Phosphorus limitation induced by nitrogen addition changed soil microbial community structure in a subtropical forest.

Soil microorganisms play an important role in the biogeochemical cycles of terrestrial ecosystems. How-ever, it is still unclear how the amount and duration of nitrogen (N) addition affect soil microbial community structure and whether there is a correlation between the changes in microbial community structure and their nutrient limi-tation status. In this study, we conducted an N addition experiment in a subtropical forest to simulate N deposition with three treatments: control (CK, 0 kg N·hm·a), low N (LN, 40 kg N·hm·a), and high N (HN, 80 kg N·hm·a).

[Effects of root growth on leaf litter decomposition and enzyme activity in litter layer].

The growth of roots towards aboveground litter layer is a common phenomenon in forest ecosystems. It is of great significance to examine the effects of root presence on litter decomposition for understanding nutrient cycling in forest ecosystems. We explored the effects of root growth on leaf litter decomposition, nutrient release and enzyme activities by establishing treatments with and without root with a one year field decomposition experiment in and forests at Sanming, Fujian.

[Effects of broadleaved tree species on soil microbial stoichiometry in clear-cut patches of plantation].

Investigating the response of soil microbial biomass and ecological stoichiometry to tree species transition is of great significance for understanding soil nutrient cycling and availability in forest ecosystems. We measured soil microbial biomass carbon (MBC), nitrogen (MBN), phosphorus (MBP) and their stoichiometry across 0-40 cm soil depth between and plantations by the chloroform fumigation extraction method, which were replanted after the harvest of plantation. The results showed that soil MBC in the 0-10 cm layer and soil MBN and MBP in the 0-20 cm layer under the were significantly higher than those under the .

[Soil C:N:P stoichiometry and nutrient dynamics in plantations during different growth stages].

We investigated soil C:N:P stoichiometry and nutrient dynamics of plantations at different stand ages (5, 8, 21, 27 and 40 years old) in Fujian Baisha Fores-try Farm. We measured the concentrations of soil total carbon (TC), total nitrogen (TN), total phosphorus (TP), total potassium (TK), total calcium (Ca), total magnesium (Mg), and soil C:N:P stoichiometry at 0-10, 10-20, and 20-40 cm soil layers during different growth stages. The results showed that soil TC and TN concentrations and C:N remained unchanged during stand development.

[Effects of broadleaved tree plantation on soil phosphorus fractions and availability in diffe-rent soil layers in a logged Cunninghamia lanceolata woodland].

Phosphorus (P) limitation is one of the major issues for the management of subtropical plantations. Understanding the effects of tree species transition from conifer to broadleaved trees on soil P fraction and availability in different soil layers are of great significance for the sustainable development of subtropical forests. We compared changes in soil chemical properties, P fraction and availability across 0-100 cm soil profile between Mytilaria laosensis and Cunninghamia lanceolata plantations, which were initially reforested from C.

[Dynamics of nutrient concentration and microbial community composition during fine root decomposition in subtropical Mytilaria laosensis and Cunninghamia lanceolata plantations.].

We conducted a 12-month fine root decomposition experiment under 19-year-old Mytilaria laosensis and Cunninghamia lanceolate plantations to explore the dynamics of nutrient concentration and microbial community composition. The aim of this study was to provide insights into nutrient cycling under plantations with different tree species. Our results showed that the initial concentrations of phosphorus (P) and potassium (K) were significantly higher in the fine root of M.

[Effects of litter and root exclusion on soil microbial community composition and function of four plantations in subtropical sandy coastal plain area, China].

We conducted detritus input and removal treatment (DIRT) to examine the effects of shifting above- and belowground carbon (C) inputs on soil microbial biomass, community composition and function in subtropical Pinus elliottii, Eucalyptus urophylla × Eucalyptus grandis, Acacia aulacocarpa and Casuarina equisetifolia coastal sandy plain forests, and the treatments included: root trenching, litter removal and control. Up to September 2015, one year after the experiment began, we collected the 0-10 cm soil samples from each plot. Phospholipid fatty acid (PLFA) analysis was used to characterize the microbial community composition, and micro-hole enzymatic detection technology was utilized to determine the activity of six kinds of soil enzymes.

[Seasonal dynamics of soil mineral nitrogen pools and nitrogen mineralization rate in different forests in subtropical China].

