Nitric Oxide as Attenuator Changes Ecophysiological in Maize Plants (Zea mays L.) Subjected to Copper Toxicity

Abstract

The objective of this work was to evaluate the attenuating effect of the nitric oxide donor (sodium nitroprusside -NPS) on the ecophysiological responses of corn plants (Zea mays L.) submitted to copper toxicity. Corn seeds of the K9606 VIP3 variety were soaked for 48 hours in Germitest paper with a solution containing treatment with sodium nitroprusside Na ₂ [Fe (CN) ₅ NO] 2H ₂ O (0, 200 and 300µM), sodium ferrocyanide Na ₄ Fe (CN) ₆ (300, 100 and 0 µM) respectively and deionized water (control), sown in buckets with 15 kg of soil incubated for 50 days containing copper concentrations CuSO ₄ .5H ₂ O (0, 60 and 200 mg kg ^-1). The design consisted of randomized blocks with 12 treatments and 4 repetitions, making a total of 48 plants. The data were submitted to ANOVA, using the Tukey test at 5% using SISVAR. There was no effect of treatments on height, leaf area and number of leaves, observing an increase in stem diameter of plants that received copper concentrations. There was no effect of treatments on the chlorophyll content measured by the SPAD index and gas exchange. The concentrations of 60 mg kg^-1 and 200mg kg^-1 of copper did not negatively affect the fluorescence variables of chlorophyll a, acting as a micronutrient within favorable limits. The variable chlorophyll fluorescence of the demonstrated the protective effect of nitric oxide present in nitroprusside sodium cyanide and sodium ferrocyanide present in the corn plants of the variety subjected to K9606VIP3 are copper concentrations.