Functional diversity dominates positive species mixture effects on ecosystem multifunctionality in subtropical plantations

Mixed-species plantations generally exhibit higher ecosystem multifunctionality than monospecific plantations.However,it is unclear how tree species functional composition influences species mixture effects on ecosystem multifunctionality.We selected 171 monospecific and mixed-species plantations from nine regions across subtropical China,and quantified 13 key ecosystem functional properties to investigate how species mixture effects on ecosystem multifunctionality are modulated by functional diversity and identity.We found that ecosystem multifunctionality was significantly higher(p<0.05)in mixed tree plantations than in monospecific plantations except the mixed-conifer species plantations.Across all regions,ecosystem multifunctionality was significantly higher(p<0.05)in mixed conifer-broadleaf plantations than in monospecific plantations of the corresponding species,but not different between mixed and monospecific coniferous plantations.The magnitude of species mixture effects on ecosystem multifunctionality varied greatly with tree species compositions.Taking Cunninghamia lanceolata Lamb.as an example,the effects varied from a range of 2.0%–9.6%when mixed with a conifer species to 36%–87%when mixed with a broadleaf species.The functional diversity was the dominate driver shaping ecosystem multifunctionality,while functional identity,as expressed by community-weighted mean of specific leaf area,also had a positive effect on ecosystem multifunctionality through the increased below-ground nitrogen and phosphorus stocks regulated by specific leaf area of the mixing tree species.Our study highlights the important role of functional diversity in shaping ecosystem multifunctionality across region-wide environmental conditions.Mixed conifer-broadleaf tree plantations with distinct functional traits benefit the enhancement of ecosystem multifunctionality,and the magnitude of species mixture effects is modulated by the functional identity of tree species composition;those relationships deserve a special consideration in multifunctional management context of subtropical plantations.

Adsorptive interaction between typical VOCs and various topological zeolites:Mixture effect and mechanism

Adsorption is one of the most feasible and effective methods to alleviate the volatile organic compounds(VOCs)pollution.However,the mixture effect and mechanism for competitive adsorption of VOCs on zeolites are barely addressed.In this study,toluene,acetone,and ethyl acetate as prevalent VOCs species were removed by four potential zeolites(13X,USY,Beta,ZSM-5)in both single-and multi-component systems.The structure-property relationship between adsorbate-adsorbent pairs was revealed by X-ray diffraction,scanning electron microscopy,energy dispersive spectrometer,X-ray fluorescence,N_(2) adsorption and density function theory calculation.The molecular polarity and volatility of VOCs species played key roles in adsorption and the dynamic uptakes were generally listed as follows:ethyl acetate>toluene>acetone.As for the above VOCs mixtures,13X zeolite selectively adsorbed oxygenated VOCs rather than toluene.In contrast,USY exhibited a preference to trap toluene.Ethyl acetate could be readily enriched by ZSM-5 and Beta selectively.The possible explanations and implications are discussed based on the subtle change in electron density.The results obtained are vital for understanding the mixture effect of VOCs adsorption and may guide the selection of proper adsorbent for real applications.

Effects of a mixture of Cu, Cd, Hg and Zn on marine plankton: Marine Ecosystem Enclosure Experiment

Five experiment ecosystems (MEEE) were employed in April, 1985 to test the effects of a mixture of Cu, Cd, Hg, Pb and Zn on a subtropical planktonic ecosystem in Xiamen Bay, Xiamen, China. The results indicated that the ppb-level of the mixture could suppress the planktonic production. Zooplankton in Xiamen were very sensitive to the metal contamination, especially the larvaceans.

Phenotypic Modulation of Mesangial Cells in Diabetic Rats and Effect of Tujian Mixture (菟箭合剂) on It

Objective: To explore whether there is phenotypic modulation of mesangial cells in streptozotocin (STZ) induced diabetic rats and study the effect of Tujian Mixture (TJM) on it. Methods: SD rats were divided into the normal control group , the unilateral nephrectomized control group , the STZ induced diabetes mellitus with unilateral nephrectomy model group , the Valsartan treated group (VT group, n=8) and the TJM treated group , rats in the latter two groups were modeled as in the DM group and treated with Valsartan (20 mg/kg·d) and TJM (20g/kg·d) respectively for 12 weeks. The expression of α-smooth muscle actin (α-SMA) and transforming growth factor-β 1 (TGF-β 1) in rats’ glomeruli were observed by immunohistochemistry assay, and the ratio of α-SMA and TGF-β 1 positive area/total glomerule tuft area (SMA/GT and TGF/GT) were analyzed using computer-assisted image analysis software. Results: In the NC and the QC groups, only trace of α-SMA positive staining was found. But there was prominant α-SMA positive staining in glomeruli of the DM group, with SMA/GT and TGF/GT increased significantly , and marked increase of 24 hrs proteinuria excretion ( P<0 01). As compared with the DM group, the three indexes were all significantly lower in the VT and ZY groups , and the lowering of proteinuria was more significant in the ZY group than that in the VT group (P<0 01). Conclusion: The expression of α-SMA in glomeruli in STZ induced diabetic rats with unilateral nephrectomy is pronounced, indicating that phenotypic modulation of mesangial cells involvement in the pathogenesis of diabetic nephropathy. TJM and Valsartan can reduce 24 hrs proteinuria excretion, inhibit the phenotypic modulation of mesangial cells and the expression of TGF-β 1 in glomeruli of diabetic rats, and the effect of TJM is more potent than that of Valsartan in lowering urinary protein excretion..

