100
(d)
y=1.71x+1.00 P<0.01
10
Aarea (umol m-2 s-1)
50
10
y=1.21x+0.68 P<0.01
1
2
Aarea (umol m-2 s-1)
(a)
0.2
1
5
0.1
1
100
Narea (g m-2)
(e)
y=2.18x-1.37 P<0.01
10
10
Aarea (umol m-2 s-1)
(b)
ns
1
2
Aarea (umol m-2 s-1)
50
Narea (g m-2)
10
5
10
20
40
1
10
50
SLA (m2 kg-1)
2
10
Chlarea (ug cm-2)
50
(f)
10
y=1.11x-0.03 P<0.01
2
C3 grass
C4 grass
Forbs
Legume
Global
Aarea (umol m-2 s-1)
10
(c)
2
Aarea (umol m-2 s-1)
50
SLA (m2 kg-1)
100
Grassland
Global
2
10
50
Chlarea (ug cm-2)
Fig. S1 Relationships between area-based Amax and leaf traits. In panels a, b and c, for Aarea-Narea
and Aarea-Chlarea relationships, 95% CI of SMA analyses and AIC scores suggested separate
regression models for grassland PFTs. The Aarea-SLA relationship was only significant for C4
grasses. Panels d, e and f show that the regressions between Aarea and leaf traits for grassland
1
species were different from global average. Lines were drawn for significant relationships. The
global relationship between Aarea and SLA was not significant.
2
1000
0.1
2
1
y=1.33x+0.68 R
10
1
10
100
1
Narea (g m-2)
0.5
100
2
0.13
10
(d)
Glopnet grass data
Glopnet
10
ns
ns
1
0.09
Aarea (umol m-2 s-1)
100
0.1
2
SLA (m2 kg-1)
10
2
y=1.21x+0.68 R
1
Aarea (umol m-2 s-1)
(c)
0.46
0.53
Nmass (%)
y=1.68x+0.77 R
2
100
1000
y=1.72x+1.57R
(b)
y=1.74x+0.13 R
10
Amass (nmol g-1 s-1)
0.52
100
2
10
Amass(nmol g-1 s-1)
(a)
y=2.17x+1.47R
1
10
100
SLA (m2 kg-1)
Fig. S2 Comparison of Amax-leaf traits relationships between Glopnet herbaceous data and the
global average. The grey dots indicate Glopnet dataset. Red dots indicate herbaceous plant subset
of Glopnet. Regression lines were drawn for significant SMA regressions.
3
25
25
20
15
10
5
0
5
10
15
An (umol m-2 s-1)
20
(b) Jul
0
An (umol m-2 s-1)
(a) Jun
0
100
200
300
400
500
600
700
0
100
400
500
600
700
25
15
10
mean
95% CI
95% PI
0
5
An (umol m-2 s-1)
15
10
5
0
20
(d) Sep
20
(c) Aug
An (umol m-2 s-1)
300
Intercellular CO2 (ppm)
25
Intercellular CO2 (ppm)
200
0
100
200
300
400
500
Intercellular CO2 (ppm)
600
700
0
100
200
300
400
500
600
700
Intercellular CO2 (ppm)
Fig. S3 Photosynthetic responses to CO2. Black dots indicate observed values. 95% CI means
95% confidence interval. 95% PI means 95% predictive interval. CO2 response was dependent
on both plant species and month in which the measurements were taken. CO2 responses of
Andropogon gerardii through the growing season are shown in the figure. Each panel shows one
A/Ci curve in each month from June to September. Initial slope of A/Ci curve and maximum
photosynthesis rate at saturating CO2 decreased in late growing season.
4
250
200
150
100
50
Jmax (umol m-2 s-1)
_
||
|
_
_|_
___
40
|| |
|_
|
_|
|
60
__
_
|_ _
_
_
|
__| | _|
_| __ | | _
|_
_ |_
_| _ |
| |__
_
_
| ||
|
__ _| |
|__| |
_
_
_|
_ __
|
_|
|
|
|
|
|
|
C3 grass
Forb
Legume
80
100
120
140
Vcmax (umol m-2 s-1)
Fig. S4 Positive regression between Jmax and Vcmax (Jmax=1.504Vcmax-4.023).
5
Relationships
Amass-Nmass
Amass-SLA
Amass-Chlmass
Aarea-Narea
Aarea-SLA
Aarea-Chlarea
Data set
C3 grass
C4 grass
Forb
Legume
Grassland
Global
Combined
C3 grass
C4 grass
Forb
Legume
Grassland
Global
Combined
C3 grass
C4 grass
Forb
Legume
Grassland
Global
Combined
C3 grass
C4 grass
Forb
Legume
Grassland
Global
Combined
C3 grass
C4 grass
Forb
Legume
Grassland
Global
Combined
C3 grass
C4 grass
Forb
Legume
Grassland
Global
Combined
Slope
Intercept
Mean
95% CI
Mean
95% CI
1.35
1.01
1.81 2.07 1.96 2.17
1.91
1.67
2.18 2.19 2.15 2.24
2.00
1.88
2.13 1.83 1.81 1.86
2.46
2.07
2.92 1.41 1.24 1.58
1.81
1.70
1.92 1.90 1.87 1.92
1.72
1.63
1.81 1.57 1.54 1.59
1.76
1.68
1.84 1.70 1.68 1.73
3.57
2.37
5.38 -1.89 -3.69 -0.09
3.52
2.97
4.18 -1.77 -2.46 -1.07
2.52
2.30
2.77 -0.65 -0.90 -0.39
2.71
2.14
3.42 -0.93 -1.70 -0.15
2.65
2.47
2.85 -0.79 -1.01 -0.58
1.33
1.26
1.40 0.68 0.61 0.74
1.55
1.49
1.62 0.45 0.38 0.52
1.37
0.98
1.93 1.98 1.83 2.14
1.41
1.23
1.62 2.14 2.09 2.20
1.14
1.06
1.23 2.07 2.05 2.10
1.37
1.13
1.65 1.81 1.69 1.93
1.15
1.08
1.22 2.07 2.05 2.09
na
na
1.25
0.89
1.75 1.14 1.08 1.20
1.96
1.67
2.29 1.34 1.29 1.40
1.95
1.81
2.11 0.93 0.91 0.95
1.76
1.40
2.21 0.83 0.74 0.92
1.72
1.60
1.85 1.00 0.98 1.02
1.21
1.13
1.30 0.68 0.65 0.71
1.16
1.10
1.22 0.83 0.81 0.85
ns
2.73
2.24
3.33 -1.99 -2.62 -1.36
ns
ns
2.17
2.00
2.37 -1.37 -1.58 -1.16
ns
ns
1.49
1.00
2.21 -0.44 -1.10 0.22
1.35
1.15
1.58 -0.14 -0.35 0.07
1.13
1.04
1.22 -0.04 -0.13 0.05
1.18
0.97
1.44 -0.28 -0.57 0.01
1.11
1.04
1.19 -0.03 -0.11 0.05
na
na
R2 P-value
0.69
0.62
0.63
0.60
0.50
0.53
0.38
0.37
0.38
0.21
0.25
0.29
0.50
0.45
0.57
0.59
0.47
0.50
0.51
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
0.57
0.47
0.45
0.30
0.29
0.13
0.08
0.15
0.15
0.01
0.02
0.04
0.00
0.00
0.41
0.45
0.35
0.38
0.36
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
0.12
<0.01
0.10
0.27
<0.01
0.15
0.11
<0.01
<0.01
<0.01
<0.01
<0.01
Sample
AIC
size
18
-25.07
86
-10.07
363
-162.53
56
-24.64
523
-3.88
712
68.85
1235 554.88
18
-9.93
86
40.85
363
189.37
56
19.86
523
243.34
764
109.47
1287 363.91
18
-18.27
86
-2.34
362
-6.00
56
-10.37
522
-9.88
18
85
361
56
520
723
1243
18
85
361
56
520
764
1284
18
85
365
64
532
-23.91
-19.95
-107.23
-0.78
33.99
139.57
476.17
-7.20
36.53
263.02
34.77
321.70
472.85
905.21
-17.10
-15.59
-28.44
-16.60
-46.46
6
Table S1 Standardized major axis slopes and intercepts with 95% confidence intervals,
coefficients of determination (R2), P-value, sample size and AIC scores for grassland PFTs,
Glopnet and combined grassland and Glopnet data. “na”, not applicable: in these cases the global
relationships were not available. “ns”, not significant: in these cases the correlations were not
significant. While standardized major axis can still be fitted in such cases, the slopes are
essentially meaningless. All other relationships were highly significant.
