华南丘陵区2种土地利用方式下地表CH4和N2O通量研究

采用静态箱-气相色谱法对华南丘陵区马尾松林和果园地表CH4和N2O通量及其主要影响因子进行了观测(马尾松Pinus massoniana林为期16个月,果园15个月),比较和分析了不同土地利用方式下地表CH4,和N2O通量的季节变化,地表CH4和N2O通量与温度和土壤含水量的关系以及凋落物对地表CH4和N2O通量的影响.结果表明,在有凋落物覆盖下,马尾松林和果园年均地表CH4通量分别为-3.41±0.3和-3.24±0.44 kg CH,hm-2a-1;年均地表N2O通量分别为4.57±0.50和11.99±0.67 kg N2O-N hm-2a-1;去除凋落物情况下,马尾松林和果园年均地表CH4通量分别为-2.98±0.44和-1.93±0.53 kg CH4 hm-2a-1;年均地表N2O通量分别为3.12±0.28和9.42±0.56 kg N2O-N hm-2a-1.2种土地利用方式对地表CH4影响较小,对N2O通鼍的影响较大,果园地表N2O通量显著大于马尾松林(P<0.01).马尾松林和果园土壤对CH4的吸收在旱季(10～3月)高而雨季(4～9月)低,N2O排放雨季较高而旱季较低.土壤含水量对地表CH4和N2O通量的影响比温度要大.凋落物对地表CH4通量的影响较小,对N2O通量的影响较大,凋落物对马尾松林和果园N2O排放的贡献率分别为31.71%和21.40%.研究还表明,地表N2O)通量存在明显的降雨驱动效应.     

长白山阔叶红松林土壤N2O排放通量的变化特征

采用静态密闭箱 /气相色谱分析方法对长白山阔叶红松林两个样地的N2 O排放通量进行了测定。结果表明 ,凋落物对林地土壤N2 O排放的影响是显著的 ,其对全年N2 O排放的平均贡献率是 36 89%。长白山阔叶红松林土壤是大气N2 O一个重要的源 ,但在极少的天气状况下也能吸收大气中的N2 O ,而起着汇的作用。其排放通量的变化范围是 - 4 1 4 8～ 2 91 84μgN2 O·m-2 ·h-1,平均通量是 6 8 7μgN2 O·m-2 ·h-1,高于其他类型林地的排放通量 ,且变动范围也较其他森林类型大。无凋落物林地土壤N2 O排放通量变化范围是 - 2 3 2 4～ 93 75 μgN2 O·m-2 ·h-1,平均通量为 33 79μgN2 O·m-2 ·h-1。两个样地N2 O排放通量的季节变化特征相似 :夏季N2 O的排放通量最高 ,春季次之 ,秋冬两季较低且趋于平稳。昼夜变化趋势也相似 :N2 O排放通量的最大值都出现在 18∶0 0 ,最小值都出现在 12∶0 0和 14∶0 0。研究还表明 ,林地土壤N2 O的排放通量与地表温度和地下 5cm温度的相关性较好 ,无凋落物的样地N2 O的排放通量仅与地下 5cm温度的相关性较好。     

影响阔叶红松林土壤CO2排放的主要因素

采用静态封闭箱式技术对长白山阔叶红松林土壤CO2 的排放通量进行 1年的观测 ,并通过多元回归分析了土壤CO2 排放速率与 5个环境因子间的关系。结果表明 ,阔叶红松林土壤CO2 排放与表层无凋落物的土壤CO2 排放速率在测定年度内具有相同的季节变化趋势。在不同的月份中 ,以 7月份最高 ,2月份最低 ;在夏季 18∶0 0为土壤日CO2 排放的最高峰 ;土壤CO2 排放速率与 5个环境因子进行多元回归的结果显示 :林地土壤CO2 排放速率与地表温度和地下 2 0cm土壤湿度呈显著正相关。根据气象资料推算 ,阔叶红松林的年凋落物和土壤CO2排放通量分别为 2 80 4 gCO2 ·m-2 ·a-1和 3911gCO2 ·m-2 ·a-1。阔叶红松林凋落物排放CO2年通量占土壤林地CO2 排放总量的 2 8%。     

