توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱Phytoremediation and Accumulation Characteristics of Heavy Metals by Some Plants in Wadi Alargy–Wetland, Taif–KSA
اطلاعات انتشار: World Applied Sciences Journal، بيست و هشتم،شماره۵، ۲۰۱۳، سال
تعداد صفحات: ۱۰
The present study proved the phytoremediation potentiality and accumulation characteristics of sixteen elements and heavy metals; namely, N, P, K, Ca, Mg, Mn, B, Cu, Fe, Ni, Pd, Co, As, Cr, Cd, Mo, in the different plant organs of four plants; Amaranthus hybridus, Chenopodium ambrosioides, Mentha longifolia and Typha domingensis. The «translocation factor» (TF) and the «bioconcentration factor» (BCF) for element and metals within the studied species was calculated. Comparing metal contents in different plant organs growing in the contaminated soil showed relatively higher values as compared to those growing in noncontaminated one. As an example, the lead (Pd) concentrations of noncontaminated A. hybridus samples were 12.71, 11.34 and 2.53 (mg kg 1 DW) for root, stem and leaves; respectively and these values greatly increased to 93.9, 96.76 and 64.11(mg kg 1 DW) for the same plant organs but growing in contaminated soil. Accumulation rates of M.longifolia toward the measured elements and heavy metals can be arranged in the following order; Pd>Cu>Fe>Mn>K>Ca>B>Cr>As>Mg>P>N>Ni>Mo>Co>Cd. TF recorded maximum value of (5.881) for the translocation of arsenic (As) in T.domingensis growing in noncontaminated soil. According to the accumulation rates of the measured element and metals in either contaminated or noncontaminated sites, (TF) and the (BCF), the phytoremediation potentiality of the studied species can arranged in the followingorder: T.domingenesis> A.hybridus> M.longifolia> C.ambrosioides. Comparing different plant organs of the studied species in most cases, nominate the accumulation organs in the following order; stem> root> leaves.

۲Evaluation of the Growth Responses of Lemna gibba L. (Duckweed) Exposed to Silver and Zinc Oxide Nanoparticles
نویسنده(ها):
اطلاعات انتشار: World Applied Sciences Journal، سي و سوم،شماره۲، ۲۰۱۵، سال
تعداد صفحات: ۱۳
Lemna gibba L. (duckweed) is a sensitive aquatic plant often used in ecotoxicological studies. In this study we investigated the growth responses of L. gibba exposed to different concentrations of (0, 25, 50 and 100 mg\L) silver nanoparticles (AgNPs) and zinc oxide nanoparticles (ZnONPs) for 1, 5, 15 and 20 days. AgNPs are toxic to L. gibba fronds and percent mortality was significantly increased in response to the increase of concentration and the prolonged time of exposure. AgNPs exposure resulted in acute toxicity to L. gibba fronds after 15–days exposure LC50 of 100 mg\L (95% CL = 26.65–40.35 mg\L). ZnONPs stimulate the growth of L. gibba fronds. AgNPs caused significant inhibition of L. gibba root elongation and frond area in a dose–dependent manner, while ZnONPs showed stimulating effect on both root growth and frond area. However, exposure of L. gibba fronds to either type of NPs did not affect water content which recorded more than 80% in most cases. Total chlorophylls was significantly decreased progressively from 25.93 mg g 1 in control samples with increasing concentration of AgNPs into 22.04, 19.55 and 15.13 mg g 1 in the treated samples. AgNPs decrease the accumulation of (GA3) and stimulate the production of (IAA), while treatment of L. gibba samples with ZnONPs showed general increase of the two phytohormons. L. gibba growth rate progressively decreased with increasing concentration of AgNPs and as the plant age, the same trend was followed by L. gibba samples treated by ZnONPs. The impact of the two NPs on the activity of antioxidant enzymes; catalase (CAT), glutathione peroxidase (GP) and glutathione reductase (GR) was studied in shoots of L. gibba and the study revealed that both NPs progressively increased in the studied antioxidant enzyme activity as concentration of NPs increase. The overall results suggest that exposure to AgNPs and ZnONPs caused significant changes in the growth parameters, some physiological changes and oxidative stress in L. gibba fronds.
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