Sodium Nitroprusside Mitigates the Inhibitory Effect of Salt and Heavy Metal Stress on Lupine Yield and Downregulates Antioxidant Enzyme Activities

Amira Hassanein,Hanan Hashem,Nihal Esmail

doi:10.5586/aa.7336

Amira Hassanein, Hanan Hashem + Show 1 more

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https://doi.org/10.5586/aa.7336

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Abstract

This study was conducted to investigate the effects of sodium nitroprusside (SNP) on antioxidant enzyme activities in Lupinus albus subsp. termis (Forssk.) Ponert plants subjected to salt and heavy metal stress. Foliar spray of SNP (0.4 and 0.6 mM) was used as a nitric oxide (NO) donor to treat lupine plants grown under different levels of salinity (0, 75, and 150 mM NaCl) and nickel (Ni) stress (100 and 150 mM Ni sulfate). Growth parameters and yield as well as total phenols, flavonoids, and antioxidant enzyme activities (including those of superoxide dismutase, peroxidase, ascorbate peroxidase, catalase, and glutathione transferase) in NO-treated and untreated plants grown under normal or salt/heavy metal stress conditions were determined. We found that exogenously applied SNP effectively mitigated the inhibitory effects of salinity and Ni stresses on all measured growth parameters and yield components of lupine plants. In addition, NO downregulated antioxidant enzyme activities, which proved to be a good indicator reflecting changes in the oxidative status of lupine plants in response to SNP, salt, and Ni sulfate treatments.

Highlights

Nitric oxide (NO) is a ubiquitous endogenous signaling molecule involved in the regulation of a number of developmental, physiological, and biochemical processes associated with plant metabolism (Asgher et al, 2016)
The yield characteristics of lupine plants treated with 0.4 mM sodium nitroprusside (SNP) and NaCl or NiSO4 were found to be lower than those treated with the same concentration of SNP alone and higher than those treated with the corresponding concentrations of NaCl and NiSO4
We observed significant increases in the yield characteristics of lupine plants in response to application SNP to plants subjected to salt or Ni stress, compared with those of untreated plants grown under the same stress condition

Summary

Introduction

Nitric oxide (NO) is a ubiquitous endogenous signaling molecule involved in the regulation of a number of developmental, physiological, and biochemical processes associated with plant metabolism (Asgher et al, 2016). NO is a free radical of particular interest in plant science, on account of its unique properties, being small in size, short-lived, lacking a charge, and having high diffusibility through biological membranes, and its multifunctional roles in plants under both normal and stress conditions (Siddiqui et al, 2010). The distinctive reactivity properties of NO, and its eventual dual action (i.e., beneficial or harmful) in biological cells, can be attributed to the presence of an unpaired electron within the π orbital of the nitrogen atom of the NO molecule, together with NO concentration and site of production. NO has been found to play a vital role at multiple stages in plant growth and development, from germination to flowering, the ripening of fruit, apoptosis induction, and senescence, as well as in plant responses to biotic and abiotic stressors (Popova & Tuan, 2010).

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