Structure and electrical conductivity properties of K doped Sr1−xKx(Sr0.50Nb0.50)O2.75−δ complex perovskites

In the present study structural and electrical conductivity properties of complex perovskites with general formula Sr _1− _x K _x (Sr _0.50 Nb _0.50 )O _2.75− _δ have been studied. Potassium is doped in the cuboctahedral Sr site Sr _1− _x K _x (Sr _0.50 Nb _0.50 )O _2.75− _δ with different dopant concentrations such as x  = 0, 0.25, 0.50, 0.75 and 1. The structural and morphological properties of Sr _1− _x K _x (Sr _0.50 Nb _0.50 )O _2.75− _δ were studied using Thermogravimetry (TG) analysis, x-ray diffraction (XRD) and Scanning electron microscopy (SEM). Electrochemical impedance spectroscopy (EIS) was performed to investigate the electrical properties. The effect of structural and morphological variations associated with the dopant concentration affecting the electrical conductivity behaviour of Sr _1− _x K _x (Sr _0.50 Nb _0.50 )O _2.75− _δ complex perovskite oxides were studied in detail. The higher total conductivity was observed for 100% K doped ( x  = 1, 3.10 × 10 ^−5 S cm ^−1 at 800 °C) and 25% K doped ( x  = 0.25, 2.02 × 10 ^−5 S cm ^−1 at 800 °C) composition

Enhancing Resistance to Stem and Stolon Rot of Peppermint (Mentha piperita Lin.) Using Biocontrol Agents

Five isolates of Trichoderma viride, Pseudomonas fluorescens and four isolates of Bacillus subtilis were evaluated for their ability to control Rhizoctonia solani, the causal agent of stem and stolon rot of peppermint (Mentha piperita Lin.). Of the various isolates of T. viride, P. fluorescens and B. subtilis tested, TVUV10, PFMMP and BSG3 showed the maximum inhibition of mycelial growth of R. solani. Among these isolates, P. fluorescens, PFMMP recorded the highest inhibition zone against R. solani in vitro and was very effective in reducing disease incidence in greenhouse condition. The effective isolates were evaluated for their ability to induce defense related enzymes and chemicals in plants. Increased activity of phenylalanine ammonia lyase (PAL), peroxidase (PO), polyphenoloxidase (PPO) and total phenolics were recorded in the biocontrol agents pretreated peppermint plants challenged with R. solani. P. fluorescens isolate PFMMP recorded early and increased synthesis of all defense related enzymes and total phenol. Thus, the present study shows that application of biocontrol agents; induce defense related enzymes involved in phenyl propanoid pathway in addition to direct antagonism which collectively contribute for enhanced resistance against invasion of R. solani in M. piperita