title: Primary stress responses in Arabidopsis thaliana exposed to gamma radiation.
abstract: As the environment is inevitably exposed to ionizing radiation from natural and anthropogenic sources, it is important to evaluate gamma radiation induced stress responses in plants. The objective of this research is therefore to investigate radiation effects in Arabidopsis thaliana on individual and subcellular level by exposing 2-weeks-old seedlings for 7 days to total doses of 3.9 Gy, 6.7 Gy, 14.8 Gy and 58.8 Gy and evaluating growth, photosynthesis, chlorophyll a, chlorophyll b and carotenoid concentrations and antioxidative enzyme capacities. While the capacity of photosystem II (PSII measured as Fv/Fm) remained intact, plants started optimizing their photosynthetic process at the lower radiation doses by increasing the PSII efficiency (φPSII) and the maximal electron transport rate (ETRmax) and by decreasing the non-photochemical quenching (NPQ). At the highest radiation dose, photosynthetic parameters resembled those of control conditions. On subcellular level, roots showed increased superoxide dismutase (SOD) and ascorbate peroxidase (APX) capacities under gamma irradiation but catalase (CAT), syringaldazine peroxidase (SPX) and guaiacol peroxidase (GPX) activities, on the other hand, decreased. In the leaves no alterations were observed in SOD, CAT and SPX capacities, but GPX was highly affected. Based on these results it seems that roots are more sensitive for oxidative stress under gamma radiation exposure than leaves.
authors: Belgian Nuclear Research Centre (SCK·CEN), Biosphere Impact Studies, Boeretang 200, 2400 Mol, Belgium. Electronic address: nvanhoud@sckcen.be.
authors: Nathalie
authors: N
authors: Vanhoudt
authors: Belgian Nuclear Research Centre (SCK·CEN), Biosphere Impact Studies, Boeretang 200, 2400 Mol, Belgium.
authors: Nele
authors: N
authors: Horemans
authors: Belgian Nuclear Research Centre (SCK·CEN), Biosphere Impact Studies, Boeretang 200, 2400 Mol, Belgium.
authors: Jean
authors: J
authors: Wannijn
authors: Belgian Nuclear Research Centre (SCK·CEN), Biosphere Impact Studies, Boeretang 200, 2400 Mol, Belgium.
authors: Robin
authors: R
authors: Nauts
authors: Belgian Nuclear Research Centre (SCK·CEN), Biosphere Impact Studies, Boeretang 200, 2400 Mol, Belgium.
authors: May
authors: M
authors: Van Hees
authors: Belgian Nuclear Research Centre (SCK·CEN), Biosphere Impact Studies, Boeretang 200, 2400 Mol, Belgium.
authors: Hildegarde
authors: H
authors: Vandenhove
mesh_terms: D017360:Arabidopsis / Q000254:growth & development / Q000378:metabolism / Q000528:radiation effects*; D002338:Carotenoids / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism; D000077194:Chlorophyll A; D005720:Gamma Rays / Q000009:adverse effects*; D010544:Peroxidases / Q000378:metabolism; D010788:Photosynthesis / Q000528:radiation effects; D018515:Plant Leaves / Q000254:growth & development / Q000378:metabolism / Q000528:radiation effects; D018517:Plant Roots / Q000254:growth & development / Q000378:metabolism / Q000528:radiation effects; D013312:Stress, Physiological / Q000502:physiology; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D002734:Chlorophyll; D002338:Carotenoids; C037184:chlorophyll b; D010544:Peroxidases; D002374:Catalase; D013482:Superoxide Dismutase; D000077194:Chlorophyll A
keywords: Antioxidative enzymes; Arabidopsis thaliana; Chlorophyll fluorescence; Gamma radiation; Leaf pigments; Photosynthesis