Heuwinkel, H.H.HeuwinkelGutser, R.R.GutserClaassen, N.N.ClaassenSchmidhalter, U.U.SchmidhalterHorst, W. J.2023-07-142023-07-142001https://resolver.sub.uni-goettingen.de/purl?gro-2/130362N2 fixation estimated by 15N natural abundance can be erroneous because of changes in 15N discrimination during N uptakebook_chapter