Scholarlink

Key Message <p><b>Residual conductance in </b><Emphasis Type="BoldItalic">Abies alba</Emphasis><b> is developmentally dynamic, varies among sites, but is genetically constrained, highlighting its key role in acclimation to drought and heatwave-driven hydraulic failure.</b></p> Abstract <p>Residual water losses after stomatal closure are key determinants of drought-induced hydraulic failure, especially during heatwaves. However, intraspecific variability of residual conductance (<i>g</i><sub>res</sub>) and its thermal sensitivity remains poorly documented. Here, we investigated genetic and environmental sources of variation in <i>g</i><sub>res</sub> and its associated thermal parameters (phase transition temperature <i>T</i>ₚ, and temperature sensitivities <i>Q</i><sub>10a</sub> and <i>Q</i><sub>10b</sub>) in silver fir (<i>Abies alba</i> Mill.), and compared them with other hydraulic traits, including vulnerability to xylem embolism (<i>P</i><sub>50</sub>). We combined three complementary approaches: (i) seasonal monitoring to characterize temporal dynamics and biochemical determinants, (ii) a common garden experiment including seven French provenances to assess genetic variability, and (iii) comparisons across contrasting forest sites and canopy positions to quantify environmental effects. Measurements were performed using the Drought-Box, an automated chamber used to dehydrate organ under controlled temperature. Residual conductance exhibited a seasonal decline, with high values in newly formed needles followed by stabilization from late summer to the following spring, consistent with cuticular wax accumulation. Differences among provenances were weak for all traits, suggesting constraints on hydraulic safety. In contrast, <i>g</i><sub>res</sub> showed substantial site-related variations, with lower values at climatically constrained sites. No significant canopy position effects were detected, and thermal parameters of <i>g</i><sub><i>res</i></sub> and <i>P</i><sub>50</sub> remained relatively conserved across both provenances and environmental gradients. These results identify <i>g</i><sub>res</sub> as a developmentally dynamic trait showing site-related variation in silver fir, potentially contributing to acclimation to drought. Accounting for this variability should improve predictions of tree vulnerability under future climates combining intensified droughts and heatwaves.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Phenotypic variability of hydraulic residual conductance and its temperature sensitivity in Abies alba Mill

  • 期刊论文

  • 发表日期：

    2026年8月5日

查看全文
  • Stéphane Herbette,
  • Andanson Stéphane,
  • Gonzalez Alexandre,
  • J. Blackman Chris,
  • Cartailler Julien,
  • Martin Ludovic,
  • Cochard Hervé

摘要

Key Message

Residual conductance in Abies alba is developmentally dynamic, varies among sites, but is genetically constrained, highlighting its key role in acclimation to drought and heatwave-driven hydraulic failure.

Abstract

Residual water losses after stomatal closure are key determinants of drought-induced hydraulic failure, especially during heatwaves. However, intraspecific variability of residual conductance (gres) and its thermal sensitivity remains poorly documented. Here, we investigated genetic and environmental sources of variation in gres and its associated thermal parameters (phase transition temperature Tₚ, and temperature sensitivities Q10a and Q10b) in silver fir (Abies alba Mill.), and compared them with other hydraulic traits, including vulnerability to xylem embolism (P50). We combined three complementary approaches: (i) seasonal monitoring to characterize temporal dynamics and biochemical determinants, (ii) a common garden experiment including seven French provenances to assess genetic variability, and (iii) comparisons across contrasting forest sites and canopy positions to quantify environmental effects. Measurements were performed using the Drought-Box, an automated chamber used to dehydrate organ under controlled temperature. Residual conductance exhibited a seasonal decline, with high values in newly formed needles followed by stabilization from late summer to the following spring, consistent with cuticular wax accumulation. Differences among provenances were weak for all traits, suggesting constraints on hydraulic safety. In contrast, gres showed substantial site-related variations, with lower values at climatically constrained sites. No significant canopy position effects were detected, and thermal parameters of gres and P50 remained relatively conserved across both provenances and environmental gradients. These results identify gres as a developmentally dynamic trait showing site-related variation in silver fir, potentially contributing to acclimation to drought. Accounting for this variability should improve predictions of tree vulnerability under future climates combining intensified droughts and heatwaves.