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-(Effectiveness of plant growth promoting rhizobacteria in facilitating lead and nutrient uptake by little seed canary grass). We investigated the effectiveness of Nitroxin inoculation on lead (Pb) and nutrient uptakes by little seed canary grass. The factors tested included inoculation (or not) with Nitroxin and different soil concentrations of Pb (0, 200, 400 and 800 mgPb kg -1 soil). Increasing soil concentrations of Pb decreased stem, leaf and root dry weights. Shoot phosphorus concentrations increased in parallel with increasing soil Pb concentrations. Nitroxin inoculation did not alter the phosphorus concentration of the roots. The Pb translocation factor was > 1 in inoculated treatments in the Pb soil concentration range of 200 to 400 mg kg -1 ; the translocation factor for 800 mgPb kg -1 with no inoculation of Nitroxin was, however, < 1. Our results indicated that the Pb bioaccumulation factor for little seed canary grass was < 1, indicating that it is a Pb excluding plant.

Ultrasound assisted emulsification of solidified floating organic drop microextraction (USAE-SFODME), combined with electrothermal atomic absorption spectrometry (ETAAS), was developed for the preconcentration and determination of trace amounts of As(III) and As(V) in environmental water samples. At pH ¼ 1, As(III) formed complexes with ammonium pyrrolidine dithiocarbamate (APDC) and these were extracted into the fine droplets of 1-dodecanol (extraction solvent) which were dispersed with the aid of ultrasonication into the water sample solution. After extraction, the organic phase was separated by centrifugation, and was solidified by transferring into an ice bath. The solidified solvent was transferred to a vial and melted quickly at room temperature. As(III) was determined in the melted organic phase while As(V) remained in the aqueous layer. Total inorganic As was determined after the reduction of the pentavalent forms of arsenic with sodium thiosulphate and potassium iodide. The concentration of As(V) was calculated as the difference between the concentrations of total inorganic As and As(III). The variables of interest in the USAE-SFODME method, such as the volume of extraction solvent, pH, concentration of APDC (chelating agent), sonication time and salt effect were optimized using multivariate optimization approaches. A fractional factorial design (FFD) for screening and a central composite design for optimizing the significant variables were applied. A mathematical model was presented that successfully predicts changes in the response, depending on the input variables. Under the optimum conditions, the proposed method has been successfully used for the determination of inorganic arsenic in different environmental water samples and certified reference material (NIST RSM 1643e).

Purslane (Portulaca oleracea L.) is one of the valuable medical plants. Drought also is one of the most important environment stresses that influences metabolism and growth of plant. The studying of physiological plant response rather than water stress can be influential equipment for understanding drought resistance mechanisms. In this study, the drought stress effects on germination and physiological characteristic of the medical plant (purslane) were studied. Drought imposed on polyethylene glycol (PEG) seedlings and experiments were done in completely random model framework, with 3 replications. Polyethylene glycol stress was in seven levels involving blank (distilled water),-0.1,-0.2,-0.4,-0.6,-0.8 and-1 MPa. In relation to germination, meaningful difference was not observed between blank and the different levels (P<0.01); and the least rate of germination in stress level was-0.4 MPa) and the highest rate of germination in stress level was-0.2 MPa). Meaningful increase of proline and sugar synchronized with PEG concentration was observed in statistical level (P<0.01) with meaningful difference. In this, blank had the least rates and stress level of-1 MPa and the highest proline and sugar rates. Lipid content in purslane leaves with increasing stress level was decreased. In the highest lipid rate in stress level (-0.2 MPa) and the least concentration in stress level (-1 MPa), it was observed that this difference in P<0.01 was meaningful. The concentration of leave proteins with meaningful decrease (P<0.01) had the highest protein concentrations in blank and the least concentration in stress level was-1 MPa. In stress effect on leaf chlorophyll content, meaningful increase of chlorophyll a and b synchronized imposed increase of stress level. It was observed that with chlorophyll a the highest concentration in stress level was-0.6 MPa and the least concentration exists in blank; and also with chlorophyll b the stress level,-1 MPa had the highest and blank had the least concentration (P<0.01).

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