斧头湖挺水植被的群落学研究 Ⅲ.菰群落(Com. Zizania Iatifolia)的生物量动态及生产量测定

用收割法对湖北省武昌县斧头湖菰群落地上部分生物量的变化进行了研究,并测定了该群落的生产量。菰群落的抽条密度在3月下旬达到最大值97.8±13.5根/m~2,现存量在9月份达到最大值1520.88±346.32g/m~2。利用生产结构图对菰群落3—6月份的枯死叶量进行了估计,并主要利用Mason等(1975)的方法对菰群落的枯死凋落量进行了估算,由此得到菰群落的生产量为1792.02g/m~2,比最大现存量高出17.8%,P/B=1.24。菰群落的种子生产量很低,约为14.56g/m~2。     

斧头湖挺水植被的群落学研究 Ⅲ.菰群落(Com. Zizania Iatifolia)的生物量动态及生产量测定

用收割法对湖北省武昌县斧头湖菰群落地上部分生物量的变化进行了研究,并测定了该群落的生产量。菰群落的抽条密度在3月下旬达到最大值97.8±13.5根/m²,现存量在9月份达到最大值1520.88±346.32g/m²。利用生产结构图对菰群落3—6月份的枯死叶量进行了估计,并主要利用Mason等(1975)的方法对菰群落的枯死凋落量进行了估算,由此得到菰群落的生产量为1792.02g/m²,比最大现存量高出17.8%,P/B=1.24。菰群落的种子生产量很低,约为14.56g/m²。     

斧头湖挺水植被的群落学研究——Ⅰ.菰群落(Com.Zizania latifolia)的结构

本文从物种结构、水平结构和垂直结构三个方面结合其时间特征对湖北省武昌县斧头湖的菰群落进行了分析。结果表明:①菰群落的区系组成和生长型较为丰富,菰是该群落中唯一的建群种;②菰群落内部表现出不同物种的种群分布在水平方向上的分化。菰群落内部小环境多样,存在着许多小群落。菰的抽条为群聚分布,表现出形态学格局;③菰群落垂直结构简单,多数情况下仅存在一个挺水植被层。群落生产结构的变化与水位及其本身的生长特性有关。菰群落的地下成层现象也是一个值得注意的问题。     

中国蛇菰属（蛇菰科）植物的修订

本文修订了中国蛇菰属植物,新改级红烛蛇菰[Balanophoraharlandii Hook.f.var.mutinoides(Hayata)Xing,stat.nov.];杯茎蛇菰(Balanophora subcupularis Tam)为短穗蛇菰的异名;旋生蛇菰(Bala-nophora harlandii Hook.f.var.spiralis Tam)为鸟(黍离)蛇菰的异名;中国植物志中所载的日本蛇菰Balaophora Japonica Makino)和海南植物志记载的多蕊蛇菰(Balanophora polyandra Griff.)系原作者鉴定错误。     

菰属系统与演化研究——孕花外稃表皮微形态

应用扫描电子显微镜对禾本科菰属及其有关9属14种3变种1变型的孕花外稃顶端及其芒基部的表皮微形态进行观察比较研究。研究结果基本符合E.E.Terrell与W.P.Wergin的研究报道,但我们不仅种类收集齐全而且增加研究了与菰属有关的属种,及菰属下的一些变种及混淆种,更有利于探讨菰属的系统位置及其演化关系。菰属以其稻型的双胞微毛与硅质体应隶属于稻族。又根据它们所具硅质体形状及硅质乳突的数量,除揭示它为单性花一支与稻属、假稻属、水禾属等两性花一支在稻族中存在平行演化现象外,也揭示了在菰属中共有4种、2亚种,其中以菰最为原始。     

中国菰资源研究现状及应用前景

中国菰(Zizania latifolia(Griseb.)Turcz.ex Stapf)是一种多年生禾本科稻亚科稻族菰属挺水植物。研究表明,菰具有现代水稻栽培品种所需要的许多优良性状,在生态治理方面表现出应用潜力;菰米营养价值高于普通稻米,且兼具保健功效。菰的这些特性使其在水稻种质改良、重金属离子污染土壤治理以及功能性食品开发方面表现出诱人的前景。近年来,菰属植物的研究工作取得了一定的进展,主要涉及菰的起源进化、菰的经济价值、菰与生态环境的关系、菰遗传多样性分析、菰组学及育种应用等五方面。因文献报道的时间跨度大,涉及面广,目前未见详尽的有关该物种研究进展的专门论述。本文从上述5个方面进行总结,促进对菰的了解,为这种重要野生资源的研究、保护和开发利用提供借鉴,进而加速该物种的研究进程。     

