Abstract
Changes in pre-dawn water potential, soil-to-leaf hydraulic conductance, and leaf diffusive conductance were well correlated in oak trees during natural drying cycles. Maximum daily leaf conductance was highly correlated with pre-dawn water potential for blackjack oak Quercus marilandica and northern red oak Quercus rubra while leaf water potential at the time of measurement of leaf conductance was not significantly correlated with leaf conductance. Soil-to-leaf hydraulic conductance was positively correlated with pre-dawn water potential and with maximum daily leaf conductance in both species. Relationships between leaf conductance, soil-to-leaf hydraulic conductance, and pre-dawn water potential were similar for blackjack oak at 3 sites along a pronounced moisture gradient. Soil-to-leaf hydraulic conductance declined more in co-occurring northern red oak than blackjack oak as pre-dawn water potential in both species declined from near zero to -1.0 MPa. Bulk leaf water potential may not be as important a limitation to gas exchange in the field as soil/root water potential and/or vapour pressure gradient. -from Authors
| Original language | English (US) |
|---|---|
| Pages (from-to) | 719-726 |
| Number of pages | 8 |
| Journal | Functional Ecology |
| Volume | 3 |
| Issue number | 6 |
| DOIs | |
| State | Published - Jan 1 1989 |
| Externally published | Yes |