Synthesis of sp-hybridized nitrogen doped ultrathin graphdiyne and application to the electrochemical detection for 6,7-dihydroxycoumarin.

As a new type of carbon nanomaterial, graphdiyne (GDY) has unique sp hybridized carbon atom, which makes it possible to develop new nitrogen-doped configurations. In this paper, sp-hybridized nitrogen atom doped ultrathin graphdiyne (NUGDY) was prepared based on graphdiyne oxide and melamine by carbonization at high temperature. NUGDY not only preserves the typical folded and wrinkled two-dimensional morphology of GDY, but also presents a three-dimensional porous network structure, which provides sufficient interface and capacity for the loading of target analyte.

Soil biochemical responses to nitrogen addition in a secondary evergreen broad-leaved forest ecosystem.

In order to investigate the effects of N deposition on soil biochemistry in secondary forests, one N addition experiment was conducted in a secondary evergreen broad-leaved forest in the western edge of Sichuan Basin, with the highest level of background N deposition (about 95 kg N ha yr) in China. Three N treatment levels (+0, +50, +150 kg N ha yr) were monthly added to soil surface in this forest beginning in April 2013. Soil biochemistry and root biomass of the 0-10 cm soil horizon were measured from May 2014 to April 2015.

Chemical constituents of Cinnamomum septentrionale leaf litter and its allelopathic activity on the growth of maize (Zea mays).

A pot experiment was conducted to study the effect of decomposing Cinnamomum septentrionale leaf litter on the growth of maize. In this study, the morphological traits of maize were significantly inhibited when the leaf litter amount reached or exceeded 40 g per pot; Furthermore, during the early growth stage or with a large amount of litter addition, the pigment contents were inhibited by C. septentrionale leaf litter.

Isolation and characterization of cellulose nanofibers from bamboo using microwave liquefaction combined with chemical treatment and ultrasonication.

Cellulose nanofibers were successfully isolated from bamboo using microwave liquefaction combined with chemical treatment and ultrasonic nanofibrillation processes. The microwave liquefaction could eliminate almost all the lignin in bamboo, resulting in high cellulose content residues within 7min, and the cellulose enriched residues could be readily purified by subsequent chemical treatments with lower chemical charging and quickly. The results of wet chemistry analyses, SEM images, and FTIR and X-ray spectra indicated the combination of microwave liquefaction and chemical treatment was significantly efficient in removing non-cellulosic compounds.

[Inhibition of decomposing leaf litter of Cinnamomum camphora on growth of Capsicum annu- um and the alleviation effect of nitrogen application].

Effects of decomposing leaf litter of Cinnamomum camphora on growth, physiological and phenological traits of Capsicum annuum, and modification of these effects by nitrogen application were investigated using a pot experiment. C. camphora leaf litter was applied at rate of 0, 25, 50 100 g per pot, resulting into four treatments, i.

[Response of fine root decomposition to simulated nitrogen deposition in Pleioblastus amarus plantation, rainy area of West China].

As an important contributor to carbon (C) flux in the global C cycle, fine root litter decomposition in forests has the potential to be affected by the elevated nitrogen (N) deposition observed globally. From November 2007 to January 2013, a field experiment involving monthly simulated deposition of N in a Pleioblastus amarus plantation was conducted in the Rainy Area of West China. Four levels of nitrogen deposition were included as control (0 g N x m(-2) x a(-1)), low nitrogen (5 g N x m(-2) x a(-1)), medium nitrogen (15 g N x m(-2) x a(-1)) and high nitrogen (30 g N x m(-2) x a(-1)).

Soil biochemical responses to nitrogen addition in a bamboo forest.

Many vital ecosystem processes take place in the soils and are greatly affected by the increasing active nitrogen (N) deposition observed globally. Nitrogen deposition generally affects ecosystem processes through the changes in soil biochemical properties such as soil nutrient availability, microbial properties and enzyme activities. In order to evaluate the soil biochemical responses to elevated atmospheric N deposition in bamboo forest ecosystems, a two-year field N addition experiment in a hybrid bamboo (Bambusa pervariabilis × Dendrocalamopsis daii) plantation was conducted.

Allelopathic activity and chemical constituents of walnut (Juglans regia) leaf litter in walnut-winter vegetable agroforestry system.

