Relationship of selected properties of Cambisols to altitude and forest ecosystems of four vegetation grades.

Currently, little is known about the spatial variability of significant soil properties and their relationships to forest ecosystems of different vegetation grades. This work evaluates the variability of the properties of the upper layer of Cambisol taxa and their relationship to altitude and forest ecosystems of 2nd to 5th forest vegetation grades selected in the Western Carpathians using PCA and regression analysis. The content of clay, total carbon and total nitrogen, humus, energy, and ash in the soils varied between 5.43 and 11.53 %, 21-65 mg g-1, 1.9-4.7 mg g-1, 36-112 mg g-1, 438.4-5845.7 J g-1 and 852.9-946.3 mg g-1, and C/N, pHH2O, and pHKCl values ranged between 11.2 and 16.7, 4.0-5.8 and 3.1-4.6. PCA showed that EAC in the 3rd oak-beech vegetation grade had significantly higher pH values and significantly lower energy content, ESC in the 4th beech vegetation grade had a significantly higher ash content and a significantly lower energy content, and DC in the 5th fir-beech vegetation grade had a significantly higher content of Ct, Nt, and humus. Linear regression revealed a strong negative correlation between the energy content and soil reaction (R2 for pHH2O = 0.48; R2 for pHKCl = 0.38) for all Cambisol taxa. Ct content and ash show a strong negative correlation (R2 = 0.78). The positive relationship between altitude and FVGs was found only for the soil Ct (R2 = 0.87), Nt (R2 = 0.81), and humus content (R2 = 0.87). A strong negative linear relationship between altitude and FVGs showed the ash content (R2 = 0.77). In turn, the oscillatory, polynomial course had a relationship between the clay content (R2 = 0.65) and energy (R2 = 0.75) to altitude and FVGs. Recognizing significant soil variables and better understanding their impact on the development of forest ecosystems is a prerequisite for distinguishing areas with the highest risk of their damage under conditions of various anthropogenic interventions and climate change. Therefore, this topic continues to require increased research efforts. For this reason, a better understanding of the relationships between soil properties and ecologically differentiated communities of forest ecosystems will allow us to identify areas with the highest risk of ecological changes that could lead to the degradation of European forests in the future.

Content of Cadmium and Nickel in Soils and Assimilatory Organs of Park Woody Species Exposed to Polluted Air.

The rising level of pollutant emissions is becoming one of the most pressing environmental problems of our time. Therefore, this work is focused on evaluating Cd and Ni contamination of soils and assimilatory organs of two native (Acer platanoides L., Taxus baccata L.) and two non-native (Negundo aceroides Moench, Thuja occidentalis L.) woody species in urban parks of SW Slovakia. The contents of Cd and Ni in soils were determined by the AAS method and, in the assimilatory organs of trees, by the AAS-ETA method. The studied soils (Fluvisol, Phaeozem) have neutral soil reactions and a moderate organic matter content. Cadmium soil contamination is considerable to very high; in the case of Ni, it is moderate to low. Cadmium levels detected in leaves were 31% higher than in needles, while Ni levels were 27% lower. Significant ecological factors in relation to the studied woody species were evaluated using PCA. The first three principal components of PCA significantly correlated with Cd (PC1) and Ni (PC3) contents in soils and Cd content in assimilatory organs (PC2), thus suggesting that these elements could especially originate from industrial and vehicular sources. Knowledge of the factors affecting the accumulation of risk elements in the assimilatory organs of park woody species can be successfully used, especially in the assessment of the quality of the urban environment and the selection of suitable cultivars for planting in areas with air pollution.

Impact of Car Traffic on Metal Accumulation in Soils and Plants Growing Close to a Motorway (Eastern Slovakia).