7
N
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
Amass-Nmass
Species
Intercept
Slope
Mean 95% CI Mean 95% CI
na
C. bicknellii
1.35 1.01 1.81 2.07 1.96 2.17
E. canadensis
2.14 1.74 2.63 2.13 2.05 2.21
A. gerardii
na
S. scoparium
1.87 1.56 2.24 2.23 2.16 2.30
S. nutans
A. novae-angliae 2.91 2.32 3.65 1.57 1.42 1.72
1.73 1.50 2.00 1.89 1.84 1.94
C. tripteris
2.28 1.55 3.35 1.92 1.79 2.04
E. pallida
H. grosseserratus 2.14 1.69 2.72 1.78 1.63 1.92
H. helianthoides 2.40 1.97 2.93 1.73 1.63 1.83
2.37 1.86 3.01 1.70 1.57 1.84
M. fistulosa
1.74 1.09 2.78 2.06 1.96 2.15
P. integrifolium
2.03 1.47 2.80 1.94 1.84 2.05
P. digitalis
na
P. virginianum
1.91 1.67 2.19 1.85 1.79 1.90
R. pinnata
1.78 1.50 2.10 1.86 1.80 1.92
R. subtomentosa
1.83 1.47 2.28 1.82 1.74 1.91
S. integrifolium
ns
S. laciniatum
2.45 1.85 3.24 1.65 1.50 1.80
S. perfoliatum
ns
S. terebinthinaceum
1.99 1.57 2.52 1.88 1.80 1.96
S. rigida
2.93 2.18 3.93 0.95 0.53 1.36
B. leucantha
na
D. purpureum
2.77 2.36 3.26 1.36 1.19 1.53
D. canadense
3.31 2.43 4.49 1.32 1.03 1.61
L. capitata
Amass-Chlmass
Amass-SLA
Intercept
Slope
Intercept
Slope
Mean 95% CI Mean 95% CI Mean 95% CI Mean 95% CI
na
na
3.57 2.37 5.38 -1.89 -3.69 -0.09 1.37 0.98 1.93 1.98 1.83 2.14
3.19 2.46 4.15 -1.46 -2.47 -0.46 1.42 1.11 1.82 2.15 2.06 2.25
na
na
4.32 3.43 5.44 -2.58 -3.70 -1.46 1.39 1.18 1.65 2.13 2.07 2.20
3.33 2.08 5.34 -1.86 -3.83 0.10 2.00 1.42 2.82 1.76 1.58 1.95
3.17 2.31 4.35 -1.29 -2.38 -0.20 0.75 0.60 0.94 2.22 2.15 2.28
ns
ns
1.21 0.90 1.62 2.16 2.07 2.26
ns
4.69 3.41 6.43 -3.45 -5.25 -1.66 1.39 1.12 1.73 2.00 1.92 2.08
2.51 1.97 3.21 -0.93 -1.70 -0.15 1.26 0.98 1.62 2.04 1.96 2.11
1.23 0.80 1.89 2.02 1.93 2.11
ns
1.10 0.78 1.54 2.02 1.90 2.14
ns
na
na
2.61 2.14 3.19 -0.75 -1.34 -0.15 1.32 1.02 1.72 2.03 1.95 2.11
2.93 2.26 3.79 -1.23 -2.08 -0.37 1.18 0.93 1.50 2.07 1.99 2.15
2.79 2.11 3.70 -0.81 -1.61 0.00 1.20 0.94 1.53 2.01 1.93 2.09
ns
ns
4.16 3.04 5.68 -2.39 -3.79 -1.00 1.25 0.94 1.67 2.15 2.03 2.28
ns
ns
2.87 2.17 3.78 -0.90 -1.74 -0.05 1.15 0.90 1.46 1.95 1.87 2.03
1.47 1.03 2.10 1.65 1.40 1.91
ns
na
na
3.46 2.56 4.68 -1.96 -3.30 -0.63 1.25 0.95 1.63 1.89 1.74 2.05
2.15 1.71 2.71 1.66 1.52 1.81
ns
8
N
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
Aarea-Narea
Slope
Intercept
Mean 95% CI Mean 95% CI
C. bicknellii
na
E. canadensis
