Сорбция фосфатов оксигидратами железа (ІІІ) разной модификации

Методами осадження синтезовано FeOOH (аморфний оксигідроксид заліза), α-FeOOH (гетит) і γ-FeOOH (лепідокрокіт). Фізико-хімічні параметри синтезованих сполук було охарактеризовано із залученням рентгенівських досліджень, порометрії, рН-потенціометрії. За допомогою рентгенограм встановлено, що α-FeOOH і γ-FeOOH мають кристалічну структуру, тоді як FeOOH аморфний. Вивчено сорбційну активність оксигідратів заліза різної модифікації відносно фосфат-йонів. Синтезовані оксигідрати заліза мають мезопористу структуру з переважними розмірами пор 2 нм для FeOOH (аморфного)і γ-FeOOH та 16 нм для α-FeOOH. рН-метричні дослідження показали, що FeOOH (аморфний) є амфолітом із максимальною обмінною ємністю 3 ммоль/г у кислому та 3,5 ммоль/г у лужному середовищах. Порівняльна оцінка сорбційної здатності оксигідратів заліза різної модифікації відносно фосфат-йонів виявила, що найкращі показники має FeOOH (аморфний), сорбційна ємність якого дорівнює 237,5 мг/г у кислому і 104,5 мг/г у лужному середовищах.By means of precipitation method FeOOH (amorphous ferric oxyhydrate), α-FeOOH (goethite) and γ-FeOOH (lepidocrocite) have been synthesized. Physical-and-chemical parameters of the synthesized compounds have been characterized using X-ray diffraction, porosity studies, pH titration. With the aid of XRD it was found that α-FeOOH and γ-FeOOH have crystalline structure, while FeOOH is amorphous. The sorption affinity of ferric oxyhydrates of various crystalline structure towards phosphate ions has been studied. The synthesized oxyhydrates have a mezoporous structure with the pore size of 2 nm for FeOOH (amorphous), γ-FeOOH and 16 nm for α-FeOOH. рН titration has shown that FeOOH (amorphous) is an ampholite with the maximal exchange capacity of 3 mmol/g in acidic media and 3,5 mmol/g in alkaline media. The comparison of the sorption affinity of the ferric oxyhydrates with various crystalline structures towards phosphate ions shows that FeOOH (amorphous) has the best parameters, and its sorption capacity reaches 237,5 mg/g in acidic media and 104,5 mg/g in alkaline media.Методами осаждения синтезированы FeOOH (аморфный оксигидрат железа), α-FeOOH (гетит) и γ-FeOOH (лепидокрокит). Физико-химические параметры синтезированных соединений были охарактеризованы с использованием рентгеновских исследований, порометрии, рН-метрии. С помощью рентгенограмм установлено, что α-FeOOH и γ-FeOOH имеют кристаллическую структуру, тогда как FeOOH - аморфен. Изучена сорбционная активность оксигидратов железа различной модификации по отношению к фосфат-ионам. Синтезированные оксигидраты железа обладают мезопористой структурой с преобладающими размерами пор 2 нм для FeOOH (аморфного), γ-FeOOH и 16 нм для α-FeOOH. рН-метрические исследования показали, что FeOOH (аморфный) является амфолитом с максимальной обменной емкостью 3 ммоль/г в кислой и 3,5 ммоль/г щелочной средах. Сравнительная оценка сорбционной способности оксигидратов железа разной модификации по отношению к фосфат-ионам выявила, что наилучшие показатели имеет FeOOH (аморфный), сорбционная емкость которого достигает 237,5 мг/г в кислой и 104,5 мг/г в щелочной средах

Arabidopsis Fatty Acid Desaturase FAD2 Is Required for Salt Tolerance during Seed Germination and Early Seedling Growth

Fatty acid desaturases play important role in plant responses to abiotic stresses. However, their exact function in plant resistance to salt stress is unknown. In this work, we provide the evidence that FAD2, an endoplasmic reticulum localized ω-6 desaturase, is required for salt tolerance in Arabidopsis. Using vacuolar and plasma membrane vesicles prepared from the leaves of wild-type (Col-0) and the loss-of-function Arabidopsis mutant, fad2, which lacks the functional FAD2, we examined the fatty acid composition and Na+-dependent H+ movements of the isolated vesicles. We observed that, when compared to Col-0, the level of vacuolar and plasma membrane polyunsaturation was lower, and the Na+/H+ exchange activity was reduced in vacuolar and plasma membrane vesicles isolated from fad2 mutant. Consistent with the reduced Na+/H+ exchange activity, fad2 accumulated more Na+ in the cytoplasm of root cells, and was more sensitive to salt stress during seed germination and early seedling growth, as indicated by CoroNa-Green staining, net Na+ efflux and salt tolerance analyses. Our results suggest that FAD2 mediated high-level vacuolar and plasma membrane fatty acid desaturation is essential for the proper function of membrane attached Na+/H+ exchangers, and thereby to maintain a low cytosolic Na+ concentration for salt tolerance during seed germination and early seedling growth in Arabidopsis

