RESUMEN
Based on community investigation data from grasslands on two different soil parent material types (loess and sand parent materials) and under three human utilization modes in the Saihan Ullah Reserve, we calculated human disturbance index (HDI) and biodiversity indices and analyzed the interactions between species diversity and degradation levels. The results showed that degradation status varied across different soil parent material types and human utilization modes, and that degradation levels of loess and sand parent materials both increased with the enhancement of human utilization intensification. HDI of loess parent material grasslands (mean value of 1.21) was lower than sand parent material grasslands (mean value of 1.48) in the same human utilization. Biodiversity indices declined with soil sandy degree and the utilization intensification. The mean values of Margarlef richness index, Shannon diversity index, Simpson dominance index and Pielou evenness index were between 1.57-4.27, 1.16-2.39, 0.76-0.87, and 0.71-0.80, respectively. The Margalef richness index, Shannon diversity index and Simpson dominance index decreased with increasing HDI, while Pielou evenness index increased. Overgrazing could lead to serious threat on both grasslands with soil parent material types, and the optimum utilization mode of loess and sand parent material grasslands were enclosure with mowing and seasonal grazing. In the future works of biodiversity conservation, it is important to consider the influence of both different soil patent material and human utilization modes of grassland. It is urgent to develop different utilization modes for grassland under different soil parent material types, which would enhance the matchness of grassland restoration and management with local conditions.
Asunto(s)
Pradera , Suelo , Biodiversidad , Humanos , Plantas/metabolismo , ArenaRESUMEN
In this study, we examined the regularity of phenological rhythmical change of plant water-soluble compound δ13C (δ13Cwsc) in spring for two typical tree species in the warm temperate zone of China, Pinus tabuliformis and Robinia pseudoacacia. The δ13Cwsc in each organ of those two species in the spring phenological period were measured to explore the relationship between δ13Cwsc and related environmental factors. The results showed that there were significant differences in δ13Cwsc values of each organ between P. tabuliformis and R. pseudoacacia, with higher δ13Cwsc(-25.03±0.01) in the new shoot of P. tabuliformis. The δ13Cwsc value in the non-photosynthetic organs were 0.83-1.8 higher than that in the photosynthetic organs, while the δ13Cwsc value in the aboveground part was generally lower than that in the underground part. As spring progressing, different carbon storage strategies were found between two species. When the terminal bud of P. tabuliformis opened, the carbon was obtained from the proximal old leaves. At the beginning of leaf development, photosynthetic products accumulated by old leaves could not meet the growth requirements for new leaves and roots, with 90% of which depending on the carbon reserve in branches and stems. When full leaf having developed, the photosynthetic function of both new and old leaves recovered and the carbon consumed by branches and stems was gradually replenished. For R. pseudoacacia, at the beginning of leaf bud opening and leaf spreading, branches were the main carbon source for new leaves and roots. When leaves were fully unfolded, mature leaves with high capacity of carbon sequestration became the primary carbon source. Results of principal component analysis showed that temperature during observation period, ≥10 â accumulated temperature, sunshine duration and solar radiation were the main factors influencing δ13Cwsc, which could explained 86.3% of the total variation. The δ13Cwsc values of both species was negatively correlated with temperature and relative humidity, but positively correlated with the difference of saturated water pressure, ≥10 â accumulated temperature and sunshine duration. The main environmental factors affecting plant δ13Cwsc varied during the phenological process. Our results could provide a reference for more accurate estimation of spring organ carbon distribution pattern of regional typical tree species, and also a theoretical basis for formulating scientific and reasonable forest management strategy.
