Northeast Institute of Geography and Agroecology, Chinese Academy Of Sciences
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Landscape influences on water quality in riparian buffer zone of drinking water source area, Northern China
No full textThe riparian zone represents the interface between land and river and as such has an important influence on watershed export of nutrients, sediments and woody debris. Therefore, it is vital to identify the mechanisms underlying the impact of natural and anthropogenic landscape features on river conditions within this buffer zone. Here, we present data gathered between 2004 and 2010 from 50 sampling sites in a drinking water source area of Northern China. Spatial and multivariate statistical analyses revealed that the first 100 m of the riparian zone had the largest effect on river water quality. Generally, natural landscapes had positive effects. Due to intense anthropogenic disturbances close to rivers, most of the human-impacted land cover accounted for water quality deterioration. Landscape pattern metrics were also useful in explaining the water chemical variables. The covariation of natural and anthropogenic factors might be regulated by hydrologic conditions, which reached their peak influence during the rainy season. The impacts of anthropogenic variables were equal to those of natural variables before and during the rainy season, yet human landscape features had more effects beyond this season
Modified Sol-Gel Synthesis of Carbon Nanotubes Supported Titania Composites with Enhanced Visible Light Induced Photocatalytic Activity
No full textMultiwalled carbon nanotube(MWCNT) enhanced MWCNT/TiO2 nanocomposites were synthesized by surface coating of carbon nanotube with mixed phase of anatase and rutile TiO2 through a modified sol-gel approach using tetrabutyl titanate as raw material. The morphological structures and physicochemical properties of the nanocomposites were characterized by FT-IR, XRD, DTA-TG, TEM, and UV-Vis spectra. The results show that TiO2 nanoparticles with size of around 15 nm are closely attached on the sidewall of MWCNT. The nanocomposites possess good absorption properties not only in the ultraviolet but also in the visible light region. Under irradiation of ultraviolet lamp, the prepared composites have the highest photodegradation efficiency of 83% within 4 hours towards the degradation of Methyl Orange (MO) aqueous solution. The results indicate that the carbon nanotubes supported TiO2 nanocomposites exhibit high photocatalytic activity and stability, showing great potentials in the treatment of wastewater
Prediction of Nutrient Leaching from Culture of Containerized Buddhist Pine and Japanese Maple Seedlings Exposed to Extended Photoperiod
No full textLeachate nutrients from the nursery of containerized tree seedlings result in risks of inefficient fertilization through nutrient loss and contamination of ground water. In the present study, seedlings of Buddhist pine (Podocarpus macrophyllus) and Japanese maple (Acer palmatum) were cultured in containers of three differing sizes under contrasting photoperiods of naturally 11 h per day and an extended one of 20 h per day. Controlled release fertilizer (CRF, 14-14-14) was used to feed seedlings with sufficient nutrients for 5 months from June to November 2014. At the end of experiment, seedlings from all types of containers were measured for height and root collar diameter, whilst leachates were collected to determine nutrient concentrations of available phosphorus (P), potassium (K), ammonium and nitrate nitrogen (N) therein. Growth of both seedling species increased with the volume of container, but only growth of Japanese maple seedlings responded to photoperiod. In spite, there was greater amount of nutrients leached from containers planted with Buddhist pine than with Japanese maple; nearly no nutrient in the leachate affected by photoperiod. A negative correlation was found between concentrations of leachate nutrients and seedling height growth in all container sizes. In conclusion, nutrient leaching is a non ignorable but predictable factor by seedling height growth during the intensive culture of slowly growing seedlings of ornamental trees under the extended photoperiod. (C) 2016 Friends Science Publisher
Remote estimation of soil organic matter content in the Sanjiang Plain, Northest China: The optimal band algorithm versus the GRA-ANN model
