灵空山辽东栎种群年龄结构与动态

利用生存分析理论,分析了山西灵空山自然保护区辽东栎种群的年龄结构,以及树高与胸径的关系,绘制了静态生命表和存活曲线.结果表明： 辽东栎种群年龄结构金字塔呈两头小中间大的纺锤型,处于稳定状态.辽东栎种群的树高和胸径的相关关系可用一元线性方程拟合.辽东栎种群的最高生命期望值出现在死亡率最高的龄级之后,且极大值与死亡密度最小值相对应,说明在经过自然筛选和种内竞争后,存活下来的幼苗幼树具有较强的生命期望寿命.辽东栎种群的存活曲线呈Deevey-Ⅱ型,为稳定种群.辽东栎种群动态表现为前期衰退、中期增长、后期稳定.
     

黄土高原丘陵沟壑区30年柠条人工种群动态研究

通过样地调查,对黄土高原丘陵沟壑区阳坡、半阳坡、阴坡和半阴坡4个生境条件下种植30年后的柠条人工种群动态进行系统研究,分析了种群的年龄结构,编制了标准生命表及不同坡向静态生命表,绘制了存活曲线.结果表明,黄土高原丘陵沟壑区不同生境条件下的柠条人工种群年龄结构呈进展型,幼龄级个体数量多,中老龄级个体数量少;不同坡向由于环境异质性,柠条种群密度表现不同,其中以半阳坡种群密度最大,存活曲线均接近于DeeveyⅡ型;影响柠条群落恢复和种群生长的环境因素主要是水分因子和光照因子.黄土高原丘陵沟壑区,种植30年后的柠条种群生长状况良好,并具有一定的扩展潜力,说明只要对现存的人工林实行严格的保护和科学的抚育,就能够实现柠条种群自然更新和生长的目标.     

新疆野核桃自然保护区不同坡向野核桃种群生命表与波动周期

为了掌握新疆野核桃种群的波动周期、预测未来种群结构变化,在新疆野核桃自然保护区的阳坡和阴坡分别设置样地大样本调查,以径级结构代表年龄结构编制野核桃种群静态生命表,绘制其期望寿命图、年龄结构图、存活曲线和死亡率曲线,同时应用谱分析方法比较分析不同坡向生境野核桃种群的波动周期。结果表明:(1)野核桃种群不同坡向同一龄级和同一坡向不同龄级的期望寿命均存在波动,期望寿命在10龄级前为阳坡高于阴坡,10龄级后为阳坡低于阴坡。(2)阳坡和阴坡野核桃种群均为增长型年龄结构。(3)不同坡向生境野核桃种群的存活曲线均趋于Deevey-Ⅱ型,但阳坡种群各龄级的存活率均高于阴坡。(4)1龄级植株以高死亡率为代价发育为幼树;阳坡种群在其生活史中经历2个死亡高峰,最高峰在16龄级,阴坡种群经历4个死亡高峰,最高峰在9龄级。(5)谱分析表明,新疆野核桃种群的数量动态除受基波影响外,并表现明显的小周期波动,具有大周期内有小周期的多谐波迭加特征,且在11龄级的小周期波动与野核桃高生长特性有关,在17龄级的小周期波动可能与野核桃的生理特性有关。     