1.25 0.89 1.75 1.14 1.08 1.20
A. gerardii
2.05 1.56 2.69 1.33 1.24 1.43
S. scoparium
na
S. nutans
1.89 1.57 2.29 1.35 1.29 1.42
A. novae-angliae 2.80 1.88 4.17 0.95 0.81 1.10
C. tripteris
1.76 1.48 2.10 0.94 0.89 0.98
E. pallida
1.96 1.17 3.28 0.96 0.82 1.11
H. grosseserratus 1.91 1.46 2.49 0.92 0.81 1.03
H. helianthoides 1.80 1.47 2.21 1.01 0.97 1.06
M. fistulosa
ns
P. integrifolium
1.43 0.81 2.53 1.10 0.97 1.23
P. digitalis
1.97 1.28 3.03 0.98 0.83 1.13
P. virginianum
na
R. pinnata
2.22 1.75 2.81 0.94 0.89 1.00
R. subtomentosa
2.27 1.79 2.88 0.96 0.90 1.02
S. integrifolium
1.96 1.48 2.61 0.81 0.72 0.91
S. laciniatum
3.03 1.79 5.12 0.59 0.19 0.98
S. perfoliatum
2.67 1.92 3.71 0.71 0.57 0.86
S. terebinthinaceum
ns
S. rigida
2.03 1.46 2.81 0.92 0.83 1.01
B. leucantha
1.66 1.05 2.64 0.64 0.36 0.91
D. purpureum
na
D. canadense
2.33 1.78 3.05 0.86 0.76 0.96
L. capitata
3.42 1.85 6.31 0.54 0.12 0.96
Species
Aarea-SLA
Aarea-Chlarea
Slope
Intercept
Slope
Intercept
Mean 95% CI Mean 95% CI Mean 95% CI Mean 95% CI
na
ns
ns
1.49 1.00 2.21 -0.44 -1.10 0.22
2.69 1.97 3.66 -2.05 -3.06 -1.04 1.43 1.07 1.90 -0.19 -0.59 0.20
na
2.27 1.35 3.80 -1.61 -2.96 -0.26
3.2 2.47 4.15 -2.42 -3.36 -1.48 1.30 1.08 1.57 -0.11 -0.35 0.13
ns
2.57 1.74 3.78 -1.60 -2.61 -0.59
ns
0.76 0.59 0.97 0.44 0.28 0.60
ns
ns
ns
1.27 0.94 1.73 -0.09 -0.51 0.32
ns
1.04 0.81 1.32 0.03 -0.21 0.27
1.82 1.30 2.54 -1.30 -2.08 -0.53 1.14 0.82 1.58 -0.05 -0.39 0.29
ns
1.22 0.75 2.00 -0.18 -0.78 0.42
ns
1.06 0.73 1.53 -0.04 -0.38 0.30
na
1.22 0.92 1.63 -0.51 -0.88 -0.15
1.93 1.47 2.52 -1.10 -1.70 -0.51
ns
2.27 1.63 3.16 -1.61 -2.47 -0.76 1.24 0.92 1.67 -0.14 -0.48 0.19
ns
1.19 0.89 1.58 -0.18 -0.53 0.17
ns
ns
ns
1.37 1.00 1.89 -0.19 -0.57 0.20
ns
ns
2.28 1.61 3.22 -1.33 -2.18 -0.48 1.07 0.80 1.43 -0.11 -0.45 0.24
ns
1.46 1.00 2.15 -0.74 -1.49 0.02
na
0.73 0.41 1.28 0.20 -0.39 0.79
ns
1.24 0.92 1.66 -0.28 -0.71 0.15
ns
2.27 1.53 3.36 -1.50 -2.56 -0.45
9
Table S2 Within-species Amax-trait relationships. In both mass-based and area-based
relationships, Amax was positively correlated with leaf N and Chl for most species. Many species
showed non-significant relationships between Amax and SLA. “na”, not applicable: in these cases
SLA data were not collected. “ns”, not significant: in these cases the relationships between Amax
and leaf traits were not significant.
