气候变化背景下茶角胸叶甲潜在适生区预测

基于茶角胸叶甲(Basilepta melanopus Lefèvre)截至2020年底的63个有效分布点和22个环境变量,分析筛选出影响茶角胸叶甲分布的8个重要环境变量,利用最大熵模型(MaxEnt)和ArcGIS软件,对茶角胸叶甲2021—2100年气候条件下的适生区进行预测。结果表明:MaxEnt模型的受试者工作曲线面积(AUC)达0.992;在目前气候条件下,茶角胸叶甲潜在的适生区总面积为6.69×10^(5)km^(2),主要位于中国南部和东南部地区,除已报道发生过的地区外,还包括湖北、安徽、浙江、江苏和中国台湾;影响茶角胸叶甲潜在适生区分布的重要环境因子主要包括最冷季降水量、坡向和平均气温年较差,其中最冷季降水量是影响茶角胸叶甲潜在适生区分布范围的最关键环境变量;在SSP126和SSP245情景下,茶角胸叶甲的总适生区面积在2061—2080年间达到峰值后下降;在SSP370情景下,茶角胸叶甲的总适生区面积在2041—2060年间达到峰值后下降;在SSP585情景下,茶角胸叶甲总适生区面积持续上升。总体来看,茶角胸叶甲的适生区中心主要向西、向北和高纬度等内陆地区转移。

干姜附子肉桂汤诱导口腔溃疡的机制研究

[目的]通过研究干姜附子肉桂汤诱导的大鼠口腔溃疡的机制,探讨热性药诱发上火的病理生理机制。[方法]将20只健康SD大鼠随机分为两组,分别为对照组和模型组,每组10只,其中对照组用0.9%氯化钠溶液0.1mL/(10g·d)灌胃,模型组用干姜附子肉桂水煎剂0.1mL/(10g·d)灌胃,均为1次/d,连续给药21d后,腹腔主动脉取血行血常规检测,取两组大鼠的口腔黏膜组织,以HE染色检测口腔组织病理变化,免疫组化检测IgG和IgA表达差异,基因芯片技术检测相关基因表达的差异。[结果]血常规结果显示模型组大鼠的白细胞(white blood cell,WBC)总数、中性粒细胞(neutrophil,NEUT)、单核细胞(mononuclear cells,MONO)、中性粒细胞与淋巴细胞比值(neutrophils-lymphocyte ratio,NLR)均升高,对照组无明显变化;HE染色结果显示与对照组比较,模型组大鼠口腔黏膜组织出现表皮脱落、炎性浸润,表明模型组的口腔黏膜损伤,造模成功;免疫组化显示模型组的口腔黏膜组织的IgG和IgA表达升高,提示口腔黏膜组织炎性反应增强。基因芯片结果显示,对照组与模型组相比,差异表达两倍以上的基因有463个,其中上调表达基因299个,参与主要通路有脂肪的消化与吸收、类固醇的生物合成,涉及的主要基因为二酯酰甘油酰基转移酶2(acyl CoA:diacylgycerol acyltransferase 2,DGAT2)、鞘磷脂沉积病C1样蛋白1(Niemann-Pick C1-like 1,NPC1L1)、脂肪酸羟化酶结构域蛋白2(fatty acid hydroxylase domain-containing protein 2,FAXDC2)、类固醇脱氢酶样蛋白(NAD/NADP dependent steroid dehydrogenase like protein,NSDHL)等;下降表达基因164个,参与主要通路为细胞外基质(extracellular matrix,ECM)受体相互作用和黏着斑通路,涉及的主要基因有软骨素(chondroadherin,CHAD)、Ⅺ型胶原α2(collagen typeⅪalpha-2,COL11A2)、肿瘤坏死因子受体(tumor necrosis factor receptor,TNR)、促红细胞生成素(erythropoietin,EPO)、干扰素alpha 2(interferon alpha 2,IFNA2)等。[结论]干姜附子肉桂汤会引起大鼠上火,并引发口腔溃疡,其机制与多种基因的表达水平改变有关,脂肪的消化与吸收、类固醇的生物合成、ECM受体相互作用和黏着斑通路等信号通路异常可能与其发生密切相关。

