CuO Nanoparticle-Mediated Seed Priming Improves Physio-Biochemical and Enzymatic Activities of Brassica juncea.

The use of nanoparticles (NPs) in agricultural fields has risen to a level where people are considering NPs as an alternative to commercial fertilizers. The input of copper oxide NPs (CuO NPs) as seed primers was investigated in this study, and the growth indices of Brassica juncea such as phenotypic parameters, photosynthetic attributes, and biochemical parameters were measured during maximum vegetative growth stage, i.e., at 45 days after sowing. Surface sterilized seeds were soaked in varying concentrations (0, 2, 4, 8 and 16 mg/L) of CuO NPs for 15, 30, and/or 45 min. After those priming periods, the seeds were planted in pots and allowed to grow naturally. Among the different tested concentrations of CuO NPs, 4 mg/L of CuO NPs for 30 min seed priming proved to be best, and considerably increased the, shoot length (30%), root length (27%), net photosynthetic rate (30%), internal CO2 concentration (28%), and proline content (41%). Besides, the performance of the antioxidant enzymes, viz, superoxide dismutase, catalase, peroxidase, and biochemical parameters such as nitrate reductase and carbonic anhydrase were also increased by several folds after the application of CuO NPs in B. juncea. The present study suggests that CuO NPs can be effectively used to increase the performance of B. juncea and may also be suitable for testing on other crop species.

Chlorophyll fluorometry in evaluating photosynthetic performance: key limitations, possibilities, perspectives and alternatives.

Non-destructive methods for the assessment of photosynthetic parameters of plants are widely applied to evaluate rapidly the photosynthetic performance, plant health, and shifts in plant productivity induced by environmental and cultivation conditions. Most of these methods are based on measurements of chlorophyll fluorescence kinetics, particularly on pulse modulation (PAM) fluorometry. In this paper, fluorescence methods are critically discussed in regard to some their possibilities and limitations inherent to vascular plants and microalgae. Attention is paid to the potential errors related to the underestimation of thylakoidal cyclic electron transport and anoxygenic photosynthesis. PAM-methods are also observed considering the color-addressed measurements. Photoacoustic methods are discussed as an alternative and supplement to fluorometry. Novel Fourier modifications of PAM-fluorometry and photoacoustics are noted as tools allowing simultaneous application of a dual or multi frequency measuring light for one sample.

Recent advances in metabolic engineering of microorganisms for advancing lignocellulose-derived biofuels.

Combating climate change and ensuring energy supply to a rapidly growing global population has highlighted the need to replace petroleum fuels with clean, and sustainable renewable fuels. Biofuels offer a solution to safeguard energy security with reduced ecological footprint and process economics. Over the past years, lignocellulosic biomass has become the most preferred raw material for the production of biofuels, such as fuel, alcohol, biodiesel, and biohydrogen. However, the cost-effective conversion of lignocellulose into biofuels remains an unsolved challenge at the industrial scale. Recently, intensive efforts have been made in lignocellulose feedstock and microbial engineering to address this problem. By improving the biological pathways leading to the polysaccharide, lignin, and lipid biosynthesis, limited success has been achieved, and still needs to improve sustainable biofuel production. Impressive success is being achieved by the retouring metabolic pathways of different microbial hosts. Several robust phenotypes, mostly from bacteria and yeast domains, have been successfully constructed with improved substrate spectrum, product yield and sturdiness against hydrolysate toxins. Cyanobacteria is also being explored for metabolic advancement in recent years, however, it also remained underdeveloped to generate commercialized biofuels. The bacterium Escherichia coli and yeast Saccharomyces cerevisiae strains are also being engineered to have cell surfaces displaying hydrolytic enzymes, which holds much promise for near-term scale-up and biorefinery use. Looking forward, future advances to achieve economically feasible production of lignocellulosic-based biofuels with special focus on designing more efficient metabolic pathways coupled with screening, and engineering of novel enzymes.