Untersuchungen zur Aufnahme und zum Ferntransport xenobiotischer Aminosäuren in höheren Pflanzen

Abstract

Summary Uptake and long distance transport of xenobiotic amino acids (α-aminoisobutyric acid, o - and p -chlorophenoxyaminobutyric acids, 2,4-dichlorophenoxyaminobutyric acid) and o -chlorophenoxybutyric acid into the leaf tissues of Egeria densa, Vicia faba and in intact plants of Sinapis alba were investigated.It has been shown that the rate of uptake of phenoxybutyric acid derivatives is a linear function of their external concentrations in the range between 5 · 10 -5 and 10 -3 M.The membrane passage was not influenced by the inhibitors CCCP, DNP and azide (NaN 3 ).These observations suggest that the influx of phenoxyaminobutyric acids can be attributed to simple diffusion.Uptake was strongly p H-dependent and correlated with the lipophilic properties of phenoxyaminobutyric acids.Efflux experiments indicate that both the α-amino and α-carboxyl groups are essential for the high retention of xenobiotic amino acids within leaf cells.The Q tr data detected in our Sinapis test suggest that xenobiotic amino acids are transported in a manner comparable with biogenic amino acids (alanine, citrulline, glutamic acid, phenylalanine), both in phloem and in xylem.