Integration of nitrogen dynamics into the land surface model AVIM.Part 2:baseline data and variation of carbon and nitrogen fluxes in China

The spatiotemporal features of carbon and nitrogen fluxes over China between 1979 and 2015were simulated by the Atmosphere–Vegetation Interaction Model(AVIM).The carbon fluxes of gross primary production and net primary production captured the distribution pattern in China better than MODIS and TRENDY data.The results for nitrogen deposition and biological nitrogen fixation show the good performance of the AVIM simulation compared with the CMIP6 and CABLE data,with a deposition rate>4 g N m-2yr-1in south China.The variation in the gross primary production and net primary production can be up to 300 and 200 g C m-2yr-1in south and southeast China,respectively,and there is a discrepancy between the AVIM and the data from MODIS and TRENDY.This shows the difficulty in simulating the carbon flux in a monsoon climate region and the importance of coupling the nitrogen–carbon fluxes.The standard deviation of nitrogen deposition and biological nitrogen fixation is simulated well by the AVIM and there is a large range in nitrogen deposition of 0.8–1.2 g N m-2yr-1in south China.The climatological mean of the fluxes performs better than the variation in the standard deviation and anomaly and this variation in the carbon–nitrogen flux is the key to decreasing bias in future modeling studies.

The integration of nitrogen dynamics into a land surface model. Part 1: model description and site-scale validation

Nitrogen cycling has profound effects on carbon uptake in the terrestrial ecosystem and the response of the biosphere to climate changes.However,nutrient cycling is not taken into account in most land surface models for climate change.In this study,a nitrogen model,based on nitrogen transformation processes and nitrogen fluxes exchange between the atmosphere and terrestrial ecosystem,was incorporated into the Atmosphere–Vegetation Interaction Model(AVIM)to simulate the carbon cycle under nitrogen limitation.This new model,AVIM-CN,was evaluated against site-scale eddy covariance–based measurements of an alpine meadow located at Damxung station from the FLUXNET 2015 dataset.Results showed that the annual mean gross primary production simulated by AVIM-CN(0.7073 gC m^-2 d^-1)was in better agreement with the corresponding flux data(0.5407 gC m^-2 d^-1)than the original AVIM(1.1403 gC m^-2 d^-1)at Damxung station.Similarly,ecosystem respiration was also down-regulated,from 1.7695 gC m^-2 d^-1 to 1.0572 gC m^-2 d^-1,after the nitrogen processes were introduced,and the latter was closer to the observed vales(0.8034 gC m^-2 d^-1).Overall,the new results were more consistent with the daily time series of carbon and energy fluxes of observations compared to the former version without nitrogen dynamics.A model that does not incorporate the limitation effects of nitrogen nutrient availability will probably overestimate carbon fluxes by about 40%.

碳中和背景下大气科学碳氮循环研究前沿问题与建议

碳循环不断受到气候变化、大气CO_(2)浓度、人类活动和氮循环等多种因素的共同影响。然而,未来以"碳达峰和碳中和"为目标的排放情景下,中国陆地生态系统碳汇潜力仍然存在很大的不确定性,影响了实现双碳目标的碳减排和碳增汇相关政策的制定和实施。厘清大气科学中关于碳氮循环演变研究有关科学认识将会为中国碳达峰和碳中和的实现提供有力地科学支撑。文章回顾了国内外大气科学中碳氮循环研究的基础和现状,分析了当前气候变化、大气CO_(2)升高、碳氮循环相互作用的关键过程和人类活动对地球系统碳氮循环研究的影响。其中,氮营养元素对碳循环的影响充分表明生物固氮和大气氮沉降等过程对碳汇有重要影响,可以减少地球系统模式中碳汇模拟的不确定性;此外,由于气候变化是气候系统对外强迫的快变响应和慢变响应的综合结果,在大气科学中有必要区分快变响应和慢变响应对中国碳汇的影响,分析人为碳排放清零后中国陆地生态系统碳汇潜力和固碳速率的变化;最后,在此基础上获得相应的启示并给出了未来的策略建议,以期为国家碳中和战略顺利实施提供参考与借鉴。