子午岭地区辽东栎和油松林建群种的更新生态位宽度分析

通过实地调查并采用Levins生态位宽度指数对子午岭地区主要树种辽东栎(Quercus liaotungensis)和油松(Pinus tabulaeformis)的幼苗、幼树和成树在不同坡向的辽东栎林、油松 辽东栎混交林和人工油松林3种群落中的生态位宽度进行了分析研究。结果显示:(1)辽东栎和油松的更新生态位宽度在不同群落中各不相同,成树的生态位宽度与群落类型一致;(2)辽东栎幼苗和幼树在阳坡和阴坡人工油松林中的生态位宽度分别是0.951、0.95和0.98、0.94,且生态位宽度显著大于其它2个群落,表明辽东栎幼苗和幼树能很好地适应人工油松林的环境条件;(3)在阳坡,油松幼苗的生态位宽度在辽东栎林最大为0.79,且极显著大于其它2个群落,而阳坡油松幼树的生态位宽度在人工油松林中最大为1.00;在阴坡,油松幼苗的生态位宽度在人工油松林最大为0.63,而阴坡油松幼树的生态位宽度却在油松 辽东栎混交林最大为0.83,且极显著大于其它2个群落;表明油松幼苗适应阳坡的辽东栎林环境和阴坡的人工油松林环境,油松幼树适应阳坡的人工油松林环境和油松 辽东栎林环境。结果表明,人工种植油松林有利于该地区的植被恢复,人工油松林和油松 辽东栎混交林会在该地区存在较长时间,而阳坡的油松 辽东栎混交林存在时间会更长。     

北京东灵山地区辽东栎(Quercus liaotungensis)种群生活史特征与空间分布

种群生活史特征和空间分布格局对于分析种群演替动态规律、判定种群分布规律和预测种群演化过程及变化趋势均具有重要的理论和现实意义.本文从静态生命表、年龄结构、存活曲线三个方面分析了东灵山地区辽东栎种群的生活史特征.结果表明:物种生物学因素是影响辽东栎种群生存力最主要因素,辽东栎种群静态生命表中生命期望值逐渐降低反映出种群生存力下降的趋势.空间分布格局分析表明辽东栎种群各个径级的个体都属于聚集分布.辽东栎实生苗和萌生苗共存是辽东栎种群适应环境压力和与环境协同进化的结果,表明自然状态下辽东栎种群具有较高的稳定性.由于辽东栎种群的这种较强的稳定性和适应能力,随着辽东栎种群发育整个群落将趋于进展演替,最终形成稳定和充分利用环境资源的顶极群落结构.     

）种群生活史特征与空间分布

种群生活史特征和空间分布格局对于分析种群演替动态规律、判定种群分布规律和预测种群演化过程及变化趋势均具有重要的理论和现实意义。本文从静态生命表、年龄结构、存活曲线三个方面分析了东灵山地区辽东栎种群的生活史特征。结果表明：物种生物学因素是影响辽东栎种群生存力最主要因素,辽东栎种群静态生命表中生命期望值逐渐降低反映出种群生存力下降的趋势。空间分布格局分析表明辽东栎种群各个径级的个体都属于聚集分布。辽东栎实生苗和萌生苗共存是辽东栎种群适应环境压力和与环境协同进化的结果,表明自然状态下辽东栎种群具有较高的稳定性。由于辽东栎种群的这种较强的稳定性和适应能力,随着辽东栎种群发育整个群落将趋于进展演替,最终形成稳定和充分利用环境资源的顶极群落结构。     

黄土高原丘陵沟壑区封禁30年前后狼牙刺种群动态研究

以荒草坡为对照,对黄土高原丘陵沟壑区阳坡、半阳坡和半阴坡3个生境条件下经30年封禁后的狼牙刺种群动态进行系统研究,分析了种群的年龄结构、分布格局,编制了静态生命表,绘制了存活曲线. 结果表明,黄土高原丘陵沟壑区不同生境自然恢复的狼牙刺种群年龄结构均属于进展型,幼龄个体多,老龄个体少,其中以半阳坡种群密度最大,不同坡向狼牙刺种群的存活曲线均接近于DeeveyⅡ型.种群分布格局总体上呈聚集型,随年龄增加聚集强度增加.影响狼牙刺群落恢复和种群生长的环境因素主要是水分因子和光照因子.狼牙刺种群恢复状况良好,说明封禁措施是有效的.     

