Northeast Institute of Geography and Agroecology, Chinese Academy Of Sciences
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Analysis of aneuploid lines of bread wheat to map chromosomal locations of genes controlling root hair length
No full textBackground and Aims Long root hairs enable the efficient uptake of poorly mobile nutrients such as phosphorus. Mapping the chromosomal locations of genes that control root hair length can help exploit the natural variation within crops to develop improved cultivars. Genetic stocks of the wheat cultivar 'Chinese Spring' were used to map genes that control root hair length.Methods Aneuploid stocks of 'Chinese Spring' were screened using a rapid method based on rhizosheath size and then selected lines were assayed for root hair length to identify chromosomes harbouring genes controlling root hair length. A series of lines with various fractional deletions of candidate chromosomes were then screened to map the root hair loci more accurately. A line with a deletion in chromosome 5A was analysed with a 90 000 single nucleotide polymorphism (SNP) array. The phosphorus acquisition efficiency (PAE) of one deletion line was compared with that of euploid 'Chinese Spring' by growing the seedlings in pots at low and luxury phosphorus supplies.Key Results Chromosomes 1A, 1D and 5A were found to harbour genes controlling root hair length. The 90 000 SNP array identified two candidate genes controlling root hair length located on chromosome 5A. The line with a deletion in chromosome 5A had root hairs that were approx. 20 % shorter than euploid 'Chinese Spring', but this was insufficient to reduce its PAE.Conclusions A rapid screen for rhizosheath size enabled chromosomal regions controlling root hair length to be mapped in the wheat cultivar 'Chinese Spring' and subsequent analysis with an SNP array identified candidate genes controlling root hair length. The difference in root hair length between euploid 'Chinese Spring' and a deletion line identified in the rapid screen was still apparent, albeit attenuated, when the seedlings were grown on a fully fertilized soil
Spatiotemporal analyses of urban vegetation structural attributes using multitemporal Landsat TM data and field measurements
No full textKey message We conducted spatiotemporal analyses of urban vegetation structural attributes using multitemporal Landsat TM data and field measurements. We showed that multitemporal TMdata has the potential of rapidly estimating urban vegetation structural attributes including LAI, CC, and BA at an urban landscape level.Context Urban vegetation structural properties/attributes are closely linked to their ecological functions and thus directly affect urban ecosystem process such as energy, water, and gas exchange. Understanding spatiotemporal dynamics of urban vegetation structures is important for sustaining urban ecosystem service and improving the urban environment.Aims The purposes of this study were to evaluate the potential of estimating urban vegetation structural attributes from multitemporal Landsat TM imagery and to analyze spatiotemporal changes of the urban structural attributes.Methods We first collected three scenes of TM images acquired in 1997, 2004, and 2010 and conducted a field survey to collect urban vegetation structural data (including crown closure (CC), tree height (H), leaf area index (LAI), basal area (BA), stem density (SD), diameter at breast height (DBH), etc.). We then calculated and normalized NDVI maps from the multitemporal TM images. Finally, spatiotemporal urban vegetation structural maps were created using NDVI-based urban vegetation structure predictive models.Results The results show that NDVI can be used as a predictor for some selected urban vegetation structural attributes (i.e., CC, LAI, and BA), but not for the other attributes (i.e., H, SD, and DBH) that are well predicted by NDVI in natural vegetation. The results also indicate that urban vegetation structural attributes (i.e., CC, LAI, and BA) in the study area decreased sharply from 1997 to 2004 but increased slightly from 2004 to 2010. The CC, LAI, and BA class distributions were all skewed toward low values in 1997 and 2004. Moreover, LAI, CC, and BA of urban vegetation all present a decreasing trend from suburban areas to urban central areas.Conclusion The experimental results demonstrate that Landsat TM imagery could provide a fast and cost-effective method to obtain a spatiotemporal 30-m resolution urban vegetation structural dataset (including CC, LAI, and BA)
