Photosynthesis, Storage, and Allocation
135
Nicotiana tabacum
,.....
8
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A
B
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0.3
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0) I
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Q)
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•
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+NH 4 NO l T WT
o 0
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0.1
0
Q)
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0
Q)
+e::: 0
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•
..r:
L
0.1 mt.l
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~
(/)
0.0
a
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0.05
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0.03 0
Q)
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,--..
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0 I
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E 0.03
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Q)
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u
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0.00
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a
5
10
a
5
10
15
-2 -1
Photosynthesis (J-lmol m
s )
Fig.7.IA-D. The relationship between the ambient photosynthetic rate of mature source
leaves and A relative growth rate, B shoot/root ratio, C specific leaf area, and D leaf area
ratio in transgenic (T, open symbols) and wild-type (WT, full symbols) tobacco (Nicotiana
tabacum L.) grown at 300Jlmol m- 2 s- 1 irradiance, 20115°C air temperature at a 12/
12 h day/night cycle (see Quick et ai. 1992). The plants were cultivated in sand and
watered once a day with an otherwise complete nutrient solution containing 0.1 (L., A),
0.7 (0, .), and 5.0mM NH4N03 (0, .). Each symbol refers to a separate plant. (Data
from Fichtner et ai. 1993)
The above results show the relation between photosynthesis and growth
using intraspecific variation of photosynthesis, i.e., within a single species.
In an interspecific comparison, i.e., within a range of different species under
the same environmental conditions, no relation of photosynthesis and growth
may be found (e.g., Poorter et al. 1990). In this case different patterns of
biomass allocation probably have a greater influence on growth (see Potter
and Jones 1977; Poorter and Remkes 1990; Fichtner and Schulze 1992) than
the rate of photosynthesis itself.
7.2.2 Photosynthesis and Biomass Allocation
In the wild-type (WT) plants, N nutrition enhanced photosynthesis and thus
RGR (Fig. 7.1A); but this was not the only effect of N. Even at the same
rate of photosynthesis, plants at HN had a higher RGR than at LN or MN.
135
Nicotiana tabacum
,.....
8
0
..r:
A
B
+I
0.3
~
~
0
"0
0
6
L
0
I
L
~
,.....
0) I
+0.2
o
~
0
I
0)
o
D~. 4
0
0)
Q)
~
L '
.~
0)
'-"
•
"- Ol
+NH 4 NO l T WT
o 0
cw.
+'-"
0
0.1
0
Q)
5.0 mt.l 0
•
~O~ 2
0
Q)
+e::: 0
0.7 mt.l 0
•
..r:
L
0.1 mt.l
"
~
(/)
0.0
a
,.....
C
0%
0
.....
0.05
0
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+0 I
0.03 0
Q)
Ol 0.04
L
,--..
N
0 I
U
E 0.03
0.02
Q)
Ol
.....
L
'-"
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u
0.02
E
Q)
0
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.....
Q.
Q)
0
'-"
(/)
L
0.01
Q)
0
.....J
0.00
0.00
a
5
10
a
5
10
15
-2 -1
Photosynthesis (J-lmol m
s )
Fig.7.IA-D. The relationship between the ambient photosynthetic rate of mature source
leaves and A relative growth rate, B shoot/root ratio, C specific leaf area, and D leaf area
ratio in transgenic (T, open symbols) and wild-type (WT, full symbols) tobacco (Nicotiana
tabacum L.) grown at 300Jlmol m- 2 s- 1 irradiance, 20115°C air temperature at a 12/
12 h day/night cycle (see Quick et ai. 1992). The plants were cultivated in sand and
watered once a day with an otherwise complete nutrient solution containing 0.1 (L., A),
0.7 (0, .), and 5.0mM NH4N03 (0, .). Each symbol refers to a separate plant. (Data
from Fichtner et ai. 1993)
The above results show the relation between photosynthesis and growth
using intraspecific variation of photosynthesis, i.e., within a single species.
In an interspecific comparison, i.e., within a range of different species under
the same environmental conditions, no relation of photosynthesis and growth
may be found (e.g., Poorter et al. 1990). In this case different patterns of
biomass allocation probably have a greater influence on growth (see Potter
and Jones 1977; Poorter and Remkes 1990; Fichtner and Schulze 1992) than
the rate of photosynthesis itself.
7.2.2 Photosynthesis and Biomass Allocation
In the wild-type (WT) plants, N nutrition enhanced photosynthesis and thus
RGR (Fig. 7.1A); but this was not the only effect of N. Even at the same
rate of photosynthesis, plants at HN had a higher RGR than at LN or MN.