Differential biochemical responses of wheat shoots and roots to nickel stress: antioxidative reactions and proline accumulation

Abstract

Wheat (Triticum aestivum L. cv. 'Zyta') seedlings were treated with 10, 100 and 200 lM Ni. Tissue Ni accumulation, length, relative water content (RWC), proline and H 2 O 2 concentrations as well as the activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (POD) and glutathione S-transferase (GST) were studied in the shoots and roots after 6 days of Ni exposure. Treatment with Ni, except for its lowest concentration, resulted in a significant reduction in wheat growth. In comparison to the shoots, the roots showed greater inhibition of elongation, which corresponded with higher accumulation of Ni in these organs. Both shoots and roots responded to Ni application with a decrease in RWC and enhancement in proline concentration. Greater dehydration of the shoot tissue was accompanied by more intense accumulation of proline. Treatment of the wheat seedlings with the highest concentration of Ni led to about 60% increase in H 2 O 2 concentration in both studied organs. Apart from CAT, constitutive activities of antioxidative enzymes were much higher in the roots than in the shoots. Exposure of the seedlings to Ni resulted in SOD activity decline, which was more marked in the roots. While the shoots showed a substantial decrease (up to 30%) in CAT activity, in the roots the activity of this enzyme remained unchanged. After Ni application APX, POD and GST activities increased several-fold in the shoots, whereas in the roots they were not significantly altered. The results suggest that differential antioxidative responses of the shoots and roots of wheat seedlings to Ni stress might be related to diverse constitutive levels of antioxidant enzyme activities in both organs.

Modulatory role of jasmonic acid on photosynthetic pigments, antioxidants and stress markers of Glycine max L. under nickel stress

“…In present study toxic concentration of Ni initiated reduction in photosynthetic pigments 1 in G. max. Our results are in coherence with Alam et al (2007) in Cajanus with 1 mM and (Gajewska and Sklodowska 2007) in Triticum aestivum with 100 μM Ni. Latif (2010) reported similar results in Raphanus sativus where 200 ppm of NiSO 4 as a source of Ni to inhibit photosynthetic pigments.…”

“…Ni at 2 mM concentration enhanced the production of cellular H 2 O 2 to 36 % as compared to control distilled water raised seedlings in our case. This increase in H 2 O 2 lead to higher disintegration Gajewska and Sklodowska (2007) who reported significant decrease in activities of SOD and CAT in presence of 100 μM Ni in wheat leaves.…”

Nickel-induced oxidative stress and the role of antioxidant defence in rice seedlings

“…Nickel is toxic at high plant-available concentrations and can have detrimental effects on plant growth and metabolism (Parida et al 2003;Seregin and Kozhevnikova 2006;Gajewska and Skłodowska 2008). Our results show that Ni toxicity in rice seedlings is strongly correlated with increased production of O 2…”

“…Common symptoms of Ni toxicity are inhibited germination, leaf chlorosis and necrosis, increased ion leakage, reduced root development and slower plant growth (Parida et al 2003;Rao and Sresty 2000;Seregin and Kozhevnikova 2006). Many abiotic environmental stresses including salinity, drought stress, temperature extremes, and metal toxicity disrupt the redox homeostasis of cells and exert a wide range of adverse effects on plant growth and metabolism (Verma and Dubey 2003;Sharma and Dubey 2007;Gajewska and Skłodowska 2008). These stressful conditions induce overproduction of reactive oxygen species (ROS) such as O 2…”

Metal uptake, antioxidant status and membrane potential in maize roots exposed to cadmium and nickel

“…Several authors have highlighted the activation of reactive oxygen species (ROS) scavenging systems to ameliorate the oxidative burst induced upon exposure of plants to heavy metals (Baccouch et al 2001;Arvind & Prasad 2005;Rodriguez-Serrano et al 2006;Gajewska & Sk lodowska 2008). Crucial role in plant adaptation to heavy metal toxicity is played by the protective antioxidant system (Jocsak et al 2008;Maysa & Abdel-Aal 2008;Yadav 2010).…”