and Dry Weights, Water Content, Area and Specific Leaf Weight (SLW) of Leaves from Plants With or Without Fertilizer.*
Leaf Position
Fresh wt. mg.
Dry wt. mg.
H2o Content %
Area cm2
SLW mgLcm2
Control 355
136
63
22.2
6.13
2
530
156
70
33.8
4.62
3
574
158
72
27.9
5.66
4
446
112
75
25.9
4.32
Ave.
476
140
70
27.4
5.18
Total
1905
562
109.8
+NH4N03 893
261
72
50.4
5.20
2
1170
247
79
65.5
3.77
3
1073
231
78
55.8
4.14
4
629
107
83
39.0
2.74
Ave.
941
215
78
52.7
3.96
Total
3316
846
·*Average of two replications.
210.7 The difference between two replications was less
than 14% of the mean. The higher energy charge found in the fertilized plants (Table 2) may also favor endergonic pathways of biosynthesis (4).
The EC of the flag leaf in
fertilized plants is significantly higher than control (0. 691 vs. 0.563) and
Vol. 16, No. 4
TABLE 2.
607
Energy State of Wheat Leaves
Content of ATP, ADP, AMP and Total Adenosine Phosphates and Energy Charge (EC) in Leaves from Plants With or Without Fertilizer*
Leaf Position
2
3
4
1l4
Ave.
95.6
Total
Control ATP, n mole/GFW+
134.7
108.2
77.9
61.4
2.19
n mole/leaf
47.8
57.4
44.7
27.4
1. 74
141.2
108.3
60.8
51.9
2. 72
50. 1
57.4
34.9
23.1
2.17
88.3
25.1
27.9
15.3
5.77
31.4
13.3
16.0
6.8
4.62
364.2
241.8
166.8
128.5
2.83
129.3
128.1
95.7
57.3
2.26
. 563
• 672
• 650
.679
0.82
.64
127.5
ADP, n mole/GFW n mole/leaf AMP, n mole/GFW n mole/leaf Total, n mole/GFW n mole/leaf EC
177.3 90.6 165.5 39.2 67.5 225.4 410.3
+NH4N03 ATP, n mole/GFW n mole/leaf ADP, n mole/GFW n mole/leaf AMP, n mole/GFW n mole/leaf Total, n mole/GFW n mole/leaf EC
231.4
150.5
82.1
46. 1
5. 01
206.6
176 .. 1
88.1
29.0
7.12
244.2
109.1
52.6
48.0
5.09
218.1
127.6
56.4
30.2
7.22
36.2
16.8
27.0
12.4
2.92
32.3
19.7
29.0
7.8
4.14
511.8
276.4
161.7
106.5
4.80
457.6
323.4
173.5
67.0
6.83
. 691
.742
.670
.658
1. 05
499.8 113.5 432.3 23.1 88.8 264.1 1020.9 .690
*Average of two replications between which the difference was less than 15% of the mean. +GFW - gram fresh weight.
Energy State of Wheat Leaves
608
Vol. 16, No. 4
probably contributes to the high yield of grain in providing more substrates. The effect of leaf position on the EC of nucleotides is of interest, but this study is limited to offer any explanation.
In the wheat variety, Moisson, the
total AP in leaves was about 150 n moles per gram of fresh weight and the energy charge varied from 0.583 to 0.639 (9}.
Our field-grown material had 2
to 3-fold quantity in flag leaf and second leaf. were comparable to that of Moisson. materials,
indicatin~perhaps,
The third and fourth leaves
The EC ratio were all higher in our
the high genetic growth potential of this vari-
ety (10). TABLE 3.
Content of Glucose, Sucrose, Soluble Sugars, Amino Acids, Nonstructural Polysaccharids, and Chlorophylls in Leaves from Plants without Fertilizer*
Leaf Position
2
3
4
lL4
Ave. 1.42
)J
mole/GFW
1. 57
1. 69
1.11
1. 31
l. 20
)J
mole/leaf
0.56
0.90
0.64
0.58
0.96
)J
mole/GFW
13.76
15.45
10.28
10.77
1.28
}J
mole/leaf
4.88
8.19
5.90
4.80
1. 02
57.80
60.34
47.06
38.98
1.48
20.52
31.96
27.01
17.38
l. 18
2. 01
1. 92
2.40
2.02
1. 01
a. 71
1. 02
1. 38
0.90
0.79
4.10
2.80
2.95
2.40
1.71
mg/leaf
1.46
1.48
1. 96
1.07
1. 36
Chloroph. mg/GFW
1.46
1. 26
0.83
0.62
2.35
mg/leaf
0.52
0.67
0.48
0.28
1. 86
Glucose,
Sucrose.
