Ecological Archives E093-034-A2

Arnold J. Bloom, Jose Salvador Rubio Asensio, Lesley Randall, Shimon Rachmilevitch, Asaph B. Cousins, and Eli A. Carlisle. 2012. CO2 enrichment inhibits shoot nitrate assimilation in C3 but not C4 plants and slows growth under nitrate in C3 plants. Ecology 93:355–367.

Appendix B. SAS mixed procedure on square-root-transformed relative growth rates of plants exposed to one of two different CO2 levels.

Age = age of plant in days;
N = N source, ammonium (Am) or nitrate (Ni);
CO2 = CO2 level, ambient (amb) or elevated (ele);
Effect Slices presents the influence of CO2 level on plants receiving ammonium or nitrate;
Initial Exposure = data from when differential treatments were first imposed;
Second Exposure = data from after plants were randomized and differential treatements were reimposed

Table B1. Arabidopsis: two CO2 levels.

Type 3 Tests of Fixed Effects
Effect Num df Den df F P > F
Age 5 376 105.45 < 0.0001
N 1 122 46.97 < 0.0001
Age × N 5 376 7.67 < 0.0001
CO2 1 122 10.62 0.0014
Age × CO2 5 376 3.50 0.0041
N × CO2 1 122 14.72 0.0002
Age × N × CO2 5 376 3.52 0.0040

Least Squares Means
Effect N CO2 Estimate SE df t P > |t|
N × CO2 Am amb 0.4358 0.003343 122 130.35 < 0.0001
N × CO2 Am ele 0.4611 0.003288 122 140.25 < 0.0001
N × CO2 Ni amb 0.4739 0.004163 122 113.84 < 0.0001
N × CO2 Ni ele 0.4718 0.003402 122 138.69 < 0.0001

Tests of Effect Slices
Effect N Num df Den df F P > F
N × CO2 Am 1 122 29.13 < 0.0001
N × CO2 Ni 1 122 0.15 0.7021

Table B2. Wheat: two CO2 levels.

Type 3 Tests of Fixed Effects
Effect Num df Den df F P > F
Age 3 138 7.41 0.0001
N 1 46 75.63 < 0.0001
Age × N 3 138 1.52 0.2112
CO2 1 46 112.51 < 0.0001
Age × CO2 3 138 3.45 0.0185
N × CO2 1 46 10.77 0.0020
Age × N × CO2 3 138 0.35 0.7919

Least Squares Means
Effect N CO2 Estimate SE df t P > |t|
N × CO2 Am amb 0.4217 0.001402 46 300.69 < 0.0001
N × CO2 Am ele 0.4408 0.001347 46 327.14 < 0.0001
N × CO2 Ni amb 0.4381 0.001402 46 312.43 < 0.0001
N × CO2 Ni ele 0.4482 0.001347 46 332.67 < 0.0001

Tests of Effect Slices
Effect N Num df Den df F P > F
N × CO2 Am 1 46 96.46 < 0.0001
N × CO2 Ni 1 46 26.83 < 0.0001

Table B3. Loblolly pine initial exposure: two CO2 levels.

Type 3 Tests of Fixed Effects
Effect Num df Den df F P > F
Age 4 144 3.61 0.0077
N 1 36 16.29 0.0003
Age × N 4 144 2.28 0.0632
CO2 1 36 0.13 0.7183
Age × CO2 4 144 1.47 0.2132
N × CO2 1 36 18.83 0.0001
Age × N × CO2 4 144 0.18 0.9468

Least Squares Means
Effect N CO2 Estimate SE df t P > |t|
N × CO2 Am amb 0.1469 0.003073 36 47.79 < 0.0001
N × CO2 Am ele 0.1613 0.003073 36 52.50 < 0.0001
N × CO2 Ni amb 0.1478 0.003073 36 48.10 < 0.0001
N × CO2 Ni ele 0.1356 0.003073 36 44.12 < 0.0001

Tests of Effect Slices
Effect N Num df Den df F P > F
N × CO2 Am 1 36 11.06 0.0020
N × CO2 Ni 1 36 7.91 0.0079

Table B4. Loblolly pine second exposure: two CO2 levels.

