新疆农田和荒漠生态系统土壤有机碳储量及其影响因素

基于中国生态系统研究网络 (CERN) 长期监测数据,选取新疆维吾尔自治区代表暖温带干旱区的绿洲农田生态系统 (阿克苏站)、代表暖温带荒漠区 (策勒站) 以及温带荒漠区 (阜康站) 的绿洲农田和荒漠生态系统综合观测场、辅助观测场和农户调查点2005-2020年0-100 cm土层的土壤有机碳 (SOC) 储量数据,分析新疆农田和荒漠生态系统SOC储量的影响因素。研究结果表明,2005-2020年0-100 cm土层SOC总储量平均值为阿克苏站 (5.17 kg/m²)>阜康站 (4.20 kg/m²)>策勒站 (2.96 kg/m²)。0-20 cm、20-40 cm、40-60 cm土层的SOC分别约占0-100 cm土层储量的27.3%-35.3%、23.1%-24.6%和15.8%-17.5%。在阿克苏站,施肥量最高、灌溉量最低的农户调查点SOC储量最高;而在策勒站和阜康站,农户调查点和辅助观测场的施肥和灌溉措施分别最有利于提高SOC储量。总体来看,土壤含水量、地上生物量与SOC储量呈正相关关系;年平均气温与0-40 cm土层的SOC储量呈负相关关系。在单一生态站的生态系统尺度,年平均气温与SOC储量相关性不显著;地上生物量与策勒站和阜康站的SOC储量呈正相关关系,但是与阿克苏站0-40 cm土层的SOC储量呈负相关关系;施纯钾量与策勒站0-60 cm土层的SOC储量呈正相关关系,但与阜康站40-100 cm土层的SOC储量呈负相关关系。总之,与自然状态下的荒漠和农田不施肥相比,灌溉和施肥的农田管理措施有利于增加干旱区SOC储量。不同生态站要根据自身区域特点制定合理的农田管理模式,以维持较高的SOC储量。     

CO2-Assisted Induced Self-Assembled Aramid Nanofiber Aerogel Composite Solid Polymer Electrolyte for All-Solid-State Lithium-Metal Batteries

All-solid-state lithium metal batteries (ASSLMBs) hold great promise for the development of next-generation high-safety, high-energy-density lithium batteries, but still face the challenges of lithium dendrite growth and thickness. Herein, the ultrathin PEO-based composite solid polymer electrolyte (denoted as PAL) supported by a low-density self-supporting aramid nanofiber (ANF) aerogel framework is developed. The ANF aerogel obtained by a novel CO₂-assisted induced self-assembly method has a well-designed bilayer structure with double cross-linking degree. Benefiting from the intermolecular interaction between ANFs and PEO, the PAL achieves an ultrathin thickness (20 µm) with excellent thermal stability and mechanical strength. Meanwhile, due to the modulation of ionic pathways by the functionalized ANF, the PAL achieves uniform lithium deposition without dendrites, resulting in stable long cycling (1400 h) for symmetric cells. Consequently, the Li|PAL|LiFePO₄ (LFP) cell has excellent long-term cycling stability (1 C, >700 cycles, Coulombic efficiency > 99.8%) and fast charge/discharge performance (rate, 10 C). More practically, the Li|PAL|LFP cell achieves an energy density of 180 Wh kg⁻¹ due to the ability to match a high-loading (8 mg cm⁻²) cathode. Furthermore, the double-layer Li|PAL|LFP pouch cell demonstrates excellent flexibility and safety in cycling and abuse tests.     

3种城市生境间蚂蚁群落组成的比较研究——以四川省南充市城区为例

作为重要的人为影响因素,城市化改变了自然生境的景观结构,并影响到动物群落的组成。蚁科Formicidae动物种类繁多,且易于捕获,是研究城市中不同土地利用类型对动物群落影响的理想指示生物。2018年5月,在四川省南充市城区中选择"公园与绿地""旱地"和"乔木林地"3种土地利用类型作为不同的生境类型,并通过陷阱法对蚂蚁群落组成进行调查。共采集到1 847只个体;其中,津岛铺道蚁Tetramorium tsushimae在"公园与绿地"中的个体数占比最高(73.80%),并明显高于"旱地"群落中占比最高的中华小家蚁Monomorium chinense(25.48%)和"乔木林地"群落中占比最高的宽结大头蚁Pheidole nodus(28.79%)。3种生境间,群落的蚂蚁个体数和物种丰富度间差异无统计学意义,但"公园与绿地"的Simpson多样性指数和Pielou均匀度指数均显著低于"旱地"和"乔木林地"的;"公园与绿地"(q=0.444)和"旱地"(q=0.500)与"乔木林地"间的群落组成均存在中度不相似,而"公园与绿地"与"旱地"间为中度相似(q=0.647)。因此,不同的城市土地...     