Sugars, mg/GFW mg/leaf Amino Acids, mg/GFW mg/leaf Polysacch. mg/GFW
Total
2.67 12.56 23.77 51.04 96.87 2.08 4.01 3.06 5.97 1. 04 1. 95
*Average of two replications between which the difference was less than 16% of the mean.
Vol. 16, No. 4
Energy State of Wheat Leaves
609
The concentrations of glucose including glucose-6-phosphate, free amino acids and chlorophylls were elevated in fertilized plants to 240, 196 and 192% respectively, of those of control materials (Table 3 and 4).
Conversely, the
concentrations of sucrose, total soluble sugars and non-structural polysaccharides were decreased in fertilizer-treated plants to 58, 49 and 64%, respectively, of the control.
The reduced level of sugars and polysaccharides
in leaves of nitrogen-fertilizer-treated plants is well known (6).
The increase
of free amino acids is apparently at the expense of soluble sugars (11) and further indicates that more photosynthate is channeled to the synthesis of nitrogenous compounds. TABLE 4.
An unanimously higher ratios of carbohydrates, amino
Content of Glucose, Sucrose, Soluble Sugars, Amino Acids, Nonstructural Polysaccharids and Chlorophylls in Leaves from Plants Treated 170 kg/ha NH 4N03.*
Leaf Position
2
3
4
1L4
Ave. 3.43
)J
mole/GFW
3.54
4.58
4.04
1.55
2.28
)J
mole/leaf
3.16
5.36
4.33
0.97
3.26
)J
mole/GFW
14.71
1o. 11
2.66
1. 90
7.74
}J
mole/leaf
13.14
11.83
2.85
1. 19
11.04
50.62
27.42
13.25
8.49
5.97
45.20
32.08
14.22
5.34
8.46
6.42
3.92
3.29
2.66
2. 41
5.73
4.62
3.53
1.67
3.43
2.87
1.80
1.17
1.65
1. 74
mg/leaf
2.51
2.11
1. 26
1.04
2.41
Ch1oroph. mg/GFW
3.37
2.52
1.45
0.67
5.03
mg/leaf
3.01
2.95
1. 56
0.42
7.17
Glucose,
Sucrose,
Sugars, mg/GFW mg/leaf Amino Acids, mg/GFW mg/leaf Polysacch. mg/GFW
Total
13.82 7.34 29.01 24.94 96.84 4.08 15.55 1. 87
6.92 2.00 7.94
*Average of two replications between which the difference was less than 15% of the mean.
Energy State of Wheat Leaves
610
Vol. 16, No. 4
Acids and chlorophylls in leaf 1 to leaf 4 in plants with fertilizer than that of control clearly indicates the effect of fertilizer.
The significant
increase of these compounds in leaves of fertilized plants infers more utilization of photosynthate than in the control.
The reduction of polysaccharides in
leaves of fertilized plants probably is because of the limitation of substrate (soluble sugars).
The limitation may be imposed partly by the synthesis of
amino acids and partly because of more efficient transport of photosynthate to other parts of the plant.
The efficient transport may be facilitated by the
favorable energy state in the leaf tissue as transport is an energy-demanding process ( ll). When the metabolites were calculated as per leaf basis, a general increase was observed except total sugars which was equal in both materials (Tables 3 and 4).
The increases of 400% of total glucose and glucose-6-phosphate and 300%
of free amino acids which are synthesized by fertilized plants with 300% more chlorophylls and 50% more leaf weight are of interest.
More efficient synthetic
mechanisms must be functioning in this tissue and the common denominator of biosynthesis, the energy supply could be the cause, in addition to increased substrate from nitrogen fertilizer. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12.