Remote estimation of K-d (PAR) using MODIS and Landsat imagery for turbid inland waters in Northeast China
No full textLight availability for photosynthetically active radiation (PAR) is one of the major factors governing photosynthesis in aquatic ecosystems. Conventional measurements of light attenuation in the PAR domain (K-d(PAR)) is representative for only small areas of water body. Remotely sensed optical imagery can be utilized to monitor K-d(PAR) in large areas of water bodies, based on the relationship between water leaving radiance and K-d(PAR). In this study, six field surveys were conducted over 20 lakes (or reservoirs) across Northeast China from April to September 2015. In order to derive the K-d(PAR) at regional scale, the Landsat/TM/ETM+/OLI and the MODIS daily surface reflectance data (MOD09GA similar to 500 m, Bands 17) were used to establish empirical inversion models. Through multiple stepwise regression analysis, the band difference (Red-Blue) and band ratio (NIR/Red) were used in Landsat imagery modeling, and the band difference (Red-Blue) and ratio (Red/Blue) were used in MODIS imagery modeling. The accuracy of the two models was evaluated by 10-fold cross-validation in ten times. The results indicate that the models performed well for both Landsat (R-2 = 0.83, RMSE = 0.95, and MRE = 0.33), and MODIS (R-2 = 0.86, RMSE = 0.91, and MRE = 0.19) imagery. However, the K-d(PAR) derived by MODIS is slightly higher than that estimated by Landsat (slope = 1.203 and R-2 = 0.972). Consistency of model performance between the MODIS daily (MYDO9G A) and the 8-Day composite reflectance (MYDO9A1) data was verified by K-d(PAR) estimations and regression analysis (slope = 1.044 and R-2 = 0.966). Finally, the spatial and temporal distribution of K-d(PAR) in Northeast China indicated that specific geographical characteristics as well as meteorological alterations can influence K-d(PAR) calibrations. Specifically, we have revealed that the wind speed and algal bloom are the major determinants of K-d(PAR) in Lake Hulun (2050 km(2)) and Xingkai (4412 km(2)). (C) 2016 International Society for Photogrammetry and Remote Sensing, Inc. (ISPRS). Published by Elsevier B.V. All rights reserved
Effects of urbanization intensity on forest structural-taxonomic attributes, landscape patterns and their associations in Changchun, Northeast China: Implications for urban green infrastructure planning
No full textUnderstanding the associations between urbanization intensity and urban forest structural-taxonomic attributes is a central theme of urban ecology, biodiversity conservation and forest management for maximizing ecological services to design proper urban green infrastructure. By selecting a typical provincial capital city of Changchun as an example, the effects of urbanization intensity (low, medium and heavy urbanization as measured by impervious surface area, ISA) on landscape patterns and structural-taxonomic attributes of urban forests were investigated in this study. The results showed that the urban forest Patch Density (PD), Landscape Shape Index (LSI), Interspersion & Juxtaposition Index (IJI), Tree Density (TD), Canopy Density (CD), Species Richness (SR) and Species Diversity (H' index) exhibited strictly monotonic increases with urbanization intensity, increasing by 162%, 60%, 44%, 37%, 50%, 85%, and 84% from low to heavy urbanization areas, respectively. In contrast, the forest Mean Euclidian Nearest Neighbor Distance (ENN-MN) and Health Condition grade (HC) monotonically decreased by 12% and 37%, respectively. Furthermore, regression analysis suggested that structural-taxonomic attributes were closely associated with forest-related landscape patterns, but urbanization intensity dramatically influenced these associations. Our findings highlight that the planning of urban green infrastructure, in particular, urban afforestation and associated management, should be different at different urbanization intensities. In low urbanization areas, low Total area (TA, forest area) requires construction of larger forest patches and the protection of large remnant trees, and TD and above ground biomass (AGB) could be increased by enhancing the Mean Fractal Dimension (FRAC-MN) and PD, respectively. In medium urbanization areas, the same increases in TD and AGB could be more effectively achieved by decreasing the LE and Area-Weighted Mean Contiguity (CONTIG-MN). Moreover, in heavy urbanization areas, more attention should be paid to increasing forest patch aggregation and contiguity, and both tree diversity and evenness could be increased by enhancing the FRAC-MN index. Because these structural -taxonomic attributes are the basis of various forest ecological services, our findings indicate that regulation of some of these landscape metrics could improve urban forest services in Changchun