No full textSoil organic matter content (SOMC) is an important factor that reflects soil fertility, land production capacity, and the degree of soil degradation. The objectives of this study were to (i) test various regression models for estimating SOMC based on published spectral parameters in the Sanjiang Plain, (ii) develop optimal band difference, ratio, and normalized difference algorithms for assessing SOMC using spectral data, and (iii) compare the performance of the proposed models using grey relational analysis-artificial neural networks (GRA-ANN) and the band difference algorithm. The SOMC data and concurrent spectral parameters were acquired in the Sanjiang Plain of Northest China in 2006. For the GRA-ANN model, GRA was used to select the sensitive spectral parameters and ANN was established to estimate SOMC. The results showed that reflectance (R) gradually decreased with increasing SOMC and the regression equations based on the spectral parameter 1/R-588, Diff (1/R-535), R-610, R-554, R-550, and R-520 could be used to estimate SOMC, respectively. The SOMC model based on the optimal difference index (ODI; R-2= 0.63 and RMSE= 1.43%) outperformed those based on the optimal ratio vegetation index (ORVI; R-2=0.48 and RMSE = 1.82%) and normalized difference vegetation index (ONDVI, R-2 = 0.57 and RMSE= 1.56%). The GRA-ANN model presented better SOMC estimation results (R-2 = 0.90 and RMSE = 0.88%). Thus, the GRA-ANN model has great potential for SOMC estimations; however, the ODI also has merit, especially when taking into consideration the simplicity of its application. Combining different algorithms may improve SOMC estimations on a regional scale. (C) 2015 Elsevier B.V. All rights reserved
A rice LSD1-like-type ZFP gene OsLOL5 enhances saline-alkaline tolerance in transgenic Arabidopsis thaliana, yeast and rice
No full textBackground: Zinc finger proteins (ZFPs) play an important role in regulating plant responses to abiotic stress. However, little is known about the function of LSD1-like-type ZFP in saline-alkaline (SA) stress resistance of rice. In this study, OsLOL5 (GenBank No. AJ620677), containing two LSD1-like-type C2C2 domains, was isolated and analyzed its protection roles in transgenic plants and yeast. OsLOL5 was located in the nucleus as evidenced by the bombardment of onion epidermal cells. Results: OsLOL5 expression significantly increased in rice leaves and roots under 150 mmol L-1 NaCl, 30 mM NaHCO3, and 10 mmol L-1 H2O2 treatment, respectively. Overexpression of OsLOL5 in yeast resulted in SA tolerance at significant level. Transgenic Arabidopsis plants overexpressing OsLOL5 grew well in the presence of both NaCl and NaHCO3 treatments, whereas wild-type plants exhibited chlorosis, stunted growth phenotype, and even death. SA stress caused significant changes in the malondialdehyde (MDA) contents in non-transgenic plants compared with those in transgenic lines. Transgenic rice overexpressing OsLOL5 exhibited stronger resistance than NT under NaHCO3 treatment, as demonstrated by its greater shoot length, and fresh weight. The genes associated with oxidative stress, such as OsAPX2, OsCAT, OsCu/Zn-SOD, and OsRGRC2, were significantly upregulated in OsLOL5-overexpressing rice. The results suggested that OsLOL5 improved SA tolerance in plants, and regulated oxidative and salinity stress retardation via the active oxygen detoxification pathway. Conclusions: The yeast INVScI bacterium grew significantly better than the control strain under NaCl, NaHCO3, and H2O2 treatments. These findings illustrated that OsLOL5 overexpression enhanced yeast resistance for SA stress through active oxygen species. The present study showed that the OsLOL5 genes involved in the ROS signaling pathways may combine with the model plant Arabidopsis and rice in LDS1-type ZFP by ROS signaling pathways that regulate cell necrosis. We speculated that the OsLOL5 active oxygen scavenging system may have coordinating roles. The present study further revealed that OsLOL5 ZFP could regulate oxidative stress function, but could also provide a basis for salt-resistant rice strains
The visible spectroscopy of iron oxide minerals in dust particles from ice cores on the Tibetan Plateau
No full textGoethite (Gt) and hematite (Hm) are the most abundant forms of iron oxides in dust and the major light absorbers in the shortwave spectrum in air and snow. Diffuse reflectance spectrometry was performed to investigate the reflectance spectra of goethite and hematite in dust particles from ice cores, aerosol samples and glacier cryoconite on the northern and central Tibetan Plateau. The results showed that two peaks in the first derivative value of the spectra at 430 and 560 nm were determined to be goethite and hematite, respectively. The high iron content samples have a higher first derivative value, and prominent and much more distinct peaks for Hm and Gt. We propose that the strength of the Hm and Gt peaks may probe the iron content, and then in our samples hematite has a stronger correlation than goethite. However, when the iron content reaches a threshold, the iron oxides have little or no impact on the reflectance spectra. The fine fraction of glacier dust has a greater abundance of iron, and the first derivative values of hematite are higher than goethite, indicating that hematite might be concentrated in the fine fraction. The distinguishable differences in the Hm/Gt ratio among these ice core samples and other aerosol data indicate the regional to continental difference in composition, which can be used to simplify the iron oxides in snow radiation models
