尖峰岭热带山地雨林生态系统碳平衡的初步研究

报道了我国海南岛目前保存面积较大,林分的组成和结构复杂的热带山地雨林生态系统的Ｃ素库和群落的ＣＯ２排放动态,通过在尖峰岭林区进行为期３ａ的研究,结果表明,热带山地雨林的碳素库主要有３个方面,即森林生物量中的Ｃ为２３４．３０５６ｔ／ｈｍ＾２,森林凋落的现存是中的Ｃ为２．９８ｔ／ｈｍ＾２以及土壤层中的Ｃ为１０４．６９６ｔ／ｈｍ＾２,合计为３４１．９８１６ｔ／ｈｍ＾２,森林生态系统中的ＣＯ２平衡的基本动     

尖峰岭热带山地雨林生态系统 碳平衡的初步研究

报道了我国海南岛目前保存面积较大、林分的组成和结构复杂的热带山地雨林生态系统的Ｃ素库和群落的ＣＯ２排放动态。通过在尖峰岭林区进行为期３ａ的研究,结果表明：热带山地雨林的碳素库主要有３个方面,即森林生物量中的Ｃ为２３４．３０５６ｔ／ｈｍ２,森林凋落物现存量中的Ｃ为２．９８ｔ／ｈｍ２以及土壤层中的Ｃ为１０４．６９６ｔ／ｈｍ２,合计为３４１．９８１６ｔ／ｈｍ２。森林生态系统中的ＣＯ２平衡的基本动态为：每年用于群落总第一性生产力所同化的ＣＯ２总量为７４．２８ｔ／ｈｍ２,其中４２．６９ｔ／ｈｍ２的ＣＯ２又通过群落呼吸作用而释放出来,用于净第一性生产力为３１．５９ｔ／ｈｍ２;另一方面,凋落物层每年通过呼吸而释放的ＣＯ２量为３．２７ｔ／ｈｍ２,土壤的释放（不包括根系的呼吸）量约为２６．９６ｔ／ｈｍ２。收支相抵,热带山地雨林生态系统每年对大气中的ＣＯ２的固定量为１．３６６ｔ／ｈｍ２,折合Ｃ为０．３７２５ｔ／ｈｍ２。由此可见,恢复、发展和保护热带林生态系统是解决大气中ＣＯ２浓度升高、温室效应等全球性的生态问题的重要途径之一。     

中国热带天然林变迁对大气CO2的影响及经济损益评估

我国目前保存较好的热带天然林（包括热带原始林、结构良好的天然更新林,而不包括疏林、残次林、灌木林等）面积约１１８７万ｈｍ２,其中云南南部约有６０万ｈｍ２,海南中南部山区约有５８７万ｈｍ２。在过去的４５年中,我国的热带原始林面积减少了５０％（约１１０ｈｍ２）。在海南岛尖峰岭的实例结果表明,热带原始林的生态系统的Ｃ素库为３４２ｔ／ｈｍ２（其中,森林群落Ｃ素库为２３４ｔ／ｈｍ２,土壤为１０５ｔ／ｈｍ２,凋落物层为３ｔ／ｈｍ２）,系统每年净固定ＣＯ２量为１３３６ｔ／ｈｍ２,折合Ｃ量为０３７３ｔ／ｈｍ２;热带天然更新林生态系统每年净固定ＣＯ２量为７２１３ｔ／ｈｍ２,折合成Ｃ量为１９７ｔ／ｈｍ２。在我国现有的热带天然林生态系统中,森林植被层的Ｃ素库为１４４８亿ｔ,土壤中的Ｃ素库为１４２２亿ｔ,与植被层Ｃ库相当。在减少的热带森林中,Ｃ素库减少了约２２３１亿ｔ、ＣＯ２净同化量减少了０１８３亿ｔ,其经济损益高达２２００亿元。最后从森林与ＣＯ２的关系方面探讨了热带林可持续经营的问题。     

