title: Oxidative stress and antioxidant response in Hypericum perforatum L. plants subjected to low temperature treatment.
abstract: Extreme low temperatures cause plants multiple stresses, among which oxidative stress is presumed to be the major component affecting the resultant recovery rate. Plants of Hypericum perforatum L., which are known especially for the photodynamic activities of hypericins capable of producing reactive oxygen species under exposure to visible light, were observed to display a substantial increase and persistence in active oxygen production at least two months after recovery from cryogenic treatment. In an effort to uncover the causative mechanism, the individual contributions of wounding during explant isolation, dehydration and cold were examined by means of antioxidant profiling. The investigation revealed activation of genes coding for enzymatic antioxidant catalase and superoxide dismutase at both the transcript and protein levels. Interestingly, plants responded more to wounding than to either low-temperature associated stressor, presumably due to tissue damage. Furthermore, superoxide dismutase zymograms showed the Cu/Zn isoforms as the most responsive, directing the ROS production particularly to chloroplasts. Transmission electron microscopy revealed chloroplasts as damaged structures with substantial thylakoid ruptures.
authors.affiliation: Pavol Jozef Šafárik University in Košice, Faculty of Science, Institute of Biology and Ecology, Mánesova 23, 04154 Košice, Slovakia.
authors.forename: Matúš
authors.initials: M
authors.lastname: Skyba
authors.forename: Linda
authors.initials: L
authors.lastname: Petijová
authors.forename: Ján
authors.initials: J
authors.lastname: Košuth
authors.forename: Dimitrina Petrova
authors.initials: DP
authors.lastname: Koleva
authors.forename: Tsveta Gancheva
authors.initials: TG
authors.lastname: Ganeva
authors.forename: Veneta Mihova
authors.initials: VM
authors.lastname: Kapchina-Toteva
authors.forename: Eva
authors.initials: E
authors.lastname: Cellárová
mesh_terms: D015100:3,3'-Diaminobenzidine / Q000378:metabolism; D000975:Antioxidants / Q000378:metabolism*; D002374:Catalase / Q000235:genetics / Q000378:metabolism; D002736:Chloroplasts / Q000648:ultrastructure; D003080:Cold Temperature; D015925:Cryopreservation; D005452:Fluoresceins / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D005838:Genotype; D006861:Hydrogen Peroxide / Q000378:metabolism; D020902:Hypericum / Q000201:enzymology / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D018384:Oxidative Stress / Q000235:genetics; D059828:Plant Cells / Q000648:ultrastructure; D018520:Plant Shoots / Q000201:enzymology / Q000235:genetics; D017382:Reactive Oxygen Species / Q000378:metabolism; D013194:Staining and Labeling; D013312:Stress, Physiological / Q000235:genetics; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism; D013997:Time Factors
chemical_list: D000975:Antioxidants; D005452:Fluoresceins; D007527:Isoenzymes; D017382:Reactive Oxygen Species; C029569:diacetyldichlorofluorescein; D015100:3,3'-Diaminobenzidine; D006861:Hydrogen Peroxide; D002374:Catalase; D013482:Superoxide Dismutase