Assessment of Foliar Application of Copper and Zinc to Elevate the Defence Response of Bacopa monnieri (L.)

Abstract

Each of the nutrients is needed in different amounts and carries specific functions in the plant. Also, nutrients do not work in isolation; therefore, balanced nutrition is needed to optimize crop quality. Nutrient interactions may be synergistic or antagonistic and also possible to have no interactions. However, nutrients also stimulates the antioxidant activity in medicinal plants that improves the secondary metabolite production. To investigate the Zn and Cu response in Bacopa monnieri, an experiment was consisted of ZnSO4 and CuSO4 (BM0: CONTROL; BM1:1ppm Cu; BM2:2.5ppm Zn; BM3:5ppm Zn; BM4:0.5ppm Cu+5ppm Zn; BM5:1ppm Cu+2.5ppm Zn; BM6:1ppm Cu+5ppm Zn) during two successive years (2019-2020). Two foliar applications was given at 30 days of interval and samples were collected and analysed after 10 days of each spray. Most of the results showed that Zn concentration increased with BM6 treatment and Cu content recorded a rise with BM1 and BM6 treatments respectively, compared with control plants. Also, MDA content and H2O2 activity were observed higher in the presence of BM6. Meanwhile, all the treated plants induced the activity of SOD that found maximum at BM6 while APOX activity mostly increased at BM3 and BM6. The highest proline accumulation took place BM1 and BM3. The result also showed 2.5ppm Zn treatment gave the highest content of bacoside-A (0.31%). From the research it seems that all the parameters were significantly increased when compared to control. It was suggested from the present experiment that foliar spray of Zn and Cu accelerated antioxidative activities that provides Bacopa to compensate the oxidative damage along with Zn and Cu content along with Bacoside production.