Stable Cu Isotope Ratios Show Changes in Cu Uptake and Transport Mechanisms in Vitis vinifera Due to High Cu Exposure

Even though copper (Cu) is an essential plant nutrient, it can become toxic under certain conditions. Toxic effects do not only depend on soil Cu content, but also on environmental and physiological factors, that are not well understood. In this study, the mechanisms of Cu bioavailability and the homeostasis of Vitis vinifera L. cv. Tannat were investigated under controlled conditions, using stable Cu isotope analysis. We measured Cu concentrations and δ65Cu isotope ratios in soils, soil solutions, roots, and leaves of grapevine plants grown on six different vineyard soils, in a 16-week greenhouse experiment. The mobility of Cu in the soil solutions was controlled by the solubility of soil organic matter. No direct relationship between Cu contents in soils or soil solutions and Cu contents in roots could be established, indicating a partly homeostatic control of Cu uptake. Isotope fractionation between soil solutions and roots shifted from light to heavy with increasing Cu exposure, in line with a shift from active to passive uptake. Passive uptake appears to exceed active uptake for soil solution concentrations higher than 270 μg L–1. Isotope fractionation between roots and leaves was increasingly negative with increasing root Cu contents, even though the leaf Cu contents did not differ significantly. Our results suggest that Cu isotope analysis is a sensitive tool to monitor differences in Cu uptake and translocation pathways even before differences in tissue contents can be observed.

The content of heavy metals in the raw materials of some representatives of the genus Paeonia L. in an urbanized environment

At present, heavy metals are generally recognized as priority soil pollutants, while the most active pollutants are their mobile forms, which can pass from solid phases into soil solutions and be absorbed by plants. It is known that the vegetative mass of agricultural crops is capable of accumulating large amounts of heavy metals. Ornamental flower crops, which firmly occupy their ecological niche, are practically not considered from this point of view. The aim of this work was to study the features of the accumulation of heavy metals in the aboveground and underground organs of some representatives of the genus Paeonia L. in the urbanized environment of the city of Ufa. The objects of research were four species ( P. peregrina Mill., P. lactiflora Pall., P. lactiflora f. rosea, P. delavayi Franch.) (Family Paeoniaceae Rudolphi) and three varieties of hybrid peony (Appassionata, Mustai Karim, Jeanne dArc). The study of the elemental composition of the aboveground and underground parts was carried out according to the method Determination of As, Pb, Cd, Sn, Cr, Cu, Fe, Mn and Ni in samples of food products and food raw materials by the atomic absorption method with electrothermal atomization. Mathematical data processing was carried out using generally accepted methods of variation statistics using the AgCStat software package in the form of an Excel add-in. Eight element studies are presented for each raw material group. Quantitative indicators of elements are given in mmol/kg of air-dry raw materials. It was revealed that in the studied samples the copper content was 4.152520.00 times higher than that of other elements. The minimum concentrations of arsenic (0.00350.0064 mmol/kg), chromium (0.00190.0046 mmol/ kg), manganese (0.01740.0219 mmol/ kg) and iron (0.00590.0125 mmol/ kg) were noted in the roots; lead (0.0030.037 mmol/kg), cadmium (0.00020.001 mmol/kg) and copper (0.14770.2134 mmol/kg) - in the leaves; nickel (0.00820.0179 mmol/kg) - in the flowers of the studied paeonies. The maximum content of arsenic (0.00620.0123 mmol/kg) and chromium (0.00280.0063 mmol/kg) was found in the leaves; lead (0.00270.0223 mmol/kg), nickel (0.01670.0209 mmol/kg), manganese (0.01730.0212 mmol/kg) and iron (0.00870.0138 mmol/kg) - in stems; cadmium (0.00020.0009 mmol/kg) and copper (0.1440.244 mmol/kg) - in flowers. Therefore, cutting paeonies in the autumn before retirement avoids the accumulation of these microelements in the soil. The results of the correlation analysis showed that the absolute values of the concentrations of the studied elements in the considered taxon of paeonies correlate with each other to a moderate and strong degree.