菰属Zizania L.植物的分支分类研究

本文应用分支分类学中的最大同步法对全世界菰属Zizania L.及其有关属种进行定量分析研究其种系发生后所得出的分支树谱图上明显表示出法洛斯属Pharus Br.不应该与菰属、稻属Oryza L.等同位在稻族Oryzeae内,而应另立法洛斯族Phareae.菰属在稻族中独立出较进化的一支,当今称为菰亚族Zizaniinae.在菰属内全世界有4种.2亚种,其演化关系为菰Z.latifolia是最原始,由它分别向得克萨斯菰Z.texana及水生菰Z.aquatica演化,再由水生菰演化至沼生菰Z.palustris。     

高寒草甸地区小哺乳动物群落与植物群落沉静替关系的研究

本文阐述了小哺乳动物群萍和植物群落的演替关系;验证了动物群落对植物群薄结构的非独立性假设。小哺乳物群落种的多样与植物群薄的盖度和高度呈显著负相关,植物群落的演替引起小哺乳动物群落的相应演替,并通过加速次生植被演替进程的试验,调控了有害小哺乳动物群落,提出从生态演替规律出发,在退化严重的草地上,通过人的合理参与,协调动物群落间的结构关系,以达到人类获取畜牧业最大持续生产量,最终使生物生产量得到永续利     

菰和菖蒲对重金属的胁迫反应及其富集能力

通过盆栽实验研究了Cu—Zn—Ph-Cd复合污染条件下,菰和菖蒲的生长状况、生理特性及吸收和富集重金属的能力。结果表明,高浓度污染下菰和菖蒲不能存活;低、中浓度中菖蒲的生长受到抑制,菰各生长指标与对照相比差异不显著,表明菰对低、中浓度重金属的耐性强于菖蒲。随着污染浓度的增加,菰和菖蒲叶片叶绿索含量显著降低;菰叶绿素a／b值略有降低,菖蒲叶绿素a／b值显著降低;菰和菖蒲叶片脯氨酸含量、相对电导率显著升高,超氧化物歧化酶（SOD）、过氧化物酶（POD）活性在低浓度时升高,中浓度时降低。菰体内重金属含量为Zn〉Cu〉Pb〉Cd,菖蒲体内的含量为Cu〉Zn〉Pb〉Cd,且二者体内的重金属含量都随着污染浓度的增加而升高。菰和菖蒲对Cd的富集系数较大,地上部分（茎与叶）和地下部分（根与根状茎）均大于1;对Pb的富集系数较小,地上部分和地下部分均小于1。菰和菖蒲地下部分重金属含量均高于地上部分含量,二者根系对4种重金属都有较强的滞留效应,平均滞留率均大于50％。各处理中菰对重金属的吸收量均高于菖蒲。综合分析菰和菖蒲的生长、生理及富集重金属的能力,菰比菖蒲更适用于低、中浓度重金属污染水体的生态修复。     

菰（Zizania latifolia）ISSR反应体系的建立及优化

菰是一种稻族野生资源,水生或沼生,在我国有着广泛的分布。野生菰群体不仅是一种重要的育种基因资源,同时还有着巨大的生态作用。为建立适宜于菰的ISSR反应体系,以菰DNA基因组为模板对ISSR反应体系中的主要影响因子进行优化。采用单因素变量法在12个不同梯度水平上设计正交试验针对体系中d NTPs浓度、Mg2+浓度、Taq聚合酶浓度、引物浓度、模板DNA浓度及引物退火温度等6个因子进行优化,确定了在20μL ISSR反应体系中各组分的最适因素水平分别为:3.0 mmol Mg2+(10×Buffer),0.5 mmol d NTPs、1.0μmol引物浓度、0.24 U/μL Taq聚合酶、1.5 ng/μL DNA模板以及55℃退火温度。应用该优化体系对80个菰材料进行扩增,证实了该体系的适用性和稳定性,为菰遗传资源的鉴定、评价与利用提供了技术支撑。     

