Cadmium stress alters the redox reaction and hormone balance in oilseed rape (Brassica napus L.) leaves.
In order to understand the physiological response of oilseed rape (Brassica napus L.) leaves to cadmium (Cd) stress and exploit the physiological mechanisms involved in Cd tolerance, macro-mineral and chlorophyll concentrations, reactive oxygen species (ROS) accumulation, activities of enzymatic antioxidants, nonenzymatic compounds metabolism, endogenous hormonal changes, and balance in leaves of oilseed rape exposed to 0, 100, or 200 μM CdSO4 were investigated. The results showed that under Cd exposure, Cd concentrations in the leaves continually increased while macro-minerals and chlorophyll concentrations decreased significantly. Meanwhile, with increased Cd stress, superoxide anion (O2(• -)) production rate and hydrogen peroxide (H2O2) concentrations in the leaves increased significantly, which caused malondialdehyde (MDA) accumulation and oxidative stress. For scavenging excess accumulated ROS and alleviating oxidative injury in the leaves, the activity of enzymatic antioxidants, such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), was increased significantly at certain stress levels. However, with increased Cd stress, the antioxidant enzyme activities all showed a trend towards reduction. The nonenzymatic antioxidative compounds, such as proline and total soluble sugars, accumulated continuously with increased Cd stress to play a long-term role in scavenging ROS. In addition, ABA levels also increased continuously with Cd stress while ZR decreased and the ABA/ZR ratio increased, which might also be providing a protective role against Cd toxicity.
Key Laboratory of Poyang Lake Basin Agricultural Resources and Ecology of Jiangxi Province, Jiangxi Agricultural University, Nanchang, Jiangxi, 330045, People's Republic of China.
Hui
H
Yan
Queensland Department of Agriculture and Fisheries, Ecosciences Precinct, Brisbane, QLD, 4001, Australia.
Fiona
F
Filardo
Key Lab of Agricultural Soil and Water Engineering in Arid and Semiarid Areas, Ministry of Education, Northwest A & F University, Yangling, Shaanxi, 712100, People's Republic of China.
Xiaotao
X
Hu
Key Laboratory of Poyang Lake Basin Agricultural Resources and Ecology of Jiangxi Province, Jiangxi Agricultural University, Nanchang, Jiangxi, 330045, People's Republic of China.
Xiaomin
X
Zhao
Key Laboratory of Crop Physiology, Ecology and Genetic Breeding, Ministry of Education, Agronomy College, Jiangxi Agricultural University, Nanchang, Jiangxi, 330045, People's Republic of China. fudhui@163.com.
DongHui
D
Fu
D000975:Antioxidants / Q000378:metabolism; D029688:Brassica napus / Q000187:drug effects* / Q000378:metabolism; D002104:Cadmium / Q000032:analysis / Q000633:toxicity*; D002374:Catalase / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D008315:Malondialdehyde / Q000378:metabolism; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000187:drug effects*; D009195:Peroxidase / Q000378:metabolism; D010544:Peroxidases / Q000378:metabolism; D010937:Plant Growth Regulators / Q000378:metabolism*; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D012639:Seeds / Q000187:drug effects* / Q000378:metabolism; D012989:Soil Pollutants / Q000032:analysis / Q000633:toxicity*; D013482:Superoxide Dismutase / Q000378:metabolism
D000975:Antioxidants; D010937:Plant Growth Regulators; D017382:Reactive Oxygen Species; D012989:Soil Pollutants; D002104:Cadmium; D002734:Chlorophyll; D008315:Malondialdehyde; D006861:Hydrogen Peroxide; D010544:Peroxidases; D002374:Catalase; D009195:Peroxidase; D013482:Superoxide Dismutase
Brassica napus L; Cadmium stress; Endogenous hormones; Enzymatic and nonenzymatic antioxidants; ROS; Tolerance