Resumo A natureza é presenteada com uma grande variedade de plantas ornamentais que embelezam e limpam a natureza. Por causa de seu grande valor estético, existe a necessidade de proteger essas plantas de uma variedade de estresses bióticos e abióticos. Hibiscus rosa-sinensis (L.) é uma planta ornamental comumente conhecida como rosa-da-China ou graxa-de-estudante. É afetada por vários patógenos fúngicos e bacterianos. O presente estudo buscou isolar o patógeno da mancha foliar de H. rosa-sinensis e seu controle usando nanopartículas de prata (AgNPs). Com base nas características moleculares e morfológicas, o patógeno isolado da mancha foliar foi identificado como Aspergillus niger. As AgNPs foram sintetizadas no extrato de folhas de Calotropis procera e caracterizadas. A análise de espectroscopia UV-vis mostrou discretas bandas de ressonância plasmônica na superfície das AgNPs sintetizadas, mostrando a presença de aminoácidos aromáticos. A espectroscopia no infravermelho com transformada de Fourier (FTIR) descreveu a presença de grupos funcionais C-O, NH, C-H e O-H, que atuam como moléculas estabilizadoras e redutoras. A difração de raios X (DRX) revelou o tamanho médio (~32,43 nm) das AgNPs e a microscopia eletrônica de varredura (MEV) mostrou sua natureza esférica. Neste estudo, foi investigada a atividade antifúngica in vitro e in vivo de AgNPs. A análise da atividade antifúngica in vitro revelou a maior inibição do crescimento de micélio (87%) na concentração de 1,0 mg/ml de AgNPs. A mesma concentração de AgNPs inibiu a propagação da doença em folhas infectadas de H. rosa-sinensis. Esses resultados demonstraram significativa capacidade de controle de doenças das AgNPs e sugeriram seu uso em diferentes plantas ornamentais.

Abstract Nature is gifted with a wide range of ornamental plants, which beautify and clean the nature. Due to its great aesthetic value, there is a need to protect these plants from a variety of biotic and abiotic stresses. Hibiscus rosa-sinensis (L.) is an ornamental plant and it is commonly known as China rose or shoeblack plant. It is affected by several fungal and bacterial pathogens. Current study was designed to isolate leaf spot pathogen of H. rosa-sinensis and its control using silver nanoparticles (AgNPs). Based on molecular and morphological features, the isolated leaf spot pathogen was identified as Aspergillus niger. AgNPs were synthesized in the leaf extract of Calotropis procera and characterized. UV-vis spectral analysis displayed discrete plasmon resonance bands on the surface of synthesized AgNPs, depicting the presence of aromatic amino acids. Fourier transform infrared spectroscopy (FTIR) described the presence of C-O, NH, C-H, and O-H functional groups, which act as stabilizing and reducing molecules. X-ray diffraction (XRD) revealed the average size (~32.43 nm) of AgNPs and scanning electron microscopy (SEM) depicted their spherical nature. In this study, in vitro and in vivo antifungal activity of AgNPs was investigated. In vitro antifungal activity analysis revealed the highest growth inhibition of mycelia (87%) at 1.0 mg/ml concentration of AgNPs. The same concentration of AgNPs tremendously inhibited the spread of disease on infected leaves of H. rosa-sinensis. These results demonstrated significant disease control ability of AgNPs and suggested their use on different ornamental plants.

In Pakistan, salinization of agricultural lands is a serious problem prevailing in arid and semi-arid regions of the country. The main objective of the present study was to investigate the carbohydrates dynamics of the salt-affected soil, amended with different organic matter combinations and incubated for varying time periods (0, 15, 30 and 60 days) and temperatures (15 and 37 ºC). Replenishment of soil organic matter (SOM) was made with Green manure (GM) and Farmyard manure (FYM). The soil pH, EC, Na+ and K+ contents were evaluated through standard methods. An improvement in the soil organic carbon (OC) and nitrogen (N) contents ranging from 0.10 to 1.40% and 0.05 to 0.55% was achieved through the selected soil amendment practices. Total carbohydrates were found to be enhanced with organic treatments alone or in combination, accounting for 13.20% to 26.30% of the total soil. Non-glycosidic interactions of soil carbohydrates with minerals were investigated by applying powdered X-Ray diffraction (XRD) analysis using a Rigaku wide range goniometer (PW 1050/23). Semi-quantitative analysis of the soil organo-mineral interactions, based on their relative frequency abundance, was expressed in terms of a system of nine components. X-Ray diffraction (XRD) analysis revealed interactions of varying magnitude namely major, minor, trace and rare between the soil carbohydrates and minerals.