海南霸王岭油丹所在群落的优势种群种间联结性研究

基于2×2联列表,以X2统计量、Ochiai联结测度指数和多物种关联指数为参数,分析了海南霸王岭油丹所在群落中油丹(Alseodaphne hainanensis)等17个主要种群(物种)的种间联结性特征。结果表明, 17个主要种群(物种)总体水平上表现为不显著的正联结。17个物种组成的136个种对中：当取样面积在100 m2时,有72对表现正关联,63对为负关联,1对无关联。X2检验有2对表现显著正关联,有3对表现显著或极显著负关联。有125个种对的0＜OI＜0.6,仅有9个种对的OI≥0.6, 另有2个种对OI=0;当取样面积为50 m2时,有59对表现正关联,70对为负关联,7对无关联。X2检验有6对表现显著或极显著正关联,有2对表现显著负关联。有129个种对的0＜OI＜0.6,而OI≥0.6的种对没有, 另有7个种对OI=0。不同优势种群下的种间联结性存在一定的差异,而以线枝蒲桃(Syzygium araiocladum)等为优势种群的群落种间联结性较高,群落结构较稳定。     

子午岭辽东栎群落乔木种间联结与取样面积

以x2检验、种间联结系数(AC)、Person相关系数(r)、方差比率(馏)和某一取样面积尺度下的样方中未共同出现的物种对数目Na为参数,探讨黄土高原子午岭辽东栎群落主要乔木种间联结特性与取样面积的关系.x2检验和AC分析表明,显著的种问联结关系仅出现在25和50 m22个取样面积中;相关分析表明,显著的种间相关出现在取样面积25～200 m2,但r值的变化在25～100 m2较稳定;VR分析未能有效地区分不同取样面积中多物种关联的特性;Na值在面积为100～200 m2、样方数为40～80时较稳定.从合理的样方面积和适当的样方数量综合考虑,样方面积在100 m2、样方数为45个,能比较客观、稳定地反映辽东栎群落植物种间联结特性.     

秦巴山地栓皮栎所在群落主要乔木树种种间联结性的研究

应用方差比率法,并通过2×2列联表χ2检验法及利用Jaccard指数测定法研究了秦岭北坡和巴山北坡栓皮栎所在群落主要乔木树种的种间联结性.结果表明: 1 两地栓皮栎所在群落主要乔木种群间在总体上呈显著正关联; 2 2×2列联表的χ2检验共有9 7为秦岭北坡的种对数,下同 个种对为显著正关联,1 25 个种对为显著负关联; 3 Jaccard指数标量出了两地栓皮栎所在群落中种对间的联结程度和相伴随出现的机率,两地栓皮栎所在群落中多数乔木种群间的联结性不显著且联结程度较低; 4 种对间的正关联,主要是由于它们具有相近的生物学特性以及对生境具有相似的生态适应性所致,种对间的负关联主要是由于物种间的空间排斥,适应不同的微环境的结果; 5 两地栓皮栎所在的群落处于演替的不稳定阶段.     

长苞铁杉林乔木层优势种群种间关联及尺度效应研究

通过设定不同尺度的样方面积,根据2×2联列表,运用方差分析、联结系数AC、2统计量度量、 Ochiai指数系列技术,测定天宝岩国家级自然保护区长苞铁杉群落乔木层10个优势种群间的总体联结关系、 种对间联结显著性和关联系数。结果表明:长苞铁杉群落乔木层10个优势种群的总体种间关联性均呈正关 联,反映该群落处于稳定的顶极阶段;10个优势种群的种间联结关系中,有26个种对在不同尺度样方设计中 均未达到一般显著水平,种对间的相互独立性较强;样方设计为100 m2时,各项指标上规律性比较明显,它的 研究结果与实际情况相吻合。群落虽处于比较稳定的顶极阶段,但应适当调整群落结构,为长苞铁杉的生长 更新提供良好的生态环境。     

