Effect of 2850MHz electromagnetic field radiation on the early growth, antioxidant activity, and secondary metabolite profile of red and green cabbage (Brassica oleracea L.).

Abstract

The proliferation of wireless and other telecommunications equipment brought about by technological advances in the communication industry has substantially increased the radiofrequency radiation levels in the environment. The emphasis is, therefore, placed on investigating the potential impacts of radiofrequency radiation on biota. In this work, the impact of 2850MHz electromagnetic field radiation (EMF-r) on early development, photosynthetic pigments, and the metabolic profile of two Brassicaoleracea L. cultivars (red and green cabbage) was studied. On a daily basis for seven days, seedlings were exposed to homogeneous EMF-r for one, two, and four hours, and observations were carried out at 0-h, 1-h, and 24-h following the final dose. Irrespective of the duration of harvest, exposure to EMF-r resulted in a dose-dependent reduction in both root (from 6.3 cm to4.0cm in red; 6.1 cmto3.8cm in green) and shoot lengths (from 5.3 cm to⁓3.1cm in red; 5.1cm to3.1cm in green), as well as a decrease in biomass (from 2.9 mg to⁓1.1mg in red; 2.5 to0.9mg in green) of the seedlings when compared to control samples. Likewise, the chlorophyll (from 6.09 to⁓4.94mgg-1 d.wt in red; 7.37 to6.05mgg-1 d.wt. in green) and carotenoid (from 1.49 to1.19mgg-1 d.wt. in red; 1.14 to0.51mgg-1 d.wt. in green) contents of both cultivars decreased significantly when compared to the control. Additionally, the contents of phenolic (28.99‒45.52mg GAE g-1 in red; 25.49‒33.76mg GAE g-1 in green), flavonoid (21.7‒31.8mg QE g-1 in red; 12.1‒19.0mg QE g-1 in green), and anthocyanin (28.8‒43.6mg per 100g d.wt. in red; 1.1‒2.6mg per 100g d.wt. in green) in both red and green cabbage increased with exposure duration. EMF-r produced oxidative stress in the exposed samples of both cabbage cultivars, as demonstrated by dose-dependent increases in the total antioxidant activity (1.33‒2.58mM AAE in red; 1.29‒2.22mM AAE in green), DPPH activity (12.96‒78.33% in red; 9.62‒67.73% in green), H2O2 content (20.0‒77.15nMg-1 f.wt.in red; 14.28‒64.29nMg-1 f.wt. in green), and MDA content (0.20‒0.61nMg-1 f.wt. in red; 0.18‒0.51nMg-1 f.wt. in green) compared to their control counterparts. The activity of antioxidant enzymes, i.e., superoxide dismutases (3.83‒8.10 EU mg-1 protein in red; 4.19‒7.35 EU mg-1 protein in green), catalases (1.81‒7.44 EU mg-1 protein in red; 1.04‒6.24 EU mg-1 protein in green), and guaiacol peroxidases (14.37‒47.85 EU mg-1 protein in red; 12.30‒42.79 EU mg-1 protein in green), increased significantly compared to their control counterparts. The number of polyphenols in unexposed and EMF-r exposed samples of red cabbage was significantly different. The study concludes that exposure to 2850MHz EMF-r affects the early development of cabbage seedlings, modifies their photosynthetic pigments, alters polyphenol content,and impairs their oxidative metabolism.