Characterization of CDOM of river waters in China using fluorescence excitation-emission matrix and regional integration techniques
No full textThe spatial characteristics of fluorescent dissolved organic matter (FDOM) components in river waters in China were first examined by excitation-emission matrix spectra and fluorescence regional integration (FRI) with the data collected during September to November between 2013 and 2015. One tyrosine-like (R1), one tryptophan-like (R2), one fulvic-like (R3), one microbial protein-like (R4), and one humic-like (R5) components have been identified by FRI method. Principal component analysis (PCA) was conducted to assess variations in the five FDOM components (F-Rl (l = 1, 2, 3, 4, and 5)) and the humification index for all 194 river water samples. The average fluorescence intensities of the five fluorescent components and the total fluorescence intensities F-SUM differed under spatial variation among the seven major river basins (Songhua, Liao, Hai, Yellow and Huai, Yangtze, Pearl, and Inflow Rivers) in China. When all the river water samples were pooled together, the fulvic-like F-R3 and the humic-like F-R5 showed a strong positive linear relationship (R-2 = 0.90, n = 194), indicating that the two allochthonous FDOM components R3 and R5 may originate from similar sources. There is a moderate strong positive correlation between the tryptophan-like F-R2 and the microbial protein-like F-R4 (R-2 = 0.71, n = 194), suggesting that parts of two autochthonous FDOM components R2 and R4 are likely from some common sources. However, the total allochthonous substance FR(3+5) and the total autochthonous substances FR(1+2+4) exhibited a weak correlation (R-2 = 0.40, n = 194). Significant positive linear relationships between F-R3 (R-2 = 0.69, n = 194), F-R5 (R-2 = 0.79, n = 194), and chromophoric DOM (CDOM) absorption coefficient alpha(254) were observed, which demonstrated that the CDOM absorption was dominated by the allochthonous FDOM components R3 and R5
Preparation of a Reduced Graphene Oxide @ Stainless Steel Net Electrode and Its Application of Electrochemical Removal Pb(II)
No full textA novel RGO@SSN electrode prepared by directly electrodepositing reduced graphene oxide (RGO) on stainless steel net (SSN) was applied to remove Pb(II) from the aqueous solution. The RGO@SSN electrode exhibits substantial apparent current densities and the presence of RGO on SSN affects the morphology of deposited crystal. After electrochemical treatment with RGO@SSN for 200 min, the Pb(II) removal efficiency of Pb(II) solution (1000 mg L-1) gets to 97.2%, which is promoted by 12.0% compared to that with the SSN treatment. The removal rate of RGO@SSN is 4.45 times higher than that of SSN. The polarization resistance is promoted by 55.3 and 89.5% in 0.1 M NaCl and 0.1 M HCl solution, respectively, indicating stronger protection against corrosion. Moreover, the RGO@ SSN electrode can be efficiently recycled in dilute HNO3 solution. These results suggest that RGO@ SSN electrode possesses a good potential to be applied for the treatment of Pb(II) in wastewater. (C) 2017 The Electrochemical Society. All rights reserved
Spatiotemporal Changes of Reference Evapotranspiration in the Highest-Latitude Region of China