The paper evaluates the impact of car transport on the distribution and accumulation of Zn, Cu, Pb and Cd in soils, as well as in the vegetation near a newly built R4 motorway Kosice-Milhost (Slovakia). Samples were taken from surface humus layer (litter) and 0−5, 10−20 and 20−30 cm mineral layers of Cambisol and Luvisol, as well as from assimilatory organs of Fraxinus excelsior, Quercus cerris, Quercus rubra, Negundo aceroides and Anthriscus sylvestris growing in the segments of geobiocoenosis Querci-Fageta Typica. The concentrations of total Zn and Cu were determined using SensAA AAS and the total concentrations of Cd and Pb using an instrument iCE 3000 Series AAS-F. Contamination factor (CF) values showed that surface humus layer of both soil units is moderately contaminated with Zn (1 ≤ CF ˂ 3), low contaminated with Cu (CF ˂ 1) and considerably contaminated with Pb and Cd (3 ≤ CF ˂ 6). Contamination of the surface humus layer of Luvisol with Pb is very high (CF > 6), while in the case of mineral layers with Zn and Cu it is low (CF ˂ 1). The mineral layers of Luvisol are moderately contaminated with Pb and Cd (1 ≤ CF ˂ 3) and Cambisol layers with Zn, Cu, Pb and Cd. For the group of 5 tested plants, higher values of toxic elements in the leaves were observed on Luvisol compared to Cambisol. However, only Cu conconcentrations in Luvisol significantly correlated with Cu concentrations in plants (r > 0.4 or r < 0.6). The same can be said for Zn concentrations in Cambisol (r > 0.8). The best indicator of the environment polluted by car traffic appears to be A. sylvestris. Transfer coefficients (TC ˃ 1) revealed that this species concentrated the most Zn and Cu on Luvisol and close to 1 are also the TC values found for Cu in F. excelsior and Q. cerris leaves taken on Luvisol. Lead is accumulated most efficiently in N. aceroides leaves and Cd in A. sylvestris leaves regardless of soil unit. Compared to background values, the total concentrations of trace elements in soils and plants were significantly higher and point to the pollution of forest ecosystems already in the initial stage of motorway operation.

Salinity Stress Affects Photosynthesis, Malondialdehyde Formation, and Proline Content in Portulaca oleracea L.

In this investigation, the effect of salt stress on Portulaca oleracea L. was monitored at salinity levels of 100 and 300 mM NaCl. At a concentration of 100 mM NaCl there was a decrease in stomatal conductance (gs) simultaneously with an increase in CO2 assimilation (A) at the beginning of salt exposure (day 3). However, the leaf water potential (ψw), the substomatal concentration of CO2 (Ci), the maximum quantum yield of photosystem II (Fv/Fm), and the proline and malondialdehyde (MDA) content remained unchanged. Exposure to 300 mM NaCl caused a decrease in gs from day 3 and a decrease in water potential, CO2 assimilation, and Fv/Fm from day 9. There was a large increase in proline content and a significantly higher MDA concentration on days 6 and 9 of salt stress compared to the control group. After 22 days of exposure to 300 mM NaCl, there was a transition from the C4 cycle to crassulacean acid metabolism (CAM), manifested by a rapid increase in substomatal CO2 concentration and negative CO2 assimilation values. These results document the tolerance of P. oleracea to a lower level of salt stress and the possibility of its use in saline localities.

Effect of Acetaminophen (APAP) on Physiological Indicators in Lactuca sativa.

This study analyzes the effects of acetaminophen (APAP) as a contaminant on physiological characteristics of lettuce plants (Lactuca sativa L.). Experiments were provided in an experimental greenhouse with semi-controlled conditions. The effect of different amounts of contaminant was evaluated by using regression analysis. Plants were grown in five concentrations of APAP: 0 µM, 5 µM, 50 µM, 500 µM, and 5 mM for 14 days in two variants, acute and chronic. The obtained results show that the monitored parameters were demonstrably influenced by the experimental variant. Plants are more sensitive to chronic contamination compared to acute. Significant (p < 0.05) deviation in photosynthesis and fluorescence was observed compared to the control in different variants. The highest doses of APAP reduced the intensity of photosynthesis by a maximum of more than 31% compared to the control. A reduction of 18% was observed for the fluorescence parameters. Pronounced correlation was described between chlorophyll fluorescence parameters and yield mainly under APAP conditions. The amount of chlorophyll was influenced by exposure to APAP.

Spatial variability of nutrients in soils and plants of forest ecosystems located near the highway.

The variability of selected biogenic elements in soils and leaves of three dominant plant species was studied in segments of Querci-Fageta typica and Fagi-Querceta typica forest ecosystems located near R1 Pribina highway in SW Slovakia. The amounts of nutrients (Mg, K, Na and Zn) in soils distant 30 m from the highway were mostly low and increased significantly with a depth of soil. On the other hand, the highest Ca concentrations were found in the surface humus horizons and decreased significantly with soil depth. The Mg, K and Zn contents found in soil mineral horizons 8000 m from the highway were more balanced than those found at 30 m from the highway. The nutrient content of plant leaves was mostly significantly higher at a distance of 30 m from the highway than 8000 m from the highway, for Ca (Prunus spinosa, Melica uniflora), Mg (P. spinosa), Na (Quercus cerris, P. spinosa) and Zn (Q. cerris, M. uniflora). The tightness of the relationships between nutrient contents in leaves and the distance from the highway was the highest for Ca (P. spinosa, M. uniflora), Mg, Na, Zn (Q. cerris, P. spinosa) and K (M. uniflora). The K/(Mg + Ca) ratios in Q. cerris and P. spinosa leaves distant 8000 m from the highway were more balanced than those found at 30 m from the highway. This markedly points to favourable biological activity and better stability of the more distant control ecosystem with lower level of pollutants.

The Impact of Highway Motor Vehicle Traffic on Energy Stores in Selected Plant Species.

This paper assesses the impact of vehicle emissions on energy stores in assimilation organs of five plant species on plots at different distances from the highway. On more remote plots (500 m away from the road) with lower level of pollutants there was a significant increase in the amount of energy in leaves of Negundo aceroides, Quercus rubra and Anthriscus sylvestris. The increase of energy in Quercus cerris was negligible and in the case of Fraxinus excelsior was even recorded a decrease in energy store. The tightness of the relationships between energy accumulated in plant leaves and the distance from the highway was as follows: N. aceroides > Q. cerris > Q. rubra > A. sylvestris. The most suitable for energy biomonitoring appear N. aceroides and A. sylvestris, which in the period of full highway operation bound significantly less energy than before its construction. Q. cerris have demonstrated greater ability to accumulate energy on Cambisols, F. excelsior on Fluvisols.

Isoflavones Production and Possible Mechanism of Their Exudation in Genista tinctoria L. Suspension Culture after Treatment with Vanadium Compounds.

The family Fabaceae traditionally serves as a food and herbal remedies source. Certain plants serve for treatment of menopausal symptoms based on a presence of typical secondary metabolites, isoflavones. Beside soybean and clovers, other plants or cultures in vitro can produce these molecules. A cultivation in vitro can be enhanced by elicitation that stimulates metabolites biosynthesis via stress reaction. Vanadium compounds have been already described as potential elicitors, and the aim of this study was to determine the impact of NH4VO3 and VOSO4 solutions on isoflavones production in Genista tinctoria L. cell cultures. The significant increase of isoflavones content, such as genistin, genistein, or formononetin, was measured in a nutrient medium or dry mass after NH4VO3 treatment for 24 or 48 h. The possible transport mechanism of isoflavones release as a result of elicitation was further evaluated. An incubation with different transport inhibitors prior to elicitation took effect on isoflavones content in the medium. However, there was a non-ended result for particular metabolites such as genistein and daidzein, where ATP-binding cassette (ABC) or, alternatively, multidrug and toxin extrusion (MATE) proteins can participate. Possible elicitation by some inhibitors was discussed as a result of their pleiotropic effect. Despite this outcome, the determination of the transport mechanism is an important step for identification of the specific transporter.

The disadvantages of being a hybrid during drought: A combined analysis of plant morphology, physiology and leaf proteome in maize.

