ABSTRACT
In the present study, SeNPs were synthesized using Melia azedarach leaf extracts and investigated for growth promotion in wheat under the biotic stress of spot blotch disease. The phytosynthesized SeNPs were characterized using UV-visible spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), and Fourier-transformed infrared spectroscopy (FTIR). The in vitro efficacy of different concentrations of phytosynthesized SeNPs (i.e., 100 µg/mL, 150 µg/mL, 200 µg/mL, 250 µg/mL, and 300 µg/mL) was evaluated using the well diffusion method, which reported that 300 µg/mL showed maximum fungus growth inhibition. For in vivo study, different concentrations (10, 20, 30, and 40 mg/L) of SeNPs were applied exogenously to evaluate the morphological, physiological, and biochemical parameters under control conditions and determine when infection was induced. Among all treatments, 30 mg/L of SeNPs performed well and increased the plant height by 2.34% compared to the control and 30.7% more than fungus-inoculated wheat. Similarly, fresh plant weight and dry weight increased by 17.35% and 13.43% over the control and 20.34% and 52.48% over the fungus-treated wheat, respectively. In leaf surface area and root length, our findings were 50.11% and 10.37% higher than the control and 40% and 71% higher than diseased wheat, respectively. Plant physiological parameters i.e., chlorophyll a, chlorophyll b, and total chlorophyll content, were increased 14, 133, and 16.1 times over the control and 157, 253, and 42 times over the pathogen-inoculated wheat, respectively. Our findings regarding carotenoid content, relative water content, and the membrane stability index were 29-, 49-, and 81-fold higher than the control and 187-, 63-, and 48-fold higher than the negative control, respectively. In the case of plant biochemical parameters, proline, sugar, flavonoids, and phenolic contents were recorded at 6, 287, 11, and 34 times higher than the control and 32, 107, 33, and 4 times more than fungus-inoculated wheat, respectively. This study is considered the first biocompatible approach to evaluate the potential of green-synthesized SeNPs as growth-promoting substances in wheat under the spot blotch stress and effective management strategy to inhibit fungal growth.
ABSTRACT
Membraned Sediment Plant Microbial Fuel cells (SPMFCs) are appealing bioelectrochemical systems that generate power from organic compounds in sediment through exoelectrogen decomposition and are used to treat wastewater. This research was designed to develop a single-chambered sediment plant microbial fuel cell using two membrane electrodes; one carbon plate cathode and one anode. Wastewater and sediment mixture was sampled from Rawalpindi, Pakistan, and bacterial isolation was performed by serial dilution. Five strains were selected on the basis of morphology and growth-promoting characteristics. The selected strains were identified by 16s rRNA sequencing and designated as A (Geobacter sulfurreducens OP527025), B (Shawanella putrefaciens OP522353), C (Bacillus subtilus OP522349), D (Azospirillum humicireducens OP527050) and E (Pseudomonas putida OP526951). Consortium of five strains was developed. Two aquatic plants pennyworts (Hydrocotyle umbellate), and Hyacinth (Eichhornia crassipes) were used in the SPMFCs along with consortium. A maximum voltage of 1120mv was observed in SPMFCs treated with the consortium and water hyacinth, which was followed by 543.3 mv of SPMFCs treated with water pennyworts. Physicochemical analysis of wastewater showed a remarkable reduction of 74.5%, 71%, and 76% in nitrate, phosphate, and sulphate content of wastewater treated with microbes and water hyacinth. The heavy metal analysis showed a reduction of Zn (99.8%), Mg (99.9%), and Ni (98.4%) in SPMFCs treated with the consortium and water hyacinth. Mebraned SPMFCs showed an increase of 30% and 20% in shoot and root length of water hyacinth. A remarkable increase of 25%, 18%, and 12% were recorded in chlorophyll content, membrane stability index and relative water content of water hyacinth in SPMFCs treated with consortium compared to untreated cells. Osmolyte content had shown significant increase of 25% with consortium treated water hyacinth plant as compared to untreated one. An increase of 15%, 20% and 12% was noted in superoxide dismutase (SOD), peroxidase dismutase (POD) and catalase content of consortium treated water hyacinth as compared to control one. The present research gave insight into the potential of sediment plant microbial fuel cells along with aquatic plants for treatment of wastewater. This could be a effective method for removal of hazrdaous substances from wastewater and alternative approach for voltage production.
