The impact of biochemical composition and nature of paramagnetic species in grains on stress tolerance of oat cultivars.
The aim of this work was to investigate the relationships between the chemical composition of oat grains and the tolerance to oxidative stress of oat genotypes. The studies were based on the results of biochemical analyses and both EPR and Raman spectroscopies on whole grains and their parts (embryo, endosperm, seed coat) originating from oat genotypes with different sensitivities to stress. We found that the amounts of fats and especially unsaturated fatty acids, proteins rich in glutamic acid and glycine, as well as phenolics and tocopherols were higher in grains of the tolerant genotype. Moreover, fats and proteins were distributed not only in embryos, but also in endosperms. The grains of tolerant genotypes exhibited high antioxidant activity and contained greater amounts of β-glucan. EPR data pointed to higher concentrations of various kinds of stable organic radicals (semiquinone, tyrosyl and carbon-centered radicals) in whole grains (and their parts) of sensitive genotypes. EPR spectra revealed the character of interactions of paramagnetic transition metal ions Fe(III) and Mn(II) with organic and inorganic structures of grains. The quantitative EPR measurements showed the dependence between the amount of radical species and the content of transition metal ions, mainly Fe(III) bonded to inorganic structures.
Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Kraków, Poland. Electronic address: labanows@chemia.uj.edu.pl.
Maria
M
Łabanowska
Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Kraków, Poland.
Magdalena
M
Kurdziel
Institute of Biology, Pedagogical University, Podchorążych 2, 30-084 Kraków, Poland; The Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, Niezapominajek 21, 30-239 Kraków, Poland.
Maria
M
Filek
Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Kraków, Poland.
Aleksandra
A
Wesełucha-Birczyńska
D000596:Amino Acids / Q000032:analysis; D018554:Avena / Q000737:chemistry* / Q000235:genetics / Q000502:physiology; D055864:Droughts; D056625:Endosperm / Q000737:chemistry / Q000235:genetics / Q000502:physiology; D005227:Fatty Acids / Q000032:analysis; D005290:Ferric Compounds / Q000737:chemistry; D005838:Genotype; D018384:Oxidative Stress; D012639:Seeds / Q000737:chemistry* / Q000235:genetics / Q000502:physiology; D013059:Spectrum Analysis, Raman
D000596:Amino Acids; D005227:Fatty Acids; D005290:Ferric Compounds
Biochemical analyses; EPR; Oat grains; Paramagnetic centers; Raman spectroscopy; Stress tolerance