| Comments |
P.406 bottom paragraph: "Even though photosynthesis and transpiration depend on environmental conditions, we can still make some generalizations about WUE for different types of plants. Specifically, WUE’s averaged over a day for mature leaves are usually 1 to 3 gCO2/(kg H2O) for C3 plants, 2 to 5 gCO2/(kgH2O) for C4 plants, and 10 to 40 g CO2/(kg H2O) for CAM plants. C4 plants have approximately double the WUE of C3 plants because C4 plants tend to have lower gas-phase conductances (which conserves water with a relatively small negative effect on photosynthesis) and higher liquid-phase conductances (which affects photosynthesis positively) than do C3 plants. However, maximizing WUE may not always be adaptive, e.g., water is generally not limiting for an aquatic plant." |