Fusicoccin Counteracts the Toxic Effect of Cadmium on the Growth of Maize Coleoptile Segments

The effects of cadmium (Cd; 0.1–1000 μM) and fusicoccin (FC) on growth, Cd2+ content, and membrane potential (Em) in maize coleoptile segments were studied. In addition, the Em changes and accumulation of Cd and calcium (Ca) in coleoptile segments treated with Cd2+ combined with 1 μM FC or 30 mM tetraethylammonium (TEA) chloride (K+-channel blocker) were also determined. In this study, the effects of Ca2+-channel blockers [lanthanum (La) and verapamil (Ver)] on growth and content of Cd2+ and Ca2+ in coleoptile segments were also investigated. It was found that Cd at high concentrations (100 and 1000 μM) significantly inhibited endogenous growth of coleoptile segments and simultaneously measured proton extrusion. FC combined with Cd2+ counteracted the toxic effect of Cd2+ on endogenous growth and significantly decreased Cd2+ content (not the case for Cd2+ at the highest concentration) in coleoptile segments. Addition of Cd to the control medium caused depolarization of Em, the extent of which was dependent on Cd concentration and time of treatment with Cd2+. Hyperpolarization of Em induced by FC was suppressed in the presence of Cd2+ at 1000 μM but not Cd2+ at 100 μM. It was also found that treatment of maize coleoptile segments with 30 mM TEA chloride caused hyperpolarization of Em and decreased Cd2+ content in coleoptile segments, suggesting that, in the same way as for FC, accumulation of Cd2+ was dependent on plasma membrane (PM) hyperpolarization. Similar to FC, TEA chloride also decreased Ca2+ content in coleoptile segments. La and Ver combined with Cd2+ (100 μM) significantly decreased Cd content in maize coleoptile segments, but only La completely abolished the toxic effect of Cd2+ on endogenous growth and growth in the presence of FC. Taken together, these results suggest that the mechanism by which FC counteracts the toxic effect of Cd2+ (except at 1000 μM Cd2+) on the growth of maize coleoptile segments involves both stimulation of PM H+-ATPase activity by FC as well as Cd2+-permeable, voltage-dependent Ca channels, which are blocked by FC and TEA chloride-induced PM hyperpolarization

Estimation of bulk density of the mountain soils from the organic carbon content

The missing data on bulk density make impossible the calculations of soil water retention, organic carbon pools and evaluation of the numerical indices of soil and forest habitat fertility and potential productivity. A common reason of skipping of bulk density measurement is the high content of rock fragments in soil, in particular in the subsoil layers, that may hamper the collection of samples with undisturbed soil structure. The aim of present study was to analyse the relationships between bulk density and basic properties of mountain soils, where the problem of high skeleton content is relatively common, selection of the properties of the largest impact on the soil bulk density, and the fitting of the mathematical model (equation) that allows the prediction of soil bulk density at the highest available statistical significance. Forest soils in the Sudeten Mountains and the Sudeten Foreland, SW Poland (total number of samples N=580), situated on various bedrocks (granite, basalts, gneiss, mica schists, sandstones, mudstones, etc.) were selected to analysis. It was found in those soils featured by large variability of soil texture (the range of clay content 0−40%), skeleton content (0−74%), and organic carbon content (0.09−50%) in the soil profile, that the bulk density (having the values 0.10−1.87 g/cm3 in mineral layers and 0.04−0.58 g/cm3 in organic/litter layers) was individually correlated with the organic carbon content, skeleton content, clay content, and the depth of sampling (depth of particular soil layer), but the multifactor analysis has shown, that the organic carbon content has the highest impact on the bulk density and the organic carbon alone is sufficient for reliable prediction of soil bulk density. The best fitting of the measured and predicted bulk densities (R2=0.83) was provided by ‘dose−response’ Hill model: dv=1.72–[(2.36·Corg0.6)/(13.80.6+Corg0.6)], that returned dv values between 0.10 and 1.72 g/cm3 in a range of Corg content between 50 and 0%

Zawartość i rozpuszczalność metali ciężkich w próchnicach leśnych na terenach zdegradowanych przez hutnictwo miedzi

