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Cadmium‐induced oxidative stress and the response of the antioxidative defense system in Spartina densiflora
Author(s) -
Martínez Domínguez David,
Córdoba García Francisco,
Canalejo Raya Antonio,
Torronteras Santiago Rafael
Publication year - 2010
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.2010.01368.x
Subject(s) - superoxide dismutase , catalase , oxidative stress , lipid peroxidation , glutathione reductase , reactive oxygen species , antioxidant , spartina , chemistry , peroxidase , biochemistry , biology , botany , glutathione peroxidase , enzyme , ecology , marsh , wetland
Spartina densiflora is an invasive cordgrass that is colonizing new habitats and ousting indigenous species in pro‐oxidative environments like cadmium‐polluted salt marshes in the Odiel estuary (Spain). The aim of our study was to characterize its antioxidative system in order to find out if the system underlies the tolerance of S. densiflora to cadmium toxicity. S. densiflora plants were firstly evaluated to ascertain its antioxidative status in the natural habitat and then they were cultured in the laboratory in unpolluted sand for 28 days. Throughout this period, plants acclimatized and oxidative stress markers reached stable low levels. Then, S. densiflora plants were exposed to cadmium concentrations (10, 100 and 1000 µ M Cd) for another 28 days. Higher Cd content in leaves was related to higher level of reactive oxygen species (ROS) causing important oxidative cell damage (lipid peroxidation and lower chlorophyll content). However, S. densiflora possesses a well‐organized and appropriately modulated antioxidative defense system which comprises enzymatic activities of guaiacol peroxidase (EC 1.11.1.7), catalase (EC 1.11.1.6), ascorbate peroxidase (EC 1.11.1.11) and superoxide dismutase (EC 1.15.1.1) coupled with the activation of the ascorbate cycle, including enzymatic activities of glutathione reductase (EC 1.6.4.2), dehydroascorbate reductase (EC 1.8.5.1) and monodehydroascorbate reductase (EC 1.6.5.4). This activation was sufficient to reduce Cd‐induced ROS accumulation and oxidative damage caused by the lowest Cd‐concentrations, but not by the highest Cd‐concentration (1000 µ M ). Nevertheless, the antioxidant system seems to be efficient to achieve a tolerance to cadmium toxicity, allowing normal plant development, even at the presence of highest Cd concentration.