Antioxidant Defence Response and Micronutrient Content Availability in Cyamopsis Varieties in eCO2 Concentration

There is need for research that explores the impact of elevated carbon dioxide on the antioxidant defense system, crop nutrition andsoil micro-nutrients availability which was not investigated much in past studies.A pot experiment was performed to analyse antioxidant defence response including Superoxide dismutase (SOD) enzyme assay, totalAscorbate, Ascorbate peroxidase (APX) leaf data assay, Flavanoid and Total Phenolic content (TPC) in leaves samples. Micronutrientsanalysis and nutritional quality were estimated including Cr, Mn, Fe, Co, Cu, Zn, As, Se, Mo and Pb elements. Micronutrients analysiswere determined in soil, leaves, pods and seeds of RGC 1002 and RGC 1066 Cyamopsis varieties fumigated under e[CO2]=550±20ppmand a[CO2]=420±20ppm maintained at FACE setup at CSIR- NBRI, Lucknow.Superoxide dismutase activity was found to decline in RGC 1002 [-16.63%] and RGC 1066 [-17.90%] while total ascorbate, ascorbateperoxidise activity, total phenol and flavonoid content increased in RGC 1002 [+9.37%, +6.30%, +11.53%, +10.46%] and RGC 1066[+66.32%, +12.17%, +76.50%, +19.82%] under elevated carbon dioxide e[CO2] concentration in both the cultivars. Micronutrient contentdeclined in leaves but it was enhanced in pods and seeds of both the cultivars under e[CO2] concentration. In leaves, pods and seedsof RGC 1002 micro-nutrient contents were Fe [-56.00%, +6.00%, +9.75%], Cu[-23.16%, +7.45%, +10.46%], Zn[-30.61%,+28.30%,+7.41],Mn[-32.29%, +23.05., +7.52] content. However in RGC 1066, there was a differential response regarding some of the metals Cu[-52.81%,+5.58%, +6.42%], Zn[-20.29%.+9.50%.+6.50%], Mn[+31.54%, +11.18%, +9.96%], Fe[+32.99%, +4.00%, +8.71%] content wasfound to increased under e[CO2] concentration.Antioxidant response in both the cultivars was enhanced under e[CO2] concentration that leads to the scavenging of ROS particles thusleading to declining of ROS and mitigating the plant against abiotic stress condition. This conditions leads to altogether improvementin plant antioxidant defences system. It was observed that the interaction between e[CO2] and both plant varieties increased uptake ofmicro-nutrients in pods and seeds in both the cultivars. Apart from these RGC 1066 varieties showed better uptake and translocationof micro-nutrient content (Fe, Cu, Zn) than RGC 1002 plant variety under e[CO2] concentration. Thus, it can be concluded that RGC 1066is better than RGC 1002 plant variety which is adapting and performing in better way under e[CO2] concentration.