Asunto(s)
Árboles , Agua , Carbono , Isótopos de Carbono , Bosques , Hojas de la Planta , Estaciones del AñoRESUMEN
Apoptosis of cardiomyocytes and oxidant stress are considered essential processes in the progression of cardiovascular diseases. A hypoxic stress which causes apoptosis of cardiomyocytes is the main problem in ischemic heart disease. The aim of the present study was to explore the functional role and potential mechanisms of miR-223-3p in hypoxia-induced cardiomyocyte apoptosis and oxidative stress. Here, we observed a increment of miR-223-3p level accompanied by the decrease of Krüppel-like zinc-finger transcription factor 15 (KLF15) expression in response to hypoxia. Additionally, absence of miR-223-3p manifestly dampened hypoxia-induced cardiomyocyte injury in H9c2 cells, including improving cell viability, attenuating the LDH leakage and preventing cardiomyocyte apoptosis accompanied by an increase in the expression of Bcl-2 and a decrease in the expression of Bax and C-caspase 3 in the setting of hypoxia. Moreover, depletion of miR-223-3p evidently retarded oxidant stress by inhibiting reactive oxygen species generation and lipid peroxidation, as well as enhancing antioxidant enzyme activity in H9c2 cells following exposure to hypoxia. More importantly, KLF15 was a direct and functional target of miR-223-3p. Further data validated that miR-223-3p negatively regulated the expression of KLF15. Mechanistically, deletion of KLF15 partly abrogated the suppressive effects of miR-223-3p deletion on hypoxia-induced cardiomyocyte apoptosis and oxidative stress. Taken all data together, our findings established that our study defines a novel mechanism by which miR-223-3p protects against cardiomyocyte apoptosis and oxidative stress by targeting KLF15, suggesting that the miR-223-3p/KLF15 may be a potential therapeutic target for ischemic heart conditions.
Asunto(s)
Apoptosis/genética , Factores de Transcripción de Tipo Kruppel/genética , MicroARNs/genética , Miocitos Cardíacos/citología , Miocitos Cardíacos/metabolismo , Proteínas Nucleares/genética , Estrés Oxidativo/genética , Eliminación de Secuencia , Secuencia de Bases , Hipoxia de la Célula/genética , Línea Celular , Regulación de la Expresión Génica , Humanos , MicroARNs/metabolismoRESUMEN
This study investigated PM2.5 adsorption by leaves of six tree species (Pinus bungeana, Pinus tabuliformis, Salix babylonica, Acer mono, Ginkgo biloba, Populus davidiana) in the West Mountain of Beijing. An aerosol generator was used for quantitative determination of PM2.5 adsorption. Atomic force microscopy (AFM) was used to determine micro morphology characteristics on the leaf surface, including roughness parameters and the PM2.5 absorption mechanism of tree leaves. The results showed that the PM2.5 adsorption capacity per unit leaf area was as follows: P. bungeana (2.44±0.22 µg·cm-2) > P. tabuliformis (2.40±0.23 µg·cm-2) > S. babylonica (1.62±0.09 µg·cm-2) > A. mono (1.23±0.01 µg·cm-2) > G. biloba (1.00±0.07 µg·cm-2) > P. davi-diana (0.97±0.03 µg·cm-2). In autumn, PM2.5 adsorption capacity per unit leaf area was as follows: November (2.33±0.43 µg·cm-2) > October (1.62±0.64 µg·cm-2) > September (1.51±0.50 µg·cm-2). The leaves of P. bungeana and P. tabuliformis were rugged with many recesses and protrusions, large relative height difference, and high roughness, and their absorption ability of PM2.5 was strong. The leaves of S. babylonica and A. mono had folded leaf lamina and were covered by fine hairs, and their roughness was relatively high, with many protrusions and fillisters on the leaf surface. Since G. biloba and P. davidiana had smooth leaves, mostly oblong stomata and low roughness, their PM2.5 absorption ability was weaker. The ranking of average roughness on the ada-xial and abaxial side of the leaves was as follows: P. bungeana (149.91±16.38 nm) > P. tabuliformis (124.47±10.52 nm) > S. babylonica (98.85±5.36 nm) > A. mono (93.74±21.75 nm) > G. biloba (80.84±0.88 nm) > P. davidiana (67.72±8.66 nm). This accorded with PM2.5 adsorption per unit leaf area, and leaf roughness had a significant positive correlation with PM2.5 adsorption amount per unit leaf area as well (R2=0.9498). To improve the environmental effects of city vegetation, tree species with leaf surface morphology that facilitates absorption of PM2.5 and other particles should be selected.