新疆西天山峡谷不同坡向野核桃幼苗种群动态及生长分析

在非破坏性判定幼苗年龄及大样方逐苗调查的基础上,编制了新疆西天山峡谷不同坡向野核桃幼苗种群静态生命表,分析了幼苗株高的数量特征和生长规律。结果表明:不同坡向野核桃幼苗的期望寿命均以1龄最大,阳坡为2.018,阴坡为1.766,1~6龄普遍为阳坡大于阴坡。不同坡向幼苗种群均以1龄个体数量所占比率最大,阳坡为39.7%,阴坡为44.2%;3龄幼苗死亡率均最高,阳坡为82.0%,阴坡为78.3%;均为增长型年龄结构;存活曲线均趋于Deevey-Ⅱ型。1龄幼苗在阳坡和阴坡分别仅有3.3%和1.1%可以存活到7龄。不同坡向幼苗株高随着年龄的增加均为指数函数异速生长,其模型的生长速度(b值)也大体相同。     

不同生境条件下四合木（Tetraena mongolicaMaxim.）种群结构特征

对天然分布区及不同生境内四合木种群的径级结构、年龄结构、冠幅结构、高度结构及空间结构特征进行了比较分析,运用静态生命表描述了四合木种群年龄结构动态变化规律,应用Clark-Evans的 R值法计算出四合木个体空间分布格局指标.结果表明:四合木种群径级、龄级与高度级结构均基本呈正态分布,冠幅级结构呈现出近乎指数型的衰减趋势;但不同生境的四合木种群因所处微环境各异,在径级、龄级、高度级、冠幅级结构上表现出一定差异.四合木种群的存活率随龄级的增大而降低,死亡率和消失率随龄级的增大而升高,其存活曲线接近于DeeveyⅠ型,表明该种群为下降种群.不同生境的四合木种群个体分布均不均匀,其空间分布为随机型.     

甘肃小陇山锐齿栎种群结构分析

利用种群统计中的年龄结构,静态生命表和波谱分析的方法,对甘肃小陇山沙坝林业实验基地和麦草沟自然保护区中的锐齿栎种群结构动态进行分析,结果表明该种群年龄结构为衰退型。而静态生命表分析显示锐齿栎种群的存活曲线为DeeveyⅡ型,死亡率曲线有两个高峰;谱分析结果表明在锐齿栎种群自然更新的过程表现出明显的周期性。     

Systematic significance of mature embryo of bamboos

The mature embryo of seven species belonging to five genera of Indian bamboos is described. In all these the basic pattern of embryo organisation is same: the scutellar and coleoptilar bundles are not separated by an internode, the epiblast is absent, the lower portion of the scutellum and the coleorhiza are separated by a cleft and the margins of embryonic leaves overlap. The features unique to fleshy fruited bamboos are: presence of a massive scutellum, the juxtaposition of plumule and radicle and the occurrence of a bud in the axil of the coleoptile. The fleshy fruit bearing bamboos should be classified into one group, the tribeMelocanneae. Evidence is provided to recognise additional groups in the subfamilyBambusoideae.     

Taxonomic status of the species of the green algal genusNeochloris

Komárek has recently reviewed the various species assigned to the green algal genusNeochloris Starr (Chlorococcales, Chlorococcaceae) and removed those with uninucleate vegetative cells to a new genus,Ettlia. Watanabe & Floyd, unaware ofKomárek's work, also reviewed the species ofNeochloris and distributed them among three genera—Neochloris, Chlorococcopsis gen. nov., andParietochloris gen. nov.—on the basis of details of the covering of the zoospore and the arrangement of the basal bodies of the flagellar apparatus. This paper reconciles these two treatments and makes additional recommendations at the ranks of genus, family, order, and class.     