Type 3 Tests of Fixed Effects
Effect Num df Den df F P > F
Age 4 80 1.39 0.2461
N 1 20 23.75 < 0.0001
Age × N 4 80 0.10 0.9825
CO2 1 20 0.01 0.9206
Age × CO2 4 80 0.40 0.8098
N × CO2 1 20 33.83 < 0.0001
Age × N × CO2 4 80 0.08 0.9883

Least Squares Means
Effect N CO2 Estimate SE df t P > |t|
N × CO2 Am amb 0.1218 0.003383 20 36.01 < 0.0001
N × CO2 Am ele 0.1429 0.003654 20 39.10 < 0.0001
N × CO2 Ni amb 0.1253 0.004003 20 31.31 < 0.0001
N × CO2 Ni ele 0.1035 0.003654 20 28.33 < 0.0001

Tests of Effect Slices
Effect N Num df Den df F P > F
N × CO2 Am 1 20 17.84 0.0004
N × CO2 Ni 1 20 16.14 0.0007

Table B5. Sugar maple: two CO2 levels.

Type 3 Tests of Fixed Effects
Effect Num df Den df F P > F
Age 4 144 1.20 0.3129
N 1 36 1.11 0.2995
Age × N 4 144 0.08 0.9874
CO2 1 36 17.43 0.0002
Age × CO2 4 144 0.58 0.6765
N × CO2 1 36 6.55 0.0148
Age × N × CO2 4 144 0.27 0.8938

Least Squares Means
Effect N CO2 Estimate SE df t P > |t|
N × CO2 Am amb 0.09983 0.005775 36 17.29 < 0.0001
N × CO2 Am ele 0.09050 0.005775 36 15.67 < 0.0001
N × CO2 Ni amb 0.1085 0.005775 36 18.79 < 0.0001
N × CO2 Ni ele 0.06964 0.005775 36 12.06 < 0.0001

Tests of Effect Slices
Effect N Num df Den df F P > F
N × CO2 Am 1 36 1.31 0.2608
N × CO2 Ni 1 36 22.68 < 0.0001

Table B6. Sweet gum initial exposure: two CO2 levels.

Type 3 Tests of Fixed Effects
Effect Num df Den df F P > F
Age 4 116 87.52 < 0.0001
N 1 29 739.00 < 0.0001
Age × N 4 116 0.11 0.9802
CO2 1 29 49.97 < 0.0001
Age × CO2 4 116 5.43 0.0005
N × CO2 1 29 40.93 < 0.0001
Age × N × CO2 4 116 2.26 0.0669

Least Squares Means
Effect N CO2 Estimate SE df t P > |t|
N × CO2 Am amb 0.2302 0.002814 29 81.80 < 0.0001
N × CO2 Am ele 0.2285 0.002633 29 86.78 < 0.0001
N × CO2 Ni amb 0.1760 0.002482 29 70.92 < 0.0001
N × CO2 Ni ele 0.1409 0.002482 29 56.78 < 0.0001

Tests of Effect Slices
Effect N Num df Den df F P > F
N × CO2 Am 1 29 0.21 0.6534
N × CO2 Ni 1 29 99.99 < 0.0001

Table B7. Sweet gum second exposure: two CO2 levels.

Type 3 Tests of Fixed Effects
Effect Num df Den df F P > F
Age 3 36 1.27 0.2995
N 1 12 111.61 < 0.0001
Age × N 3 36 5.54 0.0031
CO2 1 12 11.85 0.0049
Age × CO2 3 36 1.66 0.1927
N × CO2 1 12 16.40 0.0016
Age × N × CO2 3 36 0.74 0.5373

Least Squares Means
Effect N CO2 Estimate SE df t P > |t|
N × CO2 Am amb 0.1324 0.003922 12 33.75 < 0.0001
N × CO2 Am ele 0.1348 0.003922 12 34.36 < 0.0001
N × CO2 Ni amb 0.1068 0.003922 12 27.24 < 0.0001
N × CO2 Ni ele 0.07745 0.003922 12 19.75 < 0.0001

Tests of Effect Slices
Effect N Num df Den df F P > F
N × CO2 Am 1 12 0.18 0.6753
N × CO2 Ni 1 12 28.07 0.0002

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