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Purpose: Although the combined plant-biochar remediation in improving soil contaminated by polycyclic aromatic hydrocarbons (PAHs) is considered efficient (Singha and Pandey in Crit Rev Biotechnol 41:749–766, 2021), the potential for application remains poorly known. This study used clones of Buchloe dactyloides to evaluate the effects of biochar on the capability of phytoremediation and rhizosphere soil contaminated with PAH. Materials and methods: Pot experiments were conducted to assess the effects of biochar on growth physiological parameters of B. dactyloides growth, accumulation of PAHs in B. dactyloides, and soil environment. Results and discussion: The results showed that the application of biochar increased the levels of antioxidants (free proline, glutathione, and ascorbic acid), antioxidant enzymes (catalase and laccase), and phytohormones (abscisic acid, indole acetic acid, jasmonic acid, salicylic acid, and gibberellin), decreased the accumulation of reactive oxygen species and lipid peroxidation in the roots, thereby enhancing the antioxidant defense ability and improving PAHs tolerance in roots of B. dactyloides. Moreover, the activities of enzymes (catalase, dehydrogenases, urease and protease) and soil nutrients in the rhizosphere soil were significantly increased, the content of PAHs decreased, and the health of the rhizosphere soil was improved. Conclusions: Biochar treatment promoted the accumulation of PAHs, improved soil environment and significantly enhanced the effects of phytoremediation. Therefore, the combined application of B. dactyloides and biochar can be considered as a feasible approach for the phytoremediation of PAH-contaminated soil. [ABSTRACT FROM AUTHOR]

Solar steam generators based on photothermal materials are important in producing fresh water. However, conventional solar steam generators are difficult to self-adapt to the complex external environment as organisms. Herein, inspired by the plant leaf, we propose a photothermal composite based on MXene and silk to add more functionality. On one hand, the composite achieves an evaporation rate of 1.51 kg·m−2·h−1 and a conversion efficiency of 86.9% under a solar intensity of 1 kW·m−2, mimicking the water transpiration of plant leaf. On the other hand, the MXene-silk-based actuator shows a maximum bending curvature of 0.91 cm−1 under a solar intensity of 5 kW·m−2. Furthermore, an intelligent solar system is constructed utilizing the synergy of solar steam generator and actuator, which advances the research from the material level to the system level. Mimicking the behavior of plant leaf, the system can automatically open during the day to generate steam and fresh water. And at night or in bad weather, it will automatically close to prevent external pollution such as dust, achieving intelligent anti-fouling. This research will have good application prospects in less developed areas. Meanwhile, it also provides a certain reference value for exploring multi-functional photothermal devices in the future. [ABSTRACT FROM AUTHOR]

Melatonin is an important secondary messenger in plant innate immunity against the bacterial pathogen Pseudomonas syringe pv. tomato (Pst) DC3000 in the salicylic acid (SA)- and nitric oxide (NO)-dependent pathway. However, the metabolic homeostasis in melatonin-mediated innate immunity is unknown. In this study, comparative metabolomic analysis found that the endogenous levels of both soluble sugars (fructose, glucose, melibose, sucrose, maltose, galatose, tagatofuranose and turanose) and glycerol were commonly increased after both melatonin treatment and Pst DC3000 infection in Arabidopsis. Further studies showed that exogenous pre-treatment with fructose, glucose, sucrose, or glycerol increased innate immunity against Pst DC3000 infection in wild type (Col-0) Arabidopsis plants, but largely alleviated their effects on the innate immunity in SA-deficient NahG plants and NO-deficient mutants. This indicated that SA and NO are also essential for sugars and glycerol-mediated disease resistance. Moreover, exogenous fructose, glucose, sucrose and glycerol pre-treatments remarkably increased endogenous NO level, but had no significant effect on the endogenous melatonin level. Taken together, this study highlights the involvement of sugars and glycerol in melatonin-mediated innate immunity against bacterial pathogen in SA and NO-dependent pathway in Arabidopsis. [ABSTRACT FROM AUTHOR]