鼎湖山主要森林生态系统地表CH4通量

利用静态箱-气相色谱法对鼎湖山3种处于演替不同阶段的森林类型-季风常绿阔叶林、针阔叶混交林和马尾松林-的地表CH4通量进行了为期一年的原位观测和研究,结果表明:3种林型地表吸收CH4通量按从大到小的顺序为:季风林>混交林>松林,不同林型间的CH4通量差异与森林土壤的性质有密切关系,即土壤容重越小、有机质含量与土壤温度和湿度都没有明显的相关性,但在旱季土壤温度成为控制地表CH4通量的主要因子。     

青藏高原高寒草甸非生长季温室气体排放特征及其年度贡献

高寒草甸是青藏高原地区的主要植被类型,目前对其温室气体研究多集中于生长季.本文利用静态箱-气相色谱法,对非生长季高寒草甸温室气体排放特征及其与主要环境因子的关系进行了研究.结果表明:非生长季高寒草甸表现为CO2和N2O的源、CH4的汇.其中非生长季CO2通量平均值为89.33 mg·m-2·h-1,累积排放通量为280.01g· m-2;CH4通量平均值为-11.35 μg·m-2·h-1,累积吸收通量为124.74 mg·m-2;N2O通量平均值为8.02 μg·m-2·h-1,累积排放通量为39.51 mg·m-2.非生长季CO2、CH4和N2O累积排放通量分别占全年的13.33％、53.47％和62.67％.冻融期(2012年4月)CH4累积吸收通量较小,只占非生长季的4.5％;而CO2和N2O累积排放通量较大,分别占非生长季的25.8％和20.8％.非生长季CO2通量与温度(气温、5和10 cm土壤温度)和5 cm土壤湿度均存在显著正相关关系,而CH4和N2O通量仅与5 cm土壤湿度存在显著正相关.研究表明,虽然冻融期CH4累积吸收通量在非生长季累积量中比重较小,但非生长季CH4和N2O累积排放量却占全年累积排放量的1/2以上,在温室气体累积通量评估中不容忽视.     

长白山四种林分土壤CO2释放通量的研究

对长白山地区 4种典型林分下土壤释放CO2 通量的研究表明 ,在较短的时间尺度上 ,4种林型在CO2 释放通量上有显著的差别 ,各林型CO2 通量的释放表现出明显的空间异质性 ,其释放顺序为 :山杨白桦混交林 >原始阔叶红松林 >白桦林 >山杨林 ,其中山杨白桦混交林对CO2 释放的贡献最大 ,而山杨林最小。 4种林分土壤CO2 通量的全日变化过程并不一致 ,除山杨白桦混交林和气温有较一致性的规律 ,呈较明显的单峰型外 ,其余并无明显的变化规律。凋落物对林地CO2 释放通量的变化有显著的影响 ,有凋落物覆盖的林地土壤CO2 释放量明显大于无凋落物覆盖的林地 ,其平均通量为 2 6 2 86～ 5 5 6 5 5mgC·m-2 ·h-1,而无凋落物覆盖林地土壤CO2 的平均通量为 2 0 5 85～ 395 6 9mg·m-2 ·h-1。凋落物排放CO2 量占林地总排放量的14 %～ 30 % ,并且改变了林地CO2 释放通量大小的排序。     

小兴安岭阔叶林沼泽土壤CO_2、CH_4和N_2O排放规律及其影响因子

采用野外静态箱-气相色谱法,研究了小兴安岭典型阔叶林沼泽生长季节土壤CO2、CH4和N2O排放季节变化规律、源/汇功能及主要影响因子。结果表明:①苔草沼泽、毛赤杨沼泽和白桦沼泽生长季节土壤CO2、CH4、N2O排放分别集中在夏季、夏秋季、春夏季,平均排放通量依次为487.89、382.27、514.63 mg.m-2.h-1,1.88、1.03、0.04 mg.m-2.h-1,3.70、58.61、11.73μg.m-2.h-1。②三者生长季节土壤CO2排放通量与气温和0-20 cm土壤温度均呈显著正相关;苔草沼泽CH4排放通量与30-40cm土壤温度呈显著正相关,毛赤杨沼泽CH4排放通量与地表温度呈显著负相关;白桦沼泽N2O排放通量与地表温度呈显著正相关。苔草沼泽N2O排放与水位呈显著负相关;毛赤杨沼泽CH4排放与水位呈显著正相关;白桦沼泽CO2排放与水位呈显著负相关。③三者生长季节土壤均为CO2、CH4、N2O排放源(17.56、13.76、18.53 t.hm-2;67.54、37.05、1.30 kg.hm-2;0.13、2.11、0.42 kg.hm-2),三者CO2排放量相近(5.5%-21.6%);苔草沼泽为CH4的强排放源,毛赤杨沼泽为中排放源,白桦沼泽为弱排放源;毛赤杨沼泽为N2O的强排放源,白桦沼泽为中排放源,苔草沼泽为弱排放源。     