Blood Oxidant/Antioxidant Status in overfed Aging Rats: Comparative Effects of Sunflower and Olive-Linseed Mixture Oil Rich Diets

Obesity, one of the most common health problems, is associated with glucose and lipid metabolism abnormalities, increased cardiovascular risk and oxidative stressI1}. Aging is also associated with an increase in oxidative stress[2]. Considering that older adults are already at risk for oxidant stress, the additional metabolic perturbations of obesity aggravated the susceptibility to oxidant stress. Modulating age-related oxidative stress via dietary interventions could reduce free radical production and significantly improve health in aging.

Replanting of broadleaved trees alters internal nutrient cycles of native and exotic pines in subtropical plantations of China

Background:The replanting of broadleaved trees in pure coniferous plantations is widely implemented,as mixed plantations are generally more stable and functional.However,the effect of interspecific interactions between broadleaved and coniferous trees on internal nutrient cycles of conifers remains unclear.Methods:We selected pure coniferous plantations of a native(Pinus massoniana)and an exotic(P.elliottii)pine species and their corresponding mixed plantations with broadleaved trees(Schima superba)in subtropical China,and measured the nitrogen(N)and phosphorus(P)contents in the rhizosphere soils,fine roots,twigs,needles and needle litter of pines.We calculated the root capture,needle resorption and translocation of N and P by pines to determine the mobility of nutrients in trees.Results:Although the N and P in the rhizosphere soils increased due to the replanting of broadleaved trees,the N and P contents in the aboveground tissues of the two pine species did not increase in mixed plantations.Mixed planting had a negative effect on the N and P capture of native pine and a positive effect on that of exotic pine.The N and P resorption efficiencies increased in native pine but were unchanged in exotic pine after the replanting of S.superba.Native pine preferentially employed an aboveground nutrient resorption strategy,whereas exotic pine tended to adopt a belowground nutrient capture strategy after replanting.Translocation of N and P in trees was detected,which reflected the trade-offs between root nutrient capture and needle nutrient resorption.Conclusions:The effect of mixed planting varied between the species of native and exotic pines,and the internal nutrient cycles of both pine species might be dominated by interspecific interaction effects on nutrients rather than soil nutrients.Our study highlights the importance of selecting suitable broadleaved species for replanting in coniferous plantations.

N-acetyl cysteine alters the genotoxic and estrogenic properties of Alternaria toxins in naturally occurring mixtures

It is unclear if complex mycotoxin mixtures produced by Alternaria spp.act estrogenic and/or genotoxic under physiological conditions,particularly considering the co-occurrence with antioxidants in food.Thus,this study focused on enlightening the impact of N-acetyl cysteine(NAC),as a representative antioxidative SH-donor,on the mentioned toxicological endpoints of the signature Alternaria toxins alternariol(AOH),altertoxin-II(ATX-II)and a complex extract(CE)of an Alternaria alternata culture.Using Ishikawa cells as an in vitro model,we monitored alterations in toxin concentrations by LC-MS/MS,estrogenicity by alkaline phosphatase assays,cytotoxicity by sulforhodamine B assays,genotoxicity by single-cell gel electrophoresis and the transcription of selected genes of interest by quantitative realtime PCR.The results indicate that the strong genotoxic effects of epoxide-carrying perylene quinones such as ATX-II are erased in the presence of NAC.The cellular effects of ATX-II/AOH mixtures are dominated by the genotoxicity of the perylene chinone.In this mixture,AOH regained its estrogenicity when coincubated with NAC.In contrast,NAC treatment of an AOH/CE mixture did not result in a recovery of estrogenicity,but in potentiated anti-estrogenic effects.These findings were in line with gene transcription data,that indicated the aryl hydrocarbon receptor(AhR)to be a prime mediator of Alternaria toxin e induced antagonistic effects towards estrogen receptor signaling.Taken together,further studies on potential endocrine-disruptive properties of non-genotoxic perylene quinones should be a future research priority in the field of these emerging contaminants.