THE DIATOMS OF TIMPANOGOS CAVE NATIONAL MONUMENT,UTAH

The diatom flora of the cavern system of Timpanogos Cave National Monument was investigated. Diatoms were found throughout the cave system and were distributed according to moisture and natural openings. Twenty-six species were identified and described, including eight not previously collected from caves and four new records for the state of Utah.     

MICROENVIRONMENTS AND MICROSCALE PRODUCTIVITY OF CYANOBACTERIAL DESERT CRUSTS1

We used microsensors to characterize physicochemical microenvironments and photosynthesis occurring immediately after water saturation in two desert soil crusts from southeastern Utah, which were formed by the cyanobacteria Microcoleus vaginatus Gomont, Nostoc spp., and Scytonema sp. The light fields within the crusts presented steep vertical gradients in magnitude and spectral composition. Near-surface light-trapping zones were formed due to the scattering nature of the sand particles, but strong light attenuation resulted in euphotic zones only ca. 1 mm deep, which were progressively enriched in longer wavelengths with depth. Rates of gross photosynthesis (3.4–9.4 mmol O₂·m^?2·h^?1) and dark respiration (0.81–3.1 mmol O^?2·m^?2·h^?1) occurring within 1 to several mm from the surface were high enough to drive the formation of marked oxygen microenvironments that ranged from oxygen supersaturation to anoxia. The photosynthetic activity also resulted in localized pH values in excess of 10, 2–3 units above the soil pH. Differences in metabolic parameters and community structure between two types of crusts were consistent with a successional pattern, which could be partially explained on the basis of the microenvironments. We discuss the significance of high metabolic rates and the formation of microenvironments for the ecology of desert crusts, as well as the advantages and limitations of microsensor-based methods for crust investigation.     

宝天曼自然保护区植物区系初步研究

宝天曼自然保护区,位于伏牛山南麓,地处北亚热带向南暖温带过渡区域,植物种类丰富,有高等植物2771种,隶属223科, 1002属。其区系地理成分复杂,有15个分布区类型和17个分布区亚型。通过科属分析,本区植物区系具有以温带成分为主,呈现多方交汇和一定古老性的特点。     

安徽大别山马鬃岭自然保护区木本植物区系的研究

马鬃岭自然保护区是大别山木本植物区系最丰富的地区之一,共有木本植物７７科,１９４属,５２４种,我们对该区木本植物的科,属,种进行了详细的统计分析,认为该区木本植物区系中古老孑遗植物和稀濒危植物较多,温带和亚热带成分占优势,与世界各地有广泛的联系,是华东,华中、华北等植物的交汇地及我国南北植物区系的过渡地带之一,在植物区系的分区上,将该区归入华东区。     

THE GUT FLORA OF THE CHICK. II. THE ESTABLISHMENT OF THE FLORA

SUMMARY: Viable counts were made in three media of material from the crop, gizzard, duodenum, ileum and caeca of chicks. Groups of birds 2, 4, 7, 10, 13, 16 and 30 days old were studied. The results showed that a balanced gut flora is established one day after feeding. An indication of the actual development of the flora was obtained in chicks 4 hr after feeding. The relationship between the flora at different ages and that in newly-hatched chicks before feeding is discussed.     

FLORA OF THE LOWER CRETACEOUS CEDAR MOUNTAIN FORMATION OF UTAH AND COLORADO. PART III: ICACINOXYLON PITTIENSE N. SP

Icacinoxylon pittiense, a new species of angiospermous wood from the Lower Cretaceous Cedar Mountain Formation of Utah is described and compared with similar fossil and modem woods. It is distinguished from other species of Icacinoxylon by its thick-walled fiber-tracheids with their walls making up at least 50% of the total diameter of the cells, conspicuous bordered pits with obliquely crossing extended apertures on both the tangential and radial walls of its fiber-tracheids, scalariform perforation plates with as few as four or greater than 30 bars, transitional opposite to scalariform pitting on its vessel walls, thick-walled ray cells, and distinct sheath or border cells in its rays. Icacinoxylon pittiense is the first species of this genus to be reported from Cretaceous sediments. This wood is of special interest because very few angiosperm woods have been reported from lower Cretaceous strata.     

澳门的植物区系

通过作者实地考察和收集前人的研究资料,概述了澳门的自然条件与植被。对澳门维管植物的区系组成、特点、分布区类型等进行较详细地研究,并与邻近植物区系比较,同时对作者在野外调查中发现的澳门新纪录植物进行了统计。最后根据澳门植物分布的特点和自然地理特征,把澳门植物区系划分为3个部分来讨论。     

THE GUT FLORA OF THE CHICK. I. THE FLORA OF NEWLY HATCHED CHICKS

SUMMARY: The presence of a caecal microflora has been demonstrated in newly hatched chicks that had not received food or water. The flora was composed mainly of clostridia, sometimes with Escherichia coli .     

