Reduced growth response of ornamental plant Nicotiana alata L. upon selected heavy metals uptake, with co-application of ethylenediaminetetraacetic acid

The use of ornamental plant will increase with the improvement in living standards in green and blue-green infrastructure of urban settings. Nicotiana alata is an ornamental plant, frequently grown as a model plant for horticulture, medicine, and scientific research studies throughout the world. Despite its popularity, little is known about the response of N. alata against heavy metals (HMs). This work is based on the hydroponic study to identify the impacts of selected HMs (Cd, Cr, Cu, Ni and Pb) on N. alata, at 0, 50 and 100 μM concentration, with the co-application of EDTA, at 0 and 2.5 mM in hydroponics system. The HMs uptake was found to be dose dependent, with significant higher uptake at 100 μM of respective HM. Highest cumulative uptake (mg kg⁻¹ of HMs in root, shoot, and leaf dried weight) noted were 767.50 ± 50.83, 862.30 ± 23.83, 271.29 ± 18.68, 1117.49 ± 46.10 and 2166.81 ± 102.09, for Cd, Cr, Cu, Ni, and Pb at 100 μM, respectively. It was identified that EDTA co-application with HMs resulted in boosted HMs uptake, with cumulative uptake percentage increment of 41.62, 54.67, 53.98, 34.48 and 19.92% for 100 μM of Cd, Cr, Cu, Ni, and Pb, respectively. Higher uptake led to negative impact on plant physiology, photosynthetic pigments, and higher lipid peroxidation, H₂O₂ contents, and electrolyte leakage that increased the stress. Higher HMs uptake induced higher antioxidant enzymatic response. It is recommended to incorporate appropriate soil modification to grow N. alata in sustainable infrastructures.