Three permanent study areas, each consisting of four sarapling sites, located at distances of 500, 1500 and 2100 m from emission source, were established iii poplar plantings surrounding a large copper smelter near the town Legnica in Lower Silesia region of SW Poland. Total content as well as water and acetic acid extractable contents of Cu. Za. Fe, Ca and Mg were analyzed in saraples of forest litter (ectohumus) collected in November 2007. The total content of Cu reached 9590 mg o kg-1, and Zn - 4020 mg o kg-1 d.m. in the site located 500 m away of smelter, and rapidly decreased with distance, while the content of Fe, Ca and Mg decreased insignificantly. Up to 0.5 % of total Cu and up to 1.2 % of total Zn was in water-extractable form, while 0.11 mol o dm-3 acetic acid released up to 7.2 % of Cu and 41 % of Zn, and more than 50 % of total Ca and Mg. Copper and zinc are immobilized in alkaline litter under poplar stands surrounding copper smelter, but any factor acidifying the litter may rapidly enhance solubility of accumulated heavy metals.Trzy stałe powierzchnie obserwacyjne, każda obejmująca po cztery punkty pobierania próbek, zlokalizowane w odległości 500, 1500 i 2100 m od źródła emisji zostały założone na obszarze zadrzewionym topolą wokół dużej huty miedzi w pobliżu Legnicy, w południowo-zachodniej Polsce. W próbkach próchnic nadkładowych pobranych w listopadzie 2007 r. analizowano całkowitą zawartość Cu. Zn, Fe, Ca i Mg oraz zawartość form rozpuszczalnych w wodzie i 0.11 mol o dm kwasie octowym. Całkowita zawartość miedzi w ściółce osiągała poziom 9590 mg o kg-1 suchej masy. a cynku -1020 mg o kg-1 s.m. na powierzchni zlokalizowanej 500 m od huty i raptownie zmniejszała się wraz z odległością.. Zawartość Po, Ca i .Mg w ściółkach również zmniejszała się wraz z odległością, lecz w znacznie mniejszym stopniu niż Cu i Zn. Do 0,5 % całkowitej zawartości Cu i do 1,2 % całkowitej zawartości Zn występowało w analizowanych ściółkach w formach rozpuszczalnych w wodzie destylowanej. 0.11 mol o dm-3 kwas octowy uwalniał nawet do 7.2 % całkowitej zawartości Cu i do 41 % całkowitej zawartości Zn oraz ponad 50 % całkowitej ilości Ca i Mg. Miedź i cynk są słabo rozpuszczalne w warunkach alkalicznego odczynu próchnic nadkładowych w drzewostanach topolowych, lecz jakichkolwiek naturalny lub antropogenny czynnik prowadzący do zakwaszenia ściółek może spowodować raptowny wzrost rozpuszczalności nagromadzonych metali ciężkich

Problems of trophic status diagnosis in the forest habitats on former arable alluvial soils

The morphology and properties of the post−arable soils that influence the trophic status of forest habitats on the Barycz river terraces (south−western Poland) were analyzed. The fieldwork included the characterization of the soil, tree layer, and the vegetation of the forest floor, as required for the forest habitat evaluation. In the collected soil samples, a set of physico−chemical analysis was carried out, that included: soil texture, bulk density, pH in KCl and water, total organic carbon, total nitrogen, hydrolytic acidity, base cations, and the content of plant−available phosphorus, potassium, and magnesium. Sandy post−arable soils in the Barycz valley have a thick, double− or triple−layered ploughed humus horizon, and the high stock of humified organic matter, nitrogen, and phosphorus, that emphasizes anthropogenic transformation of soils and differentiates them from the natural soils of river valleys. The diagnosis based on the soil trophic index (SIG) indicates generally lower trophic status (mesotrophic) as compared to the diagnoses based on forest floor vegetation and tree−stand (eutrophic status). The SIG model for the post−agrar moist valley habitats should be supplemented with the factors, which improve the apparent trophic status of sandy soils, including the thick humus horizon (post−ploughing) and shallow table of eutrophic ground water

Forest habitats on dystric Cambisols developed from granite in the Stolowe Mountains

