Authors:J. Du, W. Li, H. Zhang, X. Wang, Z. You, C. Zhou, W. Dong, and Z. Tao
The stability constants for tracer concentrations of Co(II) complexes with both the red earth humic and fulvic acids were
determined at pH 5.9 and ionic strength 0.010 mol/l by using theArdakani-Stevenson cation exchange equilibrium method and the radiotracer60Co. It was found that the 1:1 complexes of Co(II) with the red earth humic and fulvic acids were formed and that the average
values of logβ (stability constant) of humic and fulvic acid complexes were 5.76±0.19 and 4.42±0.03, respectively.
Authors:L. Fu, Y. Chen, H. Du, J. Mao, X. Shi, and S. Li
A novel double -diketone 1,6-bis(1-phenyl-3-methyl-5-oxo-pyrazol-4-yl) hexanedione-[1,6] (BPMOPH) was further studied on its coordination compounds with uranium and thorium, respectively. The IR, UV, and1H-NMR spectra were examined, and the proposed structure is discussed.
Authors:J. Du, H. Song, D. Mu, D. Li, S. Yan, and Y. Gu
The sorption/desorption of radioruthenium was investigated by the batch method in sea water system at ambient temperature
on the surface sediments obtained around the Daya Bay of Guangdong Province, where the first nuclear power station of China
has been running from 1994. It was found that the sorption percentage was obtained to be around 40% for all the surface sediments
in 60 minutes. Then, the sorption percentage goes up slowly. The sorption percentage of radioruthenium reached around 80%
in 113 days (2713 hours). The distribution coefficients decreased from 3.16·104 to 1.35·103 ml/g with the increasing of sediment concentration in the range of 4–10000 mg/l. The results of the desorption experiments
suggest that the sorption of radioruthenium is irreversible with 81.5% relative hysteresis coefficient.
Authors:D. Mu, H. Song, S. Yan, Y. Gu, D. Li, and J. Du
Three kinds of marine bivalves (wild Saccostrea cucullata, aquacultured Perna viridis and aquacultured Pinctada martens), collected from Daya Bay, the South China Sea, were used to investigate the bio-accumulation of radioruthenium in the glass
aquarium with natural seawater (pH 8.20, 35‰ salinity, filtered by 0.45 μm) at ambient temperature under laboratory feeding
conditions. The experimental results show that the stead-state of biology concentration factor (BCF, ml/g) of radioruthenium
was approached around 6 days for most species of bivalves. The values of BCF in shells are the highest in organs all the three
bivalves. The orders of BCF values (ml·g−1) are as: Perna viridis (33.2) < Saccostrea cucullata (47.0) < Pinctada martensi (208.4) for shells and Saccostrea cucullata (1.5) < Pinctada martensi (2.2) ≈ Perma viridis (2.4) for soft tissues, respectively, after exposed for 14 days. The rate constants of uptake and elimination of radioruthenium
on marine bivalves were also discussed by first-order kinetics model. The Pinctada martensi may be applicable to be an indicator for monitoring radioruthenium among the three bivalves.
Authors:H. Xie, Z. Lin, Z. Zhang, L. Du, Z. Xin, Y. Ma, X. Ye, and X. Chen
The common wheat line, YW243, developed in our research group, was tested for the resistances of barley yellow dwarf virus (BYDV), powdery mildew (Pm) and stripe rust in field, and was analyzed by molecular markers for convenient trace of the resistant genes in breeding. Genomic in situ hybridization (GISH) analysis and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) assay further demonstrated that YW243 was a homozygous multiple translocation line of
Triticum aestivum, Thinopyrum intermedium
(T7DS·7DL-7XL & 1BL·1RS). The disease resistance test and marker analysis showed that YW243 carried seven resistance genes to the three diseases, including
to BYDV on 7DL-7XL,
to powdery mildew on 2AL,
Yr2, Yr9, Sr 31
and a new
to stripe rust on 7B, 1BL, 1RS and 2BL. Restriction fragment length polymorphism (RFLP) markers
, sequence tagged site (STS) marker STS
, simple sequence repeat (SSR) markers
, SSR markers
can be used as diagnostic tools to track
Bdv2, Pm4, Yr2, Yr9
, respectively; and two amplified fragment length polymorphism (AFLP) markers
can also be used to select
Authors:M. Li, Z. Du, H. Pan, C. Yan, W. Xiao, and J. Lei
Plant-plant interaction plays a key role in regulating the composition and structure of communities and ecosystems. Studies of plant-plant interactions in forest ecosystems have mainly concentrated on growth effects of neighboring plants on target trees. Physiological effects of neighboring plants on target trees, in particular understorey effects on physiology of overstorey trees, have received less attention. It is still unclear what is the physiological mechanisms underlying positive growth effects of understorey removal, although understorey removal has been applied to improve the wood production for hundreds of years worldwide. Only 17.5% of published works dealt with understorey-overstorey interactions and only a few of those researched the understorey effects on the physiology of overstorey trees. Case studies indicated that overstorey Abies faxoniana trees grown with different understorey shrubs showed significantly different levels of tissue nitrogen and mobile carbohydrates. Removal experiment showed that nitrogen and mobile carbohydrates concentrations in Cunninghamia lanceolata trees grown in the absence of understorey shrubs differed significantly (pure stand > mixture) with those in trees grown in the presence of understorey shrubs, in particular during the dry season. This review highlighted that the neighboring woody plants affect Cand N-physiology in overstorey trees. These effects may be mainly resulted from underground competition for soil water rather than for other resources as the effects were more pronounced during the dry season. The present review suggests that positive effects of neighboring removal (e.g., understorey removal, thinning) on overstorey trees can be expected more rapidly and strongly in stressful area (e.g., low rainfall, nutrient-poor site) than in areas with optimal growth conditions. Hence, ecophysiology-based management strategies for dealing with neighboring plants in forest ecosystems should take into account: 1) site conditions, 2) timing, duration and frequency of management practices, and 3) species-specific properties and other aspects such as biodiversity conservation and soil erosion.
