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921.
Shan Xu Nico Eisenhauer Olga Ferlian Jinlong Zhang Guoyi Zhou Xiankai Lu Chengshuai Liu Deqiang Zhang 《Proceedings. Biological sciences / The Royal Society》2020,287(1939)
Plant diversity has a strong impact on a plethora of ecosystem functions and services, especially ecosystem carbon (C) storage. However, the potential context-dependency of biodiversity effects across ecosystem types, environmental conditions and carbon pools remains largely unknown. In this study, we performed a meta-analysis by collecting data from 95 biodiversity-ecosystem functioning (BEF) studies across 60 sites to explore the effects of plant diversity on different C pools, including aboveground and belowground plant biomass, soil microbial biomass C and soil C content across different ecosystem types. The results showed that ecosystem C storage was significantly enhanced by plant diversity, with stronger effects on aboveground biomass than on soil C content. Moreover, the response magnitudes of ecosystem C storage increased with the level of species richness and experimental duration across all ecosystems. The effects of plant diversity were more pronounced in grasslands than in forests. Furthermore, the effects of plant diversity on belowground plant biomass increased with aridity index in grasslands and forests, suggesting that climate change might modulate biodiversity effects, which are stronger under wetter conditions but weaker under more arid conditions. Taken together, these results provide novel insights into the important role of plant diversity in ecosystem C storage across critical C pools, ecosystem types and environmental contexts. 相似文献
922.
Roberto L. Salomón Kathy Steppe Jean M. Ourcival Selwyn Villers Jesús Rodríguez-Calcerrada Roderick Schapman Jean M. Limousin 《Plant, cell & environment》2020,43(6):1528-1544
Stem water storage capacity and hydraulic capacitance (CS) play a crucial role in tree survival under drought-stress. To investigate whether CS adjusts to increasing water deficit, variation in stem water content (StWC) was monitored in vivo for 2 years and related to periodical measurements of tree water potential in Mediterranean Quercus ilex trees subjected either to permanent throughfall exclusion (TE) or to control conditions. Seasonal reductions in StWC were larger in TE trees relative to control ones, resulting in greater seasonal CS (154 and 80 kg m−3 MPa−1, respectively), but only during the first phase of the desorption curve, when predawn water potential was above −1.1 MPa. Below this point, CS decreased substantially and did not differ between treatments (<20 kg m−3 MPa−1). The allometric relationship between tree diameter and sapwood area, measured via electrical resistivity tomography, was not affected by TE. Our results suggest that (a) CS response to water deficit in the drought-tolerant Q. ilex might be more important to optimize carbon gain during well-hydrated periods than to prevent drought-induced embolism formation during severe drought stress, and (b) enhanced CS during early summer does not result from proportional increases in sapwood volume, but mostly from increased elastic water. 相似文献
923.
硫氧化细菌源单质硫的生成、转运和回收 总被引:1,自引:0,他引:1
单质硫(硫粒)是硫化物生物氧化的中间产物.按化学计量式精准调控O/S比(溶解氧与硫化物的摩尔比),单质硫可成为硫氧化细菌(Sulfur-oxidizing bacteria,SOB)的主要代谢产物.根据单质硫的分布,单质硫可分为胞内硫粒和胞外硫粒.单质硫由胞内向胞外的跨膜转运过程是泌硫型SOB的重要生理特征.从生物脱硫... 相似文献
924.
Shangcong Sun Guoqiang Shen Jiawei Jiang Wenbo Mi Xianlong Liu Lun Pan Xiangwen Zhang Ji‐Jun Zou 《Liver Transplantation》2019,9(30)
Solar‐driven water splitting is in urgent need for sustainable energy research, for which accelerating oxygen evolution kinetics along with charge migration is the key issue. Herein, Mn3+ within π‐conjugated carbon nitride (C3N4) in form of Mn–N–C motifs is coordinated. The spin state (eg orbital filling) of Mn centers is regulated by controlling the bond strength of Mn–N. It is demonstrated that Mn serves as intrinsic oxygen evolution reaction (OER) site and the kinetics is dependent on its spin state with an optimized eg occupancy of ≈0.95. Specifically, the governing role of eg occupancy originates from the varied binding strength between Mn and OER intermediates. Benefiting from the rapid spin state‐mediated OER kinetics, as well as extended optical absorption (to 600 nm) and accelerated charge separation by intercalated metal‐to‐ligand state, Mn–C3N4 stoichiometrically splits pure water with H2 production rate up to 695.1 µmol g?1 h?1 under simulated sunlight irradiation (AM1.5), and achieves an apparent quantum efficiency of 4.0% at 420 nm, superior to most solid‐state based photocatalysts to date. This work for the first time correlates photocatalytic redox kinetics with the spin state of active sites, and suggests a nexus between photocatalysis and spin theory. 相似文献
925.