Spruce forest afforestation leading to increased Fe mobilization from soils

Increasing exports of Fe and DOC from soils, causing browning of freshwaters, have been reported in recent decades in many regions of the northern hemisphere. Afforestation, and in particular an increase of Norway spruce forest in certain regions, is suggested as a driver behind these trends in water chemistry. In this study, we tested the hypothesis that the gradual accumulation of organic soil layers in spruce forests, and subsequent increase in organic acid concentrations and acidity enhances mobilization of Fe. First generation Norway spruce stands of different ages (35, 61, 90 years) and adjacent arable control plots were selected to represent the effects of aging forest. Soil solutions were sampled from suction lysimeters at two depths (below organic soil layer and in mineral soil) during two years, and analyzed for Fe concentration, Fe speciation (XAS analysis), DOC, metals, major anions and cations. Solution Fe concentrations were significantly higher in shallow soils under older spruce stands (by 5- and 6-fold) than in control plots and the youngest forest. Variation in Fe concentration was best explained by variation in DOC concentration and pH. Moreover, Fe in all soil solutions was present as mononuclear Fe(III)-OM complexes, showing that this phase is dominating Fe translocation. Fe speciation in the soil was also analyzed, and found to be dominated by Fe oxides with minor differences between plots. These results confirmed that Fe mobilization, by Fe(III)-OM complexes, was higher from mature spruce stands, which supports that afforestation with spruce may contribute to rising concentrations of Fe in surface waters.

Zinc Plant Uptake as Result of Edaphic Factors Acting

The influence of soil characteristics on the lability and bioavailability of zinc at both background and phytotoxic concentrations in Albic Retisol soil (Loamic, Ochric) was studied using various methods. Ranges of insufficient, non-phytotoxic, and phytotoxic zinc concentrations in soil solutions were established in an experiment with an aqueous barley culture. It was experimentally revealed that for a wide range of non-toxic concentrations of Zn in the soil corresponding to the indicative type of plant response, there was constancy of the concentration ratio (CR) and concentration factor (CF) migration parameters. As a result, a new method for assessing the buffer capacity of soils with respect to Zn (PBCZn) is proposed. The transformation processes of the chemical forms and root uptake of native (natural) zinc contained in the Albic Retisol (Loamic, Ochric) through the aqueous culture of barley were studied using a cyclic lysimetric installation and radioactive 65Zn tracer. The distribution patterns of Zn(65Zn) between different forms (chemical fractions) in the soil were established using the sequential fractionation scheme of BCR. The coefficients of distribution and concentration factors of natural Zn and 65Zn, as well as accumulation and removal of the metal by plants were estimated. The values of the enrichment factor of natural (stable) Zn contained in sequentially extracted chemical fractions with the 65Zn radioisotope were determined and the amount of the pool of labile zinc compounds in the studied soil was calculated.

THE LONG ROAD TO THE LIGHT: ON THE NINETIETH ANNIVERSARY OF T.L. BYSTRITSKAYA

Tatyana Lvovna Bystritskaya is a prominent representative of the post-war pleyade of Soviet soil scientists, who laid the foundations of functional ecological soil science in connection with the problem of bioproductivity of terrestrial ecosystems. She can rightfully be considered as one of the most signifi Russian researchers of the year-round carbon cycle and conjugated biophilic elements in natural and anthropogenic steppe ecosystems on the chernozem soils of the USSR. Tatyana Lvovna Bystritskaya is also the developer of the methodology for instrumental monitoring of “soil life” (the daily and seasonal dynamics of soil solutions using ion-selective electrodes), an international expert on black fusion soils of Eurasia and on the fusion processes unfavorable to agricultural soils, author and co-author of classical monographs on the bioproductivity of herbal ecosystems in connection with soil processes and nature management, on the genesis and evolution of soils in the opolian landscapes of Central Russia, on the vertisols of Eurasia, soil solutions of chernozems and gray forest soils in Russia and Ukraine. In November this year, Tatyana Lvovna celebrates her ninetieth birthday, and we present this publication as a humble gift on this momentous occasion.

ON THE ACTIVITY OF THE Na+ CATION IN SOIL SOLUTIONS ON THE IRRIGATED TERRITORY OF CENTRAL FERGANA

В работе приведены концентрация иона, активность и коэффициент активности катиона натрия в почвенных растворах засоленных луговых сазовых почв с различными глубинами нахождения арзык-шоховых горизонтов.