References Ti11111is, J. N. and J. Ingle. Nature New Biol. 244:235-236, 1973. St. John, J. B. Anal. Biochem. 37:409-416, 1970. Ching, T. M. and K. K. Ching. Plant Physiol. 50:536-540, 1972. Atkinson, D. E. Ann. Rev. Microbial. 23:47-68, 1969. Ching, T. M. Plant Physiol. 41:1313-1319, 1966. Smith, D. l!l"Chemistry and Biochemistry of Herbage." G. W. Butler and R. W. Bailey (eds.). pp. 105-155. Academic Press, N. Y., 1973. Bruinsma, J. Photochem. and Photobiol. 2:241-249, 1963. Langer, R. H. M. and F. K. Y. liew. Aust. J. Agri. Res. 24:647-656, 1973. Bomsel, J. l. and A. Pradet. Biochem. Biophys. Acta. 162:230-242, 1968. Ching, T. M. and W. E. Kronstad. Crop Sci. 12:785-789, 1972. Zelitch, I. "Photosynthesis, Photorespiration and Plant Productivity." Academic Press, N.Y., 1971. Meister, A. Sci. 180:33-39, 1973.
Life Sciences Vol. 16, pp. 603-610 Printed in the U.S.A.
ENERGY STATE OF WHEAT LEAVES IN AMMONIUM NITRATE-TREATED PLANTS Te May Ching, Saundra Hedtke and Adriel E. Garay Crop Science Department Oregon State University Corvallis, Oregon 97331 (Received in final form January 16, 1975)
Summary Energy state, as indicated by content of ATP and total adenosine phosphates and energy charge, is higher in leaves of the fertilizertreated plants of wheat {Triticum aestivum L. var. Yamhill) than those without fertilizer. Structural components and amino acid pool are also larger, but sucrose, total sugars and stanch content are smaller, indicating efficient biosynthesis and facilitated transport of photosynthetic products in leaves of fertilized plants. Technical Paper number 3958, Oregon Agricultural Experiment Station. Nitrogen-containing fertilizers are generally used to increase plant productivity.
It is commonly accepted that the fertilizer provides the sub-
strate for enzymic and structural nitrogenous compounds which in turn stimulate growth and yield.
The increased ribosomal RNA genes in the large genotroph of
flax by successive applications of nitrogen fertilizer {1) is one of the mechanisms by which fertilizer exerts its effect on growth. however, have not been explored extensively.
Other mechanisms,
This paper reports for the first
time the influence of ammonium nitrate on adenylate energy state of wheat leaves. Materials and Methods High quality seeds of wheat {Triticum aestivum L. var. Yamhill) were planted at a rate of 80 kg/ha in October, 1973, on Woodburn silt loam with 35 kg/ha of N as urea at planting time in Corvallis, Oregon. An additional 150 kg/ha of N as ammonium nitrate was applied on March 16, 1974, on one-haif of the wheat field.
On May 30, when the plants were at heading, two replications
of 10 leaves each from 4 positions (lst leaf being the flag leaf) on the plant 603
604
Energy State of Wheat Leaves
were collected at 9:00a.m. in liquid nitrogen.
Vol. 16, No. 4
Approximately two grams of
frozen leaves were hand ground with 10 ml of 0.25 N perchloric acid in a supercooled mortar with pestle.
The slurry was centrifuged at 10,000 g for 10 min
and the supernatant collected. combined.
The extraction was repeated twice and extracts
The combined extracts were neutralized with potassium hydroxide and
the precipitate was removed.
The neutralized extract was diluted 100 times with
0.025 M HEPES containing 0.025 M Mg acetate, pH 7.5.
ATP was determined in the
diluted extract by the luciferin-luciferase system with an Aminco Chem-glow photometer {2).
ADP was converted to ATP by phosphoenol-pyruvate and pyruvate
Kinase {EC 2.7.1. 40) and then assayed.
AMP was converted to ADP with endogenous
ATP by adenylate kinase {EC 2.7.4.3) and the resulting ADP was converted to ATP and assayed (3).
Energy charge {EC) was calculated according to Atkinson {4):
EC =([ATP]+l/2[ADP]}A[ATP]+[ADP]+[AMP]).
Extraction was conducted at 0 to 3C
and extracts were kept fn an ice bath to prevent deterioration. For estimation of metabolites in the extract. glucose plus glucose-6phosphate and sucrose were determined in the neutralized extracts.
Glucose was
assayed by a modification of the "Glucose stat pack" of the Cal Biochem.