不同功能区城市林业土壤黑碳含量及来源——以南京市为例 总被引:4,自引:0,他引:4
由于城市化过程中人为活动的影响,城市林业土壤的性质发生了很大变化。城市林业土壤黑碳由于来源的多样性和受到人为活动的影响,其分布表现出独特的特征。以南京市为对象,调查分析了不同功能区城市林业土壤黑碳的含量及可能来源。结果表明:不同功能区城市林业土壤黑碳含量差异很大,其变幅为0.77-21.27g/kg。道路绿化带土壤黑碳含量显著高于其它功能区,居民区含量最低。黑碳在土壤表层中含量均高于表下层,黑碳富集于土壤表层。道路绿化带表层土壤黑碳含量与有机碳含量的比值(BC/SOC)为0.55,土壤黑碳的碳同位素比值(δ13CPDB)为-27.04‰,与其它功能区差异显著,城市交通污染对土壤黑碳积累产生强烈影响。 相似文献
926.
Richard C. Leegood Carlos A. Labate Steven C. Huber H. Ekkehard Neuhaus Mark Stitt 《Planta》1988,176(1):117-126
Glycerol induced a limitation on photosynthetic carbon assimilation by phosphate when supplied to leaves of barley (Hordeum vulgare L.) and spinach (Spinacia oleracea L.). This limitation by phosphate was evidenced by (i) reversibility of the inhibition of photosynthesis by glycerol by feeding orthophosphate (ii) a decrease in light-saturated rates of photosynthesis and saturation at a lower irradiance, (iii) the promotion of oscillations in photosynthetic CO2 assimilation and in chlorophyll fluorescence, (iv) decreases in the pools of hexose monophosphates and triose phosphates and increases in the ratio of glycerate-3-phosphate to triose phosphate, (v) decreased photochemical quenching of chlorophyll fluorescence, and increased non-photochemical quenching, specifically of the component which relaxed rapidly, indicating that thylakoid energisation had increased. In barley there was a massive accumulation of glycerol-3-phosphate and an increase in the period of the oscillations, but in spinach the accumulation of glycerol-3-phosphate was comparatively slight. The mechanism(s) by which glycerol feeding affects photosynthetic carbon assimilation are discussed in the light of these results.Abbreviations Chl
chlorophyll
- C
i
intercellular concentration of CO2
- P
phosphate
- PGA
glycerate-3-phosphate
- Pi
orthophosphate
- triose-P
sum of glyceraldehyde-3-phosphate and dihydroxyacetone phosphate 相似文献
927.
Aziza Kouchou Naoual Rais Jeanne-Chantal Thoisy Joëlle Duplay Malika Ghazi Françoise Elsass 《Soil & Sediment Contamination》2017,26(3):259-276
To investigate the relevance of biochemical parameters in biogeochemical mechanisms of the soil, it is important to gather data related to different soil types under different pedogeoclimatic conditions. In this study, we investigated on the calcareous agricultural soils in the Saiss plain (North Morocco). Four agricultural soils exposed to multi-metal (Cr, Cu, Zn, and Ni) and organic matter (OM) contamination as a result of irrigation with Oued Fez and Oued Sebou waters that are affected by urban and industrial activities around the city of Fez were studied and compared to a reference site irrigated with uncontaminated water. The study concerned soil physicochemical properties and the activity of a range of enzymes [phosphatase (PHOS), arylsulfatase (SULF), urease (UREA), arylamidase (AMID), β-galactosidase (GALA), glucosidase (GLUC), and laccase (LACA)] related to nutrients cycles. Pearson's correlations between these parameters showed that soil enzymatic activities (PHOS, SULF, UREA, GALA, GLUC, and LACA) were correlated positively with heavy metals (Cu, Zn, and Cr) concentrations in the soil and also with dissolved organic carbon (DOC), and negatively with the aromaticity (AROM) of these compounds. Interestingly, analysis of intra-site correlations showed strong relationships among enzyme activities in the reference soil, while in contaminated soils, these activities were largely unrelated to each other. It was concluded that soil irrigation with heavy-metal- and OM-contaminated watercourses over decades has resulted in soils with high enzymatic activities function and nutrient turnover but altered relationships among geochemical cycles. 相似文献
928.
