3.7 | Mesophyll conductance assumptions
The third objective was to compare GPPiso/SF using
different methods of estimating gm. Globally, there was
a significant effect of ‘plot’ (p-value = 0.007, df = 5, F = 19) and
‘gm assumptions’ (p-value = 0.0002, df = 5, F = 75).
Focusing on one plot at a time, we found a significantly lower
GPPiso/SF in the control plot estimates when using
gm/\(g_{C\hat{\alpha}}\) = 2.67 as compared to the
others. In the fertilised plot, we found significantly lower
GPPiso/SF of gm/\(g_{C\hat{\alpha}}\) =
2.67 compared to gm∞. The F plot was not significantly
different from the R plot by any of these methods (Figure 8).