Xylem resistance to cavitation increases during summer in Pinus halepensis

Citations Over TimeTop 10% of 2023 papers

Abstract

Cavitation resistance has often been viewed as a relatively static trait, especially for stems of forest trees. Meanwhile, other hydraulic traits, such as turgor loss point (Ψ_tlp ) and xylem anatomy, change during the season. In this study, we hypothesized that cavitation resistance is also dynamic, changing in coordination with Ψ_tlp . We began with a comparison of optical vulnerability (OV), microcomputed tomography (µCT) and cavitron methods. All three methods significantly differed in the slope of the curve,Ψ₁₂ and Ψ₈₈ , but not in Ψ₅₀ (xylem pressures that cause 12%, 88%, 50% cavitation, respectively). Thus, we followed the seasonal dynamics (across 2 years) of Ψ₅₀ in Pinus halepensis under Mediterranean climate using the OV method. We found that Ψ₅₀ is a plastic trait with a reduction of approximately 1 MPa from the end of the wet season to the end of the dry season, in coordination with the dynamics of the midday xylem water potential (Ψ_midday ) and the Ψ_tlp . The observed plasticity enabled the trees to maintain a stable positive hydraulic safety margin and avoid cavitation during the long dry season. Seasonal plasticity is vital for understanding the actual risk of cavitation to plants and for modeling species' ability to tolerate harsh environments.

Related Papers

• → Xylem development – from the cradle to the grave(2015)171 cited
• → Ion-mediated changes of xylem hydraulic resistance in planta: fact or fiction?(2007)64 cited
• → Bicarbonate-Induced Alkalinization of the Xylem Sap in Intact Maize Seedlings as Measured in Situ with a Novel Xylem pH Probe(2004)38 cited
• → Xylem Development and Xylem Conductivity of Furrowed Xylem in Stem Terminals of Five Species of Aristolochia (Aristolochiaceae)(2022)1 cited
• → On-Line Measurements of Ion Relations in the Xylem Sap of Intact Plants(2007)5 cited