Effects of exogenous nitric oxide on cadmium toxicity and antioxidative system in perennial ryegrass

Abstract

The effects of sodium nitroprusside (SNP, a donor of NO) on cadmium (Cd) toxicity in ryegrass seedlings (Lolium perenne L.) were studied. 100 and 150 μM Cd stress had a detrimental effect on ryegrass seedlings. Exposure of 100 and 150 μM Cd inhibited plant growth, decreased chlorophyll concentration, and reduced the absorption of Fe, Cu and Zn. Excess Cd also altered the activities of antioxidant enzymes, and increased the accumulation of reactive oxygen species (ROS). Exogenous NO alleviated Cd toxicity of ryegrass plants, especially under the stress of 150 μM Cd, as evidenced by improved plant growth and increased concentrations of chlorophyll and mineral nutrients. Exogenous NO also mitigated oxidative stress by regulating the activities of antioxidant enzymes and the contents of non-antioxidants. Moreover, the absorption of Fe, Cu and Zn was increased, indicating that exogenous NO stimulated H + -ATPase activity to promote sequestration or uptake of ions. The applications of NO also reduced the translocation of Cd from roots to the leaves. These results indicate that the mechanisms of NO for mitigating Cd toxicity may be associated with reduced root-to-shoot translocation of Cd and enhanced capacity of antioxidative systems to protect plants from oxidative stress.

Cadmium Toxicity Alleviates by Seed Priming with Proline or Glycine Betaine in Cowpea ( Vigna unguiculata (L.) Walp.)

“…In the current experiment, Cd toxicity markedly reduced the growth attributes of cowpea plants, including shoot length, shoot biomass and leaf area. These results are in conformity with the previous findings on different plant species (Jhanji et al, 2012;Perveen et al, 2016;Sun et al, 2016;Chen et al, 2018). Nonetheless, seed priming with Pro or GB, especially 50mM Pro, improved all measured growth parameters under Cd stress.…”

“…MDA, an end product of membrane lipid peroxidation is a proper marker for oxidative stress by heavy metal toxicity. In the current experiment, an elevated level of MDA in cowpea leaves was observed in Cd treated plants, which is conformity with the other findings (Shamsi et al, 2008;Ahmad et al, 2016;Chen et al, 2018). However, in this study, seed priming with Pro or GB significantly reduced the MDA level under Cd toxicity.…”

Responses of nitric oxide and hydrogen sulfide in regulating oxidative defence system in wheat plants grown under cadmium stress

“…Similarly, other bioactive compounds such as melatonin reversed the oxidative stress in tomato plants grown under high temperature (Ahammed et al ). NO may also increase the activities of antioxidant enzymes in plants subjected to stress regimes (Kovacik et al , Chen et al ). This study also showed that SNP augmented the antioxidant enzyme activities in the leaves to scavenge ROS induced by Cd stress.…”

Nitric oxide‐mediated regulation of oxidative stress in plants under metal stress: a review on molecular and biochemical aspects

“…As stated earlier, metals induce ROS accumulation in plant cells, often resulting in a marked reduction of the photosynthetic efficiency. However, according to multiple records, the signaling molecule NO is able to counteract the negative effects of metals on the redox state of the cell, helping towards a better photosynthetic yield (Jhanji et al , Khairy et al , Chen et al ). The mechanisms by which NO is able to protect the photosynthetic machinery, as well as its metabolic chains, are illustrated in Fig.…”