缙云山风灾迹地恢复群落主要乔木树种种间联结性

应用方差比率法,并通过2×2列联表χ2检验法及利用联结系数AC指数测定法研究了缙云山自然保护区风灾迹地恢复群落自然恢复样地和人工恢复样地中主要乔木树种的种间联结性。结果表明:(1)自然恢复样地主要乔木种群间在总体上呈一定的正关联;而人工恢复样地种群间在总体上呈负关联;(2)2×2列联表的χ2检验共有5个(3)种对为显著正关联(括号内为人工恢复群落的种对数,下同),2个(1)种对为显著负关联;(3)联结系数(AC)指数标量出了自然恢复和人工恢复样地中种对间的联结程度和相伴随出现的机率,两种恢复方式中的多数乔木种群间的联结性不显著且联结程度较低,绝大多数乔木树种之间无显著关联,而且人工恢复比自然恢复无关联性更强;(4)种对间的正关联,主要是由于它们具有相近的生物学特性以及对生境具有相似的生态适应性所致,种对间的负关联主要是由于物种间的空间排斥,适应不同的微环境的结果;(5)人工恢复和自然恢复所在的群落处于演替的不稳定阶段。     

庐山常绿阔叶,落叶阔叶混交林乔木种群种间联结性研究

本文通过２×２联列表以多种指标分别测定了庐山常绿阔叶、落叶阔叶混交林３６个乔木种群在抽样面积分别为１００ｍ２和４００ｍ２时的种间联结性。结果表明：在中亚热带山地森林植被研究中,以Ｘ２检验为基础,结合联结系数ＡＣ和共同出现百分率ＰＣ来测定植物种群的联结性,效果较好。一方面,不同大小的样方能反映物种种间联结性的空间变化;另一方面,抽样面积为１００ｍ２,更能准确全面地表现优势种群种间联结性的特征。种间正联结性越强,其生态位重叠值越大,反之,种间负联结性越强,其生态位重叠值越小。最后,还将这３６个种群按其联结性划分为４个生态种组。     

珍稀植物对开蕨与其伴生物种的联结性及群落稳定性

基于2×2联列表,采用X2和W检验,联结系数(AC)、点相关系数(PPC)、Ochiai指数(OI)、共同出现百分率(PC)的种间联结性分析和M.Godron群落稳定性测定方法,以长白山极其狭小地区分布的国家Ⅱ级保护植物——对开蕨(Phyllitis scolopendrium)为研究对象,分析了其在海拔729、1008m群落内,对开蕨与其伴生种联结性及群落稳定性。调查显示:吉林省临江区域自然分布的对开蕨种群为小片状聚集分布,数量较少,局部大尺度上分布频度极低,为偶见种。与对开蕨伴生的植物共有70种,其中乔木16种,灌木16种,草本植物38种。联结性分析表明:群落总体联结性VR(方差比率)1,检验统计量WX20.05(N),显示群落种群间均表现出正关联,但没有达到显著水平。联结性测度指标显示对开蕨种群与乔木、灌木联结性低于与草本的联结性;其中对开蕨与乔木联结种对均不显著(X23.841);与灌木正联结种对以凤城卫矛(Euonymus maximowiczianus)达到显著正联结(X23.841),其它联结均不显著;对开蕨与草本植物三叉耳蕨(Polystichum tripteron)达到极显著正联结(X26.635),与粗茎鳞毛蕨(Dryopteris crassirhizoma)为显著正联结,与野芝麻(Lamium barbatum)为显著负联结(3.841X26.635),反映出对开蕨与大多数植物种群关联不显著或显著关联的种群极少,种间联结关系较为松散趋向于相互独立,有很大的随机性。群落稳定性测定得出:海拔1008m的01群落和海拔729m的02群落,其总体的累计种类倒数百分数与累积相对频度比值分别为35/65、34/66,均远离20/80;各群落内乔木层、灌木层、草本层的比值也远离稳定点坐标,显示出群落总体均不稳定;两个群落内部各层次的稳定性排序均为草本层灌木层乔木层。结论提示:现存对开蕨群落极不稳定,亟待加强保护。在物种保护和回归实践中可通过保护和选择与之正联结较强的物种来保护和建立对开蕨生存环境以求对开蕨分布群落的稳定,最终达到实效保护目的。     

