Examination of Correlation between Histidine and Cadmium Absorption by Eleagnus angustifolia L.,Vitisvinifera L.and Nerium oleander L.Using HPLC-MS and ICP-MS

In this study,HPLC-MS and ICP-MS methods wereused for the determination of histidine and cadmiumin Eleagnusangustifolia L.,Vitisvinifera L.and Nerium oleander L.leaves taken from industrial area including Gaziantep and Bursa cities.To histidine determination by HPLC-MS,flow rate of mobile phase,fragmentor potential,injection volume and column temperature were optimized as 0.2mL·min^(-1),70V,15μL and 20℃,respectively.For extraction of histidine from plants,distilled water was used by applying on 90℃and 30min.The concentrations(as mg·kg^(-1))of histidine were found to be in range of 8~22for Eleagnusangustifolia L.,10~33for Vitisvinifera L.and 6~11for Nerium oleander L.The concentrations of cadmium were found to be in ranges of 6~21μg·kg^(-1) for Vitisvinifera L.15~110μg·kg^(-1) for Eleagnusangustifolia L.and 63~218μg·kg^(-1) for Nerium oleander L.

Interactions Between Arbuscular Mycorrhizae and Plants in Phytoremediation of Metal-Contaminated Soils: A Review

Metal contamination in the environment is a global concern due to its high toxicity to living organisms and its worldwide distribution. The principal goal of this review is to examine the current strategies and technologies for the remediation of metal- contaminated soils by metal-accumulating plants and assess the roles of arbnscular mycorrhizal （AM） fungi in remediation of soils under hyperaccumulator or non-accumulator plants. The use of plants to remove metals from the environment or reduce the toxicity, known as phytoremediation, is an environmentally sustainable and low cost remediation technology. The mechanisms of the use of hyperaccumulator plants for phytoremediation included solubilization of the metal in the soil matrix, the plant uptake of the metal, detoxification/chelation and sequestration, and volatilization. Recently, some ecologists have found that phytoremediation with the aids of mycorrhizae can enhance efficiency in the removal of toxic metals. AM fungi can facilitate the survival of their host plants growing on metal-contaminated land by enhancing their nutrient acquisition, protecting them from the metal toxicity, absorbing metals, and also enhancing phytostabilization and phytoextraction. Such information may be useful for developing phytoremediation program at metal-contaminated sites.

Effects of Double Harvesting on Heavy Metal Uptake by Six Forage Species and the Potential for Phytoextraction in Field

The pollution of soils by heavy metals has dramatically increased in recent decades. Phytoextraction is a technology that extracts elements from polluted soils using hyperaccumulator plants. The selection of appropriate plant materials is an important factor for successful phytoextraction in field. A field study was conducted to compare the efficiency of six high-biomass forage species in their phytoextraction of heavy metals(Cd, Pb, and Zn) from contaminated soil under two harvesting strategies(double harvesting or single harvesting). Among the tested plants, amaranth accumulated the greatest amounts of Cd and Zn, whereas Rumex K^(-1) had the highest amount of Pb in the shoot under both double and single harvesting. Furthermore, double harvesting significantly increased the shoot biomass of amaranth, sweet sorghum and sudangrass and resulted in higher heavy metal contents in the shoot. Under double harvesting, the total amounts of extracted Cd, Pb and Zn(i.e., in the first plus second crops) for amaranth were 945, 2 650 and 12 400 g ha^(-1), respectively, the highest recorded among the six plant species. The present results indicate that amaranth has great potential for the phytoextraction of Cd from contaminated soils. In addition, the double harvesting method is likely to increase phytoextraction efficiency in practice.

Arsenic in Rice Soils and Potential Agronomic Mitigation Strategies to Reduce Arsenic Bioavailability： A Review

Soils used for rice （Oryza sativa L.） cultivation in some areas contain high concentrations of arsenic （As）due to irrigation with groundwater containing As and intensive use of agrochemicals or industrial residues containing As. To restrict rice uptake of As in these soils, approaches to reduce As input and bioavailability must be considered. One approach to reduce As input into rice soils or uptake by rice is cultivating rice under aerobic, intermittent flooding, or alternate wetting and drying （AWD） conditions, rather than in submerged soils, or use of irrigation water low in As. For reducing As bioavailability in soil, aerobic or AWD rice culture and application of biochar, sulfur （S）, and/or rice polish to soil are promising. Moreover, use of As-hyperaecumulating plant species （e.g., Pteris vittata L.） in rotation or combinations with favourable plant species （e.g., Azolla, Chlorella, or Nannochloropsis species） can also be promoted, in addition to using rice cultivars that are tolerant to As. Though applications of high doses of phosphorus （P）, iron （Fe）, and silicon （Si） fertilizers have shown promise in many instances, these methods have to be practiced carefully, because negative effects have also been reported, although such incidents are rare. Major factors affecting As speciation and bioavailability in soil are chemical properties such as redox status, pH, and Fe, P, Si, and S concentrations, physical properties such as texture and organic matter, and biological properties such as methylation activity by soil microorganisms. However, as many of these factors interact, long-term examination under field conditions is needed before measures are recommended for and implemented in farmers＇ fields.