title: Early osmotic adjustment responses in drought-resistant and drought-sensitive oilseed rape.
abstract: The impact of osmotic stress on growth, physiology, and metabolism of winter oilseed rape (Brassica napus L.) was investigated by detailed analysis of biomass traits, hormone metabolites and osmolytes in two genetically unrelated drought-tolerant genotypes and two unrelated drought-sensitive genotypes. Seedlings were grown in vitro under controlled conditions and osmotic stress was simulated by applying a gradual treatment with polyethylene glycol (PEG 6000), followed by hypo-osmotic treatment of variants used for metabolite determination. The results provide a basis for the identification of reliable selection criteria for drought resistance in oilseed rape. The in vitro cultivation system established during this study enabled effective discrimination of early osmotic stress responses between drought-resistant and -susceptible oilseed rape genotypes that also show large differences in relative seed yield under drought conditions in the field. Clear physiological and metabolic differences were observed between the drought-resistant and drought-sensitive genotypes, suggesting that osmotic adjustment is a key component of drought response in oilseed rape. Unexpectedly, however, the drought-resistant genotypes did not show typical hormonal adjustment and osmolyte accumulation, suggesting that they possess alternative physiological mechanisms enabling avoidance of stress symptoms.
authors.affiliation: Department of Plant Breeding, IFZ Research Centre for Biosystems, Land Use and Nutrition, Justus Liebig University, 35392, Giessen, Germany.
authors.forename: Sarah
authors.initials: S
authors.lastname: Hatzig
authors.forename: L Irina
authors.initials: LI
authors.lastname: Zaharia
authors.forename: Suzanne
authors.initials: S
authors.lastname: Abrams
authors.forename: Marie
authors.initials: M
authors.lastname: Hohmann
authors.forename: Laurie
authors.initials: L
authors.lastname: Legoahec
authors.forename: Alain
authors.initials: A
authors.lastname: Bouchereau
authors.forename: Nathalie
authors.initials: N
authors.lastname: Nesi
authors.forename: Rod J
authors.initials: RJ
authors.lastname: Snowdon
mesh_terms: D029688:Brassica napus / Q000502:physiology*; D050260:Carbohydrate Metabolism; D055864:Droughts; D009952:Ornithine / Q000378:metabolism; D009997:Osmotic Pressure; D010937:Plant Growth Regulators / Q000378:metabolism; D011392:Proline / Q000378:metabolism; D036226:Seedlings / Q000502:physiology; D013402:Sugar Alcohols / Q000378:metabolism; D013696:Temperature; D014867:Water / Q000502:physiology*
chemical_list: D010937:Plant Growth Regulators; D013402:Sugar Alcohols; D014867:Water; D011392:Proline; D009952:Ornithine
keywords: Abscisic acid; Brassica napus; drought; hormones; metabolites