Phylogeny of cardinalfishes (Teleostei: Gobiiformes: Apogonidae) and the evolution of visceral bioluminescence

The cardinalfishes (Apogonidae) are a diverse clade of small, mostly reef-dwelling fishes, for which a variety of morphological data have not yielded a consistent phylogeny. We use DNA sequence to hypothesize phylogenetic relationships within Apogonidae and among apogonids and other acanthomorph families, to examine patterns of evolution including the distribution of a visceral bioluminescence system. In conformance with previous studies, Apogonidae is placed in a clade with Pempheridae, Kurtidae, Leiognathidae, and Gobioidei. The apogonid genus Pseudamia is recovered outside the remainder of the family, not as sister to the superficially similar genus Gymnapogon. Species sampled from the Caribbean and Western Atlantic (Phaeoptyx, Astrapogon, and some Apogon species) form a clade, as do the larger-bodied Glossamia and Cheilodipterus. Incidence of visceral bioluminescence is found scattered throughout the phylogeny, independently for each group in which it is present. Examination of the fine structure of the visceral bioluminescence system through histology shows that light organs exhibit a range of morphologies, with some composed of complex masses of tubules (Siphamia, Pempheris, Parapriacanthus) and others lacking tubules but containing chambers formed by folds of the visceral epithelium (Acropoma, Archamia, Jaydia, and Rhabdamia). Light organs in Siphamia, Acropoma, Pempheris and Parapriacanthus are distinct from but connected to the gut; those in Archamia, Jaydia, and Rhabdamia are simply portions of the intestinal tract, and are little differentiated from the surrounding tissues. The presence or absence of symbiotic luminescent bacteria does not correlate with light organ structure; the tubular light organs of Siphamia and chambered tubes of Acropoma house bacteria, those in Pempheridae and the other Apogonidae do not.     

Apoptotic Regulation of Caspase Activity

Intracellular cysteine aspartate-specific proteases (caspases) play both signaling and effector roles in realizing the program of cell death. Caspases function as proteolytic cascades unique for each cell type and signal triggering apoptosis. All parts of the proteolytic cascades are duplicated and controlled by feedback signals. Amplification cycles between pairs of caspases (the third and the sixth, the ninth and the third, the twelfth and the sixth, and others) help multiply the initial apoptotic signal. The presence of physiological inhibitors of apoptosis that directly interact with caspases creates a multilevel regulatory network of apoptosis in cell. The caspase proteolytic cascades are also regulated by sphingolipid secondary messengers, among them ceramide, sphingosine, and their phosphates. Moreover, an association of the caspase signaling with ubiquitin-dependent proteolysis is shown in cells. In particular, the use of extracellular activators and inhibitors of caspases allows irreversible activation of apoptosis in tumor cells or the prevention of apoptosis in cortical neurons under neurodegenerative diseases.     

Analysis of twin of eyeless regulation during early embryogenesis in Drosophila melanogaster

The Drosophila Pax6 homolog twin of eyeless (toy) is so far the first zygotically expressed gene involved in eye morphogenesis in Drosophila. The study of its expression during embryogenesis is therefore informative of the initial events of eye development in Drosophila. We have analyzed how the initial expression domain of toy at cellular blastoderm is regulated. We show that the three maternal patterning systems active in the cephalic region (the anterior, terminal and dorsal-ventral systems) cooperate with zygotically activated gap genes to shape the initial expression domain of toy. Whereas Bicoid, Dorsal and Torso signaling synergistically act as activators, Hunchback, Knirps and Decapentaplegic act as repressors.     

New species of Peruvian Orchidaceae III

Sixteen new species are proposed in the generaAckermania, Dressleria, Epidendrum, Maxillaria, Oncidium, Rodriguezia, Sigmatostalix, andTrigonidium. All new species are illustrated.Maxillaria vittariifolia L. O. Williams is newly recorded for Peru. A key is provided forTrigonidium of Peru.Trigonidium loretoense Schltr. andT. peruvianum Schltr. are lectotypified.     

Host plants of someRhinanthoideae (Scrophulariaceae) of eastern North America

Twenty three species in 11 genera were examined in the field to determine hosts. OnlyStriga asiatica andSeymeria cassioides have a narrow host range being restricted to grasses and pines, respectively. These are the only species which cause pronounced and sometimes serious host damage. The other species attach to a great diversity of hosts.     