Deep dystric Cambisols developed on the homogenous regoliths of granite in the Stołowe Mountains National Park (SW Poland). In general, the soils have a texture of gravelly sandy loam, apparently silty, the strong acid reaction and the base saturation below 30% throughout the profile (oligotrophic variant). Only the soils developed in lower parts of slopes have a base saturation up to 40−50% or more (oligo−mesotrophic and mesotrophic variants respectively). These soils rich in humus and biologically active create in the low mountain zone the habitats suitable for the mixed mountain forests and, in a less acid variant, for the broadleaf mountain forests. Combined trophic soil index reached the values from 29 to 33 that confirmed mesotrophic type of the forest habitats. Most Cambisols developed from granite in the Stołowe Mountains are currently covered with spruce stands of artificial origin. However, a phytosociological analyses of vegetation carried out in preserved beech stands documented the presence of Luzulo luzuloidis−Fagetum community of poor beech forest that should be considered a potentially natural forest community on these soils and the strategic goal of the forest reconstruction in the national park

Regulation of V-ATPase by jasmonic acid: possible role of persulfidation

Peer reviewe

Regulation of V-ATPase by Jasmonic Acid: Possible Role of Persulfidation

Vacuolar H+-translocating ATPase (V-ATPase) is a proton pump crucial for plant growth and survival. For this reason, its activity is tightly regulated, and various factors, such as signaling molecules and phytohormones, may be involved in this process. The aim of this study was to explain the role of jasmonic acid (JA) in the signaling pathways responsible for the regulation of V-ATPase in cucumber roots and its relationship with other regulators of this pump, i.e., H2S and H2O2. We analyzed several aspects of the JA action on the enzyme, including transcriptional regulation, modulation of protein levels, and persulfidation of selected V-ATPase subunits as an oxidative posttranslational modification induced by H2S. Our results indicated that JA functions as a repressor of V-ATPase, and its action is related to a decrease in the protein amount of the A and B subunits, the induction of oxidative stress, and the downregulation of the E subunit persulfidation. We suggest that both H2S and H2O2 may be downstream components of JA-dependent negative proton pump regulation. The comparison of signaling pathways induced by two negative regulators of the pump, JA and cadmium, revealed that multiple pathways are involved in the V-ATPase downregulation in cucumber roots

Influence of stands with diversed share of Norway spruce in species structure on soils of various forest habitats in the Stolowe Mountains

Chemical properties and fertility of soils were compared under spruce, mixed and beech stands in four types of forest habitat (mountain broadleaf forest, mountain mixed broadleaf forest, mountain mixed coniferous forest and mountain coniferous forest) in 373 sites of forest monitoring in the Stołowe Mountains National Park, SW Poland. Soils under the spruce stands had higher organic carbon pools in their upper horizons, but lower pH, increased activity of exchangeable aluminum, lower contents of exchangeable base cations, available potassium and magnesium, resulting finally in lower values of the soil trophic index (SIG). The negative impact of spruce monocultures on the physicochemical soil properties was much stronger in the eutrophic habitats (dedicated to broadleaf forest) than in dystrophic ones. Weak positive effect of the beech introduction on soils in the dystrophic habitats indicated that the conversion of the coniferous into mixed or deciduous stands would not cause a rapid improvement in the physicochemical properties deformed previously under spruce monocultures

Content of mineral nitrogen in sandy soils after an application of slow-release fertilisers in sweet sorghum cultivation

In 2013-2014, field experiments were conducted at the Agricultural Research Station in Pawłowice (Department of Crop Production of the Wroclaw University of Environmental and Life Sciences), using sorghum as a test plant. The purpose was to determine the influence of the type of fertiliser on the content of mineral nitrogen (N-NO3 and N-NH4) in the top soil layer (0-60 cm). Soil samples were collected three times during the growing season: in the spring before sowing, during the phase of shoot formation (July), and after the harvest (October). The fertilisers used in the experiment were ammonium nitrate, urea and slow-release coated urea (Meister). Regardless of the weather conditions in 2013 and 2014, similar tendencies were found with respect to the differentiation of the nitrogen content in soil. The total nitrogen content was the highest in the middle of the growing season, and the amounts of nitrate form differed greatly among the treatments. The content of N-NO3, measured in that period was 20-44% lower in the soil fertilised with coated urea than with standard urea. After the harvest, the stock of nitrogen in soil fertilised with ammonium nitrate was 58-61 kg ha-1, which was classified as a medium-high level (posing a threat to water quality), while being on a low level of 31-46 kg ha-1 in soils fertilised with standard urea and coated urea, which is considered to be harmless for the groundand surface waters under climate conditions of Poland. The stocks of N-NO3 left in soil after sorghum harvest fell into the medium-high level according to the limits recommended for sandy soils in Poland after fertilisation with ammonium nitrate, and into the low level if fertilised with standard urea and coated urea, in both years