Linking xylem water storage with anatomical parameters in five temperate tree species

Area of Science:

• Plant Physiology
• Forest Ecology
• Wood Anatomy

Background:

• Hydraulic capacitance is vital for buffering water potential fluctuations in trees.
• Tissue anatomy is assumed to influence hydraulic capacitance, but specific links are unclear.

Purpose of the Study:

• To investigate the relationship between specific anatomical parameters and sapwood hydraulic capacitance in temperate trees.
• To differentiate contributions of capillary and elastic storage to capacitance.

Main Methods:

• Sapwood capacitance (C) was measured in branches and roots of five temperate tree species.
• Capacitance was partitioned into capillary (CI) and elastic (CII) components based on water release curves.
• Correlations between anatomical traits (density, cell ratios, lumen area, wall thickness) and capacitance were analyzed.

Main Results:

• Overall capacitance (C) was higher in roots than branches.
• Capillary storage (CI) was 3-11 times greater than elastic storage (CII).
• Sapwood density and the ratio of dead to living xylem cells correlated strongly with C; CI linked to fibre/tracheid lumen area; CII linked to parenchyma cell wall thickness.

Conclusions:

• Capillary water release predominates over elastic storage in temperate tree xylem.
• Parenchyma cells play a limited role in water storage in juvenile xylem.
• Anatomical traits, particularly fibre/tracheid features, significantly determine hydraulic capacitance and water release dynamics.