Vinod Saharan

To determine the defence enzymes activity in chilli varieties against M. incognita an experiment was laid out. The enzyme (PO, PPO, PAL and SOD) activity was analyzed in resistant variety (Pusajwala and NP 46-A) and susceptible variety (S-5 and Ghoomar) of chilli. The roots of inoculated and un-inoculated plants were analyzed after 7, 14, 21, 28 and 60 days after transplanting. Enzyme activity was observed maximum in resistant as compared to susceptible varieties which was increased after root-knot nematode infection. The highest activity of enzymes was found between 21 and 28 days after transplanting. Among all the treatments, resistant varieties of chilli were found to be the best in highest enzyme activities, improving plant growth character and reducing nematode population over other treatment.

The use of novel active ingredients for the functional modification of chitosan nanoformulations has attracted global attention. In this study, chitosan has been functionalized via histidine to craft novel chitosan-histidine nanoformulation (C-H NF) via the ionic gelation method. C-H NF exhibited elite physico-biochemical properties, influencing physiological and biochemical dynamics in tomato crops. Elite properties include homogenous-sized nanoparticles, lower PDI, viscosity, higher zeta potential, nanoparticle concentration/ml, conductivity, encapsulation efficiency, and yield. FTIR spectroscopy revealed histidine interaction with C-H NF, while SEM and TEM exposed its porous structure. Application of C-H NF to tomato seedling and potted plants via seed treatment and foliar spray positively impacts growth parameters, antioxidant-defense enzyme activities, reactive oxygen species (ROS) content, and chlorophyll and nitrogen content. We claim that the histidine-functionalized chitosan nanoformulation enhances physico-biochemical properties, highlighting its potential to elevate biochemical and physiological processes of tomato plant.

The extensive usage of iron oxide nanoparticles (FeO NPs) in commercial and biomedical applications raises the risk of releasing their remains into the aquatic ecosystems and this could possibly cause cytotoxic effects on aquatic organisms. Thus, the toxicity assessment of FeO NPs on cyanobacteria, which are primary producers at the bottom of food chain in aquatic ecosystems, is essential to gain information about the potential ecotoxicological threat on aquatic biota. The present study investigated the cytotoxic effects of FeO NPs on Nostoc ellipsosporum using different concentrations (0, 10, 25, 50 and 100 mg L⁻¹) to track the time-dependent and dose-dependent effects and compared with its bulk equivalent. In addition, the impacts of FeO NPs and bulk counterpart on cyanobacterial cells were assessed under nitrogen as well as nitrogen-deficient conditions, because of ecological role of cyanobacteria in nitrogen fixation. The study revealed that the highest protein content was observed in the control in both types of BG-11 media compared to treatments of nano and bulk particles of Fe₂O₃. A 23% reduction in protein in nanoparticle treatment and a 14% reduction in bulk treatment at 100 mg L⁻¹ was observed in BG-11 medium. At same concentration, in BG-11₀ media, this decline was even more intense with 54% reduction in nanoparticle and a 26% reduction in bulk. Catalytic activity of catalase and superoxide dismutase was found to be linearly correlated with the dose concentration for nano and bulk form in BG-11 as well as BG-11₀ media. The increased levels of lactate dehydrogenase act as biomarker of the cytotoxicity brought on by nanoparticles. Optical, scanning electron, and transmission electron microscopy all demonstrated the cell entrapment, nanoparticle deposition on the cell surface, cell wall collapse and membrane degradation. A cause for concern is that nanoform was found to be more hazardous than bulk form.

Boron nanoparticles have emerged as promising nanomaterials with a wide array of applications in the biomedical, industrial, and environmental fields. However, the potential impact of these nanoparticles on aquatic organisms is not yet known. In the present study, the comparative impact of boron nitride nanoparticles and its bulk form is investigated on two freshwater algae. For this purpose, the effect on the physiological index, cellular morphology, and biochemistry profiles are examined. In Chlorella vulgaris, nano form of boron nitride is found to reduce the growth more (40%) than its bulk form (with ~ 25% growth reduction) at 50 mgl⁻¹ treatment level. While in case of Coelastrella terrestris, 40% reduction under nano form and 33.33% reduction under bulk form is observed at 100 mgl⁻¹ of boron nitride. Chlorophyll and carotenoid levels were also reduced under nanoparticles compared to the bulk. Proline, lactate dehydrogenase, and malondialdehyde assay were found significantly high under nanoparticle exposure. Additionally, increased catalase and superoxide dismutase enzyme activity under nanoparticle exposure revealed that the antioxidant system was activated in both the algae to eliminate the adverse influence of reactive oxygen species. The shading effect and aggregation of nanoparticles over the surface of algal cells are also important factors in attributing toxicity which are confirmed through the compound, TEM, and SEM micrographs. The study suggests that the nano form is more toxic than the bulk form and toxicity is concentration-dependent.