In
this procedure, 50JUl of the extract were added to 2 ml reaction mixture containing buffer, hexokinase (EC 2.7.1.1), glucose-6-phosphate dehydrogenase {EC 1.1.1.49) and NAD.
The 0 time absorbence at 340 nm was read immediately in order
to correct for absorbence of the extracts.
The absorbence was read again after
15 min incubation at 30C, and the increment from 0 time was calculated as glucose plus glucose-6-phosphate.
Sucrose in extract was hydrolyzed by invertase
(EC 3.2.1.26) in acetate buffer (pH 5.0, 0.1 M) at 30C for 15 min then assayed as glucose.
The difference of glucose content in original extract and inver-
tase-hydrolyzed-extract was multiplied by a factor of 1.9 and considered as sucrose.
Total sugars were estimated in diluted extracts by the anthrone
method ( ).
Insoluble polysaccharides in the residue were hydrolyzed by 0.2N
H2S04 (6) and assayed by the anthrone method with a correction factor of 0.9. Another two sets of comparable samples were collected in polyethylene bags
Vol. 16, No. 4
605
Energy State of Wheat Leaves
and packed in ice-chest.
One set was for the determination of fresh weight,
dry weight (24 hrs at 85C), water content, leaf area and specific leaf weight (SLW, mg/cm2).
The other set was for the analyses of chlorophylls (7) and free
amino acids in the ethanol extract by ninhydrin method (5). Results and Discussion The application of 150 kg/ha of N as ammonium nitrate to young wheat plants increased the total leaf fresh weight, dry weight, water content and area (Table 1) to 174, 150, 111 and 192% of control plants, respectively.
The
specific leaf weight, however, was reduced by the fertilizer to 76% of the control.
This decrease probably is caused by more water content in fertilized
material.
The fertilizer-induced increases are not equal in leaves at differ-
ent positions of the plant.
For instance, the number one leaf from the top
(flag leaf) was always the most stimulated one among the four viable leaves. Usually five or six leaves were found on each tiller, but the fifth and sixth leaves were generally senescent and yellowish.
These effects of fertilizer
prevail in all plant species and have already been reported (8). The contents of ATP, ADP and total adenosine phosphates (AP) per gram of leaf fresh weight averaged 25% higher in plants with fertilizer than without. AMP content, however. was 40% lower in fertilized plants (Table 2). When the contents were compared on per-leaf basis, the fertilizer-stimulated total increases reached 32 to 281% of the control on all three nucleotides and the total.
These increases in pool size of nucleotides indicate that not only the
phosphorylation of ADP to ATP via photosynthesis is more efficient in fertilized plants but also the synthesis of nucleotides are more.
Based on the increase of
50% in total leaf dry weight (Table 1) and 300% in chlorophyll content (Table 3 and 4) in fertilized plants. the total synthesis of ATP and AP must be more than 3-fold of the control. One more interesting aspect is the effect of leaf position on the pool size of the nucleotfdes.
The flag leaf had 0 to 7 %more ATP, ADP and total
AP per unit weight than that of the control, whereas the 4th leaf had 10 to
%
606
Vol. 16, No. 4
Energy State of Wheat Leaves
less than the control (Table 2).
The ratio of all the criteria measured in leaf
1 to leaf 4 of fertilized plants further indicates the effect of NH4N03, because leaf 4 was completely formed before the application of fertilizer while the flag leaf was developed after the application.
This position effect is also
evident in control material and it is probably related to light availability and water content (Table 1). TABLE 1.
Fresh and Dry Weights, Water Content, Area and Specific Leaf Weight (SLW) of Leaves from Plants With or Without Fertilizer.*
Leaf Position
Fresh wt. mg.
Dry wt. mg.
H2o Content %
Area cm2
SLW mgLcm2
Control 355
136
63
22.2
6.13
2
530
156
70
33.8
4.62
3
574
158
72
27.9
5.66
4
446
112
75
25.9
4.32
Ave.
476
140
70
27.4
5.18
Total
1905
562
109.8
+NH4N03 893
261
72
50.4
5.20
2
1170
247
79
65.5
3.77
3
1073
231
78
55.8
4.14
4
629
107
83
39.0
2.74
Ave.
941
215
78
52.7
3.96
Total
3316
846
·*Average of two replications.
210.7 The difference between two replications was less
than 14% of the mean. The higher energy charge found in the fertilized plants (Table 2) may also favor endergonic pathways of biosynthesis (4).