THE COMPONENTS OF KIN COMPETITION

It is well known that competition among kin alters the rate and often the direction of evolution in subdivided populations. Yet much remains unclear about the ecological and demographic causes of kin competition, or what role life cycle plays in promoting or ameliorating its effects. Using the multilevel Price equation, I derive a general equation for evolution in structured populations under an arbitrary intensity of kin competition. This equation partitions the effects of selection and demography, and recovers numerous previous models as special cases. I quantify the degree of kin competition, α, which explicitly depends on life cycle. I show how life cycle and demographic assumptions can be incorporated into kin selection models via α, revealing life cycles that are more or less permissive of altruism. As an example, I give closed‐form results for Hamilton's rule in a three‐stage life cycle. Although results are sensitive to life cycle in general, I identify three demographic conditions that give life cycle invariant results. Under the infinite island model, α is a function of the scale of density regulation and dispersal rate, effectively disentangling these two phenomena. Population viscosity per se does not impede kin selection.     

药物动力学中矩量计算的方法

本文给出了计算药物动力学的矩的一种方法,并给出了截断误差公式。最后,通过例题,将梯形法、对数梯形法及文[5]的方法以及本文的方法,作了比较,并可看出本文方法算出的结果最为精确。     

南亚热带森林土壤动物群落多样性研究

以鼎湖山为代表,研究南亚热带常绿阔叶林土壤动物群落的多样性。首先比较了几种多样性测度的效果,由于Ｇｏｗｅｒ系数和作者１９９０年提出的ＤＧ指数都是基于各物种在群落中都有同等独立性,宜在不同群落间进行种类比较的假设,因而对于复杂的土壤动物群落多样性测度可以获得比较贴切的结果,但ＤＧ指数可以为多个群落同时比较,计算也简单,其次比较了中亚热带的资料,表明南亚热带土壤动物具有的多样性和更多的热带成分,两地区     

Calculating the intrinsic growth rate: comparison of definition and model

It was shown that well known equation r = ln[N(t2)/N(t1)]/(t2 - t1) is the definition of the average value of intrinsic growth rate of population r within any given interval of time t2-t1 and changing arbitrarity its numbers N(t). The common opinion considering the equation as suitable only for exponentially growing population was found to be incorrect. The fundamentally different approach is based on the calculation of r within the framework of demographic model, realized as Euler - Lotka equation or population projection matrices. However this model requires simultaneous realization of several assumptions improbable for natural populations: exponential change in population size, stable age structure and maintaining constant age-dependent birth and death rates. The calculation of r by definition requires the data on the dynamics of population numbers, whereas calculation on the basis of the model requires the demographic tables of birth and death rate, but not the population numbers. With the example of American ginseng it was shown that evalution of r by definition and model approaches could produce opposite results.     

THE ROLE OF LARGE-SCALE DATA COLLECTION PROJECTS IN THE STUDY OF SOUTHERN AFRICAN BIRDS

Underhill, L.G., Oatley, T.B. & Harrison, J.A. 1991. The role of large-scale data collection projects in the study of southern African birds. Ostrich 62:124-148.

The major ornithological data collections in southern Africa (checklists, migration enquiry, atlas projects, censuses, bird ringing and recoveries, biometric data, nest record cards, moult cards and beached birds) are described. For each project, current volumes of data are tabulated. The Southern African Bird Atlas Project database contained 5,0 million records in December 1990. 1,25 million birds of 810 species had been ringed with South African Bird Ringing Unit rings by June 1989, resulting in 22 000 recoveries. There were more than 100 recoveries for 27 species. The nest record card scheme of the Southern African Ornithological Society had 117 000 cards on file in February 1990, representing 696 species, with more than 1 000 cards for 18 species. There were 4 040 cards of 380 species in the moult record scheme. African Seabird Group beach patrols had found 10 057 seabirds by the end of 1985. A selection of published applications for each data set is given. The potential of the data sets for further analyses is considered, especially in relation to key demographic characteristics such as abundance, productivity and survival. It is recommended that volunteer participation projects should concentrate on monitoring and that indices for change in the demographic characteristics be developed. Most of the projects could be incorporated into an Avian Demography Unit.     

