Root water gates and not changes in root structure provide new insights into plant physiological responses to drought, flooding and salinity

摘要: The influence of aquaporin (AQP) activity on plant water movement remains unclear, especially in plants subject to unfavorable conditions. We applied a multitiered approach at range scales (i) characterize the resistances controlling transport under drought, flooding and plus salinity conditions; (ii) quantify respective effects AQP xylem structure root (Kroot), stem (Kstem) leaf (Kleaf) conductances, (iii) evaluate impact AQP-regulated capacity gas exchange. found that flooding-salinity reduced Kroot Pinus taeda, whereas flood-tolerant Taxodium distichum did not decline flooding. extent AQP-control efficiency varied among organs species, ranging from 35%-55% 10%-30% Kstem Kleaf. In response treatments, AQP-mediated inhibition rather than changes acclimation controlled fluctuations Kroot. reduction stomatal conductance its sensitivity vapor pressure deficit were direct responses decreased whole-plant triggered by lower larger resistance belowground. Our results provide new mechanistic functional insights hydraulics are essential quantifying influences future stress ecosystem function.