The EC of the flag leaf in
fertilized plants is significantly higher than control (0. 691 vs. 0.563) and
Vol. 16, No. 4
TABLE 2.
607
Energy State of Wheat Leaves
Content of ATP, ADP, AMP and Total Adenosine Phosphates and Energy Charge (EC) in Leaves from Plants With or Without Fertilizer*
Leaf Position
2
3
4
1l4
Ave.
95.6
Total
Control ATP, n mole/GFW+
134.7
108.2
77.9
61.4
2.19
n mole/leaf
47.8
57.4
44.7
27.4
1. 74
141.2
108.3
60.8
51.9
2. 72
50. 1
57.4
34.9
23.1
2.17
88.3
25.1
27.9
15.3
5.77
31.4
13.3
16.0
6.8
4.62
364.2
241.8
166.8
128.5
2.83
129.3
128.1
95.7
57.3
2.26
. 563
• 672
• 650
.679
0.82
.64
127.5
ADP, n mole/GFW n mole/leaf AMP, n mole/GFW n mole/leaf Total, n mole/GFW n mole/leaf EC
177.3 90.6 165.5 39.2 67.5 225.4 410.3
+NH4N03 ATP, n mole/GFW n mole/leaf ADP, n mole/GFW n mole/leaf AMP, n mole/GFW n mole/leaf Total, n mole/GFW n mole/leaf EC
231.4
150.5
82.1
46. 1
5. 01
206.6
176 .. 1
88.1
29.0
7.12
244.2
109.1
52.6
48.0
5.09
218.1
127.6
56.4
30.2
7.22
36.2
16.8
27.0
12.4
2.92
32.3
19.7
29.0
7.8
4.14
511.8
276.4
161.7
106.5
4.80
457.6
323.4
173.5
67.0
6.83
. 691
.742
.670
.658
1. 05
499.8 113.5 432.3 23.1 88.8 264.1 1020.9 .690
*Average of two replications between which the difference was less than 15% of the mean. +GFW - gram fresh weight.
Energy State of Wheat Leaves
608
Vol. 16, No. 4
probably contributes to the high yield of grain in providing more substrates. The effect of leaf position on the EC of nucleotides is of interest, but this study is limited to offer any explanation.
In the wheat variety, Moisson, the
total AP in leaves was about 150 n moles per gram of fresh weight and the energy charge varied from 0.583 to 0.639 (9}.
Our field-grown material had 2
to 3-fold quantity in flag leaf and second leaf. were comparable to that of Moisson. materials,
indicatin~perhaps,
The third and fourth leaves
The EC ratio were all higher in our
the high genetic growth potential of this vari-
ety (10). TABLE 3.
Content of Glucose, Sucrose, Soluble Sugars, Amino Acids, Nonstructural Polysaccharids, and Chlorophylls in Leaves from Plants without Fertilizer*
Leaf Position
2
3
4
lL4
Ave. 1.42
)J
mole/GFW
1. 57
1. 69
1.11
1. 31
l. 20
)J
mole/leaf
0.56
0.90
0.64
0.58
0.96
)J
mole/GFW
13.76
15.45
10.28
10.77
1.28
}J
mole/leaf
4.88
8.19
5.90
4.80
1. 02
57.80
60.34
47.06
38.98
1.48
20.52
31.96
27.01
17.38
l. 18
2. 01
1. 92
2.40
2.02
1. 01
a. 71
1. 02
1. 38
0.90
0.79
4.10
2.80
2.95
2.40
1.71
mg/leaf
1.46
1.48
1. 96
1.07
1. 36
Chloroph. mg/GFW
1.46
1. 26
0.83
0.62
2.35
mg/leaf
0.52
0.67
0.48
0.28
1. 86
Glucose,
Sucrose.
Sugars, mg/GFW mg/leaf Amino Acids, mg/GFW mg/leaf Polysacch. mg/GFW
Total
2.67 12.56 23.77 51.04 96.87 2.08 4.01 3.06 5.97 1. 04 1. 95
*Average of two replications between which the difference was less than 16% of the mean.
Vol. 16, No. 4
Energy State of Wheat Leaves
609
The concentrations of glucose including glucose-6-phosphate, free amino acids and chlorophylls were elevated in fertilized plants to 240, 196 and 192% respectively, of those of control materials (Table 3 and 4).