Asunto(s)
Monitoreo del Ambiente , Material Particulado , Hojas de la Planta/fisiología , Árboles/fisiología , Acer , Adsorción , Contaminantes Atmosféricos , Beijing , Ciudades , Ginkgo biloba , Pinus , Populus , Salix , Estaciones del AñoRESUMEN
Seasonal variation of heavy metal contents in leaves and their relationships with soil heavy metal pollution levels were studied through measuring and analyzing the leaves of the common tree species in Beijing and soil heavy metal contents, to detect heavy metal accumulation ability of plant leaves. The results showed that: (1) the contents of Cu, Pb, Zn in plant leaves first decreased and then increased, again declined with changing the seasons (from spring to winter). Cr concentration showed the trend of first increase and then decrease from spring to winter, and the highest in the autumn; the accumulation capacities of Cu for Babylonica and Japonica were higher in the spring, summer and autumn, while Tabuliformis was in winter; the higher accumulation capacities for Cr, Pb were Japonica and Platycladus, and in winter were Platycladus and Bungeana; the higher accumulation capacities for Zn were Babylonica and Bungeana, while Platycladus in winter; (2) the pollution degree of four kinds of heavy metals (Cu, Cr, Pb, Zn) from downtown to suburbs showed that: Jingshan (C =2.48, C is contamination factor) > Olympic (C = 1.27) > Songshan (C = 1.20) > Shuiguan (C = 1. 18); (3) the heavy metals concentration of same plant leaves in the water of the Great Wall changed larger, but those in the other three areas showed that: Jingshan > Olympic > Songshan; the ability of same species leaf to absorb different sorts of heavy metals showed that: Zn >Cu >Pb >Cr; the difference between Zn content and Cr content was significant (P <0.01); (4) the relationship between heavy metal content in plant leaves and soil heavy metal pollution levels presented a quadratic polynomial relation; the significant correlation was found between other three heavy metal contents of plant samples and soil samples, but they were not the case for the Cu, and the correlation coefficients were above 0. 9.
Asunto(s)
Metales Pesados/química , Hojas de la Planta/química , Estaciones del Año , Contaminantes del Suelo/química , Árboles/metabolismo , China , Ciudades , Monitoreo del Ambiente , Suelo/químicaRESUMEN
Both inhalable particulate matter (PM10) and fine particulate matter (PM2.5) are not only one of the main causes of air pollution, but also the primary pollutants in most cities. Based on the analysis of the impacts of PM10 and PM2.5 on the environment and human health, this paper summarized the components, sources, and mass concentration variations of PM10 and PM2.5 and related affecting factors, and introduced the network layout of PM10 and PM2.5 monitoring and its principles and features. The research methods on the removal of PM10 and PM2.5 by forests, the removal rates of PM10 and PM2.5 by different forests, and the related affecting mechanisms were summed up at regional and individual scales, and the existed problems in this research field were discussed. Due to the lack of the comparable observation studies on the atmospheric PM10 and PM2.5 along different gradients and in background areas, the joint effects of multiple factors on the PM10 and PM2.5 concentrations are not revealed. It was suggested that to make a rational network layout of PM10 and PM2.5 monitoring, to correctly select proper monitoring methods, and to compare and calibrate the observed results from classical manual methods would be the bases to guarantee the validity of PM10 and PM2.5 monitoring data. At present, there are few reports about the PM2.5 removal by forests, and it's not clear about the physiological processes and ecological mechanisms of PM10 and PM2.5 removal at cell, tissue, organ, and individual level.