Potassium induces positive changes in nitrogen metabolism and antioxidant system of oat (Avena sativaL cultivar Kent)

Abstract

Potassium is actively involved in many functions such as enzyme activation, osmotic adjustment and uptake of deleterious ions like Na. Present report analyses the effectivity of different potassium salts on growth and certain components of nitrogen metabolism and antioxidant system in oat and their possible role in amelioration of water stress. Potassium induced enhancement in the activities of nitrate reductase and aminotransferases was evident indicating a positive role of potassium in nitrogen metabolism. Potassium supplementation enhanced activities of antioxidant enzymes (superoxide dismutase, catalase and ascorbate peroxidase) and contents of total phenols and tannins, probably strengthening both the enzymatic as well as non enzymatic antioxidant system. Free amino acids, proline and free sugars also exhibited the same trend in treated plants ensuring better plant growth.

Zinc application mitigates the adverse effects of NaCl stress on mustard [Brassica juncea (L.) Czern & Coss] through modulating compatible organic solutes, antioxidant enzymes, and flavonoid content

“…Furthermore, zinc application caused rapid ROS elimination, thereby further enhancing antioxidant enzyme activity coupled with better plant growth. Previous research supports our findings that supplementation of optimal mineral concentrations keeps ROS at nontoxic levels (Ahanger et al 2015;Iqbal et al 2015). SOD acts on superoxide radicals, which are further scavenged by either CAT or APX through the ascorbate-glutathione pathway; as a result, superoxide radicals are removed and prevented from forming more toxic radicals (Ahmad et al 2010;Bose et al 2014).…”

“…However, in salt-stressed plants, flavonoids are thought to act as chelators (Winkel-Shirley 2002). Mineral supplementation has been shown to enhance polyphenol accumulation in Avena sativa, leading to growth maintenance (Ahanger et al 2015). Besides their role as antioxidants, flavonoids function in plant metabolism and are likely involved in various signaling mechanisms, as suggested by their interaction with protein kinases involved in initiating cell growth and differentiation (e.g.…”

“…Increased proline accumulation is believed to maintain tissue water potential under environmental stresses, thus offering an important tolerance strategy (Ahanger et al 2014(Ahanger et al , 2015Ahmad et al 2015aAhmad et al , 2015b. Saltstressed plants maintain higher proline content through enhancing the activity of key enzymes involved in proline synthesis .…”

“…For example, supplementation of mineral macroand micro-nutrients at optimal concentrations allays adverse effects of stressors, leading to growth maintenance and yield increases (Ahanger et al 2015;Ahmad et al 2015b;Siddiqui et al 2015;Ahanger and Agarwal 2017). Among microelements, Zn is vital for regulating enzyme activity, the protein and membrane stabilization; it is a component of Zn finger, a major structural motif critical for DNA binding (Tavallali et al 2009).…”

“…proline, glycine betaine, and soluble sugars) synthesis and accumulation protect proteins, enzymes, and other biologically important molecules (Hayat et al 2012;Ahanger and Agarwal 2017). These osmotically active solutes act as antioxidants and contribute to water content maintenance for optimal cellular functioning (Ahanger et al 2014(Ahanger et al , 2015Anjum et al 2014).…”