茶树根腐病拮抗放线菌分离、鉴定及生防潜能研究

为了开发对茶树根腐病菌具有拮抗作用的放线菌资源,从茶树根际土壤中筛选得到一株对根腐病具有良好防治效果的拮抗菌株JK-13,基于形态特征观察、生理生化试验及16S rRNA序列分析,确定菌株JK-13为胶样链霉菌Streptomyces gelaticus。平板对峙试验结果表明,菌株JK-13对茶树根腐病菌Fusarium cugenangense抑菌率达67.06%,对多种作物的病原真菌表现出了良好的抑菌活性。此外,该菌通过产生具有抑菌活性的挥发性与非挥发性有机物、代谢产物与淀粉水解酶、纤维素水解酶和β-1,3-葡聚糖酶等胞外酶抑制病原菌生长,对峙培养5 d后病原菌菌丝出现分枝、缢缩、扭曲、畸形、相互缠绕等现象。通过优化发酵培养条件来提升活性代谢产物的含量与病原菌抑制率,结果表明,最适生长碳源、氮源、无机盐分别为麦芽糖、(NH_(4))_(2)SO_(4)、KCl,最佳发酵培养基配方为小米10 g/L、麦芽糖10 g/L、(NH_(4))_(2)SO_(4)5 g/L、KCl 2.5 g/L、CaCO_(3)3 g/L,无菌发酵滤液对病原菌抑制率为51.03%,较初始培养条件提高了12.26%。因此,胶样链霉菌JK-13在防控茶树根腐病方面具有较好的开发价值及应用潜力。

Prediction of carbon exchanges between China terrestrial ecosystem and atmosphere in 21st century

The projected changes in carbon exchange between China terrestrial ecosystem and the atmosphere and vegetation and soil carbon storage during the 21st century were investigated using an atmos-phere-vegetation interaction model (AVIM2). The results show that in the coming 100 a, for SRES B2 scenario and constant atmospheric CO2 concentration, the net primary productivity (NPP) of terrestrial ecosystem in China will be decreased slowly, and vegetation and soil carbon storage as well as net ecosystem productivity (NEP) will also be decreased. The carbon sink for China terrestrial ecosystem in the beginning of the 20th century will become totally a carbon source by the year of 2020, while for B2 scenario and changing atmospheric CO2 concentration, NPP for China will increase continuously from 2.94 GtC·a?1 by the end of the 20th century to 3.99 GtC·a?1 by the end of the 21st century, and vegetation and soil carbon storage will increase to 110.3 GtC. NEP in China will keep rising during the first and middle periods of the 21st century, and reach the peak around 2050s, then will decrease gradually and approach to zero by the end of the 21st century.

The terrestrial NPP simulations in China since Last Glacial Maximum

Based on Atmosphere-Vegetation Interaction Model (AVIM), the magnitude and spatial distribution of terrestrial net primary productivity (NPP) in China is simu-lated during three different geological eras, Last Glacial Maximum (LGM), Mid-Holocene (MH) and the present. The simulation shows that the glacial-interglacial variation of East Asian summer monsoon in China is the key factor af-fecting the NPP change. During the three eras, mean NPPs are 208 g/m2·a, 409 g/m2·a, and 355 g/m2·a. The total NPPs are 2.05 Pg/a, 3.89 Pg/a and 3.33 Pg/a, respectively. The ter-restrial NPP in China during warm-humid climate is larger than that during cold-arid eras, and the correlation analysis between NPP and climate factors suggests that temperature is the primary factor affecting the terrestrial NPP during 21 kaBP (LGM), and for 6 kaBP (MH) and the present the pri-mary factor is precipitation.