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A greenhouse experiment was conducted to compare the effects of biosurfactant Rhamnopyranoside and chemical surfactant Triton X-100 on the uptake of phenanthrene by mycorrhizal alfalfa (Medicago sativa L.) and phenanthrene dissipation in soil. Mycorrhizal treatment led to a higher phenanthrene accumulation in alfalfa and enhanced phenanthrene dissipation from the treated soil compared with non-mycorrhizal control. Inoculation combined with Rhamnopyranoside application gave the highest phenanthrene removal rate of 85.50% from treated soil and highest phenanthrene accumulation in plants (2.92 μg in root and 1.58 μg in shoot per pot) among all treatments. Besides, such combination treatment resulted in the highest freeze-dried biomass of plant (4.13 g for root and 3.31 g for shoot per pot), suggesting low toxicity for this treatment. These observations indicate co-effects of Rhamnopyranoside and inoculation may have potential as a biotechnological approach for decontamination of soil contaminated with phenanthrene.

Effects of inoculation with three different arbuscular mycorrhizal (AM) fungi (Glomus etunicatum, Glomus constrictum, and Glomus mosseae) on arsenic (As) accumulation by maize were investigated by using soil spiked with As at rates of 0, 25, 50, and 100 mg kg-1. The root colonization rates by the three fungi were significantly different (G. mosseae > G. etunicatum > G. constrictum) and decreased markedly with increasing As concentration in the soil. Inoculation with G. etunicatum or G. mosseae increased maize biomass and phosphorus (P) accumulation (G. mosseae > G. etunicatum) and reduced As accumulation in shoots (G. mosseae ≈ G. etunicatum), whereas inoculation with G. constrictum had little effect on these parameters. Inoculation with G. mosseae produced greater biomass and P uptake and less shoot As accumulation, and therefore it may be a promising approach to reduce As translocation from contaminated soils to plants. [ABSTRACT FROM AUTHOR]

The present study examined the naphthalene stress responses of the aquatic fern Azolla filiculoides Lam. and evaluated its phytoremediation potential. A. filiculoides were grown in nitrogen (N)-free Hoagland containing 25, 50, and 75 mg L−1 naphthalene in the greenhouse. At 75 mgL−1 naphthalene concentration, the percentage of plant growth and relative growth rates were 118% and 0,09 gg−1d−1 respectively. Photosynthetic pigment contents increased in parallel with the increasing naphthalene concentrations on the third day. In 75 mg L−1 naphthalene, the flavonoid and phenolic contents of the plant increased as secondary metabolites compared to the control. Gas Chromatography-Mass Spectrometry analysis showed that naphthalene is absorbed, accumulated and/or biodegraded by the A. filiculoides. Percentages of biodegradation from planted samples treated with all naphthalene concentrations on day 10 were ≥ 94% compared to unplanted controls. Data on growth parameters, photosynthetic pigments and secondary metabolite contents, and biodegradation percentages indicated that the effective phytoremediation potential of A. filiculoides for naphthalene was ≤ 75 mg L−1. In conclusion, the biodegradation values of over 90% obtained in a short time from the planted samples compared to the unplanted controls showed that A. filiculoides tolerates naphthalene stress highly, is effective in its phytoremediation and can be used efficiently. [ABSTRACT FROM AUTHOR]

A new design concept of electrochemical pH-controllable molecular switch is presented by utilizing a new electrochemical measurement system as switching transducer. A pH sensor is connected in series between the terminal points of the working and counters electrodes of a potentisostat, and immersed in the solution together with a reference electrode, establishing a novel electrochemical measurement system. In this system, the variation of pH-controllable interface potential at the pH-sensing film/solution interface can be converted to current response when amperometry technique is employed. Based on this unique current-potential relationship, a pH-controllable switch is designed to monitor the protonation and deprotonation reaction of pH-sensing molecule. The current direction interchanges between positive and negative via pH control, illustrating a reversible conformation transition between protonated state and deprotionated state of molecule. The magnitude of current value represents the degree of protonation and deprotonation reaction of molecule. The strategy is successfully demonstrated with a remarkably reversible polyaniline-based pH-controllable switch, which confirms the feasibility of the novel electrochemical measurement system as switching transducer for designing electrochemical pH-controllable switches. This study may open up a potential avenue to construct the electrochemical pH-controllable switches. [ABSTRACT FROM AUTHOR]