热带山地雨林生态系统的水分生态效应——冠层淋溶、水化学贮滤

以小集水区定位测定方法,系统地测定了海南尖峰岭热带山地雨林更新林系统水文分量及水化学组成,分析比较了热带林生态系统降水化学含量及冠层的淋溶效应;其本实验区年降水量在１８２２．２ｍｍ～３２２５．８ｍｍ林冠层年均截留率为１４．３％,年径流系数在０．３３～０．７１之间,降水养分元素输入总量均值为８５．８１ｋｇ／ｈｍ＾２,ａ．林层的淋溶效应使养分元素增加５７．０４ｋｇ／ｈｍ＾２,ａ。５～１０月是降水,不化     

热带山地雨林生态系统的水分生态效应

基于对尖峰岭热带山地雨林集水流域的定位研究,分析了３年间该群落冠层对大雨、暴雨及大暴雨势能的消减、缓冲耗能效应以及年暴雨携带养颁系统中贮存效应,其冠层消减大雨、暴雨及大暴雨势能占总消减能在６１．８－７１．８％之间,其中大暴雨势能量占年总消减势能的４３．９％;大雨、暴雨及大暴雨雨水的年均养分一为５５．１２２ｋｇ／ｋｍ＾２,其产流流失为４２．９１７ｋｇ／ｈｍ＾２,年均净积累１２．２０５ｋｇ／ｈｍ＾２,     

鼎湖山锥栗+黄果厚壳桂+荷木群落生物量及其特征

通过永久性地调查编目和生物量预测模型估算了鼎湖山季风常阔叶林锥栗＋黄果厚壳桂＋荷木群落植物现存量。结果表明：（１）群落植被生物总量为２９５．６４０ｔ／ｈｍ＾２,其中乔木层为２８６．０６１ｔ／ｈｍ＾２,灌木层８．９００ｔ／ｈｍ＾２,草本层０．３３０ｔ／ｈｍ＾２,层间植物０．３４９ｔ／ｈｍ＾２,分别占植被总生物量的９６．７６％、３．０１％、０．１１％和０．１２％。（２）乔木层生物总量中、树干、枝、叶和     

西双版纳季节雨林与橡胶多层林凋落物动态的比较研究

本语文对西双版纳季节雨林及橡胶多层林的凋落物量动态、各组分的季节变化规律、林地残留物现存量及其分解进行了研究,分析比较了两个种群落的凋落节律,结果显示,“双凋落峰”及“叶分解速率较枝分解更快”为两类群落的共有特征;森林凋落物量及凋落物分解速率则因群落类型而异,橡胶多层林年凋落物总量为９．８５±０．７８ｔ·ｈｍ＾－２·ａ＾－１,大于季节雨林的年凋落物总量８．４２±０．１６ｔ·ｈｍ＾－２·ａ＾－１。     

热带山地雨林生态系统的水分生态效应——冠层对暴雨势能的消减、暴雨养分贮存

基于对尖峰岭热带山地雨林集水流域的定位研究,分析了３年间该群落冠层对大雨、暴雨及大暴雨势能的消减、缓冲耗能效应以及年暴雨携带养分在系统中贮存效应,其冠层消减大雨、暴雨及大暴雨势能占年总消减势能在６１．８％～７１．８％之间,其中消减（≥２００ｍｍ）大暴雨势能量占年总消减势能的４３．９％;大雨、暴雨及大暴雨雨水的年均养分含量为５５．１２２ｋｇ／ｈｍ２,其产流流失为４２．９１７ｋｇ／ｈｍ２,年均净积累为１２．２０５ｋｇ／ｈｍ２,除取Ｓｉ外,年净积累量达３２．６７４ｋｇ／ｈｍ２,充分体现出热带山地雨林生态系统具有的环境生态效应。     

