caa a22 4500 397520913 CHVBK 20180308164632.0 cr unu---uuuuu 161202e199501 xx s 000 0 eng 10.1093/jxb/46.1.101 doi (NATIONALLICENCE)oxford-10.1093/jxb/46.1.101 The control of leaf conductance of white lupin by xylem ABA concentration decreases with the severity of water deficits [Elektronische Daten] [M.J. Correia, J.S. Pereira] We studied the effects of drought on leaf conductance (g), leaf water relations and on the concentration of abscisic acid (ABA) in the xylem sap of Lupinus albus L. plants. Drought was imposed by withholding watering until predawn leaf water potential (ψpd) decreased below -0.7 MPa. The abaxial stomata of water-stressed plants closed to a greater extent than the adaxial stomata and the same trend was evident after feeding exogenous ABA. Under moderate water deficits {ψpd = − 0.32 ± 0.05 MPa) xylem ABA concentration was significantly higher in water-stressed plants (0.1 mmol m-3) than in the controls, and the observed depression in g could be mimicked when excised leaves of well-watered plants were fed with exogenous ABA at the same concentration found in the xylem sap of moderately stressed plants. As soil drying progressed xylem ABA concentration increased further, reaching 0.8-0.9 mmol m-3 after 17 d without watering. However, feeding a similar concentration of exogenous ABA to leaves of well-watered plants failed to reproduce the depression in g observed in severely stressed plants. After rewatering, full recovery of g was not achieved immediately, in spite of xylem ABA concentration and ψpd returning to pre-stress levels. Our results indicate that the increase in xylem ABA concentration is quantitatively sufficient to account for the depression in leaf conductance observed in white lupin plants subjected to moderate water deficits, but the role of xylem ABA in controlling g apparently decreases when soil drying and plant water stress becomes severe. © Oxford University Press Research Papers nationallicence Lupinus albus L nationallicence stomatal conductance nationallicence drought nationallicence after-effect nationallicence root-to-shoot communication nationallicence abscisic acid nationallicence Correia M.J. Universidade do Algarve, UCTA Campus de Gambelas 8000 Faro, Portugal aut Pereira J.S. Instituto Superior de Agronomia 1399 Lisboa codex, Portugal aut Journal of Experimental Botany Oxford University Press 46/1(1995-01), 101-110 0022-0957 46:1<101 1995 46 exbotj https://doi.org/10.1093/jxb/46.1.101 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1093/jxb/46.1.101 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Correia M.J. Universidade do Algarve, UCTA Campus de Gambelas 8000 Faro, Portugal aut NATIONALLICENCE 700 1- Pereira J.S. Instituto Superior de Agronomia 1399 Lisboa codex, Portugal aut NATIONALLICENCE 773 0- Journal of Experimental Botany Oxford University Press 46/1(1995-01), 101-110 0022-0957 46:1<101 1995 46 exbotj Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford