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Natural disaster can disrupt soil structure and replace established vegetation with younger plants, altering the local hydrological processes. We used hydrogen and oxygen stable isotopes to examine soil water dynamics and plant water uptake patterns in two adjacent fir stands in the eastern Qinghai-Tibet Plateau: a primeval mature stand (MF, finer- textured soil) and a debris flow-developed half-mature stand (HMF, coarser-textured soil). Our results showed that the isotopic composition and soil gravimetric water content (SWC) in deep soil water in MF exhibited a more pronounced hysteresis pattern in response to precipitation compared to HMF, indicating lower turnover rate of soil water in MF. This was also confirmed by a smaller contribution of preferential flow to deep soil water in MF compared to HMF. The higher water storage (higher SWC values) and lower turnover rate of soil water suggest a higher soil water buffer capacity in MF. Additionally, both stands showed no significant difference in plant water sources, but plants in MF used more winter precipitation due to the lower soil water turnover rate. These differences suggest MF may be more vulnerable to water disasters, while HMF may be more susceptible to seasonal droughts under climate change. Our insights enhance understanding of hydrological processes linked to changing surface conditions and offer valuable information for managing forest water resources in mountainous regions.
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In the context of climate change, extreme precipitation events are continuously increasing and impact the watercarbon coupling of ecosystems. The vertical vegetation zonation, as a characteristic of mountain ecosystems, reflects the differences in vegetation response to climate change at different elevations. In this study, we used the water use efficiency (WUE) as an indicator to evaluate the watercarbon relationship. By using MODIS data, we analyzed the spatiotemporal patterns of gross primary productivity (GPP), evapotranspiration (ET), and WUE from 2001 to 2020, as well as the responses of WUE to extreme wetness factor Number of precipitation days (R0.1), extreme dryness factor Consecutive dry days (CDD), and meteorological factors under the vertical vegetation zonation. Our results showed that annual GPP and ET displayed a significant increasing trend between 2001 and 2020, whereas WUE showed a weak decreasing trend. Spatially, GPP and WUE decreased with increasing elevation. Analyzing the WUE of mountainous ecosystems as a unified whole may not precisely capture the reactions of vegetation to severe rainfall occurrences. In fact, across different vegetation belts in mountainous areas, there exists a negative correlation between WUE and R0.1, and a positive correlation with CDD. In terms of meteorological factors, the temporal variation of GPP was primarily associated with vapor pressure deficit (VPD) and temperature (Ta), while those of ET was mainly related to soil water content (SWC). WUE was affected by a combination of meteorological factors and had a certain degree of variation between different altitude intervals. These findings contribute to a better understanding and prediction of the relationship between extreme rainfall climate and watercarbon coupling in mountainous areas.
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The evapotranspiration (ET) plays a crucial role in shaping regional climate patterns and serves as a vital indicator of ecosystem function. However, there remains a limited understanding of the seasonal variability of future ET over China and its correlation with environmental drivers. This study evaluated the skills of 27 models from the Six Phase of Coupled Model Intercomparison Project in modeling ET and the Bayesian Model Averaging (BMA) method was employed to merge monthly simulated ET based on the top five best-performing models. The seasonal changes in ET under three climate scenarios from 2030 to 2099 were analyzed based on the BMA-merged ET, which was well validated with observed ET collected from fourteen flux sites across China. Significant increasing ET over China are projected under all seasons during 2030-2099, with 0.05-0.13 mm yr-1, 0.11-0.23 mm yr-1, and 0.20-0.41 mm yr-1 under SSP1-2.6, SSP2-4.5 and SSP5-8.5 scenarios, respectively. Relative to the historical period (1980-2014), the relative increase in ET over China is highest in winter and lowest in summer. Seasonal ET increases significantly in all seven climate sub-regions under high forcing scenario. Higher ET increase is generally found in southeastern humid regions, while lowest ET increase occurs in northwest China. At the country level, the primary factor driving ET increase during spring, summer, and autumn seasons is the increasing net radiation and warming. In contrast, ET increase during winter is influenced not only by energy factors but also by vegetation-related factors. Future seasonal ET increase is predominantly driven by increasing energy factors in the southeastern humid region and Tibetan Plateau, while seasonal ET changes in the northwest region prevailingly depend on soil moisture. Results indicate that China will experience a "wet season will get wetter, and dry season will become drier" in the 21st century with high radiation forcing scenario.
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Recent climate change has caused an increase in warming-driven erosion and sediment transport processes on the Tibetan Plateau (TP). Yet a lack of measurements hinders our understanding of basin-scale sediment dynamics and associated spatiotemporal changes. Here, using satellite-based estimates of suspended sediment, we reconstruct the quantitative history and patterns of erosion and sediment transport in major headwater basins from 1986 to 2021. Out of 13 warming-affected headwater regions, 63% of the rivers have experienced significant increases in sediment flux. Despite such intensified erosion, we find that 30% of the total suspended sediment flux has been temporarily deposited within rivers. Our findings reveal a pronounced spatiotemporal heterogeneity within and across basins. The recurrent fluctuations in erosion-deposition patterns within river channels not only result in the underestimation of erosion magnitude but also drive continuous transformations in valley morphology, thereby endangering local ecosystems, landscape stability, and infrastructure project safety.
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Climate change altered the quantities of aboveground plant litter and root inputs, but the effects on soil CH4 uptake rates and underlying mechanisms remain unclear. To investigate these factors, a three-year detritus input and removal treatment (DIRT) study including six treatments (namely, CK, control; NL, litter removal; DL, double litter; NR, root exclusion; NRNL, root exclusion plus litter removal; and NRDL, root exclusion plus double litter) was conducted in broadleaf and coniferous forest subalpine forest ecosystems. The results showed that both the subalpine forest soils acted as sink for atmospheric CH4 across all treatments, while the broadleaf forest had consistently higher CH4 uptake rates than the coniferous forest. Based on the annual mean values, root exclusion (NR, NRNL and NRDL) significantly decreased soil CH4 uptake rates by 35.9 %, 31.0 % and 43.4 % in the broadleaf forest and 36.7 %, 31.9 % and 40.6 % in the coniferous forest compared with CK treatments, respectively. Meanwhile, the mean soil CH4 uptake rates were significantly reduced by 23.6 % and 17.3 % in the broadleaf forest and the coniferous forest under the DL treatments, respectively; nevertheless, the NL treatment significantly increased soil CH4 uptake rates by 19.68 % and 14.4 %, respectively. The results clearly demonstrated that root exclusion exerted a greater influence on soil CH4 uptake rates than plant litter manipulations. Correlation and redundancy analysis (RDA) revealed that the separation of root exclusion treatments from aboveground plant litter manipulations was based on higher soil water content, NH4+-N and NO3--N concentrations, and lower DOC (dissolved organic carbon) concentrations and methanotroph pmoA gene abundance. The results suggest that future alterations in aboveground plant litter and root input, particularly a reduction in root input, can exert a stronger influence on regulating soil CH4 uptake than aboveground litter manipulations in subalpine forests with cold and humid climatic conditions in response to future climate scenarios.
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Solo , Traqueófitas , Solo/química , Ecossistema , Temperatura , Florestas , PlantasRESUMO
Climate change is resulting in accelerated retreat of glaciers worldwide and much nitrogen-poor debris is left after glacier retreats. Asymbiotic dinitrogen (N2) fixation (ANF) can be considered a 'hidden' source of nitrogen (N) for non-nodulating plants in N limited environments; however, seasonal variation and its relative importance in ecosystem N budgets, especially when compared with nodulating symbiotic N2-fixation (SNF), is not well-understood. In this study, seasonal and successional variations in nodulating SNF and non-nodulating ANF rates (nitrogenase activity) were compared along a glacial retreat chronosequence on the eastern edge of the Tibetan Plateau. Key factors regulating the N2-fixation rates as well as the contribution of ANF and SNF to ecosystem N budget were also examined. Significantly greater nitrogenase activity was observed in nodulating species (0.4-17,820.8 nmol C2H4 g-1 d-1) compared to non-nodulating species (0.0-9.9 nmol C2H4 g-1 d-1) and both peaked in June or July. Seasonal variation in acetylene reduction activity (ARA) rate in plant nodules (nodulating species) and roots (non-nodulating species) was correlated with soil temperature and moisture while ARA in non-nodulating leaves and twigs was correlated with air temperature and humidity. Stand age was not found to be a significant determinant of ARA rates in nodulating or non-nodulating plants. ANF and SNF contributed 0.3-51.5 % and 10.1-77.8 %, respectively, of total ecosystem N input in the successional chronosequence. In this instance, ANF exhibited an increasing trend with successional age while SNF increased only at stages younger than 29 yr and then decreased as succession proceeded. These findings help improve our understanding of ANF activity in non-nodulating plants and N budgets in post glacial primary succession.
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Ecossistema , Fixação de Nitrogênio , Fixação de Nitrogênio/fisiologia , Estações do Ano , Solo , Nitrogênio/análise , NitrogenaseRESUMO
Glacier retreat raises global concerns but brings about the moment to study soil and ecosystem development. In nutrient-limited glacier forelands, the adaptability of pioneering plant and microbial species is facilitated by their interactions, including rhizosphere effects, but the details of this adaptability are not yet understood. In the rhizosphere of five pioneering plants, we comprehensively deciphered the microbial taxonomic and functional compositions. Two nitrogen-fixing microbial genera, Bradyrhizobium and Mesorhizobium, were among the most abundant taxa in the rhizomicrobiome. Moreover, several rhizobial genera, including Rhizobium, Pararhizobium, Allohrizobium, and Sinorhizobium, head the list of major modules in microbial co-occurrence networks, highlighting the vital roles of nitrogen-cycling taxa in the rhizomicrobiome of pioneering plants. Microbial genes involved in nitrogen, sulfur, phosphorus, and methane cycles were simultaneously correlated with microbial community dissimilarity, and 12 functional pathways were detected with distinct relative abundances among soils. Zooming in on the nitrogen-cycling genes, nifW, narC, nasA, nasB, and nirA were mainly responsible for the significant differences between soils. Furthermore, soil pH and the carbon/nitrogen ratio were among the topsoil properties interacting with nitrogen and sulfur cycling gene dissimilarity. These results explicitly linked biogeochemical cycling genes to the rhizomicrobiome and soil properties, revealing the roles of these genes as microbial drivers in mediating rhizosphere soil-plant-microbiome interactions.
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Microbiota , Rizosfera , Camada de Gelo , Solo/química , Genes Microbianos , Nitrogênio/análise , Microbiologia do SoloRESUMO
Terrestrial mosses are promising tracers for research concerning metal atmospheric deposition and pollution. Concentrations of Cr, Co, Ni, Zn, Sr, Cd, Ba, and Pb in different moss species from Mountain Gongga, China were analyzed to investigate the effects of growth substrates, geographic elevation, and type of moss species on the accumulation characteristics of heavy metals, as well as to identify heavy metal sources. The ability of heavy metals to accumulate in moss varied significantly, with low concentrations of Cd and Co; medium concentrations of Cr, Ni, and Pb; and high concentrations of Zn, Sr, and Ba. Elevation significantly influenced the accumulation characteristics of heavy metals, with high concentrations found at lower elevations due to proximal pollution. Growth substrate and moss species were found to have certain influence on the bioconcentration capacities of heavy metals in moss in this study. Correlation analysis showed similar sources for Sr, Zn, and Ba, as well as for Ni, Co, and Cr. The positive matrix factorization (PMF) model was consistent with atmospheric deposition of Pb and Cd; substrate sources of Cr, Co, and Ni; and anthropogenic sources of Ba, Sr, and Zn. This research characterized the accumulation characteristics of heavy metals and their influence factors in different mosses found in alpine ecosystems and provides a reference for future studies in similar areas.
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Briófitas , Metais Pesados , China , Ecossistema , Monitoramento Ambiental , Metais Pesados/análiseRESUMO
Climate change is expected to affect alpine and Arctic tundra communities. Most previous long-term studies have focused on impacts on vascular plants, this study examined impacts of long-term warming on bryophyte communities. Experimental warming with open-top chambers (OTCs) was applied for 18 years to a mesic meadow and a dry heath alpine plant community. Species abundance was measured in 1995, 1999, 2001 and 2013. Species composition changed significantly from original communities in the heath, but remained similar in mesic meadow. Experimental warming increased beta diversity in the heath. Bryophyte cover and species richness both declined with long-term warming, while Simpson diversity showed no significant responses. Over the 18-year period, bryophyte cover in warmed plots decreased from 43 % to 11 % in heath and from 68 % to 35 % in meadow (75 % and 48 % decline, respectively, in original cover), while richness declined by 39 % and 26 %, respectively. Importantly, the decline in cover and richness first emerged after 7 years. Warming caused significant increase in litter in both plant communities. Deciduous shrub and litter cover had negative impact on bryophyte cover. We show that bryophyte species do not respond similarly to climate change. Total bryophyte cover declined in both heath and mesic meadow under experimental long-term warming (by 1.5-3 °C), driven by general declines in many species. Principal response curve, cover and richness results suggested that bryophytes in alpine heath are more susceptible to warming than in meadow, supporting the suggestion that bryophytes may be less resistant in drier environments than in wetter habitats. Species loss was slower than the decline in bryophyte abundance, and diversity remained similar in both communities. Increased deciduous shrub and litter cover led to decline in bryophyte cover. The non-linear response to warming over time underlines the importance of long-term experiments and monitoring.
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Effects of sample storage methods on the quantity and quality of labile soil organic carbon are not fully understood even though their effects on basic soil properties have been extensively studied. We studied the effects of air-drying and frozen storage on cold and hot water soluble organic carbon (WSOC). Cold- and hot-WSOC in air-dried and frozen-stored soils were linearly correlated with those in fresh soils, indicating that storage proportionally altered the extractability of soil organic carbon. Air-drying but not frozen storage increased the concentrations of cold-WSOC and carbohydrate in cold-WSOC, while both increased polyphenol concentrations. In contrast, only polyphenol concentration in hot-WSOC was increased by air-drying and frozen storage, suggesting that hot-WSOC was less affected by sample storage. The biodegradability of cold- but not hot-WSOC was increased by air-drying, while both air-drying and frozen storage increased humification index and changed specific UV absorbance of both cold- and hot-WSOC, indicating shifts in the quality of soil WSOC. Our results suggest that storage methods affect the quantity and quality of WSOC but not comparisons between samples, frozen storage is better than air-drying if samples have to be stored, and storage should be avoided whenever possible when studying the quantity and quality of both cold- and hot-WSOC.
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An intensive investigation was conducted to study the spatial distribution and temporal variety trend of mercury and arsenic in plant tissue and soil profile in the eastern of the Tibet Plateau and to explore the possible sources of these two elements. At present, rare information is available on mercury (Hg) and arsenic (As) of timberline forests in the Tibet Plateau. Here, we present preliminary results on these two elements in leaves, twigs, root, litterfall, and soil. Geostatistical analyst of the ArcGIS 10.0 was used to determine the trait of spatial distribution of these two elements. Total arsenic (TAs) mean concentrations in the leaves, twigs, root, litterfall, and A- and C-layer soil ranged from 0.12 mg kg(-1) (n = 60), 0.35 mg kg(-1) (n = 60), 0.48 mg kg(-1) (n = 42), 1.52 mg kg(-1) (n = 84), 16.51 mg kg(-1) (n = 69), and 26.72 mg kg(-1) (n = 69), respectively. Total Hg (THg) mean concentrations in leaves, twigs, root, litterfall, and A- and C-layer soil were 0.0121 mg kg(-1) (n = 60), 0.0078 mg kg(-1) (n = 60), 0.0171 mg kg(-1) (n = 42), 0.0479 mg kg(-1) (n = 84), 0.0852 mg kg(-1) (n = 75), and 0.0251 mg kg(-1) (n = 75), respectively. In general, litterfall trended to accumulate high concentrations of Hg and As. Mercury in the timberline forest showed an increasing trend, whereas arsenic concentrations showed a decreasing trend in A-layer soil and an increasing trend in C-layer soil due to the easy mobile ability of As. Southwest and southeast monsoon could be the influencing factors, and Hg emission from India and China was the possible source of this study area through using a HYSPLIT (Hybrid Single-Particle Lagrangian Integrated Trajectory) model. It is believed that these observations may offer scientists and policymakers additional understanding of Hg and As concentrations in the remote timberline area, eastern of the Tibet Plateau.
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Arsênio/análise , Monitoramento Ambiental , Florestas , Mercúrio/análise , Solo/química , Análise Espaço-Temporal , Traqueófitas , Folhas de Planta/química , Raízes de Plantas/química , Poluentes do Solo/análise , TibetRESUMO
Concentrations of 14 heavy metals (Ag, As, Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb, Sb, Tl, V, and Zn) in needles, twigs, bark and xylem of spruce and fir collected at the timberline of eight sites along the Hengduan Mountains, eastern Tibetan Plateau, are reported. Twigs had the highest concentration for most of elements, while xylem had the lowest concentration. The connections between elements in twigs were much richer than other organ/tissues. Pb, Ni, As, Sb, Co, Cd, Hg, Cr and Tl which are partly through anthropogenic sources and brought in by monsoon, have been accumulated in twigs and needles by wet or dry deposition in south and east sites where are within or near pollutant sources. Under moderate pollution situation, vegetation are able to adjust the nutrient element (Cu and Zn) cycle rate, thus maintain a stable concentration level. Seldom V, Ag, and Mo are from external anthropogenic sources. Needles and twigs can be used as biomonitors for ecosystem environment when needles can simply distinguish the origin of elements and twigs are more sensitive to extra heavy metal input.
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Abies/metabolismo , Monitoramento Ambiental , Poluentes Ambientais/análise , Metais Pesados/análise , Picea/metabolismo , Poluentes Ambientais/metabolismo , Metais Pesados/metabolismo , TibetRESUMO
An investigation of terrestrial bryophyte species diversity and community structure along an altitudinal gradient from 2,001 to 4,221 m a.s.l. in Gongga Mountain in Sichuan, China was carried out in June 2010. Factors which might affect bryophyte species composition and diversity, including climate, elevation, slope, depth of litter, vegetation type, soil pH and soil Eh, were examined to understand the altitudinal feature of bryophyte distribution. A total of 14 representative elevations were chosen along an altitudinal gradient, with study sites at each elevation chosen according to habitat type (forests, grasslands) and accessibility. At each elevation, three 100 m × 2 m transects that are 50 m apart were set along the contour line, and three 50 cm × 50 cm quadrats were set along each transect at an interval of 30 m. Species diversity, cover, biomass, and thickness of terrestrial bryophytes were examined. A total of 165 species, including 42 liverworts and 123 mosses, are recorded in Gongga mountain. Ground bryophyte species richness does not show any clear elevation trend. The terrestrial bryophyte cover increases with elevation. The terrestrial bryophyte biomass and thickness display a clear humped relationship with the elevation, with the maximum around 3,758 m. At this altitude, biomass is 700.3 g m(-2) and the maximum thickness is 8 cm. Bryophyte distribution is primarily associated with the depth of litter, the air temperature and the precipitation. Further studies are necessary to include other epiphytes types and vascular vegetation in a larger altitudinal range.
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Altitude , Biodiversidade , Briófitas/fisiologia , Hepatófitas/fisiologia , China , Clima , Monitoramento Ambiental , Geografia , Poaceae , Chuva , Solo , Temperatura , ÁrvoresRESUMO
Concentrations of 23 elements (Ca, K, Mg, P, Al, Cu, Fe, Mn, Mo, Na, Ni, Zn, Ag, Ba, Be, Cd, Co, Cr, Pb, Sb, Th, Tl, and V) in leaf and twig samples of a fir (Abies fabri) and a rhododendron (Rhododendron williamsianum) collected along an altitudinal gradient on Mount Gongga, China, are reported in the present study. Most of the macronutrients (K and P), micronutrients (Fe, Zn, Cu, Na, Ni, Mo, and Al), and trace elements (Pb, Tl, Ag, Cd, Ba, Co, V, Be, and Cr) are significantly enriched in fir when compared to rhododendron; however, Ca, Mg, Mn, Ba, and Cd are more enriched in rhododendron than in fir. Most of the elements in both plants are more significantly enriched in twigs than in leaves. The relationship between element concentration in plants and altitudinal gradient is nonlinear. Altitudes of 3,200 and 3,400 m are turning points for fir and rhododendron growth, respectively. Concentrations of all trace elements in the two plants along the altitudinal gradient are well below the toxic level in plants. No known industrial sources of the elements investigated exist in the Mount Gongga area, China. Element concentrations in the present study are higher than those found in mosses collected from the same area, indicating that the area is not contaminated. The element concentrations that we observed in plant samples were due to soil uptake. The pronounced differences between the two species are due to the different uptake characteristics of fir and rhododendron.
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Abies/química , Folhas de Planta/química , Caules de Planta/química , Rhododendron/química , Oligoelementos/análise , Altitude , China , Monitoramento Ambiental , Solo/química , Poluentes do Solo/análise , Especificidade da EspécieRESUMO
Antioxidative responses of the mosses Hypnum plumaeforme, Thuidium cymbifolium, and Brachythecium piligerum to short-term Pb and Ni stress were investigated. Both Pb and Ni treatment increased the formation of reactive oxygen species and lipid peroxidation, decreased superoxide dismutase (SOD), and catalase (CAT) activities in H. plumaeforme and T. cymbifolium. However, SOD activity in B. piligerum was increased under 10mM Pb stress and Ni increased CAT activity in B. piligerum under 1mM Ni stress. Peroxidase (POX) activity in the three mosses was increased by Pb and Ni exposure, indicating that POX plays an important role in preventing heavy metal-induced oxidative stress. The accumulation of O(2)(-) and H(2)O(2) in mosses is related to the decline in SOD and CAT activities. B. piligerum is the most sensitive and T. cymbifolium is the most tolerant species to Pb and Ni stress among the three bryophytes.
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Bryopsida/efeitos dos fármacos , Poluentes Ambientais/toxicidade , Chumbo/toxicidade , Níquel/toxicidade , Biomarcadores/metabolismo , Bryopsida/metabolismo , Catalase/metabolismo , Peróxido de Hidrogênio/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Estresse Oxidativo , Peroxidase/metabolismo , Peroxidases/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Superóxido Dismutase/metabolismoRESUMO
Antioxidative enzymes (superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX)), as well as lipid peroxidation and proline were studied in moss Brachythecium piligerum Card. collected from different sites in Shanghai, China, to validate the physiological parameters as biomarkers of atmospheric heavy metal pollution. Results demonstrated that the responses of POD and CAT activities, as well as MDA and proline contents were in accordance with the heavy metal contents in mosses. That is, POD activity, MDA, and proline content were activated and CAT activity was inhibited in heavier polluted sites, indicating that POD and CAT activities, and MDA and proline contents could be used as biomarkers for biomonitoring atmospheric heavy metal pollution.
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Briófitas/efeitos dos fármacos , Briófitas/metabolismo , Metais Pesados/farmacologia , Estresse Oxidativo , Ascorbato Peroxidases/metabolismo , Biomarcadores/metabolismo , Catalase/metabolismo , China , Monitoramento Ambiental , Poluentes Ambientais/farmacologia , Peroxidação de Lipídeos , Malondialdeído/análise , Prolina/análise , Superóxido Dismutase/metabolismoRESUMO
The short-term responses of H(2)O(2)-depletion-related parameters in moss Hypnum plumaeforme to the combined stress induced by Pb and Ni were investigated. The results showed that the Pb and Ni stress induced dose-dependent accumulation of hydrogen peroxide (H(2)O(2)). The increase of peroxidase (POD) activity and decrease of ascorbate peroxidase (APX) activity were observed under the combined heavy metal application. The antioxidants, ascorbate (AsA) and proline content, increased significantly when the metals were applied together. The study indicated that the cell damage caused by Pb stress was higher than that caused by Ni stress, Pb and Ni had synergistic effect in inducing the oxidative stress in moss H. plumaeforme, especially under the combination of high concentration of Ni (0.1 and 1.0 mM) and Pb. Content of proline, H(2)O(2) and the activity of POD, all showed a dose-dependent increase under Pb and Ni stress, suggesting their practical value as biomarkers in moss biomonitoring, especially in the case of light pollution caused by heavy metals without the changes in the appearance of mosses.