We conducted an in situ incubation experiment to determine soil mineral N (NH-N and NO-N) concentrations and soil net N mineralization rates (net ammonification rate and net nitrification rate) using close-top PVC tubes in three adjacent forests (natural forest, Castanopsis kawakamii and Cunninghamia lanceolata plantation) from September 2014 to August 2015 in subtropical China, investigating the effects of forest type and season on soil inorganic N concentrations and soil net N mineralization rates. Results showed that soil NO-N was the dominant form in mi-neral N pool in all three forests, and the proportion of NO-N to soil inorganic N content ranged from 55.1% to 87.

[Effects of forest types on soil dissolved organic carbon and nitrogen in surface and deep la-yers in subtropical region, China.].

Forest types have significant effects on the availability and dynamics of soil dissolved organic carbon (DOC) and dissolved organic nitrogen (DON). By now the impacts of forest types on soil DOC and DON were mainly focused on surface soil (0-10 cm). Based on the comparisons between natural forest, Phyllostachys pubescens, Castanopsis kawakamii and Cunninghamia lanceolata plantations, we investigated the effects of forest types on soil DOC and DON pools in top (0-10 cm) and deep soils (40-60 cm).

[Effects of tree species transfer on soil dissolved organic matter pools in a reforested Chinese fir (Cunninghamia lanceolata) woodland].

Based on the comparison between reforested 19-year-old Mytilaria laosensis and Cunninghamia lanceolata plantations on cut-over land of C. lanceolata, effects of tree species transfer on soil dissolved organic matter were investigated. Cold water, hot water and 2 mol x L(-1) KCl solution were used to extract soil dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) from 0-5, 5-10 and 10-20 cm soil layers.

[Effects of broadleaf plantation and Chinese fir (Cunninghamia lanceolata) plantation on soil carbon and nitrogen pools].

A comparative study was conducted on the soil C and N pools in a 19-year-old broadleaf plantation and a Chinese fir (Cunninghamia lanceolata) plantation in subtropical China, aimed to understand the effects of tree species on the soil C and N pools. In the broadleaf plantation, the C and N stocks in 0-40 cm soil layer were 99.41 Mg.

[Dynamic changes of soil respiration in Citrus reticulata and Castanea henryi orchards in Wanmulin Nature Reserve, Fujian Province of East China].

From January 2009 to December 2009, the soil respiration in the Citrus reticulata and Castanea henryi orchards in Wanmulin Nature Reserve was measured with Li-8100, aimed to characterize the dynamic changes of the soil respiration and its relationships with soil temperature and moisture in the two orchards. The monthly variation of the soil respiration in the orchards was single-peaked, with the peak appeared in July (3.76 micromol x m(-2) x s(-1)) ) and August (2.

Application of gene sequencing directly to identify the pathogens in specimens.

Background: Accurate identification of bacterial isolates is an essential task in clinical microbiology. This study compared culturing to analyzing 16S rRNA gene sequences as methods to identify bacteria in clinical samples. We developed a key technique to directly identify bacteria in clinical samples via nucleic acid sequences, thus improving the ability to confirm pathogens.

Ten-year survey on oncology publications from China and other top-ranking countries.

Background: Cancer is a global disease that knows no borders. Over the past decade, oncology research had developed rapidly worldwide. The aim of this study was to evaluate the publication characteristics in oncology journals from China and other top-ranking countries.

[Relationship between copper injury and apoptosis and the effect of curcumin on copper-injured BRL cells].

Objective: To study the relationship between copper-induced apoptosis and reactive oxygen species (ROS) in BRL cells and the effect of curcumin, a plant-derived polyphenol, on copper-injured BRL cells.

Methods: BRL cells were treated with CuSO4 (100 micromol/L) or curcumin + CuSO4. The BRL cells without any treatment were used as controls.

[Curcumin attenuated the lipid peroxidation and apoptotic liver injury in copper-overloaded rats].

Objective: Hepatolenticular degeneration (Wilson disease, WD) is an autosomal recessive disorder of copper metabolism. The clinical manifestations are dominated by the neuropsychiatric and hepatic symptoms due to copper deposition. Investigation of mechanism of copper injury should be helpful for elucidating the pathogenesis and treatment of WD.