title: Rapid changes in leaf elongation, ABA and water status during the recovery phase following application of water stress in two durum wheat varieties differing in drought tolerance.
abstract: This study aims to investigate the role of Abscisic acid (ABA) in water potential and turgor variations as well as growth recovery during the first phase of a rapid water stress induced by PEG6000. Two wheat varieties (Triticum durum L.), MBB (more tolerant) and OZ (less productive under drought), were grown in aerated nutrient solutions. Leaf elongation kinetics of the growing leaf 3 was estimated using LVDT. Water potential was measured using a pressure chamber; osmotic potential was estimated from expressed sap of elongation zone, turgor pressure of the same zone of leaf three was estimated directly by pressure probe. Growth rapidly ceased for a period of about one hour after the addition of PEG, gradual recovery was then observed for about 2 h. A significant difference was found in the % recovery of Leaf Elongation Rate (LER) and ABA between the two varieties, leading to better water status in MBB compared to OZ. The results of this study showed the possible role of ABA on growth resumption by the increase of relative water content and turgor via osmotic adjustment during the stress period in the leaves, which indicates the importance of OA in the resumption of LER even in the short term under conditions of water deficit. Full recovery of turgor but not of LER at the end stress period suggested the possible effect on cell wall extensibility (hardening) even at short term resulting from the rapid accumulation of ABA.
authors.affiliation: Faculté des Sciences Biologiques, Université des Sciences et de la Technologie Houari Boumedienne, BP 32 Bab Ezzouar, Alger, Algeria. mahdid_m@yahoo.fr
authors.forename: Mohamed
authors.initials: M
authors.lastname: Mahdid
authors.forename: Abdelkrim
authors.initials: A
authors.lastname: Kameli
authors.forename: Christina
authors.initials: C
authors.lastname: Ehlert
authors.forename: Thierry
authors.initials: T
authors.lastname: Simonneau
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism*; D000222:Adaptation, Physiological; D002473:Cell Wall / Q000187:drug effects / Q000378:metabolism; D003681:Dehydration; D055864:Droughts; D009997:Osmotic Pressure; D018515:Plant Leaves / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D054046:Plant Stomata / Q000378:metabolism; D018526:Plant Transpiration; D011092:Polyethylene Glycols / Q000494:pharmacology; D014908:Triticum / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D014867:Water / Q000378:metabolism
chemical_list: D014867:Water; D011092:Polyethylene Glycols; D000040:Abscisic Acid