Effect of tracheosyringeal denervation on call in greenfinch (Carduelis sinica)

After sections of left or right tracheosyringeal nerve (NXIIts), greenfinches may repeat everyday calls, with no effect on temporal properties. It is suggested that either side of syrinx may produce sound alone and ipsilateral innerration of NXIIts for the syringeal muscles. After section of left NXIIts, the bird produces the vocal pattern of partial tone increase, and effects on the sound intensity and sentence length average 1.4 and 2.8 times those after section of right NXIIts, suggesting that the innervation of NXIIts has left side dominance. After bilateral section of NXIIts, the call rhythm in company with expiratory motions is 98–146 times/min, on an average, and lose all sentence types and syllable structure of normal call. But the call spectra produced by tympaniform membrane vibrations without innervation still reserve frequency components similar to the tonic frequency and harmonics of normal calls.     

Overexpression of the novel human gene, nuclear apoptosis-inducing factor 1, induces apoptosis

Apoptosis is a genetically determined cell suicidal program that plays critical roles in many physiological and pathological processes. In this study, we report the cloning and characterization of a novel human gene, nuclear apoptosis-inducing factor 1 (NAIF1), overexpression of which induces apoptosis in cells. Human NAIF1 is located on chromosome 9q34.11 and encodes 327 amino acids with a homeodomain-like region and two nuclear localization signals at its N-terminal region. NAIF1 is conserved across diverse species, including human, mouse, crab-eating macaque, dog, chicken and frog, and shares no obvious homology to any known genes or proteins. Northern blot analysis revealed wide expression of NAIF1 mRNA throughout human tissues. NAIF1 was predominantly localized in the nucleus. Overexpression of NAIF1 inhibited cell growth and induced apoptosis. Furthermore, NAIF1 transfection caused both decreases in mitochondrial membrane potential and caspase-3 activation. In summary, NAIF1 is a nuclear protein that induces apoptosis when overexpressed.     

Mandelic acid chiral separation utilizing a two-phase partitioning bioreactor built by polysulfone microspheres and immobilized enzymes

A novel two-phase partitioning bioreactor (TPPB) modified by polysulfone (PSF) microspheres and immobilized enzyme (novozym-435) was formed, and the resulting TPPB was applied into mandelic acid chiral separation. The PSF microspheres containing n-hexanol (named PSF/hexanol microspheres) was prepared by using the phase inversion method, which was used as the organic phase. Meanwhile, the immobilized enzyme novozym-435 was used as a biocatalyst. The water phase was composed of the phosphate buffer solution (PBS). (R, S)-Methyl mandelate was selected as the substrate to study enzymatic properties. Different reaction factors have been researched, such as pH, reaction time, temperature and the quantity of biocatalyst and PSF/hexanol microspheres added in. Finally, (S)-mandelic acid was obtained with an 80 % optical purity after 24 h in the two-phase partitioning bioreactor. The enantiomeric excess (ee_p) values were very low in the water phase, in which the highest ee_p value was only 46 %. The ee_p of the two-phase partitioning bioreactor had been enhanced more obviously than that catalyzed in the water phase.     

Distribution of hydrogen peroxide during adventitious roots initiation and development in mung bean hypocotyls cuttings

Previous studies have shown that hydrogen peroxide (H₂O₂) may mediate the auxin response during the formation of adventitious roots (AR). However, the mechanism and distribution of H₂O₂ during AR formation remains unclear. In this study, we investigate the spatiotemporal changes and role of H₂O₂ in AR initiation and development. Application of 5?C100 mM H₂O₂ to Mung bean (Phaseolus radiatus L.) hypocotyl cuttings induced AR formation in a dose-dependent manner. The effect was blocked by ascorbic acid (AA), an important reducing substrate for H₂O₂ reduction. Depletion of endogenous H₂O₂ by AA resulted in the significant reduction of AR emergence, suggesting a physiological role for H₂O₂ in the regulation of AR formation. Determination of H₂O₂ content showed that the level of H₂O₂ increased gradually and reached the highest value 60 h after induction of AR. Further detection of endogenous H₂O₂ by the specific fluorescent probe dichlorofluorescein diacetate (H₂DCF-DA) and 3,3??-diaminobenzidine (DAB) staining in transverse sections of the basal region of cuttings revealed that obvious H₂O₂ signals were observed in the pericycle cells between the vascular bundles 24 h after the primary roots were removed. With the development of root primordia, H₂O₂ signals increased gradually and were mainly distributed in the root meristem. AA significant inhibited the H₂O₂-dependent fluorescence and the formation of AR, suggesting an essential role of H₂O₂ generation during AR initiation and development. Furthermore, the involvement of Ca²⁺ during H₂O₂-mediated AR formation was evaluated. Ca²⁺ channel inhibitors LaCl₃ and ruthenium red (RR) and Ca²⁺ chelator ethylene glycol-bis(2-aminoethylether)-N,N,N??,N??-tetraacetic acid (EGTA) prevent H₂O₂-induced AR formation, which indicate that the hypocotyl cuttings response to H₂O₂ depends on the availability of both intracellular and extracellular Ca²⁺ pools, and Ca²⁺ is a downstream messenger in the signaling pathway triggered by H₂O₂ to promote adventitious root formation.