福建永定桫椤群落内主要灌木种群的种间联结性研究

采用X^2检验、联结系数（AC）和种间共同出现百分率（PC）等指标,分析了福建省永定桫椤群落内主要灌木树种的种间联结性,结果表明：除少数种对外,绝大多数种群间的联结性不显著;在联结性显著的种对中,下述4个种对之间有较高的正联结性;赤楠-杜茎山、蔷薇属一种=细齿叶柃、沿海紫金牛-杜茎山,青冈-冬青,表明这4个种对间的生态习性和对环境的需求较一致。     

江西九连山自然保护区栲属群落优势种群的种间联结关系

采用2×2联列表,通过方差分析、χ2检验、联结系数AC值、JI指数对江西九连山栲属Castanopsis群落样地重要值前20的种群种间联结进行定量分析。结果表明,九连山栲属群落20个优势种群总体种间的正关联性不显著;但20个优势种群的种间联结关系中3对具显著正联结,2对具极显著正联结,1对具显著负联结,3对具极显著负联结。190个种对中,大多数种对联结关系未达显著水平,种对间的独立性相对较强。种群间的正联结性与种群重要值的关系分析表明,重要值高的种群间形成明显正联结性的种对数量最多,重要值高的种群与重要值低的种群之间形成明显正联结性的种对数量次之,重要值低种群间形成明显正联结性的种对数量最少。目前,群落正处于向顶级稳定群落演替的状态。     

鼎湖山森林群落数量分析——Ⅱ.优势种群间的相关性

本文对鼎湖山森林群落的乔木优势种群,应用2×2联表 X~2检验、相关系数t-检验,相关图解分析等方法,进行了种间联结测定和相关分析;并通过方差分析比较不同群落中优势种群间的分布差异。研究表明:种群间的相关性与种群的密度、年龄结构、生活型与生态幅度以及所在植物群落的演替阶段有关。取样面积的大小决定着种群联结的表征。本文应用的研究方法适用于南亚热带常绿阔叶林乔木种群相关性的研究。     

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.     

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.     

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.     

Cause of Senescence of Nine Sorts of Flowers

The levels of endogenous phytohormones and respiratory rate in nine sorts of flowers such as Cymbidium faberi Rolfe, Nopalxochia ackermannii Kunth and others were investigated both at full bloom and senescence and meanwhile the effect of exogenous phytohormones on prolonging the blossoms and promoting ethylene production were tested. There is a high content of endogenous ethylene in all the long-lived flowere, about 3–16 folds higer than the short-lived ones. There is a high level of ABA at full blooming flowers of short-lived flowers, in which there is no or only some cytokinins in it, but the ratio of CTK (6BA+zeatin)/ABA is smaller(l.7). The endogenous ABA reached a much higher level at senescence in all nine sorts of flowers, so it is reasonable to consider that it is ABA which plays an important role of regulation in controlling flower's senescence. There is a much higher level of GA3 and zeatin in the long-lived flowers which is not demonstrated in the shortlived ones. The respiratory rate is one of the factors controtling the longevity of flowers, but it does not play a decided role. Application of 6BA and zeatin prolongs distinctly orchid’s longevity, however exogenous IAA through the promotive action on ethylene production, evidently extends the longevity of the flowers of the Nopalxochia ackermannii Kunth.     

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.     

龙胆科药用植物化学成分的研究现状

龙胆科植物在我国的分布范围很广,且多数为药用植物,其多数种属的药用植物,至今其化学成分尚未被系统研究。综述了目前龙胆科药用植物的化学成分的研究现状及一般提取方法,对近年来发现的环烯醚萜及裂环烯醚萜类化合物进行了总结,为本科药用植物的更深入研究提供了参考。     

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.