Authors:Y. Jing, Y. Hao, H. Qu, Y. Shan, D. Li, and R. Du
Chitosan was obtained from cuticles of the housefly
larvae. Antibacterial activities of different Mw chitosans were examined against six bacteria. Antibacterial mechanisms of chitosan were investigated by measuring permeability of bacterial cell membranes and observing integrity of bacterial cells. Results show that the antibacterial activity of chitosan decreased with increase in Mw. Chitosan showed higher antibacterial activity at low pH. Ca
could markedly reduce the antibacterial activity of chitosan. The minimum inhibitory concentrations of chitosans ranged from 0.03% ∼ 0.25% and varied with the type of bacteria and Mw of chitosan. Chitosan could cause leakage of cell contents of the bacteria and disrupt the cell wall.
Authors:H. Bu, X. Chen, Y. Wang, X. Xu, K. Liu, and G. Du
In this paper, 633 species (involving 10 classes, 48 families, 205 genera) collected from the alpine meadow on the eastern Qinghai-Tibet plateau were studied. We tested potential factors affecting variation in mean germination time (MGT), i.e., plant traits (adult longevity, dispersal mode and seed size) or phylogeny, to evaluate if these factors were independent or they had interaction. Nested ANOVA showed that taxonomic membership accounted for the majority of MGT variation (70%), and in the generalized linear model, family membership could explain independently the largest proportion of MGT variation (29%). The strong taxonomic effect suggests that MGT variation within taxonomic membership is constrained. The other plant traits could also explain MGT variation independently (1% by adult longevity and dispersal mode, respectively, and 2% by seed size). Thus, the phylogeny was an important constraint to maintain the stability of species, and we could simplify the question if we regarded the phylogeny as an individual factor, but we could not negate the adaptive significance of the relationship between other plant traits and seed MGT. In addition, a large percentage of the variance remained unexplained by our model, thus important selective factors or parameters may have been left out of this analysis. We suggest that other possible correlates may exist between seed germination time and additional ecological factors (for example, altitude, habitat and post-dispersal predation) or phylogenetic related morphological and physiological seed attributes (e.g., endosperm mass) that were not evaluated in this study.
Authors:J. Wu, H. Xing, D. Tang, Y. Gao, X. Yin, Q. Du, X. Jiang, and D. Yang
The method of high-performance liquid chromatography (HPLC) with diode array detector (DAD) was used and validated for the simultaneous determination of nine flavonoids (rutin, myricetin, quercitrin, quercetin, luteolin, genistein, kaempferol, apigenin, and isorhamnetin) in beagle dog plasma. Plasma sample was pre-treated with acetonitrile (containing 0.05% formic acid). Chromatographic separation was performed on a kromasil C18 column (250 × 4.6 mm, 5 µm) maintained at 35 °C. The mobile phase was a mixture of methanol and 0.2% formic acid with a step linear gradient. At 1.0 mL min−1 flow rate, the eluent of other eight flavonoids was detected simultaneously at 360 nm with good separation except genistein (detected at 254 nm). Under optimum conditions, the correlation coefficient between the peak area and the concentrations for each analyte was all above 0.999. The intra-day and inter-day precisions were less than 10% for all analytes. The limit of detection and the limit of quantification for the selected nine flavonoids were 0.006–0.03 and 0.02–0.12 g mL−1, respectively. The extracted recoveries of selected nine flavonoids were 74.02%–99.37%. The assay has been successfully applied to determine concentrations of nine flavonoids in plasma from beagle dog after being intravenously administrated Ginkgo biloba extract.