Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Long-distance abscisic acid signalling under different vertical soil moisture gradients depends on bulk root water potential and average soil water content in the root zone
AU - Puertolas Simon, Jaime
AU - Alcobendas, Rosalía
AU - Alarcón, Juan J.
AU - Dodd, Ian
PY - 2013/8
Y1 - 2013/8
N2 - To determine how root to shoot abscisic (ABA) acid signalling is regulated by vertical soil moisture gradients, root ABA concentration ( [ABA]root ), the fraction of root water uptake from, and root water potential of different parts of the root-zone, along with bulk root water potential, were measured to test various predictive models of root xylem ABA concentration [RX-ABA]sap. Beans (Phaseolus vulgaris L. cv. Nassau) were grown in soil columns and received different irrigation treatments (top and basal watering, and withholding water for varying lengths of time) to induce different vertical soil moisture gradients. Root water uptake was measured at 4 positions within the column by continuously recording volumetric soil water content (θv). Average θv was inversely related to bulk root water potential (root). In turn, root was correlated with both average [ABA]root and [RX-ABA]sap. Despite large gradients in θv, [ABA]root and root water potential was homogenous within the root zone. Consequently, unlike some split-root studies, root water uptake fraction from layers with different soil moisture did not influence xylem sap [ABA]. This suggests two different patterns of ABA signalling, depending on how soil moisture heterogeneity is distributed within the root-zone, which might have implications for implementing water-saving irrigation techniques.
AB - To determine how root to shoot abscisic (ABA) acid signalling is regulated by vertical soil moisture gradients, root ABA concentration ( [ABA]root ), the fraction of root water uptake from, and root water potential of different parts of the root-zone, along with bulk root water potential, were measured to test various predictive models of root xylem ABA concentration [RX-ABA]sap. Beans (Phaseolus vulgaris L. cv. Nassau) were grown in soil columns and received different irrigation treatments (top and basal watering, and withholding water for varying lengths of time) to induce different vertical soil moisture gradients. Root water uptake was measured at 4 positions within the column by continuously recording volumetric soil water content (θv). Average θv was inversely related to bulk root water potential (root). In turn, root was correlated with both average [ABA]root and [RX-ABA]sap. Despite large gradients in θv, [ABA]root and root water potential was homogenous within the root zone. Consequently, unlike some split-root studies, root water uptake fraction from layers with different soil moisture did not influence xylem sap [ABA]. This suggests two different patterns of ABA signalling, depending on how soil moisture heterogeneity is distributed within the root-zone, which might have implications for implementing water-saving irrigation techniques.
KW - Phaseolus vulgaris
KW - partial root zone drying
KW - root-to-shoot signalling
KW - soil moisture heterogeneity
U2 - 10.1111/pce.12076
DO - 10.1111/pce.12076
M3 - Journal article
VL - 36
SP - 1465
EP - 1475
JO - Plant, Cell and Environment
JF - Plant, Cell and Environment
SN - 0140-7791
IS - 8
ER -