海南岛尖峰岭热带山地雨林的群落结构特征

本文讨论了海南岛尖峰岭热带山地雨林乔木层的群落结构的一些基本特征,结果表明：热带山地雨林种类成份复杂,生物多样性指标高,原始林的Shannon－Wiener多样性指数（乔木层）为5．8—6．3,而更新林则在4．5—4．8之间,均匀度指标均在81％以上,反映了优势种群不明显的特点。群落组成种类以热带成份占优势,达80％以上。乔木层的胸径和树高分布均合理;群落组成种群的频度分布不同于RaunKiaer提出的频度定律,而是以A＞＞B＞C＞DE→0（原始林）和A＞＞B＞C＞D→0＜E（天然更新林）的形式存在,并且以A级频度占绝对优势,反映了热带林在世界植被中的特殊性。     

宝天曼自然保护区栓皮栎林生物量和净生产力研究

对河南内乡宝天曼自然保护区４５年生天然次生栓皮栎林的生物量和净生产力的研究表明,栓皮栎林生物量为１６７．６４１７ｔ·ｈｍ－２,其中乔木层为１５８．８３８２ｔ·ｈｍ－２,占总量的９４．７５％;该林净生产力为８．４８８０ｔ·ｈｍ－２·ａ－１,其中乔木层为７．９２５４ｔ·ｈｍ－２·ａ－１,生物量平均相对生长速率为０．０４１．灌木层的生物量和净生产力分别为０．０６９４和０．０４５６ｔ·ｈｍ－２·ａ－１;而草本层的分别为０．１０４１和０．０９０８ｔ·ｈｍ－２·ａ－１．凋落物现存量为８．６３ｔ·ｈｍ－２,凋落物量为５．０３９５ｔ·ｈｍ－２·ａ－１,分别占总量的５．１５％及５９．３７％．净生产量与叶面积指数、叶量成正比关系,而与叶效率呈负相关关系．     

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.     

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.     

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。     

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.     

The effects of glutamine of the maintenance of embryogenic cultures of Cryptomeria japonica

Summary Embryogenic tissues of sugi (Cryptomeria japonica) were induced on a modified Campbell and Durzan (CD) medium containing 1 μM 2,4-dichlorophenoxyacetic acid (2,4-D) and 600 mg l⁻¹ glutamine, and subcultured in the medium of the same composition for over 1 yr. This resulted in a mixed culture of embryogenic and non-embryogenic cells. When embryogenic cells were isolated and cultured independently, their capacity to form embryogenic aggregates was lost. Thus, the non-embryogenic cells present within a mixed culture system were essential to the formation of embryogenic aggregates. When embryogenic tissues were isolated and cultured independently on a high glutamine-containing (2400 mg l⁻¹) medium, dry weights and endogenous levels of glutamine increased, and the tissue could generate a large number of embryogenic aggregates. Amino acid analysis of embryogenic and non-embryogenic cells from the maintenance culture indicated a higher level of glutamine was present in the latter. The high endogenous level of glutamine in the non-embryogenic portion of mixed cell masses may be the supplier of glutamine for maintaining the embryogenic property of the tissues.     

Specificity of action of piperidylcholine derivatives as substrates of cholinesterases of various origin

The review deals with study of enzymologic properties of a novel highly specific acetylcholinesterase substrate, N-(β-acetoxyethyl) piperidinium iodomethylate (“piperidylcholine”), and its 30 derivatives that were tested as effectors of cholinesterases of mammals and various species of Pacific squids. It was proven for the first time that responsible for specificity of action was structure of cyclic ammonium grouping of the alcohol part of molecule of the ester substrate. Analysis of specificity is performed based on enzymatic hydrolysis parameters—activity of catalytic center of cholinesterases and bimolecular constant of the reaction rate that are determined at optimal and low substrate concentrations. Among the specially synthesized group of thioester compounds there is revealed one more highly specific acetylcholinesterase substrate—N-(β-acetoxyethyl) piperidinium.     

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.