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. 2000 Jul 5;97(14):7894–7898. doi: 10.1073/pnas.97.14.7894

Table 2.

Observed and predicted leaf water δ18O values of leaf segments

Leaf segment Observed δ18O, ‰ Craig–Gordon model-predicted δ18O, ‰ Gat–Bowser model
Nonvariable E
Fitted E
E, mmol⋅m−2⋅s−1 Predicted δ18O, ‰ E, mmol⋅m−2⋅s−1 Predicted δ18O, ‰
Base 1 −7.4 11.0 7.14 −7.5 7.40 −7.4
2 1.0 11.0 7.14 −2.4 12.25 1.0
3 9.6 11.0 7.14 3.2 10.60 9.6
4 16.1 11.0 7.14 9.4 6.05 16.1
5 23.2 11.0 7.14 16.4 5.70 23.2
6 27.7 11.0 7.14 24.6 2.40 27.7
Tip 7 41.7 11.0 7.14 35.3 5.60 37.3
Mean 16.0 11.0 7.14 11.3 7.14 15.4

δ18Osource was −12.5‰, and all other environmental parameters were as mentioned in Table 1. In the Gat–Bowser model, the mean value of E for the entire leaf remains constant. However, the proportion of E within a segment was either held constant (nonvariable E) or was varied (fitted E). The calculated variations in fitted E across the length of the leaf are less than those of sugarcane (20).