Conversely, the
concentrations of sucrose, total soluble sugars and non-structural polysaccharides were decreased in fertilizer-treated plants to 58, 49 and 64%, respectively, of the control.
The reduced level of sugars and polysaccharides
in leaves of nitrogen-fertilizer-treated plants is well known (6).
The increase
of free amino acids is apparently at the expense of soluble sugars (11) and further indicates that more photosynthate is channeled to the synthesis of nitrogenous compounds. TABLE 4.
An unanimously higher ratios of carbohydrates, amino
Content of Glucose, Sucrose, Soluble Sugars, Amino Acids, Nonstructural Polysaccharids and Chlorophylls in Leaves from Plants Treated 170 kg/ha NH 4N03.*
Leaf Position
2
3
4
1L4
Ave. 3.43
)J
mole/GFW
3.54
4.58
4.04
1.55
2.28
)J
mole/leaf
3.16
5.36
4.33
0.97
3.26
)J
mole/GFW
14.71
1o. 11
2.66
1. 90
7.74
}J
mole/leaf
13.14
11.83
2.85
1. 19
11.04
50.62
27.42
13.25
8.49
5.97
45.20
32.08
14.22
5.34
8.46
6.42
3.92
3.29
2.66
2. 41
5.73
4.62
3.53
1.67
3.43
2.87
1.80
1.17
1.65
1. 74
mg/leaf
2.51
2.11
1. 26
1.04
2.41
Ch1oroph. mg/GFW
3.37
2.52
1.45
0.67
5.03
mg/leaf
3.01
2.95
1. 56
0.42
7.17
Glucose,
Sucrose,
Sugars, mg/GFW mg/leaf Amino Acids, mg/GFW mg/leaf Polysacch. mg/GFW
Total
13.82 7.34 29.01 24.94 96.84 4.08 15.55 1. 87
6.92 2.00 7.94
*Average of two replications between which the difference was less than 15% of the mean.
Energy State of Wheat Leaves
610
Vol. 16, No. 4
Acids and chlorophylls in leaf 1 to leaf 4 in plants with fertilizer than that of control clearly indicates the effect of fertilizer.
The significant
increase of these compounds in leaves of fertilized plants infers more utilization of photosynthate than in the control.
The reduction of polysaccharides in
leaves of fertilized plants probably is because of the limitation of substrate (soluble sugars).
The limitation may be imposed partly by the synthesis of
amino acids and partly because of more efficient transport of photosynthate to other parts of the plant.
The efficient transport may be facilitated by the
favorable energy state in the leaf tissue as transport is an energy-demanding process ( ll). When the metabolites were calculated as per leaf basis, a general increase was observed except total sugars which was equal in both materials (Tables 3 and 4).
The increases of 400% of total glucose and glucose-6-phosphate and 300%
of free amino acids which are synthesized by fertilized plants with 300% more chlorophylls and 50% more leaf weight are of interest.
More efficient synthetic
mechanisms must be functioning in this tissue and the common denominator of biosynthesis, the energy supply could be the cause, in addition to increased substrate from nitrogen fertilizer. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12.
References Ti11111is, J. N. and J. Ingle. Nature New Biol. 244:235-236, 1973. St. John, J. B. Anal. Biochem. 37:409-416, 1970. Ching, T. M. and K. K. Ching. Plant Physiol. 50:536-540, 1972. Atkinson, D. E. Ann. Rev. Microbial. 23:47-68, 1969. Ching, T. M. Plant Physiol. 41:1313-1319, 1966. Smith, D. l!l"Chemistry and Biochemistry of Herbage." G. W. Butler and R. W. Bailey (eds.). pp. 105-155. Academic Press, N. Y., 1973. Bruinsma, J. Photochem. and Photobiol. 2:241-249, 1963. Langer, R. H. M. and F. K. Y. liew. Aust. J. Agri. Res. 24:647-656, 1973. Bomsel, J. l. and A. Pradet. Biochem. Biophys. Acta. 162:230-242, 1968. Ching, T. M. and W. E. Kronstad. Crop Sci. 12:785-789, 1972. Zelitch, I. "Photosynthesis, Photorespiration and Plant Productivity." Academic Press, N.Y., 1971. Meister, A. Sci. 180:33-39, 1973.