No full textReference evapotranspiration (ET0) is often used to make management decisions for crop irrigation scheduling and production. In this study, the spatial and temporal trends of ET0 in China's most northern province as well as the country's largest agricultural region were analyzed for the period from 1964 to 2013. ET0 was calculated with the Penman- Monteith of Food and Agriculture Organization of the United Nations irrigation and drainage paper NO. 56 (FAO-56) using climatic data collected from 27 stations. Inverse distance weighting (IDW) was used for the spatial interpolation of the estimated ET0. A Modified Mann-Kendall test (MMK) was applied to test the spatiotemporal trends of ET0, while Pearson's correlation coefficient and cross-wavelet analysis were employed to assess the factors affecting the spatiotemporal variability at different elevations. The results from this study showed a clear decreasing trend for annual ET0 from the low elevation plain area to the high elevation mountainous area. Over the past five decades, ET0 in Heilongjiang Province decreased in all seasons, except for the winter months, during which a steady increase in temperature was found. Elevation played an important role in estimating ET0 in this higher-latitude region, while relative humidity was the most relevant meteorological factor that affected the spatiotemporal variation of ET0 in the province. Overall, the findings from the study suggest that winter ET0 in a high altitude region will continue to increase in the future as climate change persists, which could worsen spring droughts and irrigation management for semi-arid areas in the province
Two new species of the genus Thalassaphorura Bagnall, 1949 (Collembola: Onychiuridae) from south China, with an updated key to world species of the genus
No full textTwo new onychiurid species, Thalassaphorura microspinata sp. nov. and T. guangxiensis sp. nov., are reported from the karsts of south China (Guangxi). T. microspinata sp. nov. is similar to T. grandis Sun, Chen & Deharveng, 2010 in having the same dorsal and ventral pso formula, number of pseudocelli on subcoxae 1, number of chaetae in the distal whorl of tibiotarsi and number of p-chaetae between inner posterior pso on head; but it can be recognized by the smaller body size, shorter AS, 5 chaetae on baso-lateral part of labium, distinguishable S-chaetae and absence of chaetae on Th. I sternum. T. guangxiensis sp. nov. possesses the same dorsal pso formula as Chinese species T. reducta Sun, Chen & Deharveng, 2010, T. bapen Sun, Chen & Deharveng, 2010 and T. guangdongensis Sun & Li, 2015a, but they could be separated easily by ventral pso formula, number of pseudocelli on subcoxae 1 and other combined characters. An updated key of world species of the genus Thalassaphorura is provided. The species Thalassaphorura saccardyi (Denis, 1935) is transferred to the genus Protaphorura Absolon, 1901 on examination of the type material. In addition to those listed in Sun et al. (2010), two additional species placed in Thalassaphorura by Parimuchova & Kovac 2016 are considered here as incertae sedis because of insufficient descriptions: Thalassaphorura boskovae (Lucic, Dimitrijevic & Mihajlova, 2003), and T. tamdaona (Nguyen, 1995)
Reduced abscisic acid content is responsible for enhanced sucrose accumulation by potassium nutrition in vegetable soybean seeds
No full textIn order to understand the physiological mechanism of potassium (K) application in enhancing sugar content of vegetable soybean seeds, pot experiments were conducted in 2014 and 2015 with two vegetable soybean (Glycine max L. Merr.) cultivars (c.v. Zhongkemaodou 1 and c.v. 121) under normal rate of nitrogen and phosphorus application. Three potassium (K) fertilization treatments were imposed: No K application (K0), 120 kg K2SO4 ha(-1) at seeding (K1), and 120 kg K2SO4 ha(-1) at seedling + 1% K2SO4 foliar application at flowering (K2). Contents of indole-3-acetic acid (IAA), gibberellins (GA), cytokinins (ZR) and abscisic acid (ABA) in seeds were determined from 4 to 8 weeks after flowering. K fertilization increased the contents of IAA, GA, ZR, soluble sugar, sucrose and fresh pod yield, but reduced ABA content consistently. When the contents of soluble sugar and sucrose reached the highest level at 7 weeks after flowering for the 2 cultivars, the contents of IAAaEuroGAaEuroZR all reached the lowest level in general. The content of ABA in seed was negatively correlated with the sucrose content (P < 0.01, r = -0.749**, -0.768** in 2014 and -0.535**, -0.791** in 2015 for c.v.121 and c.v. Zhongkemaodou 1 respectively). The changes in ratio of the ABA to (IAA + GA + ZR) from 4 to 8 weeks after flowering affected by K application were coincident to the changes of sucrose accumulation. The reduced ratio of ABA/(IAA + GA + ZR) affected by K nutrition particularly reduced abscisic acid content plays a critical role in enhancing sucrose content, which might be a partial mechanism involved in K nutrition to improve the quality of vegetable soybean