青藏高原晚新生代植被史及其气候特征

从青藏高原目前已知的６０余个剖面和钻孔揭示的大量古植物资料来看,由于喜马拉雅山的强烈隆升、地质事件及全球气候变化,青藏高原晚新生代植被发生显著的变化。中新世进入上新世,植被由森林型变为草原型。在中新世晚期植被按纬向分为三带,南带为亚热带硬叶常绿阔叶林－雪松林,中带为暖温带落叶阔叶林及灌丛,北带即昆仑山北坡为山地常绿针叶林及森林草原。山地的高差已使植被出现垂直分带现象。上新世早中期气候转凉,原北带出     

丹江库区晚新生代三种兔形类化石

记述了丹江库区周围发现的三种兔形类化石：产在丹江二级阶地基座岩层中的淅川跳兔（新种）Alloptoxxichuanwnsissp．nov．个体小,形态较早中新世中期的A．minor原始,其时代可能是早中新世早期,同时详细讨论了Alloptox的进化和分类;发现于台子山林场裂隙堆积物中的进步上新五褶兔（新种）Pliopentalagusprogressivussp.nov.个体为该属已知各种中最大者,形态较已知种更接近于现生的Pentalagus,它的时代可能为上新世末或更新世初;产于郧县曲远河口汉水Ⅳ级阶地的复齿拟鼠兔Ochotonoidescomplicidens与蓝田金丝猴发现于同一阶地,推测其时代为早更新世晚期。     

AN AUTORADIOGRAPHIC ANALYSIS OF THE ROOT EPIDERMIS OF THE SWITCH GRASS (PANICUM VIRGATUM)

Analyses of ³H-uridine, ³H-thymidine, and ³H-lysine incorporation in the root epidermis of Panicum virgatum were undertaken. Highly significant differences between the mean incorporation of ³H-uridine and ³H-lysine in epidermal and adjacent cortical cells were observed. While the cortex exhibited a steady decrease of precursor incorporation with distance from the apex, the epidermal cells exhibited differential incorporation. These results were regarded as further evidence for the hypothesis that cells of two maturation potentials exist in the epidermis of this panicoid grass. Treatment with 20.0 μg/ml of actinomycin D resulted in a differential inhibition in the epidermal-cortical incorporation of ³H-uridine. The possibility of endopolyploidy in the epidermis was suggested by the observation that root hairs, hair initials, and some epidermal cells incorporated two to four times more ³H-thymidine than meristematic cells. Neither puromycin nor actinomycin D treatment affected the protein-positive particles present in the cytoplasm of epidermal cells in this grass. Similarly, RNase did not affect their structural integrity. Attempts to clarify the significance of these inclusions and their possible role, if any, in the differentiation of the epidermis are now in progress.     

SOME EPIDERMAL CHARACTERISTICS OF PALEAS OF DICHANTHELIUM,PANICUM, AND ECHINOCHLOA

The apical portion of paleas of the perfect (upper) floret of 11 species of Dichanthelium, 10 species of Panicum, and one species of Echinochloa were examined with a scanning electron microscope. The surfaces of the Dichanthelium palea tips uniformly had simple, rounded papillae, widely spaced in regular rows, whereas the palea tips of most Panicum species had irregularly arranged, compound or aggregated papillae. Unusual epidermal features were observed in P. obtusum, P. hians, and P. hemitomon. The Echinochloa crusgalli palea surface exhibited a pattern of papillae or spicule development similar to that of P. hians. Transverse sections of Dichanthelium palea showed the papillae to be little if at all thickened. An electron beam x-ray microanalysis indicated a high concentration of silicon in the papillae.     