广西青藓科分类学修订

通过对采自广西24个县(市)的1 147份青藓科植物标本的逐一鉴定及相关文献的查阅,确认有广西青藓科植物11属、44种,其中包括广西青藓科植物新记录属1属,即拟异叶藓属(Pseudokindbergia),新记录种7种,分别为匐枝青藓(Brachythecium procumbens)、阔叶尖喙藓(Oxyrrhynchium latifolium)、泛生尖喙藓(O. vagans)、拟异叶藓(Pseudokindbergia dumosa)、华东细喙藓(Rhynchostegiella sinensis)、长肋拟青藓(Sciurohypnum populeum)和弯叶拟青藓(S. reflexum)。该文提供了修订后的广西青藓科植物名录,并对其中的新记录属、种的主要形态学识别特征、生境和地理分布等进行了详细描述。     

Evaluation of antiprotozoal and antimycobacterial activities of the resin glycosides and the other metabolites of Scrophularia cryptophila

Resin glycosides are secondary metabolites exclusive to the convolvulaceous plants. In this study, crypthophilic acids A–C (1–3), the first resin glycosides occurring in another family (Scrophulariaceae), and the other constituents of Scrophularia cryptophila were examined for in vitro antiprotozoal and antimycobacterial potentials. Except for crypthophilic acid B (2), all tested compounds exhibited growth-inhibitory effect against Trypanosoma brucei rhodesiense, with l-tryptophan (6) and buddlejasaponin III (7) being the most potent ones (IC₅₀'s 4.1 and 9.7 μg/ml). In contrast, the activity towards Trypanosoma cruzi was poor, and only crypthophilic acid C (3), 6 and 7 were trypanocidal at concentrations above 40 μg/ml. With the exception of 2 and 6, all compounds were active against Leishmania donovani. Harpagide (4) and 3 emerged as the best leishmanicidal agents (IC₅₀'s 2.0 and 5.8 μg/ml). Only compounds 3, 6 and 7 showed antimalarial activity against Plasmodium falciparum with IC₅₀ values of 4.2, 16.6 and 22.4 μg/ml. Overall the best and broadest spectrum activity was presented by compounds 3 and 7, as they inhibited all four parasitic protozoa. None of the isolates had significant activity against Mycobacterium tuberculosis (MICs >100 μg/ml) or were toxic towards mammalian (L6) cells. This is the first report of antiprotozoal activity for natural resin glycosides, as well as for harpagide (4), acetylharpagide (5), tryptophan (6) and buddlejasaponin III (7).     

Five additional genera of conidial lichen-forming fungi from Europe

Three remarkable new genera of conidial lichen-forming fungi, with pycnidial or acervular conidiomata are described and illustrated.Hastifera tenuispora gen. et spec. nov. from the South-Tyrol, Italy, is characterized by very long and narrow hyaline conidia produced in pycnidial conidiomata immersed in thalline warts.Lichingoldia gyalectiformis gen. et spec. nov. from rocks subject to inundation by freshwater in Norway has long sigmoidly curved conidia which appear to be adapted to dispersal in water.Woessia fusarioides gen. et spec. nov. from aQuercus stump in the Burgenland, Austria, has a finely granular thallus and disc-like conidiomata producing falcate conidia; this species is also of interest in that it hasChlorella as the photobiont. The recently described hyphomyceteCheiromycina flabelliformis B. Sutton is reported from Austria for the first time, and is also lichenized. Recent collections ofNigropuncta rugulosa D. Hawksw. from Austria and Italy also show that this species is lichenized rather than parasymbiotic. In all five cases the fungal hyphae of the conidiogenous structures are continuous with those in intimate contact with cells of the algal partners and the biological relationship appears to be mutualistic giving rise to stable crustose lichen thalli.