川中丘陵区旱地小麦生态系统CO2、N2O和CH4排放特征

利用静态箱/气相色谱法观测川中丘陵旱地小麦生态系统CO2、N2O和CH4的排放通量.结果表明,旱地小麦CO2、N2O和CH4排放具有明显的日变化和季节变化特征.在小麦的整个生长季中,常规、无氮、空白、裸地等实验处理的CO2、N2O和CH4的排放通量具有显著差异.CO2排放通量表现为常规＞空白＞裸地,CO2日最高排放值在每日1300～1500时出现,最低排放值出现在凌晨300～600,且作物的不同生长季CO2排放通量具有一定的差异.在小麦生长季中,N2O通量排放呈递增趋势,N2O排放通量表现为常规＞空白＞裸地.旱地小麦CH4通量排放和温度、湿度等环境因子不具有显著的相关性,排放无规律.     

多年冻土退化地区湿地土壤温室气体排放及其影响因子

采用野外原位实验静态箱-气相色谱法,研究了兴安岭多年冻土不同程度退化地区生长季湿地土壤温室气体CH4、CO2和N2O的排放通量特征,同时分析了环境因子对土壤温室气体排放的影响。结果表明:1)3种类型冻土区(季节性冻土区、岛状多年冻土区、连续多年冻土区,分别用D1、D2、D3表示)土壤在生长季时期表现为CO2和N2O的源;D1和D3为CH4的源,D2为CH4的汇。D1、D2、D3土壤在生长季中平均CH4排放通量分别为(0.127±0.021)、(-0.020±0.006)、(0.082±0.019)mg·m^-2·h^-1;CO2排放通量分别为(371.50±66.73)、(318.43±55.67)、(213.19±37.05)mg·m^-2·h^-1;N2O排放通量分别为(24.05±2.62)、(8.07±2.42)、(2.17±0.25)μg·m-2·h-1。土壤CO2和N2O排放通量随多年冻土退化程度的加剧呈现出升高的趋势。2)细根生物量、凋落物生物量、全碳、全氮、可溶性有机碳、总可溶性氮、土壤容重、土壤温度、土壤含水量等均影响温室气体排放,3种不同类型冻土区土壤CH4、CO2和N2O的排放差异是诸多影响因子综合作用的结果。     

温带针阔混交林土壤碳氮气体通量的主控因子与耦合关系

中高纬度森林地区由于气候条件变化剧烈,土壤温室气体排放量的估算存在很大的不确定性,并且不同碳氮气体通量的主控因子与耦合关系尚不明确。以长白山温带针阔混交林为研究对象,采用静态箱-气相色谱法连续4a(2005—2009年)测定土壤二氧化碳(CO2)、甲烷(CH4)和氧化亚氮(N2O)净交换通量以及温度、水分等相关环境因子。研究结果表明:温带针阔混交林土壤整体上表现为CO2和N2O的排放源和CH4的吸收汇。土壤CH4、CO2和N2O通量的年均值分别为-1.3 kg CH4hm-2a-1、15102.2 kg CO2hm-2a-1和6.13 kg N2O hm-2a-1。土壤CO2通量呈现明显的季节性规律,主要受土壤温度的影响,水分次之;土壤CH4通量的季节变化不明显,与土壤水分显著正相关;土壤N2O通量季节变化与土壤CO2通量相似,与土壤水分、温度显著正相关。土壤CO2通量和CH4通量不存在任何类型的耦合关系,与N2O通量也不存在耦合关系;土壤CH4和N2O通量之间表现为消长型耦合关系。这项研究显示温带针阔混交林土壤碳氮气体通量主要受环境因子驱动,不同气体通量产生与消耗之间存在复杂的耦合关系,下一步研究需要深入探讨环境变化对其耦合关系的影响以及内在的生物驱动机制。     

