Table II.
Comparison of the weighted mean of measured Δlw and Craig-Gordon predicted ΔC of cotton leaves in low and high humidities
| Time of Sampling | Weighted Mean Δlw | Weighted Mean ΔC | Δlw − ΔC | (Δlw/ΔC) − 1 |
|---|---|---|---|---|
| Low humidity | ‰ | |||
| 1115–1500 | 25.7 | 23.3 | 2.4 | 0.105 |
| 1000–1225 | 27.3 | 25.1 | 2.2 | 0.088 |
| 0950–1140 | 25.9 | 23.9 | 2.0 | 0.082 |
| Mean | 26.3 | 24.1 | 2.2 | 0.092 |
| se | 0.5 | 0.5 | 0.1 | 0.007 |
| High humidity | ||||
| 1000–1240 | 18.3 | 16.9 | 1.4 | 0.082 |
| 1315–1535 | 22.0 | 19.4 | 2.6 | 0.135 |
| 1015–1330 | 18.4 | 16.2 | 2.2 | 0.138 |
| Mean | 19.6 | 17.5 | 2.1 | 0.118 |
| se | 1.2 | 1.0 | 0.4 | 0.018 |
The vapor pressure deficits of air at low (RH 35%) and high (RH 75%) humidity were 2.8 and 1.0 kPa, respectively. Weighted mean of Δlw and ΔC were calculated from the same data set of Fig. 5A, using a weighting ratio of margin:intercostal:venous:basal = 4.7:10.7:4.3:1. Leaf sampling was carried out on different days.