10
N
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
PFT
Species
C3 grass
C. bicknellii
C3 grass
E. canadensis
C4 grass
A. gerardii
C4 grass
S. scoparium
C4 grass
S. nutans
Forb
A. novae-angliae
Forb
C. tripteris
Forb
E. pallida
Forb
H. grosseserratus
Forb
H. helianthoides
Forb
M. fistulosa
Forb
P. integrifolium
Forb
P. digitalis
Forb
P. virginianum
Forb
R. pinnata
Forb
R. subtomentosa
Forb
S. integrifolium
Forb
S. laciniatum
Forb
S. perfoliatum
Forb
S. terebinthinaceum
Forb
S. rigida
Legume
B. leucantha
Legume
D. purpurea
Legume
D. canadense
Legume
L. capitata
τ(Chl τ(SLA
Proportion of
Proportion
τ(αleaf)
τ(N
τ(υleaf) fixed effects on effect) effect)
of fixed
effect)
×103
3
Vcmax and Vmax ×103
effects
on α
×10
ns
4.68
5.33
2.50
5.90
6.67
4.80
6.24
6.19
4.60
4.11
4.50
3.89
ns
3.49
4.51
4.03
1.94
5.14
ns
3.15
6.40
3.48
6.62
8.20
5.03
4.61
2.56
1.68
2.32
5.23
2.76
2.57
6.75
2.65
2.04
3.02
3.27
6.31
3.52
2.16
3.82
7.61
4.06
8.59
4.57
2.76
6.97
4.55
2.78
ns
0.50
0.68
0.60
0.72
0.56
0.63
0.71
0.48
0.63
0.67
0.60
0.54
ns
0.50
0.68
0.51
0.20
0.56
ns
0.41
0.70
0.33
0.59
0.75
ns
15.13
6.30
6.56
9.97
20.59
14.39
ns
26.24
14.99
9.98
20.47
12.83
16.68
6.79
7.51
16.34
ns
12.97
ns
10.33
17.94
17.59
18.63
18.41
na
ns
ns
na
ns
ns
ns
ns
ns
ns
10.67
ns
ns
na
13.87
12.57
ns
ns
ns
ns
7.25
ns
na
ns
ns
12.80
12.03
19.56
6.53
11.36
7.82
8.10
18.03
10.37
11.69
9.44
8.70
15.63
7.27
12.52
13.33
17.30
19.23
14.99
17.50
6.99
7.75
7.14
10.52
12.73
ns
0.56
0.24
0.50
0.47
0.72
0.64
ns
0.72
0.56
0.69
0.70
0.45
0.70
0.62
0.60
0.49
ns
0.46
ns
0.72
0.70
0.71
0.64
0.59
τ
0.93
0.47
0.42
0.32
0.50
1.10
1.21
0.28
1.00
0.97
0.90
1.05
0.83
1.00
0.83
1.70
1.58
0.61
0.32
0.41
0.85
1.03
0.55
1.05
1.30
11
N
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
Species
Mean
C. bicknellii
4.73
E. canadensis
9.85
A. gerardii
11.76
S. scoparium
10.44
S. nutans
12.47
A. novae-angliae
14.57
C. tripteris
10.53
E. pallida
18.95
H. grosseserratus
10.95
H. helianthoides
8.21
M. fistulosa
11.14
P. integrifolium
13.13
P. digitalis
11.51
P. virginianum
4.67
R. pinnata
6.93
R. subtomentosa
7.89
S. integrifolium
6.32
S. laciniatum
3.14
S. perfoliatum
7.62
S. terebinthinaceum 12.52
S. rigida
7.89
B. leucantha
12.89
D. purpurea
7.22
D. canadense
12.48
L. capitata
17.72
βN
95% CI
-2.27 10.02
7.07 12.03
8.71 14.94
4.02 15.42
9.32 15.57
13.33 16.08
7.85 12.52
17.67 20.63
8.19 13.65
5.61 10.96
8.95 14.18
10.75 15.73
10.24 12.96
-3.33 9.97
4.70
