@article{Chen2026, 
author = {Yunrui Chen and Dayong Fan and Ziliang Li and Yujie Zhang and Yang He and Minzhi Chen and Wangfeng Zhang and Yali Zhang},
title = {Critical role of outside xylem hydraulic conductance in regulating stomatal conductance and water use efficiency in cotton across different planting densities},
year = {2026},
journal = {Journal of Integrative Agriculture (JIA)},
volume = {25},
number = {3},
pages = {965-976},
keywords = {cotton, leaf hydraulic conductance, water use efficiency, planting density, mesophyll structure, stomatal conductance},
url = {https://www.sciopen.com/article/10.1016/j.jia.2024.11.012},
doi = {10.1016/j.jia.2024.11.012},
abstract = {Hydraulic theory predicts a positive coupling between leaf hydraulic conductance (Kleaf) and stomatal conductance (gs); however, this theory has not been fully supported by observations, and underlying mechanisms are poorly understood. Partitioning Kleaf into inside-xylem (Kx) and outside-xylem (Kox) components offers a refined framework for elucidating the regulation of gs by leaf hydraulics. While optimal planting density may enhance water use efficiency (WUE) through modulation of gs, corresponding changes in leaf hydraulic properties and their influence on gas exchange remain unclear. We examined relationships among Kx, Kox, gs, leaf photosynthetic rate (AN), and WUE, and analyzed the structural determinants of Kox in cotton grown under eight planting densities: 12, 18, 24, 36, 48, 60, 72, and 84 plants m–2.  Results showed that as planting density increased, Kleaf and AN remained stable, whereas Kox and gs declined significantly. Leaf thickness and the volume fraction of inter-cellular air space were key structural factors influencing Kox. Neither Kleaf nor Kx correlated with AN or gs; however, Kox exhibited a significant positive correlation with gs. Furthermore, Kox was negatively correlated with WUE. These findings indicate that Kox modulates gs to minimize water loss without compromising AN, thereby enhancing WUE in cotton across varying planting densities.}
}