Photoregulation of seed germination of wild-type and of an aurea-mutant of tomato

Seed germination of an aurea mutant of tomato ( Lycopersicon esculentum Mill.) is promoted by continuous irradiation with red, far-red or long-wavelength far-red (758 nm) light as well as by cyclic irradiations (5 min red or 5 min far-red/25 min darkness). Far-red light applied immediately after each red does not change the germination behaviour. Seed germination of the isogenic wild-type, cv. UC-105, is promoted by continuous and cyclic red light while it is inhibited by continuous and cyclic far-red light and by continious 758 nm irradiation. Far-red irradiation reverses almost completely the promoting effect of red light. The promoting effect (in the aurea mutant) and the inhibitory effect (in the wild-type) of continuous far-red light do not show photon fluence rate dependency above 20 nmol m⁻² s⁻¹. It is concluded that phytochrome controls tomato seed germination throgh low energy responses in both the wild type and the au mutant. The promoting effect of continuous and cyclic far-red light in the au mutant can be attributed to a greater sensitivity to P_fr.     

六种藓类植物茎的比较解剖学研究

通过对6种藓类植物,即褶叶青藓(Brachythecium salebrosum(Web.et Mohr.)B.S.G.)、湿地匐灯藓(Plagiomnium acutum(Lindb.)Kop.)、侧枝匐灯藓(Plagiomnium maximoviczii(Lindb.)Kop.)、大凤尾藓(Fissidensnobilis Griff.)、大羽藓(Thuidium cymbifolium(Doz.et Molk.)B.S.G.)和大灰藓(Hypnum plumaeforme Wils.)嫩茎和老茎的石蜡切片和显微观察发现,同一藓类植株的嫩茎和老茎,茎结构稳定,不同种藓类植物茎横切面具有不同特征.植物体茎横切面形状、表层细胞的层数、细胞大小和细胞壁厚薄、皮层细胞大小和形状、中轴的有无以及比例等特征可以作为藓类植物的分科分类依据之一.     

Interconnection of parameters of regulation system of lipid peroxidation and of morphophysiological parameters of mouse liver

A complex analysis of seasonal fluctuations of the mean group parameters of the system of regulation of lipid peroxidation has been performed in liver of Balb/c mice. Association of lipid characteristics and morphophysiological parameters is studied in the Balb/c mouse liver. An inter-connection is revealed between the liver index and the amount of lysoforms of phospholipids, the scale and character of the interconnection differing essentially depending on proportion of phos-phatidylcholine in mouse liver phospholipids.     

Physiological characteristics of various species of strains of carboxydobacteria

Seven strains of aerobic carbon monoxide-oxidizing bacteria (carboxydebacteria) when growing on CO as sole source of carbon and energy had doubling times which ranged from 12–42 h. The activity profiles obtained after discontinuous sucrose density gradient centrifugation indicated that the CO-oxidizing enzymes are soluble and the hydrogenases are membrane-bound in all strains examined. The CO-oxidizing enzymes of Pseudomonas carboxydohydrogena, Pseudomonas carboxydoflava, Comamonas compransoris, and the so far unidentified strains OM2, OM3, and OM4 had a molecular weight of 230,000; that of Achromobacter carboxydus amounted to 170,000. The molecular weights of the CO-oxidizing and H₂-oxidizing enzymes turned out to be identical. The cell sonicates were shown to catalyze the oxidation of both CO and H₂ with methylene blue, thionine, phenazine methosulfate, toluylene blue, dichlorophenolindophenol, cytochrome c or ferricyanide as electron acceptors. Methyl viologen, benzyl viologen, FAD⁺, FMN⁺, and NAD(P)⁺ were not reduced. The spectrum of electron acceptors was identical for all strains tested. Neither free formate, hydrogen nor oxygen gas were involved in the CO-oxidation reaction. Methylene blue was reduced by CO at a 1:1 molar ratio. The results indicate that CO-oxidation by carboxydobacteria is catalyzed by identical or similar enzymes and that the reaction obeys the equation CO+H₂OCO₂+2H⁺+2e^- as previously shown for Pseudomonas carboxydovorans.Dedicated to Otto Kandler remembering almost three decades of enjoyable cooperation     