Bioaccumulation and ecotoxicity of carbon nanotubes

Carbon nanotubes (CNT) have numerous industrial applications and may be released to the environment. In the aquatic environment, pristine or functionalized CNT have different dispersion behavior, potentially leading to different risks of exposure along the water column. Data included in this review indicate that CNT do not cross biological barriers readily. When internalized, only a minimal fraction of CNT translocate into organism body compartments. The reported CNT toxicity depends on exposure conditions, model organism, CNT-type, dispersion state and concentration. In the ecotoxicological tests, the aquatic organisms were generally found to be more sensitive than terrestrial organisms. Invertebrates were more sensitive than vertebrates. Single-walled CNT were found to be more toxic than double-/multi-walled CNT. Generally, the effect concentrations documented in literature were above current modeled average environmental concentrations. Measurement data are needed for estimation of environmental no-effect concentrations. Future studies with benchmark materials are needed to generate comparable results. Studies have to include better characterization of the starting materials, of the dispersions and of the biological fate, to obtain better knowledge of the exposure/effect relationships

Drought Impact Is Alleviated in Sugar Beets (Beta vulgaris L.) by Foliar Application of Fullerenol Nanoparticles

Over the past few years, significant efforts have been made to decrease the effects of drought stress on plant productivity and quality. We propose that fullerenol nanoparticles (FNPs, molecular formula C-60(OH)(24)) may help alleviate drought stress by serving as an additional intercellular water supply. Specifically, FNPs are able to penetrate plant leaf and root tissues, where they bind water in various cell compartments. This hydroscopic activity suggests that FNPs could be beneficial in plants. The aim of the present study was to analyse the influence of FNPs on sugar beet plants exposed to drought stress. Our results indicate that intracellular water metabolism can be modified by foliar application of FNPs in drought exposed plants. Drought stress induced a significant increase in the compatible osmolyte proline in both the leaves and roots of control plants, but not in FNP treated plants. These results indicate that FNPs could act as intracellular binders of water, creating an additional water reserve, and enabling adaptation to drought stress. Moreover, analysis of plant antioxidant enzyme activities (CAT, APx and GPx), MDA and GSH content indicate that fullerenol foliar application could have some beneficial effect on alleviating oxidative effects of drought stress, depending on the concentration of nanoparticles applied. Although further studies are necessary to elucidate the biochemical impact of FNPs on plants; the present results could directly impact agricultural practice, where available water supplies are often a limiting factor in plant bioproductivity

Complex genetic, photothermal, and photoacoustic analysis of nanoparticle-plant interactions

Understanding the nature of interactions between engineered nanomaterials and plants is crucial in comprehending the impact of nanotechnology on the environment and agriculture with a focus on toxicity concerns, plant disease treatment, and genetic engineering. To date, little progress has been made in studying nanoparticle-plant interactions at single nanoparticle and genetic levels. Here, we introduce an advanced platform integrating genetic, Raman, photothermal, and photoacoustic methods. Using this approach, we discovered that multiwall carbon nanotubes induce previously unknown changes in gene expression in tomato leaves and roots, particularly, up-regulation of the stress-related genes, including those induced by pathogens and the water-channel LeAqp2 gene. A nano-bubble amplified photothermal/photoacoustic imaging, spectroscopy, and burning technique demonstrated the detection of multiwall carbon nanotubes in roots, leaves, and fruits down to the single nanoparticle and cell level. Thus, our integrated platform allows the study of nanoparticles’ impact on plants with higher sensitivity and specificity, compared to existing assays

Effects of carbon-based nanomaterials on seed germination, biomass accumulation and salt stress response of bioenergy crops.

Bioenergy crops are an attractive option for use in energy production. A good plant candidate for bioenergy applications should produce a high amount of biomass and resist harsh environmental conditions. Carbon-based nanomaterials (CBNs) have been described as promising seed germination and plant growth regulators. In this paper, we tested the impact of two CBNs: graphene and multi-walled carbon nanotubes (CNTs) on germination and biomass production of two major bioenergy crops (sorghum and switchgrass). The application of graphene and CNTs increased the germination rate of switchgrass seeds and led to an early germination of sorghum seeds. The exposure of switchgrass to graphene (200 mg/l) resulted in a 28% increase of total biomass produced compared to untreated plants. We tested the impact of CBNs on bioenergy crops under salt stress conditions and discovered that CBNs can significantly reduce symptoms of salt stress imposed by the addition of NaCl into the growth medium. Using an ion selective electrode, we demonstrated that the concentration of Na+ ions in NaCl solution can be significantly decreased by the addition of CNTs to the salt solution. Our data confirmed the potential of CBNs as plant growth regulators for non-food crops and demonstrated the role of CBNs in the protection of plants against salt stress by desalination of saline growth medium