Abstract

The significance of shoot surface water uptake (SSWU) has been debated, and it would depend on the range of conditions under which it occurs. We hypothesized that the decline of leaf hydraulic conductance (K-leaf) in response to dehydration may be recovered through SSWU, and that the hydraulic conductance to SSWU (K-surf) declines with dehydration. We quantified effects of leaf dehydration on K-surf and effects of SSWU on recovery of K-leaf in dehydrated leaves of Avicennia marina. SSWU led to overnight recovery of K-leaf, with recovery retracing the same path as loss of K-leaf in response to dehydration. SSWU declined with dehydration. By contrast, K-surf declined with rehydration time but not with dehydration. Our results showed a role of SSWU in the recovery of leaf hydraulic conductance and revealed that SSWU is sensitive to leaf hydration status. The prevalence of SSWU in vegetation suggests an important role for atmospheric water sources in maintenance of leaf hydraulic function, with implications for plant responses to changing environments.