28 February 2022

A new paper published on low root temperature effects on water and carbon transport in trees

Wenna Wang and Günter Hoch published a new study on low temperature limits of temperate tree species in Tree Physiology. The effects of low root temperatures on xylem conductance, photosynthetic C assimilation and phloem C transport were quantified experimentally in seedlings of four temperate tree species  by applying a simultaneous stable isotope labelling of ²H-enriched source water and ¹³C-enriched atmospheric CO₂. Although all seedlings were grown in hydroponic conditions and received warm air temperatures, root cooling led to drought-like symptoms with reduced growth, leaf water potentials and stomatal conductance, indicating increasingly adverse conditions for water uptake and transport with decreasing root temperatures. Overall, this study highlights the potentially important role of hydraulic constraints induced by low soil temperatures as a contributing factor for the cold distribution limits of temperate tree species.