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Antioxidantes/metabolismo , Briófitas/metabolismo , Peróxido de Hidrogênio/metabolismo , Chumbo/farmacologia , Níquel/farmacologia , Ácido Ascórbico/metabolismo , Prolina/metabolismoRESUMO
This paper studied the accumulation and scavenging of active oxygen radicals, injury of photosynthetic system and membrane system, and changes of antioxidant enzyme system in Thuidium cymbifolium cells under single and combined stress of Pb and Ni. Under low concentration of Pb and Ni (Pb < 0.1 mmol x L(-1), Ni < 0.01 mmol x L(-1)), the chlorophyll content of T. cymbifolium increased; while under high concentration of Pb and Ni (Pb > 0.1 mmol x L(-1), Ni > 0.01 mmol x L(-1)), it was in adverse. There was a dose-dependent accumulation of reactive oxide species (ROS) and malondialdehyde (MDA) under combined Pb and Ni stress. The superoxide dismutase (SOD) and catalase (CAT) activities decreased while the peroxidase (POD) activity increased with increasing Pb and Ni concentration, indicating the important role of POD in eliminating ROS under Pb and Ni stress. The dose-dependent change of MDA content and CAT activity under Pb and Ni stress suggested that T. cymbifolium could be used as a biomarker in pollution monitoring of these two heavy metals.
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Briófitas/efeitos dos fármacos , Poluentes Ambientais/toxicidade , Chumbo/toxicidade , Níquel/toxicidade , Superóxido Dismutase/metabolismo , Briófitas/enzimologia , Catalase/metabolismo , Monitoramento Ambiental , Estresse Oxidativo/efeitos dos fármacosRESUMO
An investigation of the behavior and availability of heavy metals (HMs), i.e., Cu, Zn, Ni, Pb, Cr, and Cd, based on the analysis of correlation between HMs and physical and chemical properties of coastal soils developed from alluvial deposits in Shanghai, China, has been conducted, in order to reveal the effect of the soil formation and development and the unsuited human activities on the activities and mobility of HMs in agricultural soils. The results showed that (1) the soils still meet the needs of plant growth due to the moderate fertility with a soil texture of silty loam although the content of organic matters is lower, (2) total heavy metal content had a increase trend from the inland area to the coastal area, indicating the impact of alluvial deposits related to the soil formation on the distribution of HMs; (3) a significant positive correlation was found between HMs and some soil properties (i.e., clay content, cation exchange capacity, organic matters, total Phosphorous content, etc.), indicating that the regulation of these properties could give some great effect on the behavior and availability of HMs; (4) the positive correlation among Cu, Zn, Ni, and Cd, and between Pb and Cr is very significant, suggesting the most similar, if not the same, origins of HMs; These findings are helpful to the soil remediation, fertility adjustment, and plant cultivation.
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Monitoramento Ambiental , Metais Pesados/análise , Poluentes do Solo/análise , Solo/análise , Cádmio/análise , Cromo/análise , Cobre/análise , Chumbo/análise , Níquel/análise , Zinco/análiseRESUMO
Based on the method of moss bags, atmospheric deposition of heavy metals including Hg, Cu, Pb, Zn, and Ni was investigated using three kinds of mosses, i.e., Bazzania yoshinagana (Steph.) Steph. ex Yasuda, Dicranum nipponense Besch., and Brotherella (Duby) Fleisch, with reference to the monitoring in five sites, i.e., Jiulongpo District (JLPD), Nanan District (NAD), Jiangbei District (JBD), Beibei District (BBD), and Jinyun Mountain (JYM), in Chongqing, China. The results showed that atmospheric deposition of heavy metals in Chongqing was significantly much higher than the control site (JYM). Among the sites, JLPD, the main industrial area in Chongqing, was more seriously polluted due to the more discharge of waste gas, compared to BBD, NAD, and JBD. The atmospheric deposition of heavy metals had a trend that dry deposition (60-65%) was larger than wet deposition (35-40%) due to the climate nature in Chongqing. According to the results of principal component analysis, the five monitoring districts could be divided into three groups: (1) unpolluted: JYM; (2) light polluted: JBD, NAD, and BBD; (3) heavy polluted: JLPD. The characteristics of bryophyte could put some effects on its accumulation of atmospheric heavy metals, e.g., Brotherella (Duby) Fleisch, the one with highest abundance of branches and leaves in the three bryophyte species, could accumulate more metals than other two species according to the monitoring results.