Modulation of allostery of pyruvate kinase by shifting of an ensemble of microstates

Since the introduction of the concepts of allostery about four decades ago, much advancement has been made in elucidating the structure-function correlation in allostery. However, there are still a number of issues that remain unresolved. In this review we used mammalian pyruvate kinase (PK) as a model system to understand the role of protein dynamics in modulating cooperativity. PK has a triosephosphate isomerase (TIM)(α/β)₈ barrel structural motif. PK is an ideal system to address basic questions regarding regulatory mechanisms about this common (α/β)₈ structural motif. The simplest model accounting for all of the solution thermodynamic and kinetic data on ligand-enzyme interactions involves two conformational states, inactive E^T and active E^R. These conformational states are represented by domain movements. Further studies provide the first evidence for a differential effect of ligand binding on the dynamics of the structural elements, not major secondary structural changes. These data are consistent with our model that allosteric regulation of PK is the consequence of perturbation of the distribution of an ensemble of states in which the inactive E^T and active E^R represent the two extreme end states. Sequence differences and ligands can modulate the distribution of states leading to alterations of functions. The future work includes: defining the network of functionally connected residues; elucidating the chemical principles governing the sequence differences which affect functions; and probing the nature of mutations on the stability of the secondary structural elements, which in turn modulate allostery.     

（鱼句）亚科花（鱼骨）型鱼类骨骼系统的比较

对我国花型Hemibarbuspattern鱼类作了骨骼系统比较,结果表明,此类型鱼类脑颅较长,副蝶骨平直或稍弯曲,眶蝶骨腹纵嵴发达(铜鱼Coreius septentrionalis例外),下颞窝和咽突中等大,基枕骨后突发达;脑颅中的上筛骨的后突、侧筛骨的外筛突,蝶耳骨的外突、上耳骨的后突、围眶骨和后颞窝等均有明显的差异;咽颅中的舌颌骨、尾舌骨、鳃盖骨和下咽齿的列数等又有显著的区别;附肢骨骼中的腰带骨、脊椎骨中的复合神经骨和第4椎骨腹侧的悬器等也有不同之处。据此,这些差异和区别可作为属间或种间的分类依据。     

真菌类遗传学分析的知识结构教学

本文以认知结构理论为指导,讨论了真菌类遗传分析与高等动植物遗传分析的内在联系,认为利用这种内在联系进行教学可收到好的效果并说明了作者的具体教学过程。 Abstract:In the paper, the relationship between genetic analysis of Fungi and genetic analysis of high animal and plant was discussed.A good results were obtained when we adopted this method in the teaching.     

Isotopic studies of the diet of the people of the coast of British Columbia

In 1982, Chisholm et al. used δ¹³C data for human burials from shell midden sites widely distributed on the coast of British Columbia (BC) to show the extreme dependence of these individuals on high trophic level marine consumers, principally salmon and marine mammals. Here, we present previously unpublished analyses of δ¹⁵N for some of the same individuals as well as δ¹³C data for additional individuals. Nitrogen isotope data show that the diet was dominated by high trophic level marine fauna including carnivorous fish and marine mammals. Although most burials were found in shell middens, marine mollusks made up of only a minor component of diet. The data for δ¹³C demonstrate that terrestrial faunal foods are undetectable in the diet of the majority of individuals, and seldom constitute more than 10% of the dietary protein of individuals living on the coast although terrestrial fauna were widely available as a potential source of protein. This dietary pattern of exclusion of land‐based animals from their diet persisted for almost 6,000 years along a wide expanse of coastline. In contrast, people from the BC interior (100 km or more from the coast) consumed a mixed diet of terrestrial and marine foods including spawning salmon. Am J Phys Anthropol 155:460–468, 2014. © 2014 Wiley Periodicals, Inc.