ABSTRACT
This study aimed investigating the impact of biosynthesized nanoparticles (NPs) in enhancing the growth and yield components of rice sown in a ferruginous soil.
The study was conducted at the Botanic Garden of Department of Plant Biology and Biotechnology. Ferruginous soil used for this study was obtained from the reddish soil portion of the garden, whereas non-ferruginous soils were obtained from a mulched portion at Student Farm Project, Faculty of Agriculture. Viable seeds of rice (Oryza sativa var. Nerica), which were obtained from Raymos Guanah Farms Ltd, Delta State, were sown in both ferruginous and non-ferruginous soils. After four weeks, the plants were exposed to foliar sprays of biosynthesized NPs. These NPs were biosynthesized from silver nitrate, using extracts of leaves of Carica papaya (CA), Vernonia amygdalina (VA), Moringa oleiofera (MO), and Azadiracta indica (AZ); and the flowers of Hibiscus sabderiffa (ZO) and following standard procedure. The originally prepared stock solution was diluted to give 5, 15, and 30% concentrations of each synthesized NP. Upon initial foliar spray of Silver nanoparticles (Ag-NPs), a second dose (booster dose) was administered two weeks later. Care was taken to ensure that each experimental bowl was rid of weeds and any insect pests up to the end of the experiment.
Results showed that ferrugenicity impeded the growth and yield of rice; however, with the addition of NPs, there were improvements in plant growth and yield components. In the non-ferruginous soil (NS), plants exposed to AZ5% NPs had no grain yield. However, when the same NPs were sprayed unto the same plant in the ferruginous soil (FS), the grain yield was 0.92g per plant. Generally, it was observed that AZ showed the most promising enhancement capacity for yield irrespective of ferrugenicity. There was a 366% increase in plant yield when the rice grains were sown in FS and enhanced with AZ15%, compared to a 41% increase when the same AZ15%-enhanced plant was sown in NF. This may imply possible Fe synergy in the activities of Ag-NPs. This assumption however needs further research. There was increased antioxidant activity in rice sown in FS’s compared to NS’s; a possible evidence that ferrugenicity was a major source of physiological stress for the rice plant. The present study showed evidence that Ag-NPs can enhance plant yield by huge proportions in FS, a condition (ferrugenicity) that was hitherto inimical to yield disposition of rice.
