Anatomical, histochemical and biochemical approaches were used to study mercury uptake and phytotoxicity as well as anti-oxidative responses in two species of ferns [Chinese brake fern (Pteris vittata) and Boston fern (Nephrolepis exaltata)], grown in a hydroponic system. The roots of both cultivars accumulated large amounts of mercury, but exhibited limited mercury translocation to shoots. Mercury exposure led to more pronounced phytotoxicity accompanied by stronger oxidative stress in the shoots of P. vittata than in N. exaltata. N. exaltata established a more effective anti-oxidative system against mercury-induced oxidative stress than did P. vittata. The activity of anti-oxidative enzymes (superoxide dismutase, catalase and glutathione reductase) increased. The reduced ascorbate (ASA) and oxidized ascorbate (DHA) are regulated. Mercury exposure led to an increase in the concentration of glutathione (GSH) in both fern species. The present study suggests that N. exaltata is more tolerant to mercury exposure than P. vittata, which has been also reported to be more tolerant to arsenic exposure. N. exaltata may thus have potential for phytostabilization of soils or phytofiltration of waste water contaminated with mercury.

Cr doped WO3 nanofibers enriched with surface oxygen vacancies have been developed to smartly detect the 3H-2B biomarker for the real-time monitoring of Listeria monocytogenes.

Past geological and climatic events have promoted intraspecific divergence and range shifts in numerous plant species. This is particularly true for temperate species in climate-sensitive regions. Few previous studies have examined whether such genetic footprints were also shaped in desert plants, which can survive in arid habitats and might be "static" under the past climatic oscillations. We therefore studied the phylogeographical history of Reaumuria soongarica, a shrub species that is widely distributed across the deserts of western China. We sequenced chloroplast DNA (cpDNA) fragments of 27 natural populations across western China. Eight cpDNA haplotypes were identified, which clustered into three clades. The clades were located in the western (clade II) or eastern regions (clades I and III) of western China. Analysis of molecular variance also supported this major partitioning (∼67%) of the cpDNA variation between regions. However, within each region, genetic differentiation was low (29%-37%) and a single dominant haplotype was fixed; this indicated past regional range expansion. The deep divergence and regional range expansions of this species may have corresponded to the most recent uplift of the Qinghai-Tibet Plateau and the development of desert ecosystems during the last glacial age in western China. This is the first study to show that the evolutionary history of plants in desert habitats has been seriously affected by past geological and climatic change.

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