Modulating response of Zea mays to induced salinity stress through application of nitrate mediated silver nanoparticles and indole acetic acid

Plant growth-promoting rhizobacteria and biochar as bioeffectors and bioalleviators of drought stress in faba bean (Vicia faba L.)

Plants are subjected to a variety of abiotic stressors, including drought stress, that are fatal to their growth and ability to produce under natural conditions. Therefore, the present study was intended to investigate the drought tolerance potential of faba bean (Vicia faba L.) plants under the co-application of biochar and rhizobacteria, Cellulomonas pakistanensis (National Culture Collection of Pakistan (NCCP)11) and Sphingobacterium pakistanensis (NCCP246). The experiment was initiated by sowing the inoculated seeds with the aforementioned rhizobacterial strains in earthen pots filled with 3 kg of sand-mixed soil and 5% biochar. The morphology of biochar was observed with highly porous nature, along with the detection of various essential elements. The biochemical and physiological data showed that phenolic compounds and osmolytes were adversely affected by the induction of drought stress. However, the application of biochar and rhizobacteria boosted the level of flavonoids on average by 52.03%, total phenols by 50.67%, soluble sugar by 82.85%, proline by 76.81%, glycine betaine by 107.25%, and total protein contents by 89.18% in all co-treatments of biochar and rhizobacteria. In addition, stress indicator compounds, including malondialdehyde (MDA) contents and H2O2, were remarkably alleviated by 54.21% and 47.03%, respectively. Similarly, the amplitude of antioxidant enzymes including catalase, peroxidase, superoxide dismutase, ascorbate peroxidase, and guaiacol peroxidase was also enhanced by 63.80%, 80.95%, 37.87%, and 58.20%, respectively, in all co-treatments of rhizobacteria and biochar. Conclusively, biochar and rhizobacteria have a magnificent role in enhancing the drought tolerance potential of crop plants by boosting the physio-biochemical traits and enhancing the level of antioxidant enzymes.

Modulation of salt stress through application of citrate capped silver nanoparticles and indole acetic acid in maize

The present study was conducted to determine the effect of indole acetic acid (IAA) and Citrate Capped Silver Nanoparticles (Cit-AgNPs) on various attributes of maize under induced salinity stress. Seeds of the said variety were collected from Cereal Crop Research Institute (CCRI) Pirsabaq, Nowshera, sterilized and sown in earthen pots filled with 2 kg silt and soil (1:2) in triplicates in the green house of the Botany Department, University of Peshawar. Nanoparticles were analyzed by scanning electron microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDX), Thermo-gravimetric analysis (TGA) and Differential thermal analysis (DTA). Results of SEM revealed spherical morphology of Cit-AgNPs while EDX showed various elemental composition. TGA showed dominant weight loss up to 300 °C while the DTA showed major exothermic peaks at 420 °C. High Salinity concentration (80 mM) imposed significant detrimental impacts by reducing the agronomic attributes, photosynthetic pigments, osmolytes and antioxidant enzymes, which was remarkably ameliorated by the foliar application of Cit-AgNPs and IAA. Agronomic attributes including leaf, root and shoot fresh and dry weight was improved by 52-74%, 43-69% and 36-79% in individual as well as combined treatments of IAA and NPs. Photosynthetic pigments were amplified by 35-63%, total osmolytes were augmented by 39-68% and antioxidant enzymes including SOD and POD were boosted by 42-57% and 37-62% respectively, in combined as well as individual application. Conclusively, Cit-AgNPs are considered as salt mitigating entities that enhance the tolerance level of crop plants along with IAA, which may be beneficial for the plants growing in saline stressed environment.