Responses of growth and antioxidative enzymes to various concentrations of nickel in Zea mays leaves and roots. Fatemeh Ghasemi*, Reza Heidari, Rashid Jameii and Latifeh Purakbar

Abstract

<span style="font-family: Calibri;"><span style="font-size: medium;"><span>To assess nickel-induced toxicity in plants, <em>Zea mays</em> seeds were germinated and cultured on nutrient solution with nickel concentrations of 50-200 μM for a period of two weeks. </span><span>Observed biological makers included biomass</span><span>, soluble and total protein contents</span><span>, and the activities of</span><span> guaiacol peroxidase (GPX)</span><span>, </span><span>ascorbate peroxidase (APX), </span><span>catalase (CAT), and phenylalanine ammonia-lyase (PAL) in the leaves and roots of maize. The fresh and dry weight of leaves and<span> </span>roots increased in </span><span>50 μM</span><span> nickel but decreased in 100 and 200</span><span> μM. </span><span>Soluble and total protein contents were significantly increased by increasing nickel concentrations up to 200 </span><span>μM nickel<span> </span></span><span><span> </span>in both roots and leaves of maize</span><span>. Significant increases of ascorbate peroxidase (</span><span>the highest activity at 200 </span><span>μM</span><span> nickel)</span><span>, </span><span>catalase </span><span>(</span><span>the highest activity at 50 </span><span>μM</span><span> nickel), and phenylalanine ammonia-lyase</span><span> (</span><span>the highest activity at 100 </span><span>μM</span><span> nickel)</span><span> were observed in the leaves and roots of <em>Zea mays</em> seedlings at all tested nickel concentrations. Guiacol peroxidase activity was<span> </span>decreased in the leaves and roots of <em>Zea mays</em> seedlings exposed to different levels of nickel. The present results suggested that treatment with different levels of nickel may enhance the antioxidant activities in the leaves and roots of <em>Zea mays</em> seedlings, thus alleviate Ni-induced oxidative damage and enhance Ni tolerance.</span></span></span> <span><span style="font-family: Calibri; font-size: medium;"> </span></span>