Brassinosteroid-mediated evaluation of antioxidant system and nitrogen metabolism in two contrasting cultivars of Vigna radiata under different levels of nickel

Abstract

The role of 28-homobrassinolide (HBL) in countering nickel-induced oxidative damage through overexpression of antioxidant enzymes and proline in Vigna radiata has been investigated. Two varieties of V. radiata, one sensitive to Ni (PDM-139) and the other tolerant to Ni (T-44), were sown in the soil fed with different levels (0, 50, 100 or 150 mg kg −1 ) of Ni, and at 29-day stage, foliage of plants was applied with deionized water (control), 10 −8 or 10 −6 M of HBL. The plants were sampled at 45-day stage of growth to assess various physiological as well as biochemical characteristics. The remaining plants were allowed to grow up to maturity to study the yield characteristics. The growth traits, leghemoglobin, nitrogen and carbohydrate content in the nodules, leaf chlorophyll content, photosynthesis efficiency, leaf water potential, activities of nitrate reductase, carbonic anhydrase and nitrogenase decreased proportionately with the increasing concentrations of nickel, whereas electrolyte leakage, various antioxidant enzymes viz. catalase, peroxidase and superoxide dismutase and accumulation of proline increased at 45-day stage. However, the exogenously applied HBL to the nickel-stressed or non-stressed plants improved growth, nodulation and photosynthesis and further enhanced the various antioxidant enzymes viz. catalase, peroxidase and superoxide dismutase and accumulation of proline. The deleterious impact of Ni on the plants was concentration dependent where HBL applied to the foliage induced overexpression of antioxidant enzyme and accumulation of proline (osmolyte) which could have conferred tolerance to Ni up to 100 mg kg −1 , resulting in improved growth, nodulation, photosynthesis and yield attributes.

Alterations in photosynthetic pigments, antioxidant machinery, essential oil constituents and growth of menthol mint (Mentha arvensis L.) upon nickel exposure

“…However, Ni at 20 mg kg −1 proved beneficial for the plants as the activity of enzyme was also enhanced up to the significant level as compared to the control (Table 3). Similar outcomes were reported by Yusuf et al (2012Yusuf et al ( , 2014 on Vigna radiata (L.) R. Wilczek and Idrees et al (2013) in the case of Catharanthus roseus (L.) G. Don.…”

“…Nickel (Ni), an essential micronutrient, is required for plant metabolism (Brown et al 1987a;Chen et al 2009;Ahmad and Ashraf 2011;Harasim and Filipek 2015); however, it generates toxicity if present above the permissible limit (Küpper and Kroneck 2007a, b;Chen et al 2009). Deficiency of Ni in the plants causes generation of wide range of effects on growth and metabolism of plants such as nitrogen metabolism and iron uptake, as well as the generation of visible symptoms in plants including necrosis of leaf tips or chlorosis of older leaves, plant senescence (Graham et al 1985;Brown et al 1987b;Seregin and Kozhevnikova 2006) and ultimately leads to loss in agricultural productivity (Pandey and Sharma 2002;Yusuf et al 2014). It also inhibits the activity of urease enzyme which leads to accumulation of toxic levels of urea in shoots (Dixon et al 1975).…”

Transcriptome-based gene profiling provides novel insights into the characteristics of radish root response to Cr stress with next-generation sequencing

“…CYP450s play crucial roles in biosynthesis of a variety of endogenous lipophilic compounds such as fatty acids, sterols, phenylpropanoids, terpenoids, and phytoalexins brassinolides, which could enhance the plant tolerance under stresses (Narusaka et al, 2004 ; Vázquez et al, 2013 ; Fariduddin et al, 2014 ). It was reported that CYP450s were induced by abiotic stress, such as As (Chakrabarty et al, 2009 ) in rice, Pb (Liu et al, 2009 ) in Arabidopsis , Cr (Dubey et al, 2010 ) in rice and dehydration stress in cabbage (Yu et al, 2012 ), and biotic stress including insecticide stress in ladybirds (Zhang et al, 2012 ) and bacterial infection in tobacco (Daurelio et al, 2011 ).…”

Arsenic–silicon priming of rice (Oryza sativa L.) seeds influence mineral nutrient uptake and biochemical responses through modulation of Lsi-1, Lsi-2, Lsi-6 and nutrient transporter genes

“…Total nitrogen content was estimated by employing the method of Yusuf et al . 72 . The plant material was digested with concentrated H 2 SO 4 , followed by its neutralization with NaOH and sodium silicate solutions.…”