A comparative analysis of various parameters that characterize plant morphology, growth, water status, photosynthesis, cell damage, and antioxidative and osmoprotective systems together with an iTRAQ analysis of the leaf proteome was performed in two inbred lines of maize (Zea mays L.) differing in drought susceptibility and their reciprocal F1 hybrids. The aim of this study was to dissect the parent-hybrid relationships to better understand the mechanisms of the heterotic effect and its potential association with the stress response. The results clearly showed that the four examined genotypes have completely different strategies for coping with limited water availability and that the inherent properties of the F1 hybrids, i.e. positive heterosis in morphological parameters (or, more generally, a larger plant body) becomes a distinct disadvantage when the water supply is limited. However, although a greater loss of photosynthetic efficiency was an inherent disadvantage, the precise causes and consequences of the original predisposition towards faster growth and biomass accumulation differed even between reciprocal hybrids. Both maternal and paternal parents could be imitated by their progeny in some aspects of the drought response (e.g., the absence of general protein down-regulation, changes in the levels of some carbon fixation or other photosynthetic proteins). Nevertheless, other features (e.g., dehydrin or light-harvesting protein contents, reduced chloroplast proteosynthesis) were quite unique to a particular hybrid. Our study also confirmed that the strategy for leaving stomata open even when the water supply is limited (coupled to a smaller body size and some other physiological properties), observed in one of our inbred lines, is associated with drought-resistance not only during mild drought (as we showed previously) but also during more severe drought conditions.

24-epibrassinolide and 20-hydroxyecdysone affect photosynthesis differently in maize and spinach.

The aim of the work was to examine the effect of brassinosteroid (24-epibrassinolide; 24E) and ecdysteroid (20-hydroxyecdysone; 20E) on various parts of primary photosynthetic processes in maize and spinach. Additionally, the effect of steroids on gaseous exchange, pigment content and biomass accumulation was studied. The efficiency of the photosynthetic whole electron-transport chain responded negatively to the 24E or 20E treatment in both species, but there were interspecific differences regarding Photosystem (PS) II response. A positive effect on its oxygen-evolving complex and a slightly better energetical connectivity between PSII units were observed in maize whereas the opposite was true for spinach. The size of the pool of the PSI end electron acceptors was usually diminished due to 24E or 20E treatment. The treatment of plants with 24E or 20E applied individually positively influenced the content of photosynthetic pigments in maize (not in spinach). On the other hand, it did not affect gaseous exchange in maize but resulted in its reduction in spinach. Plants treated with combination of both steroids mostly did not significantly differ from the control plants. We have demonstrated for the first time that 20E applied in low (10nM) concentration can affect various parts of photosynthetic processes similarly to 24E and that brassinosteroids regulate not only PSII but also other parts of the photosynthetic electron transport chain - but not necessarily in the same way.

The physiology and proteomics of drought tolerance in maize: early stomatal closure as a cause of lower tolerance to short-term dehydration?

Understanding the response of a crop to drought is the first step in the breeding of tolerant genotypes. In our study, two maize (Zea mays L.) genotypes with contrasting sensitivity to dehydration were subjected to moderate drought conditions. The subsequent analysis of their physiological parameters revealed a decreased stomatal conductance accompanied by a slighter decrease in the relative water content in the sensitive genotype. In contrast, the tolerant genotype maintained open stomata and active photosynthesis, even under dehydration conditions. Drought-induced changes in the leaf proteome were analyzed by two independent approaches, 2D gel electrophoresis and iTRAQ analysis, which provided compatible but only partially overlapping results. Drought caused the up-regulation of protective and stress-related proteins (mainly chaperones and dehydrins) in both genotypes. The differences in the levels of various detoxification proteins corresponded well with the observed changes in the activities of antioxidant enzymes. The number and levels of up-regulated protective proteins were generally lower in the sensitive genotype, implying a reduced level of proteosynthesis, which was also indicated by specific changes in the components of the translation machinery. Based on these results, we propose that the hypersensitive early stomatal closure in the sensitive genotype leads to the inhibition of photosynthesis and, subsequently, to a less efficient synthesis of the protective/detoxification proteins that are associated with drought tolerance.