Abstract
Cadmium (Cd) brings a devastating health hazard to human being as a serious consequence of agricultural and environmental contamination. We demonstrated the protective effect of silicon (Si) on cadmium (Cd)-stressed rapeseed (Brassica napus L. cv. BINA Sharisha 3) plants through regulation of antioxidant defense and glyoxalase systems. Twelve-day-old seedlings were exposed to Cd stress (0.5 and 1.0 mM CdCl2) separately and in combination with Si (SiO2, 1.0 mM) for 2 days. Cadmium toxicity was evident by an obvious oxidative stress through sharp increases in H2O2 content and lipid peroxidation (malondialdehyde, MDA content), and visible sign of superoxide and H2O2. Cadmium stress also decreased the content of ascorbate (AsA) and glutathione (GSH) as well as their redox pool. The activities of monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR) and catalase (CAT) were decreased by Cd while ascorbate peroxidase (APX) and glutathione S-transferase (GST) activities were increased. The enzymes of glyoxalase system (glyoxalase I, Gly I and glyoxalase II, Gly II) were also inefficient under Cd stress. However, exogenous application of Si in Cd treated seedlings reduced H2O2 and MDA contents and improved antioxidant defense mechanism through increasing the AsA and GSH pools and activities of AsA-GSH cycle (APX, MDHAR, DHAR and GR) and glyoxalase system (Gly I and Gly II) enzymes and CAT. Thus Si reduced oxidative damage in plants to make more tolerant under Cd stress through augmentation of different antioxidant components and methylglyoxal detoxification system.
Highlights
Cadmium (Cd) is one of the most toxic elements of the earth releasing from natural and anthropogenic sources which poses detrimental hazardous effects both in plant and animal kingdoms (Wu et al, 2017)
Membrane lipid peroxidation increased under Cd stress indicated by increased MDA contents by 56% and 133% in mild and severe stress, respectively, compared with control (Figure 1A)
Our results suggest that exogenous Si serves well in regulating antioxidant metabolism in B. napus seedlings under Cd stress
Summary
Cadmium (Cd) is one of the most toxic elements of the earth releasing from natural and anthropogenic sources which poses detrimental hazardous effects both in plant and animal kingdoms (Wu et al, 2017). Cadmium exposure interrupts nutrient uptake, inhibits enzyme activities, generates reactive oxygen species (ROS) and damages cell components (Wu J. et al, 2016; Rahman et al, 2017). Cadmium induces oxidative stress indirectly by enhancing ROS production; such as singlet oxygen (1O2), superoxide radical (O2−), hydrogen peroxide (H2O2), and hydroxyl radicals (OH) (Andresen and Küpper, 2013; Rahman et al, 2016). The AsA-GSH cycle enzymes are APX, MDHAR, DHAR and GR and a good coordination among these enzymes can render better tolerance to Cd or any other metal toxicity (Hasanuzzaman et al, 2012b). The thiol-dependent glyoxalase I (Gly I) and glyoxalase II (Gly II) enzymes can detoxify it by sequential reactions (Rahman et al, 2016; Hasanuzzaman et al, 2017a,b)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