The underlined effects of diallyl sulfide (DAS) against CCL4‐induced oxidative, inflammatory, and apoptotic acute hepatic damage were assessed. Administration of DAS (50, 100, and 200 mg/kg) along with CCL 4 effectively mitigated serum aspartate aminotransferase, alanine aminotransferase activities, MDA, TNF‐α, IL‐1β, and MCP‐1 levels, as well as significantly restored HO‐1, GSH levels and SOD activity in liver tissues compared with those in rats treated with CCL 4. Moreover, DAS inhibited CCL 4‐induced increase of liver NF‐κB (p65), Bax, p38 MAPK, and JNK protein expression. In addition, DAS accelerated protein expression of Nrf2 and Bcl‐2. The hepatoprotective properties of DAS were further confirmed by the reduced severity of hepatic damage as demonstrated by histopathological findings. In conclusion, DAS achieved its protective potential against CCL4‐induced hepatotoxicity through antiapoptotic activity, as well as the synchronized modulation of NF‐κB and Nrf2 for the favor of antioxidant/anti‐inflammatory effects via suppression of the upstream stress‐activated MAPKs pathways. 相似文献
929.
Zhaozhong Feng Xiangyang Yuan Silvano Fares Francesco Loreto Pin Li Yasutomo Hoshika Elena Paoletti 《Plant, cell & environment》2019,42(6):1939-1949
Isoprene and monoterpenes (MTs) are among the most abundant and reactive volatile organic compounds produced by plants (biogenic volatile organic compounds). We conducted a meta‐analysis to quantify the mean effect of environmental factors associated to climate change (warming, drought, elevated CO2, and O3) on the emission of isoprene and MTs. Results indicated that all single factors except warming inhibited isoprene emission. When subsets of data collected in experiments run under similar change of a given environmental factor were compared, isoprene and photosynthesis responded negatively to elevated O3 (?8% and ?10%, respectively) and drought (?15% and ?42%), and in opposite ways to elevated CO2 (?23% and +55%) and warming (+53% and ?23%, respectively). Effects on MTs emission were usually not significant, with the exceptions of a significant stimulation caused by warming (+39%) and by elevated O3 (limited to O3‐insensitive plants, and evergreen species with storage organs). Our results clearly highlight individual effects of environmental factors on isoprene and MT emissions, and an overall uncoupling between these secondary metabolites produced by the same methylerythritol 4‐phosphate pathway. Future results from manipulative experiments and long‐term observations may help untangling the interactive effects of these factors and filling gaps featured in the current meta‐analysis. 相似文献
930.
从河北省迁安市马兰庄镇铁尾矿植被恢复区油松根际分离出2株溶磷细菌,经过平板初筛和摇瓶复筛得到1株溶磷能力较强的菌株D2.通过菌落形态、生理生化特性及16S rDNA序列分析,确定此菌株D2属于泛菌属.利用液体发酵试验测定不同碳源、氮源对菌株D2溶磷能力的影响,通过高效液相色谱测定D2在不同氮源条件下产生有机酸的种类和浓度.结果表明:菌株D2对磷酸三钙有较强的溶磷能力,培养液有效磷含量最高为392.13 mg·L-1,菌株D2的溶磷能力在碳源为葡萄糖、氮源为硫酸铵时效果最好;高效液相色谱测定发现,不同氮源条件下,D2分泌有机酸的种类和浓度存在差异,以硫酸铵、氯化铵、硝酸钾、硝酸钠、硝酸铵为氮源,均产生草酸、甲酸、乙酸和柠檬酸,以硫酸铵、氯化铵、硝酸铵为氮源还产生苹果酸.相关性分析表明,乙酸含量与有效磷含量间呈显著正相关(r=0.886,P<0.05),表明溶磷泛菌D2分泌的乙酸对无机磷的溶解有明显的促进作用,这也很可能是该菌株的重要溶磷机制之一. 相似文献