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1

The bioaccumulation and migration of inorganic mercury and methylmercury in the rice plants

100%
Zhu D., Han J., Wu S.
Polish Journal of Environmental Studies
|
2017
|
tom 26
|
nr 4
In the present study, (NH₄)₂S₂O₃ extraction methods were applied to assess bioaccumulation of methylmercury (MeHg) in rice grains, and inorganic mercury (IHg) concentrations in rice leaves were analyzed during the rice growing time to access the bioaccumulation of IHg in rice leaves. The results show that the IHg concentrations in leaves increased in the rice harvest stage, indicating that the limit or no IHg was migrated to the rice grain. Also, the Hg-contaminated leaves may potentially cause the input of ‘new Hg’ into soil, leading to a vicious Hg pollution cycle in a rice paddy system. Our results indicated that MeHg concentrations in leaves could not be used to predict the MeHg bioaccumulation in rice grain. Meanwhile, MeHg transferred capability from soil to leaves decreased with time, which could be the common effect of the decreased soil MeHg bioavailability and translocation of MeHg from leaves to rice grains.
2

Winter methane emission from an Alpine open fen on Tibetan Plateau

88%
Zhu D., Chen H., Wu N., Wang Y., Luo P.
Polish Journal of Ecology
|
2011
|
tom 59
|
nr 1
Methane (CH4) emission was measured from an open fen on the Zoige Plateau (3500 m a.s.l.) (the eastern edge of the Qinghai- Tibetan Plateau) during two winters of 2006 and 2007. Three dominant plant stands, including Carex muliensis Hand-Mazz. (CM), Eleocharis valleculosa Ohwif. setosa (Ohwi) Kitagawa.(EV) and Kobresia tibetica Maxim (KT) were chosen to be monitored. Winter CH4 emissions were roughly estimated to be 0.94 mg CH4 m–2 h–1. High spatialtemporal variations of the emission were found in this fen (the sequence of CM> EV> KT; 0.63 and 1.24 mg CH4 m–2 h–1 for 2006 and 2007, respectively). Factors involved in the spatial-temporal variation were: 1) water table in summer determining the winter amount of “old” CH4 stored in peat; 2) ice layer determining the release of CH4; 3) plant growth determining both the quantity of CH4 stored in peat and available substrates for CH4 production in winter. However, due to the homogeneity of freezing in winters, predictive factors such as plant growth and water table in summer could contribute more to winter CH4 emission than in situ freezing conditions. Considering that plant growth and water table are also the key factors controlling the spatial-temporal variation of CH4 emission in summer, we therefore suggested that winter CH4 emission represents the “inertia” of summer CH4 emission.
3

Seasonal variation of anammox and denitrification in sediments of two eutrophic urban lakes

88%
Zhao J., Zhu D., Fan J., Hua Y., Zhou W.
Polish Journal of Environmental Studies
|
2015
|
tom 24
|
nr 6
4

Effect of high dietary copper on the expression of hypothalamic appetite regulators in weanling pigs

88%
Zhu D., Yu B., Ju C., Mei S., Chen D.
Journal of Animal and Feed Sciences
|
2011
|
tom 20
|
nr 1
The current study evaluated appetite-related gene expression of neuropeptide Y (NPY), orexin, type 2 orexin receptor (OrexinR2), proopiomelanocortin (POMC), melanocortin-4 receptor (MC4R), AMP-activated protein kinase α2 subunit (AMPKα2) and long-form leptin receptor (LeptinRb) in hypothalamus in response to copper (Cu) supplementation. One hundred crossbred pigs were assigned to four groups of 25 pigs, each comprising five replicates of 5 animals. Groups were then randomly assigned to treatments consisted of 1. control (10 mg/kg CuSO4), 2. 100 mg/kg CuSO4, 3. 175 mg/kg CuSO4, 4. 250 mg/kg CuSO4. On d 21 of the experiment 5 pigs from each group were slaughtered and the hypothalami were collected for determination of appetite-regulating genes mRNA expression level. The results showed that average daily feed intake and average daily gain were higher (P<0.05) in 250 and 175, 250 mg/kg Cu supplemented groups, respectively, than in the 10 mg/kg group. Feed:gain ratio was lower in pigs fed the diets with 250 mg/kg Cu (P<0.05) than in the 10 mg/kg group. Furthermore, the abundances of NPY mRNA in hypothalamus were higher in 250 mg/kg Cu supplemented groups (P<0.05), whereas the abundances of POMC and LeptinRb mRNA were significantly reduced (P<0.05) in 170, 250 mg/kg and 100, 175, 250 mg/kg Cu supplemented groups, respectively. No difference was found for AMPKα2, MC4R, orexin, OrexinR2 mRNA expression (P>0.05). These data suggest that down-regulation of LeptinRb mRNA expression might contribute to the stimulation of feeding of high dietary Cu supplementation via regulation of NPY and POMC mRNA expression.
5

Variations of sediment archaea communities in different distribution areas of Bruguiera gymnoihiza Mangrove in Dongzhaigang, China

64%
Li W., Guan W., Chen H., Liao B., Hu J., Rui J., Peng C., Zhu D., He Y., Tian J.
Polish Journal of Environmental Studies
|
2019
|
tom 28
|
nr 5
Archaea communities widely exist in mangrove forest sediments, but their spatial variations among different distribution areas with salinity gradient in mangrove forest sediments is not well understood. This study used 16S rRNA Miseq sequence to investigate the sediment archaeal community structure and diversity of Bruguiera gymnoihiza mangrove forest in China along three different distribution areas. The results showed rich methanogen and ammonia-oxidizing archaea resources in the study site, with Methanobacterium, Methanothrix, Methanomassiliicoccus, Nitrosopumilus and Nitrososphaera (>1%) as the dominant genera. Mantel test and Redundancy analysis (RDA) results revealed that pH was the determinant for archaeal community structure in our study. The RDA result showed that the available K also contributed to archaeal community structure. There was a significant and positive relationship between pH and available P; in addition, the two values were significantly and negatively related to the observed OTU number. These results suggested that pH is the main determinant of the archaeal community structure and diversity in distribution areas of Bruguiera gymnoihiza in Dongzhaigang.
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