Antioxidant enzyme responses to the oxidative stress due to chlorpyrifos, dimethoate and dieldrin stress in palak (Spinacia oleracea L.) and their toxicity alleviation by soil amendments in tropical croplands.

A field experiment was conducted to assess the impact of pesticides viz., chlorpyrifos, dimethoate and dieldrin alone and in combination with different soil amendments like chemical fertilizer, farmyard manure and combination of 50% chemical fertilizer and 50% farmyard manure on the growth, photosynthetic pigments, oxidative stress markers: superoxide radical (SOR) and hydrogen peroxide (HO) and their consequent damage on lipids in terms of malondialdehyde equivalents and electrolyte leakage, and different antioxidant enzymes activity like superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), glutathione-s-transferase (GST), ascorbate peroxidase (APX) and glutathione reductase (GR) in palak (Spinacia oleracea L.) grown widely in tropical croplands. The pesticides effect was analyzed at its recommended dose in agriculture for growing plants when applied two times after germination. Our results showed distinct increase in SOR and HO which further manifested in marked oxidative damages in case of pesticides treatment individually that lead to decline in growth characteristics and yield. Further the application of different types of soil amendments led to consistent increase in levels of antioxidant system along with the amelioration in oxidative damage indices which was comparable across the combined treatments. The photosynthetic pigments, yield, antioxidants were maximum in case of pesticides applied in combination with 50% chemical fertilizer and 50% farmyard manure (pesticides+NF). It was apparent from the results that the application of pesticides+NF might be recommended in tropics as it ameliorates oxidative damages and maintains high quality of plant along yield which in turn will lead to no negative consequences on the global population.