Role of soil microbes in sustainable crop production and soil health: A review

Global food production needs to be increased in order to feed the world’s growing population and at the same time, the reliance on inorganic fertilizers and pesticides should be minimized. To accomplish this goal, the various beneficial associations between plants and soil microorganisms should be explored. The soil microbes are bacteria, actinomycetes, viruses, fungi, nematode, and protozoa. They have an important soil function that has fulfilled several useful tasks in the soil system. Microbes support biological nitrogen fixation of different biological transformations that support the accumulation and utilization of key nutrients, support root and shoot growth processes, disease control, and improve soil quality in crop cultivation. Soil microbes offer nutrient-dense nourishment improved crop production and recycle soil solutions. They play an essential role in decomposing organic matter, cycling nutrients, and fertilizing the soil. Besides, they improve plant growth on various physiological parameters of plants by a number of mechanisms. The mechanism involved in growth promotion includes plant growth regulators, production of different metabolites, and conversion of atmospheric nitrogen into ammonia in direct and indirect ways. In addition, soil microbes offer resistance against diseases. This review outlines the significant impact of soil microbes on sustainable agricultural growth, the benefits of microbes in maintaining soil health, and their interactions.

Leaching of Phosphomonoesterase Activities in Beech Forest Soils: Consequences for Phosphorus Forms and Mobility

Phosphomonoesterases play an important role in the soil phosphorus (P) cycle since they hydrolyze P monoester to phosphate. Their activity is generally measured in soil extracts, and thus, it remains uncertain how mobile these enzymes are and to which extent they can be translocated within the soil profile. The presence of phosphomonoesterases in soil solutions potentially affects the share of labile dissolved organic P (DOP), which in turn would affect P leaching. Our study aimed at assessing the production and leaching of phosphomonoesterases from organic layers and topsoil horizons in forest soils and its potential effect on dissolved P forms in leachates obtained from zero-tension lysimeters. We measured phosphomonoesterase activities in leached soil solutions and compared it with those in water extracts from litter, Oe/Oa, and A horizons of two beech forests with a contrasting nitrogen (N) and P availability, subjected to experimental N × P fertilization. In addition, we determined phosphate and DOP. In soil solutions leached from litter, Oe/Oa, and A horizons, phosphomonoesterase activities ranged from 2 to 8 μmol L–1 h–1 during summer, but remained below detection limits in winter. The summer values represent 0.1–1% of the phosphomonoesterase activity in soil extracts, indicating that enzymes can be translocated from organic layers and topsoils to greater soil depths. Activities of phosphomonoesterases obtained by water extracts were greater in the organic layer of the P-poor site, while activities of those in soil solutions were similar at the two sites. Nitrogen addition increased phosphomonoesterase activities in leached soil solutions of the organic layer of the N- and P-poor soil. Using a modeling approach, we estimated that approx. 76% of the initial labile DOP was hydrolyzed to dissolved inorganic P within the first 24 h. Back calculations from measured labile DOP revealed an underestimation of approx. 15% of total dissolved P, or 0.03 mg L–1. The observed leaching of phosphomonoesterases implies that labile organic P could be hydrolyzed in deeper soil horizons and that extended sample storage leads to an underestimation of the contribution of DOP to total dissolved P leaching. This has been neglected in the few field studies measuring DOP leaching.

Study on the corrosion behaviors of high-silicon chromium iron in acidic and alkaline soil solutions

Purpose High-silicon chromium iron (HSCI) has been used in ground grids in southern China, while there was a lack of study on its corrosion behavior in this soil environment. The purpose of this paper is to discover the corrosion of HSCI in acidic and alkaline soil solutions. Design/methodology/approach The original defects on the HSCI surface were observed using optical microscopy, and the corrosion behavior of the HSCI in the acidic and alkaline soil solutions were jointly detected using electrochemical measurements and scanning electron microscopy/energy dispersive spectrometer. Findings The results showed the corrosion rates of the HSCI in the acidic and alkaline soil solutions were limited, and the high contents of Cr and Si in matrix was responsible for its high corrosion resistance. The HSCI showed a similar corrosion tendency in the two solutions, while its corrosion rate in the acid soil solution was higher than that in the alkaline soil solution. The corrosion pits on the specimen surface were originated from the original defects in matrix, and the edges of the corrosion pits were more rounded than the original defects after 720 h immersion in the two solutions. The original defects in the HSCI matrix played a significant role in the corrosion process. Originality/value The paper discovered the corrosion evolution of HSCI in the acidic and alkaline soil solutions. What is more, the acceleration role of the original defects on the corrosion of the HSCI in the acidic and alkaline soil solutions was discovered in the paper. The results are beneficial for the material selection of ground grid equipment in engineering.