Mathematical modeling of climate and fluoride effects on sugarcane photosynthesis with silicon nanoparticles.

Fluoride (F-) stress is one of the major environmental pollutant, affecting plant growth, development and production, globally. Acquisition of eco-friendly F- stress reliever seems to be the major concern these days. Consequently, application of engineered nanomaterials (ENMs) has been increasing to improve agri-economy. However, the impact of silicon nanoparticles (Si NPs) on mitigation of F- stress has not been investigated yet. Thus, the present study was conducted to compare their protective roles against F- stress by improving diurnal photosynthetic efficiency of sugarcane plant leaves. An ability of sugarcane (Saccharum officinarum cv. GT44) plants to ameliorate F- toxicity assessed through soil culture medium. After an adaptive growth phase, 45 days old plants select to examine F- mitigative efficacy of silicon nanoparticles (SiNPs: 0, 100, 300 and 500 ppm) on sugarcane plants, irrigated by F- contaminated water (0, 100, 200 and 500 ppm). Our results strongly favour that SiNPs enhanced diurnally leaf photosynthetic gas exchange viz., photosynthesis (∼1.0-29%), stomatal conductance (∼3.0-90%), and transpiration rate (∼0.5-43%), significantly, as revealed by increments in photochemical chlorophyll fluorescence efficiency of PS II linked with performance index and photosynthetic pigments during F- stress. To the best of our knowledge, this is the first investigation to explore the impact of SiNPs improving and/or maintaining the diurnal photosynthetic responses in sugarcane plants in response to F- stress. It may also precisely unlayer action of molecular mechanism(s) mediated by SiNPs, found essential for mitigation of F--toxicity to explore nano-phytoremediation approach for crop improvement and agri-economy as well.

Pantoea conspicua promoted sunflower growth and engulfed rhizospheric arsenate by secreting exopolysaccharide.

A rhizobacterium, Pantoea conspicua, was examined against sunflower seedlings' growth under arsenate stress. Sunflower upon exposure to arsenate resulted in compromised growth that might be due to the accumulation of higher concentrations of arsenate and reactive oxygen species (ROS) in seedlings' tissues. The deposited arsenate led to oxidative damage and electrolyte leakage, making the sunflower seedlings vulnerable to compromise its growth and development. However, inoculation of sunflower seedlings with P. conspicua alleviated arsenate stress in host by initiating a multilayered defence mechanism. In fact, P. conspicua filtered out 75.1% of the arsenate from growth medium that were available to the plant roots in the absence of the said strain. To accomplish such activity, P. conspicua secreted exopolysaccharides as well as altered lignification in host roots. The arsenate (24.9%) that made its way to plant tissues was countered by helping the host seedlings to produce higher levels of indole acetic acid, non enzymatic antioxidants (phenolics and flavonoids) and antioxidant enzymes (catalase, ascorbte peroxidase, peroxidase, superoxide dismutase). As a result, ROS accumulation and electrolyte leakage were brought back to normal levels as observed in control seedlings. Hence, the rhizobacterium associated host seedlings achieved higher net assimilation (127.7%) and relative growth rate (113.5%) under 100 ppm of arsenate stress. The work concluded that P. conspicua alleviated arsenate stress in the host plants by imposing physical barrier as well as improving host seedlings' physiology and biochemistry.

MHD boundary layer slip flow and heat transfer of ferrofluid along a stretching cylinder with prescribed heat flux.

This study investigates the magnetohydrodynamic (MHD) flow of ferrofluid along a stretching cylinder. The velocity slip and prescribed surface heat flux boundary conditions are employed on the cylinder surface. Water as conventional base fluid containing nanoparticles of magnetite (Fe3O4) is used. Comparison between magnetic (Fe3O4) and non-magnetic (Al2O3) nanoparticles is also made. The governing non-linear partial differential equations are reduced to non-linear ordinary differential equations and then solved numerically using shooting method. Present results are compared with the available data in the limiting cases. The present results are found to be in an excellent agreement. It is observed that with an increase in the magnetic field strength, the percent difference in the heat transfer rate of magnetic nanoparticles with Al2O3 decreases. Surface shear stress and the heat transfer rate at the surface increase as the curvature parameter increases, i.e curvature helps to enhance the heat transfer.

Numerical study of boundary layer flow and heat transfer of oldroyd-B nanofluid towards a stretching sheet.

In the present article, we considered two-dimensional steady incompressible Oldroyd-B nanofluid flow past a stretching sheet. Using appropriate similarity variables, the partial differential equations are transformed to ordinary (similarity) equations, which are then solved numerically. The effects of various parameters, namely, Deborah numbers [Formula: see text] and [Formula: see text], Prandtl parameter [Formula: see text], Brownian motion [Formula: see text], thermophoresis parameter [Formula: see text] and Lewis number [Formula: see text], on flow and heat transfer are investigated. To see the validity of the present results, we have made the comparison of present results with the existing literature.