LIFE-HISTORY VARIATION WITHIN A POPULATION OF THE COLONIAL ASCIDIAN BOTRYLLUS SCHLOSSERI. I. THE GENETIC AND ENVIRONMENTAL CONTROL OF SEASONAL VARIATION

Many empirical analyses of life-history tactics are based on the assumption that demographic variation ought to be greatest among populations or species living in different environments. However, in a single population of the sessile colonial sea squirt Botryllus schlosseri, there are two discrete life-history morphs. Semelparous colonies are characterized by a) death immediately following the production of a single clutch, b) early age at first reproduction, c) rapid growth to first reproduction, and d) high reproductive effort. In contrast, iteroparous colonies a) produce at least three clutches before dying, b) postpone sexual reproduction until they are nearly twice the age of semelparous colonies, c) grow at about half the rate of semelparous colonies, and d) invest roughly 75% less in reproductive effort than semelparous colonies. Semelparous colonies numerically dominate the population through midsummer; later in the summer, iteroparous colonies are most numerous. Field and laboratory common-garden experiments, along with breeding studies, indicate that the demographic differences between the morphs are genetically determined. Consequently, the seasonal switch from dominance by semelparous colonies to dominance by iteroparous colonies may be an evolved response to a seasonally changing environment. On theoretical grounds, temporal variation in selection is thought to play a relatively unimportant role in maintaining genetic polymorphism; nonetheless, the seasonally recurrent life-history polymorphism shown in this study indicates that temporal variation in selection can lead to the maintenance of genetic polymorphism for traits strongly affecting fitness.     

DEMOGRAPHIC MECHANISMS DETERMINING THE DYNAMICS OF THE RELATIVE ABUNDANCE OF PHASES IN BIPHASIC LIFE CYCLES1

Studies investigating the demographic traits that drive the patterns of phase dominance (the ploidy ratio) in isomorphic biphasic life cycles have not found an integrative solution. Either fertility or survival has been suggested independently as the main driver. Here, we provide a global theoretical framework on how demographic mechanisms determine the ploidy ratio, unifying previous numerical and observational attempts at this question. The analytical solutions of both the ploidy ratio and its elasticities to model parameters of a stage/size‐structured model patterned after the life cycle of a marine alga were derived and analyzed. A complex interaction among vital rates determines the patterns of phase dominance of biphasic life cycles. Three co‐occurring processes—growth, fertility, and looping—may dominate the dynamics of the population, determining both its growth rate and ploidy ratio. Our analyses show that in species where fertility is low, the ploidy ratio is highly elastic to looping transitions (survival, breakage, and clonal growth). Consequently, the subtle morphological, ecophysiological, and biochemistry phase differences that have been reported in isomorphic life cycles as not explaining the observed ploidy ratios, may, in fact, explain them if they translate into slight phase differences in looping transitions. In species where fertility is low, the looping dissimilarities between phases cannot be too high favoring simultaneously one phase, as the population structure would be completely dominated by that phase. In the case of ecological similarity between phases (equal looping and growth rates between phases), a ploidy ratio different from one can only be set by strong phase differences in fertility.     

THE RATE OF SENESCENCE OF THE DOMESTIC FOWL AS MEASURED BY THE DECLINE IN EGG PRODUCTION WITH AGE

Data are presented showing that the course of decline of egg production with age in the domestic fowl from the time laying begins up to and including 8 years follows an exponential law, that is, each year''s egg production is a constant percentage of the preceding year''s production (88 per cent in the group of fowl studied). Since the exponential law is the same as the law of monomolecular change in chemistry, and since the course of egg production with age may be taken as an index of the course of senescence of organs, or tissues limiting egg production, it is suggested that this exponential law of egg production substantiates the idea that senescence is a physicochemical process the course of which is limited by a chemical reaction. It is shown that the exhaustion of the oocytes is not likely to be the factor limiting the course of egg production.     

TRACING BACK THE ORIGIN OF THE INDO-PACIFIC MOLLUSC FAUNA: BASAL TRIDACNINAE FROM THE OLIGOCENE AND MIOCENE OF THE SULTANATE OF OMAN

Abstract:  Two new tridacnine species are described from the Chattian and Aquitanian of the Arabian Peninsula. For these, the new names Omanidacna eos gen. et sp. nov. and Tridacna evae sp. nov. are erected. Omanidacna is interpreted as an Oligocene ancestor of Hippopus , being the oldest record of this tridacnine lineage. The Aquitanian Tridacna evae is the first occurrence of the genus Tridacna . These Arabian taxa imply that the modern tridacnine lineages are rooted in the Palaeogene and early Neogene of the East African-Arabian Province, although their Eocene ancestors, such as Byssocardium , are Western Tethyan taxa. During the Neogene they successfully settled the Indo-Polynesian Province and became typical elements of the entire Indo-West Pacific Region. The tridacnines are thus an example of a successive transformation and gradual eastward dispersal of an originally Tethyan element contributing to late Neogene diversity in the Indo-West Pacific.