Publication Abstracts
Nakad et al. 2026
, A. Potkay, M.A. Hesse, M. Mencuccini, P. Gentine, and , 2026: Spatial sucrose sink profiles shape phloem transport efficiency and xylem-phloem water exchange. J. Theor. Biol., 621, 112346, doi:10.1016/j.jtbi.2025.112346.
The transport of photosynthates, particularly sucrose, is a key process in plant physiology, eco-hydrology, and earth system modeling. The phloem plays a central role in this transport, influencing processes ranging from plant survival during drought to ecosystem-scale carbon and water cycling. The core principle underlying our understanding of phloem transport is the pressure-flow hypothesis, in which sucrose is loaded into leaves, drawing water from the xylem through osmosis and generating pressure gradients for transport. Experimental challenges in measuring sugar fluxes and phloem turgor pressure have led to a reliance on theoretical models. However, discrepancies persist, particularly for long-distance transport, where past modeling assumptions have led to difficulties in maintaining sufficient pressure, a challenge that may be alleviated when considering unloading along the transport pathway. Criticisms of the pressure-flow hypothesis often overlook the role of local unloading along the phloem pathway, which can alleviate pressure demands by reducing sucrose concentration and viscosity. To account for their effects, this study examines the influence of local sucrose sinks on transport dynamics. Osmotically driven flows are investigated through the development of a new one-dimensional numerical model that incorporates sinks toward the stem and roots. Results show that different allocation schemes of sucrose sinks along the stem influence the speed of sucrose transport, with simulations that include local sucrose sink distributions aligning more closely with past observations than those without these sinks. Sink profiles with higher demand near the stem base are more consistent with the classical pressure-flow hypothesis, referred to as the passive Münch mechanism, promoting stable pressure gradients and efficient transport. These findings provide insight into how carbon allocation within the phloem may have evolved to optimize the efficiency of soluble compound transport.
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BibTeX Citation
@article{na00700s,
author={Nakad, M. and Potkay, A. and Hesse, M. A. and Mencuccini, M. and Gentine, P. and Weng, E.},
title={Spatial sucrose sink profiles shape phloem transport efficiency and xylem-phloem water exchange},
year={2026},
journal={Journal of Theoretical Biology},
volume={621},
pages={112346},
doi={10.1016/j.jtbi.2025.112346},
}
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RIS Citation
TY - JOUR ID - na00700s AU - Nakad, M. AU - Potkay, A. AU - Hesse, M. A. AU - Mencuccini, M. AU - Gentine, P. AU - Weng, E. PY - 2026 TI - Spatial sucrose sink profiles shape phloem transport efficiency and xylem-phloem water exchange JA - J. Theor. Biol. JO - Journal of Theoretical Biology VL - 621 SP - 112346 DO - 10.1016/j.jtbi.2025.112346 ER -
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