Early changes of the pH of the apoplast are different in leaves, stem and roots of Vicia faba L. under declining water availability

0476350 - ÚEB 2018 RIV IE eng J - Journal Article
Karuppanapandian, T. - Geilfus, C.M. - Muehling, K.H. - Novák, Ondřej - Gloser, V.
Early changes of the pH of the apoplast are different in leaves, stem and roots of Vicia faba L. under declining water availability.
Plant Science. Roč. 255, FEB (2017), s. 51-58. ISSN 0168-9452. E-ISSN 1873-2259
Institutional support: RVO:61389030
Keywords : xylem sap constituents * abscisic-acid * stomatal conductance * leaf apoplast * helianthus-annuus * plant-responses * intact plants * nacl stress * drying soil * guard-cells * Drought stress * Abscisic acid * Soil drying * Xylem sap * Osmolality * Water relations * Leaf water potential
OECD category: Plant sciences, botany
Impact factor: 3.712, year: 2017

Changes in pH of the apoplast have recently been discussed as an important factor in adjusting transpiration and water relations under conditions of drought via modulatory effect on abscisic acid (ABA) concentration. Using Vicia faba L., we investigated whether changes in the root, shoot and leaf apoplastic pH correlated with (1) a drought-induced reduction in transpiration and with (2) changes in ABA concentration. Transpiration, leaf water potential and ABA in leaves were measured and correlated with root and shoot xylem pH, determined by a pH microelectrode, and pH of leaf apoplast quantified by microscopy-based in vivo ratiometric analysis. Results revealed that a reduction in transpiration rate in the early phase of soil drying could not be linked with changes in the apoplastic pH via effects on the stomata-regulating hormone ABA. Moreover, drought-induced increase in pH of xylem or leaf apoplast was not the remote effect of an acropetal transport of alkaline sap from root, because root xylem acidified during progressive soil drying, whereas the shoot apoplast alkalized. We reason that other, yet unknown signalling mechanism was responsible for reduction of transpiration rate in the early phase of soil drying.
Permanent Link: http://hdl.handle.net/11104/0272868