Résumé : Gamma-ray decay schemes have been measured with bare and Compton-suppressed Ge detectors at low-energy resonances (EP < 340 keV) in the (p, γ) reactions on 25Mg, 26Mg and 27Al. Altogether 58 new decay branches have been observed and a new 26Mg(p, γ)27Al resonance has been found at EP = 154.5 ± 1.0 keV. The new branchings lead to Jπ; T determinations (or limitations) for two states in 26Al and four states in 28Si. The absolute strengths of the 25Mg(p, γ)26Al and 26Mg(p, γ)27Al resonances have also been obtained, and the uncertainties of the stellar rates, deduced from the available data for both reactions, are significantly reduced. Some astrophysical consequences are discussed. © 1990.