Ecological Archives E093-034-A3

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 C. SAS mixed procedure on square-root-transformed relative growth rates of plants exposed to one of three diferent CO2 levels.

Age = age of plant in days;
N = N source, ammonium (Am) or nitrate (Ni);
CO2 = CO2 level, ambient (amb), elevated (ele), or subambient (sub);
Effect Slices presents the influence of CO2 level on plants receiving ammonium or nitrate.

Table C1. Loblolly pine: three CO2 levels.

Type 3 Tests of Fixed Effects
Effect Num df Den df F P > F
Age 5 75 6.93 < 0.0001
N 1 15 18.50 0.0006
Age × N 5 75 0.20 0.9600
CO2 2 15 1.18 0.3343
Age × CO2 10 75 0.42 0.9349
N × CO2 2 15 3.76 0.0476
Age × N × CO2 10 75 0.55 0.8474

Least Squares Means
Effect N CO2 Estimate SE df t P > |t|
N × CO2 Am amb 0.1420 0.007547 15 18.82 < 0.0001
N × CO2 Am ele 0.1492 0.006536 15 22.83 < 0.0001
N × CO2 Am sub 0.1420 0.006536 15 21.72 < 0.0001
N × CO2 Ni amb 0.1249 0.007547 15 16.55 < 0.0001
N × CO2 Ni ele 0.1033 0.006536 15 15.80 < 0.0001
N × CO2 Ni sub 0.1307 0.007547 15 17.32 < 0.0001

Tests of Effect Slices
Effect N Num df Den df F P > F
N × CO2 Am 2 15 0.39 0.6846
N × CO2 Ni 2 15 4.37 0.0320

Table C2. Sweet gum: three CO2 levels.

Type 3 Tests of Fixed Effects
Effect Num df Den df F P > F
Age 17 816 214.00 < 0.0001
N 1 48 4360.26 < 0.0001
Age × N 17 816 23.41 < 0.0001
CO2 2 48 10.02 0.0002
Age × CO2 34 816 2.49 < 0.0001
N × CO2 2 48 28.78 < 0.0001
Age × N × CO2 34 816 1.74 0.0062

Least Squares Means
Effect N CO2 Estimate SE df t P > |t|
N × CO2 Am amb 0.1335 0.001565 48 85.25 < 0.0001
N × CO2 Am ele 0.1411 0.001565 48 90.16 < 0.0001
N × CO2 Am sub 0.1394 0.001565 48 89.07 < 0.0001
N × CO2 Ni amb 0.05838 0.001565 48 37.30 < 0.0001
N × CO2 Ni ele 0.04337 0.001565 48 27.71 < 0.0001
N × CO2 Ni sub 0.05909 0.001565 48 37.74 < 0.0001

Tests of Effect Slices
Effect N Num df Den df F P > F
N × CO2 Am 2 48 6.65 0.0028
N × CO2 Ni 2 48 32.15 < 0.0001

Table C3. Jade: three CO2 levels.

Type 3 Tests of Fixed Effects
Effect Num df Den df F P > F
Age 4 144 0.46 0.7633
N 1 36 0.24 0.6302
Age × N 4 144 1.04 0.3909
CO2 2 36 23.81 < 0.0001
Age × CO2 8 144 0.42 0.9055
N × CO2 2 36 2.23 0.1227
Age × N × CO2 8 144 0.31 0.9595

Least Squares Means
Effect N CO2 Estimate SE df t P > |t|
N × CO2 Am amb 0.1282 0.003118 36 41.13 < 0.0001
N × CO2 Am ele 0.1105 0.003118 36 35.45 < 0.0001
N × CO2 Am sub 0.1026 0.003118 36 32.91 < 0.0001
N × CO2 Ni amb 0.1228 0.003118 36 39.38 < 0.0001
N × CO2 Ni ele 0.1059 0.003118 36 33.97 < 0.0001
N × CO2 Ni sub 0.1090 0.003118 36 34.94 < 0.0001

Tests of Effect Slices
Effect N Num df Den df F P > F
N × CO2 Am 2 36 17.71 < 0.0001
N × CO2 Ni 2 36 8.32 0.0011

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