Walnut agroforestry systems have many ecological and economic benefits when intercropped with cool-season species. However, decomposing leaf litter is one of the main sources of allelochemicals in such systems. In this study, lettuce (Lactuca sativa var.

Nitrogen addition significantly affects forest litter decomposition under high levels of ambient nitrogen deposition.

Background: Forest litter decomposition is a major component of the global carbon (C) budget, and is greatly affected by the atmospheric nitrogen (N) deposition observed globally. However, the effects of N addition on forest litter decomposition, in ecosystems receiving increasingly higher levels of ambient N deposition, are poorly understood.

Methodology/principal Findings: We conducted a two-year field experiment in five forests along the western edge of the Sichuan Basin in China, where atmospheric N deposition was up to 82-114 kg N ha(-1) in the study sites.

[Effects of Eucalyptus grandis leaf litter at its early stage of decomposition on the growth and photosynthetic characteristics of Cichorium intybus].

From March to May, 2010, a pot experiment was conducted to investigate the effects of Eucalyptus grandis leaf litter at its early stage of decomposition on the growth and photosynthetic characteristics of Cichorium intybus. Four treatments with different application rate of the leaf litter, i.e.

Comparative study of metal resistance and accumulation of lead and zinc in two poplars.

In our study, we tested two poplars, Populus beijingensis and Populus cathayana, as model species for their potential for phytoremediation by measuring changes in biomass, pigments, superoxide radicals (O2(-)), cellular ultrastructure and their ability for O2(-) quenching and heavy metal accumulation when exposed to Pb, Zn and their interaction in a hydroponic system. Exposure to Pb did not cause a significant decrease in biomass in either P. beijingensis or P.

Nitrogen distribution and cycling through water flows in a subtropical bamboo forest under high level of atmospheric deposition.

Background: The hydrological cycle is an important way of transportation and reallocation of reactive nitrogen (N) in forest ecosystems. However, under a high level of atmospheric N deposition, the N distribution and cycling through water flows in forest ecosystems especially in bamboo ecosystems are not well understood.

Methodology/principal Findings: In order to investigate N fluxes through water flows in a Pleioblastus amarus bamboo forest, event rainfall/snowfall (precipitation, PP), throughfall (TF), stemflow (SF), surface runoff (SR), forest floor leachate (FFL), soil water at the depth of 40 cm (SW1) and 100 cm (SW2) were collected and measured through the whole year of 2009.

Impact of decomposing Cinnamomum septentrionale leaf litter on the growth of Eucalyptus grandis saplings.

A pot experiment was performed to study the impact of decomposing Cinnamomum septentrionale leaf litter on the growth of Eucalyptus grandis saplings. The experimental design scheme was 0 (CK), 40 (A1), 80 (A2) and 120 g pot(-1) (A3) of E. grandis leaves, and changes in the volatile oil chemical composition during litter decomposition were assessed in the present study.

[Effects of simulated nitrogen deposition on soil enzyme activities in a Betula luminifera plantation in Rainy Area of West China].

From January 2008 to January 2009, a field experiment was conducted to investigate the effects of simulated nitrogen (N) deposition (0, 5, 15, and 30 g N x m(-2) x a(-1)) on the soil enzyme activities in a Betula luminifera plantation in Rainy Area of West China. As compared with the control (0 g N x m(-2) x a(-1)), simulated N deposition stimulated the activities of soil hydrolases (beta-fructofuranosidase, cellulase, acid phosphatase, and urease) significantly, but depressed the activities of soil oxidases (polyphenol oxidase and peroxidase). These results suggested that the increased exogenous inorganic N could stimulate soil microbial activity and increase the demands of both B.

[Effects of drought stress and nitrogen fertilization rate on the accumulation of osmolytes in Jatropha curcas seedlings].

A pot experiment with controlled water supply was conducted to study the effects of different drought stress degree (80% FC, 60% FC, 40% FC, and 20% FC) and nitrogen fertilization rate (0 g x pot(-1), 1.2 g x pot(-1), 3.6 g x pot(-1), and 6.

[Characteristics of soil respiration components and their temperature sensitivity in a Pleioblastus amarus plantation in rainy area of West China].

