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Liu Junjie Wang Juan Han Yanan Yuan Shunjie Gao Yunfei Rong Zhanlei Zhao Chuanyan 《New Forests》2022,53(3):511-531
New Forests - Qinghai spruce (Picea crassifolia Kom.) forests play a key role in the carbon sequestration in the Qilian Mountains, Northwestern China. Carbon sequestration is closely related to... 相似文献
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预处理过程可以破坏木质纤维素生物质的致密结构、降低生物抗性,是木质纤维素生物质经酶解制备糖基平台化学的重要步骤。该研究以蔗渣为原料,在预处理温度为160 ℃、预处理时间为10 min时,选取0.025 mol/L 的不同金属盐FeCl3、CrCl3、AlCl3、CuCl2、FeCl2、ZnCl2、MnCl2、MgCl2、CaCl2、NaCl、LiCl、Na2CO3对蔗渣进行乙醇/水预处理,并对预处理后样品进行酶解,探究不同金属盐强化乙醇/水预处理对蔗渣酶解效率的影响和规律,并进一步通过扫描电镜(scanning electron microscopy, SEM)、X射线衍射(X-ray diffraction, XRD)、傅里叶变换红外光谱(fourier transform infrared spectroscopy, FT-IR)和热重(thermogravimetric, TG)对蔗渣原料和预处理后的固体进行表征,探究金属盐强化乙醇/水预处理后蔗渣表面形貌与结构变化对酶解效率的影响,分析作用机理。结果表明:与原料甘蔗渣相比,不同金属盐强化乙醇/水预处理后样品中葡聚糖的质量分数从45.5%增加到77.2%,预处理后样品酶解48h后的葡萄糖得率也由51.14%增加到最高93.08%。其中,三价金属盐(FeCl3、CrCl3和AlCl3)对蔗渣酶解效率的提升最为显著,这可归因于三价金属盐强化乙醇/水预处理可以更加有效的去除蔗渣中的半纤维素和木质素,增加酶对纤维素的可及性。后续表征分析也表明经过三价金属盐(FeCl3、CrCl3和AlCl3)强化乙醇/水预处理后的样品比经过二价金属盐(CuCl2、FeCl2、ZnCl2、MnCl2、MgCl2和CaCl2)和一价金属盐(NaCl、LiCl和Na2CO3)强化乙醇/水预处理表面结构破坏更为彻底,结晶度相对增加最大,木素和半纤维素去除率最多,热稳定性也相对最高。该研究结果将为后续木质纤维素生物质的高效转化与利用提供参考。 相似文献
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氟原子半径小、电负性强、具有与(-OH)官能团类似的氢键形成能力,是"超级卤素"。生物大分子核酸中引入氟原子,会使得氟原子附近的原子电子云密度、碱性及酸性发生明显变化,从而导致整个核酸分子构象由于偶极相互作用发生变化。本文主要综述最近几年含氟核苷在蛋白质与核酸的相互作用及其动力学机制、DNA和RNA的二级结构等生物大分子结构机理研究中的应用,同时,进一步阐述了利用含氟核苷,结合19F-NMR核磁共振波谱技术,研究核酸与蛋白质之间特异性识别的结构与动态机制及核酸二级结构的研究进展,以期氟化学在我国化学和生物学领域得到更为广泛的应用。 相似文献
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Zhanlei Wang Yongfu Li Scott X. Chang Jiaojiao Zhang Peikun Jiang Guomo Zhou Zhenming Shen 《Biology and Fertility of Soils》2014,50(7):1109-1119
The effects and associated mechanisms of the application of organic residues or their derived biochar on the dynamics of soil organic C and soil CO2 efflux in planted soils are poorly understood. This paper investigated the impact of bamboo leaf and the derived biochar applications on soil CO2 efflux and labile organic C in an intensively managed Chinese chestnut plantation in a 12-month field study. The treatments studied included Control, application of bamboo leaf (Leaf), and application of biochar (Biochar). The Leaf treatment increased (P?0.05) soil CO2 efflux and concentrations of water-soluble organic C (WSOC) and microbial biomass C (MBC). The Biochar treatment increased soil CO2 efflux and WSOC and MBC only in the first month after application, but such effects diminished thereafter. The annual cumulative soil CO2 emission was increased by 16 % by the Leaf treatment as compared to the Control, but there was no difference between the Biochar and Control treatments. The soil organic C (SOC) storage was increased by biochar addition but not by bamboo leaf addition. An exponential relationship between soil temperature and soil CO2 efflux was observed regardless of the treatment. Soil CO2 efflux was correlated to soil WSOC (P?0.05) but not to soil MBC or moisture content. The apparent temperature sensitivity (Q 10) of soil CO2 efflux was ranked as Leaf?>?Biochar?>?Control. In comparison with the application of fresh bamboo leaf, pyrolyzed bamboo leaf (biochar) application decreased CO2 effluxes and increased C sequestration in the soil. 相似文献
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反硝化过程是集约化农田土壤剖面硝态氮(NO3--N)去除的重要途径。但对土壤剖面反硝化氮气(N2)产生速率的准确定量很难,尤其不同深度的土壤氧气(O2)浓度状况如何影响土壤N2的产生仍不清楚。本研究依托集约化管理的冬小麦-夏玉米轮作田间长期定位试验(始于2006年),采集传统施肥处理0~2.5 m剖面的原状土柱,并基于在玉米生长季田间原位观测的不同深度土壤O2浓度和温度状况,设置不同O2浓度水平(15.0%、12.0%、2.5%和0)和培养温度(26℃和20℃),采用氦培养-直接测定N2法测定3个不同深度(0~0.2、0.5~0.7 m和2.0~2.2 m)土壤N2O和N2产生速率。结果显示:无论是有氧还是无氧条件,土壤剖面N2和N2O的产生均表现为表层高于深层;有氧条件下(2.5%~15.0%O2)土壤... 相似文献
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