Recently, the research team of professor Xi Benye from the College of Forestry of Beijing Forestry University published a paper entitled "Evaporation-driven internal hydraulic redistribution alleviates root drought stress: The research paper "mechanisms and modeling" in Plant Physiology (Q1, IF=8.005) , which provides new insights into water physiology and drought resistance mechanism of woody plants.

Many tree species have developed extensive root systems that allow them to survive in arid environments by obtaining water from a large soil volume. These root systems can transport and redistribute soil water during drought by hydraulic redistribution (HR). A recent study revealed the phenomenon of evaporation-driven hydraulic redistribution (EDHR), which is driven by evaporative demand (transpiration). In this study, the research team confirmed the occurrence of EDHR in Chinese white poplar (Populus tomentosa) through root sap flow measurements. Microcomputed tomography technology was utilized to reconstruct the xylem network of woody lateral roots and proposed conceptual models to verify EDHR from a physical perspective. The results indicated that EDHR is driven by the internal water potential gradient within the plant xylem network, which requires 3 conditions: high evaporative demand, soil water potential gradient, and special xylem structure of the root junction. The simulations demonstrated that during periods of extreme drought, EDHR could replenish water to dry roots and improve root water potential up to 38.9% to 41.6%. This highlights the crucial eco-physiological importance of EDHR in drought tolerance. The proposed models provide insights into the complex structure of root junctions and their impact on water movement, thus enhancing our understanding of the relationship between xylem structure and plant hydraulics.

The first author of the paper is Ph.D student Liu Yang from the College of Forestry, and the corresponding author is professor Xi Benye from the College of Forestry. Professor Nadezhdina from Mendel University in Brno, researcher Hu Wei from the New Zealand Institute for Plant & Food Research Ltd, and other faculties and students from BFU and universties and institutes at home and abroad also participated in the study.

This research was supported by the National Natural Science Foundation of China [grant numbers 32171763, 31872702].

Paper link: https://academic.oup.com/plphys/advance-article-abstract/doi/10.1093/plphys/kiad364/7205635