湖南植物区系的特点

在大地构造上,湖南属华南地台东部的杨子准地台和南华准地台两个大地构造单元¹⁾,系渊源于震旦纪杨子陆台和华夏陆台^[1]。此陆台自寒武纪至二迭纪反复受海浸,直至二迭纪印支运动地壳普遍抬升,海水从此全部退出地面,逐渐形成今日地貌雏形,再经侏罗纪-白垩纪燕山运动,第三纪喜马拉亚运动始成为现代湖南地貌。     

安徽省鹞落坪自然保护区植物区系的数量分析

鹞落坪自然保护区是大别山中植物的集中分布地,植物区系成分丰富,也是我国北亚热带生物多样性保护的关键区域。其地理成分以北温带、泛热带、东亚三种为主,显示出区系成分的过渡特征。以植物地理成分为指标,对鹞落坪与全国其它14个山地的植物区系的模糊聚类分析,表明了华东与华中植物区系无明显的分界线,大别山成为联系这两大植物区系的纽带。     

CONSERVATION OF THE FLORA OF THE MASCARENE ISLANDS

Summary. The current threatened state of the Mascarene flora is described and some remedial measures are proposed.     

植物配糖体对人肠道厌氧菌群的影响

通过从我国传统中药三七、薯蓣、青叶胆、天麻中分离到的天然植物配糖体三七皂甙Ｒ１、Ｄｉｏｓｃｉｎ、Ｐｒｏｔｏｄｉｓｃｉｎ、Ｇｒａｃｉｌｌｉｎ、Ｇａｓｔｒｏｓｉｄｅ及Ｓａｐｏｎｉｎ Ｄ等对下沉人肠道厌氧菌群进行６４ｈ生长培养,用比浊法测定培养液中厌氧菌的数量,发现不同的植物配糖体对不同人的肠道厌氧菌群生长活性影响不同,为我国传统中药的辩证施治提供了现代的试验依据。     

EPIPELIC AND EPILITHIC DIATOM ASSEMBLAGES IN MONTEZUMA WELL NATIONAL MONUMENT,ARIZONA1

Epipelic and epilithic diatom assemblages in Montezuma Well National Monument, Arizona, were identified and analyzed by H' (species diversity), species number, J' (evenness), relative abundance, SIMI (similarity index), and DI (dissimilarity index) values. The epipelic assemblage was found to be a tri-dominant association of Cyclotella pseudostelligera f. parva Czar. & Blinn, Cocconeis placentula var. lineata (Ehr.) V.H. and Achnanthes linearis (W. Sm.) Grun. The epilithic assemblage was a tri-dominant association of Rhoicosphenia curvata (Kütz.) Grun. ex Rabh., Cy. Pseudostelligera f. parva and Synedra ulna (Nitz.) Ehr. Both associations persisted throughout the year. Of the 83 taxa observed, 51 were common to both assemblages, 24 were restricted to the epipelon, and 8 were restricted to the epilithon. On a yearly basis, the epipelic assemblage exhibited less diversity (H') than the epilithon, even though the latter exhibited fewer taxa. The use of mean diversity values was also determined to be unacceptable. Cy. Pseudostelligera f. parva and S. ulna appeared more abundant under high light intensity and duration, Fragilaria construens var. venter (Ehr.) Grun. favored low light intensity and duration, whereas A. linearis, R. curvata and Co. placentula var. lineata were tolerant of a variety of intensities and durations. On a yearly basis, both assemblages exhibited slight similarity (SIMI, DI). The use of SIMI values for comparing assemblages with few highly abundant taxa was determined to be unacceptable and under these conditions, the use of DI was recommended.     

广西大瑶山植物区系资料

<正> 蔓生或近直立草本;茎具棱,密生灰白色长硬毛。叶纸质,椭圆形或卵形,长5—9厘米,宽2.5—4厘米,先端钝,基部狭楔形,边缘有疏齿,两面被灰色长硬毛;叶柄长1—1.5厘米,被长硬毛。聚伞花序具4—5朵花,连总梗长约1.5—2.5厘米,总梗及花梗均被长硬毛;花梗长0.8—1.5厘米,花萼钟状,长5—6毫米,脉不明显,萼齿5,近等大,披针形,边缘被长硬毛;花冠白色,长约5厘米,无毛,近二唇形,上唇较短,长约3.5毫米,先端钝,下唇3裂,中裂片长圆形,长约7毫米,宽约4毫长,先端钝圆,雄蕊     

腾格里沙漠固定沙丘藓类植物结皮层的自然恢复及人工培养试验研究

 通过藓类结皮层的自然恢复和人工培养藓类植物促进结皮层形成试验,研究了腾格里沙漠固定沙丘生物结皮层形成过程中优势成分真藓 （Bryum argenteum） 的繁殖生物学特性,结果表明：藓类结皮层人工去除后在3～4年内70%的样方基本恢复,在此过程中真藓主要靠茎叶碎片传播和繁殖;通过分株法、撒茎叶法培养的真藓在1个月后长满整个样地, 主要通过如下方式繁殖——茎的碎片连续分枝可产生小植株,茎、叶均可产生原丝体,由原丝体发育产生小植株,小植株又可再生原丝体,如此反复产生新植物体,这一过程是野外人工促进生物结皮层形成过程中真藓主要的繁殖途径。与室内培养中真藓的繁殖特性相比较,野外培养的真藓在繁殖过程中产生的原丝体较粗壮,分枝多,但在两种条件下的繁殖特性相同,能够揭示该地区自然条件下藓类植物萌发和定居的繁殖机理。该研究为人工促进生物结皮层形成及治理受损结皮层提供了实验依据。