title: Lead-stress induced changes in the content of free, thylakoid- and chromatin-bound polyamines, photosynthetic parameters and ultrastructure in greening barley leaves.
abstract: The aim of this study was to determine the impact of lead (Pb) stress as 0.6mM Pb(NO3)2 on the content of free, thylakoid- and chromatin-bound polyamines (PAs) and diamine oxidase (DAO) activity in detached greening barley leaves. Additionally, photosynthetic-related parameters, generation of hydrogen peroxide (H2O2) and malondialdehyde (MDA) content and ultrastructural changes under Pb-stress were studied. The level of putrescine (Put) was reduced progressively to 56% at 24h of Pb stress, and it was correlated with 38% increase of DAO activity. Spermidine (Spd) content was not affected by Pb-stress, while the free spermine (Spm) level significantly increased by about 83% at 6h, and in that time the lowest level of H2O2 was observed. The exogenous applied Spm to Pb-treated leaves caused a decrease in the content of H2O2. In greening leaves exposed to Pb an accumulation of chlorophylls a and b was inhibited by about 39 and 47%, respectively, and photosynthetic parameters of efficiency of electron transport and photochemical reaction in chloroplasts as ΦPSII, ETR and RFd were lowered by about 23-32%. The level of thylakoid-bound Put decreased by about 22%. Moreover, thylakoids isolated from chloroplasts of Pb-treated leaves were characterized with lower Put/Spm ratio as compared to control leaves. In the presence of Pb the significant decrease in the number of thylakoids per granum and cap-shape invaginations of cytoplasmic material were noticed. In Pb-stressed leaves the level of chromatin-bound Spm increased by about 48% and sometimes condensed chromatin in nuclei was observed. We conclude that in greening barley leaves exposed to Pb-stress changes in free, thylakoid- and chromatin-bound PAs play some role in the functioning of leaves or plants in heavy metal stress conditions.
authors: Department of Plant Physiology, Faculty of Biology, Adam Mickiewicz University in Poznan, ul. Umultowska 89, 61-614 Poznań, Poland. Electronic address: legocka@amu.edu.pl.
authors: Jolanta
authors: J
authors: Legocka
authors: Department of Plant Physiology, Faculty of Biology, Adam Mickiewicz University in Poznan, ul. Umultowska 89, 61-614 Poznań, Poland.
authors: Ewa
authors: E
authors: Sobieszczuk-Nowicka
authors: Department of Plant Physiology, Faculty of Biology, Adam Mickiewicz University in Poznan, ul. Umultowska 89, 61-614 Poznań, Poland.
authors: Łukasz
authors: Ł
authors: Wojtyla
authors: Laboratory of Electron and Confocal Microscopy, Faculty of Biology, Adam Mickiewicz University in Poznan, ul. Umultowska 89, 61-614 Poznań, Poland.
authors: Sławomir
authors: S
authors: Samardakiewicz
mesh_terms: D002734:Chlorophyll / Q000378:metabolism; D002843:Chromatin / Q000378:metabolism; D001467:Hordeum / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D006861:Hydrogen Peroxide / Q000378:metabolism; D007854:Lead / Q000378:metabolism / Q000633:toxicity*; D008315:Malondialdehyde / Q000378:metabolism; D010788:Photosynthesis / Q000187:drug effects*; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D011073:Polyamines / Q000378:metabolism*; D011700:Putrescine / Q000378:metabolism; D013095:Spermidine / Q000378:metabolism; D013096:Spermine / Q000378:metabolism; D013312:Stress, Physiological; D020524:Thylakoids / Q000378:metabolism
chemical_list: D002843:Chromatin; D011073:Polyamines; D002734:Chlorophyll; D013096:Spermine; D007854:Lead; D008315:Malondialdehyde; D006861:Hydrogen Peroxide; D013095:Spermidine; D011700:Putrescine
keywords: Chlorophyll; Free and bound polyamines; Greening; Heavy metal; Hordeum vulgare; Hydrogen peroxide; Malondialdehyde; Ultrastructure