To understand the characteristics of soil respiration components and their temperature sensitivity in a Pleioblastus amarus plantation in the Rainy Area of West China, a one-year periodic monitoring was conducted in a fixed plot of the plantation from February 2010 to January 2011. In the plantation, the mean annual soil respiration rate was 1.13 micromol x m(-2) x s(-1), and the soil respiration presented a clear seasonal pattern, with the maximum rate in mid-summer and the minimum rate in late winter.

[Effects of Eucalyptus grandis leaf litter decomposition on the growth and photosynthetic characteristics of Cichorium intybus].

A pot experiment was conducted to study the effects of Eucalyptus grandis leaf litter during its early stage decomposition on the growth and the photosynthesis of Cichorium intybus. Each pot contained 12 kg soil mixed with different amounts of E. grandis leaf litter (30 g x pot(-1), A1; 60 g x pot(-1), A2; 90 g x pot(-1), A3; and 0 g x pot(-1), CK), and sowed with C.

[Effects of simulated nitrogen deposition on soil respiration in a Bambusa pervariabilis x Dendrocala mopsi plantation in rainy area of West China].

From January 2008 to February 2009, a field experiment was conducted in Rainy Area of West China to understand the effects of nitrogen (N) deposition on the soil respiration in a Bambusa pervariabilis x Dendrocala mopsi plantation. Four treatments were installed, i. e.

[Effects of fertilization level on diurnal variation of gas exchange of young Eucalyptus grandis leaf].

Different levels (0, 90, 180, and 270 g per tree) of compound fertilizer containing 15% N, 15% P2O5, and 15% K2O were applied to young Eucalyptus grandis to study the diurnal variations of its leaf stomatal conductance (Gs), intercellular CO2 concentration (Ci), net photosynthesis rate (Pn), transpiration rate (Tr), water use efficiency (WUE), and vapor pressure deficit on leaf surface (Vpdl) as well as the variation of leaf chlorophyll content, aimed to approach the relationships of E. grandis photosynthesis with fertilization and environmental factors. In all treatments, the diurnal variation of Pn presented a single-peak curve, with the peak at 14:00 and not showing midday depression.

[Effects of simulated nitrogen deposition on the fine root characteristics and soil respiration in a Pleioblastus amarus plantation in rainy area of West China].

Fine root is critical in the belowground carbon (C) cycling in forest ecosystem. Aimed to understand the effects of nitrogen (N) deposition on the fine root characteristics and soil respiration in Pleioblastus amarus plantation, a two-year field experiment was conducted in the Rainy Area of West China. Four treatments with different levels of N deposition were installed, i.

[Effects of simulated nitrogen deposition on soil respiration in a Neosinocalamus affinis plantation in rainy area of west China].

From December 2007 to November 2008, an in situ experiment was conducted to study the effects of simulated nitrogen deposition on the soil respiration in a Neosinocalamus affinis plantation in Rainy Area of West China. Four treatments were installed, i.e.

[Fractal features of soil aggregate structure in slope farmland with different de-farming patterns in South Sichuan Province of China].

By using fractal model, this paper studied the fractal dimension of soil aggregate structure (D) in the slope farmland (CK), its 5-year de-farmed Neosinocalamus affinis plantation (NAP), Bambusa pervariabilis x Dendrocalamopsis oldhami plantation (BDP), Alnus crenastogyne + Neosinocalamus affinis plantation (ANP), and abandoned farmland (AFL) in south Sichuan Province of China, and analyzed the relationships between the D and soil physical and chemical properties. In the de-farmed plantations and abandoned farmland, the contents of > 0.25 mm soil aggregates and water-stable aggregates were increased significantly, compared with those in the slope farmland.

[Effect of drought on photosynthetic characteristics and growth of Jatropha curcas seedlings under different nitrogen levels].

A pot experiment with controlled water supply was conducted to study the effects of drought stress (continuous drought for 0 d, 5 d, 10 d, ...

[Soil enzyme activities in a Pleioblastus amurus plantation in Rainy Area of West China under simulated nitrogen deposition].

From November 2007 to May 2009, a simulation test was conducted in a Pleioblastus amarus plantation in Rainy Area of West China to study the effects of nitrogen deposition on the activities of soil enzymes. Four treatments were installed, i.e.