9.49
5.31 10.35
2.81
9.54
1.19
5.15
4.81 10.39
-14.70 38.72
4.90 11.20
11.30 14.29
5.71
9.10
11.03 14.11
15.24 19.78
N
0.88
1.78
1.29
1.08
1.08
1.62
1.35
1.24
1.69
1.50
1.66
0.99
0.95
1.19
1.58
1.36
1.31
1.29
1.44
1.26
1.34
2.97
2.71
2.33
1.88
Mean
1.34
4.87
1.54
1.62
2.55
8.23
3.53
1.00
5.49
4.21
3.84
5.70
3.41
2.32
2.13
2.17
3.20
3.18
3.20
1.68
2.03
2.94
1.29
3.52
4.19
βChl×103
95% CI
-2.71 5.07
3.91
5.87
1.04
1.99
1.41
1.84
1.95
3.11
7.21
9.40
2.88
4.23
-9.24 10.33
4.53
6.43
3.28
5.09
3.36
4.32
4.90
6.56
2.60
4.22
1.79
2.84
1.62
2.82
1.22
3.02
2.54
4.09
-2.41 8.72
2.50
3.97
-7.50 10.30
1.35
2.93
2.34
3.58
0.79
1.69
2.94
4.43
2.70
5.74
Chl
10.74
12.72
9.31
12.29
9.81
10.02
7.24
11.72
10.58
8.56
8.10
8.53
7.34
10.02
10.28
7.90
10.33
11.62
6.97
13.57
13.13
21.04
25.04
14.44
14.56
Mean
5.66
3.53
0.88
1.16
1.68
0.57
3.04
1.09
2.56
-1.30
3.15
4.60
3.51
3.48
-2.10
5.92
-1.05
3.04
-0.94
4.21
9.83
βSLA×103
95% CI
na
-5.59 19.87
-17.56 22.19
na
-0.93 2.89
-3.13 6.06
-3.91 6.75
-4.13 5.74
-1.96 7.35
-0.87 3.05
1.95
3.71
-18.94 18.97
-36.85 41.24
na
3.88
5.31
2.98
4.08
-6.32 14.80
-16.74 15.40
-5.66 17.49
-10.85 8.50
2.27
3.80
-10.73 7.65
na
-3.44 10.51
-4.84 21.96
SLA
15.81
15.79
13.12
16.39
11.76
10.47
12.39
15.70
17.85
12.63
11.23
13.68
13.42
10.33
7.91
11.55
10.64
11.31
14.41
18.10
12.76
Table S3 Variability of Vcmax, Vmax and quantum efficiency contributed by fixed and random
effects.
τ(N effect): standard deviation of fixed leaf N effect on Vcmax or Vmax (N effect=βN×(N- N )).
τ(υleaf): standard deviation of random individual leaf effect on Vcmax or Vmax (υleaf).
Proportion of fixed effects on Vcmax or Vmax: proportion of variability in Vcmax or Vmax contributed by fixed
effect.
τ(Chl effect): standard deviation of fixed chlorophyll effect on quantum efficiency (Chl effect=βChl×(Chl-
Chl )).
τ(SLA effect): standard deviation of fixed chlorophyll effect on quantum efficiency (SLA
effect=βSLA×(SLA- SLA )).
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τ(αleaf): standard deviation of random individual leaf effect on quantum efficiency (αleaf).
Proportion of fixed effects on α: proportion of variability in quantum efficiency contributed by fixed
effect.
τ: model residual error.
“na”, not applicable: in these cases SLA data were not collected for the given species.
“ns”, not significant: in these cases the fixed effects of leaf traits on photosynthetic parameters
were not significant.
13