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Arsenic (As) hyperaccumulator Pteris ferns are renowned for their capacity to accumulate As and have been used to remediate As-contaminated environmental. However, there is less information on how they perform under low temperature though it is important for practical phytoremediation. The purpose of this study was to identify the effect of temperature on As accumulation by three As hyperaccumulators, Pteris multifida, Pteris cretica and Pteris vittata. Ferns were cultured with 5 mg/L As addition under 25 °C to 5 °C for 15 days. The results showed that dropping of temperatures reduced As accumulation by P. vittata moderately but not P. multifida and P. cretica until 10 °C. At 5 °C, all ferns discontinued As accumulation, and the morphology showed necrosis in P. vittata, wherein P. multifida and P. cretica kept healthy. The As distribution showed that As was mainly accumulated in fronds, while P. multifida stored partial As in its root. Both translocation factor and As efflux showed that temperate zone ferns manage As more strictly as compared to P. vittata. Our findings demonstrated that temperature should be considered when applying Pteris ferns for As phytoremediation, and P. multifida could be the most suitable fern for treating As-contaminated water in temperate zone area. [ABSTRACT FROM AUTHOR]

To assess genetic variation, 33 novel microsatellite markers were identified through nucleotide sequencing of enriched genomic libraries of Pteris cretica. Di- repeats (79.7 %) were found to be most predominant followed by tri (15.8 %), tetra (2.3 %) and hexa (2.3 %) type of repeat motifs. Evaluating these markers in six populations ( N = 48) of Western Himalayan range detected average polymorphism information content (PIC) of 0.32. Combined neighbor joining (NJ) and principal coordinate analysis (PCoA) grouped all the populations in two major clusters with high levels of intermixing of accessions in each cluster. This suggests that P. cretica populations of Western Himalaya have broadly been mixed with two sub-populations. High within population variance (98.7 %) and low genetic differentiation (Φ: 0.013), recorded in the analysis of molecular variance (AMOVA). For the first time, highly polymorphic novel genomic microsatellite markers were identified and utilized for revealing genetic diversity of P. cretica in Western Himalayan range in context of established hypothesis of genetic variations based on allozyme markers. [ABSTRACT FROM AUTHOR]

The ploidy levels, morphologies of gametophytes and young sporophytes, and reproductive modes of Pteris cretica, P. pellucidifolia, and P. wulaiensis were determined in this study. Pteris cretica and P. wulaiensis were diploid while P. pellucidifolia was triploid. Sporophytes of all three species produced 32-spored sporangia. Spore sizes of the triploid P. pellucidifolia were significantly larger than those of the other two diploid species. However, the frequencies of normal spores were lower in P. pellucidifolia (73%) than those of the other two species (95%-98%). Gametophytes of P. cretica and P. pellucidifolia produced normal antheridia but no archegonium. Although P. wulaiensis produced archegonia, those archegonia had lost their function. Every antheridium of these three species produced 32 active sperms. All of these three species apogamously produced sporophytes. Young sporophytes were produced directly on the gametophytes without fertilization. The first fronds of young sporophytes predominantly possessed midribs, with only a few of them lacking midribs. This study also suggests that the best way to infer the reproductive mode of ferns is to detect whether the embryo formed from the vegetative cells of gametophytes, although those other reproductionrelated traits may provide useful indicators. [ABSTRACT FROM AUTHOR]

The ability of Phaseolus vulgaris, Mentha aquatica, and Pteris cretica to release arsenic (As) species from contaminated soil was tested in rhizobox experiments in three soils differing in their physicochemical parameters and total and mobile As concentration. Relatively low uptake of arsenic by P. vulgaris and M. aquatica resulted in very low and ambiguous changes in rhizosphere soil compared to bulk soil. However, there were observed differences in the distribution of the mobile As portion in soil to individual As species as affected by plant species and/or plantation conditions of these plants. Higher percentage of mobile arsenite in mint rhizosphere seems to be related to more reducing conditions during cultivation of these wetland plants. P. cretica planted in the soils containing between 36 and 1436 mg As kg−1 was able to accumulate between 80 and 500 mg As kg−1 in aboveground biomass. The extractable concentrations of As compounds in rhizosphere soil of P. cretica showed a clear depletion of arsenate (representing more than 90% of extractable arsenic) with the distance from plant roots. However, the As uptake mechanisms, as well as As transformation within hyperaccumulating fern plants, differ substantially from those in higher plants. Therefore the finding of suitable higher plant tolerant to the As soil contamination with good ability to accumulate As in aboveground biomass remains for the further research. [ABSTRACT FROM AUTHOR]

The article presents abstracts of several studies on environmental geochemistry. Some of the abstracts presented include "Biogeochemical Cycling of Nutrients in Karstic Catchments, Southwestern China: Linkages to Changes of Eco-Environments," by Congqiang Liu and "Emerging Organic Contamination in China," by Guibin Jiang and colleagues.

A new flavone glycoside isolated from the fern Pteris cretica has been shown to be luteolin 7-O-robinobioside ( 1) by chemical and spectral methods. In addition luteolin 7-O-rutinoside ( 2) and luteolin 7-O-glucoside ( 3) have been isolated from this plant. Flavonoid 2 is reported for the first time in ferns. [ABSTRACT FROM AUTHOR]