黑龙江省富拉尔基晚新生代孢粉分析及其意义

本文根据富拉尔基 QH70孔(井深226.07m)73块孢粉样所取得的123科属埴物孢粉,依据其孢粉组合特征,从下至上划分出七个区域性孢粉带。第Ⅰ带属晚白垩世早期,植物群具热带-亚热带的面貌,反映当时的气候热而潮湿。第Ⅱ—Ⅲ带,地质时代为晚第三纪。组合中除葇荑花序植物为主外,同时又保存较多的亚热带落叶和常绿阔叶乔木树种,气候温暖潮湿。至第Ⅲ带晚期,草本植物和半灌木已占优势,表明气温下降,变干。第Ⅳ带由蒿、藜科、禾本科、蓼等中旱生的草本及半灌木组成温性草原,气候冷干。孢粉组合特征结合热释光和磁性地层,将该区上新世和更新世界限确定为距今240万年左右。第Ⅳ—Ⅶ带属更新世,各孢粉组合具明显的差异。在Ⅴ带的早期,植被尚属草原或冻原,气候寒冷干燥,但在其晚期,则属落叶阔叶林和草原,表明气候温暖半潮湿。在Ⅵ—Ⅶ带内,草本植物占优势,但在末次冰期时,由云杉、冷杉、落叶松和桦等组成的北方针叶林曾一度繁盛在低地和平原,气候寒冷潮湿。     

MORPHOLOGY AND ULTRASTRUCTURE OF EMBRYOGENIC CELL SUSPENSION CULTURES OF PANICUM MAXIMUM (GUINEA GRASS) AND PENNISETUM PURPUREUM (NAPIER GRASS)

Morphological and ultrastructural changes during the growth of embryogenic cell suspension cultures of Panicum maximum and Pennisetum purpureum have been studied. The suspensions consist almost entirely of cell aggregates of 50–75 embryogenic cells. The cell aggregates vary in size from 90–400 μm in P. maximum and from 70–340 μm in P. purpureum. Following the period of exponential growth starch grains gradually disappear and vacuolation increases. Ten to 16 days after subculture, P. maximum cells enlarge and separate from each other, and organized embryo-like structures appear. Ultrastructural studies show that the cell aggregates are made up of discrete, individual groups of 2–6 cells each. Each cell group appears to arise from a single cell and breaks away from the ‘mother group’ as cell divisions continue. The embryogenic cells are small (20 μm), isodiametric with many starch grains and contain a large nucleus with a prominent nucleolus. Extensive profiles of endoplasmic reticulum, many small peripheral vacuoles, and several amyloplasts are present. Plasmodesmatal connections exist only between cells within a cell group but not between cells of different cell groups in the large cell aggregates.     

河北泥河湾盆地晚新生代介形类生物地层

通过河北阳原、蔚县泥河湾盆地晚新生代20余条剖面介形类生物地层的调查研究,发现非常丰富的介形类化石,计23属60余钟,自下而上可明显地划分为5个介形类化石组合带:1.Potamocypris plana-Candoniella-Ilyocypris组合带;2.Leucocythere-Ilyocypris-Candon...     

OBSERVATIONS ON THE MORPHOLOGY AND PHYSIOLOGY OF MARSILEA SPERM

The multiciliated sperm of the water fern Marsilea vestita was examined with a view to establishing its suitability as an experimental subject. Time-course experiments revealed spermatid development to be temperature dependent. Sterile techniques were devised for observation of sperm on both a population and an individual basis. Sperm discharge, active and senescing sperm were examined by phase-contrast microscopy. A regular pattern of senescence was ascertained. This included vacuolation of the cytoplasmic vesicle, loss of motility, and ultimate loss of the helical structure of the sperm coil. Sperm life spans were recorded using motility and O₂ uptake as criteria. Sperm populations are active 3–3½ hr at ambient temperature (22–25 C). Individual sperm are active less than 1 hr. Sperm suspensions show a decline in O₂ uptake which parallels the loss of motility. Various constituents affecting the life span were investigated. A twofold prolongation of the sperm life span occurred in the presence of 0.1 m sucrose. An ultrastructural examination of the mature sperm was made to aid in assessing its metabolic potential. The sperm shows little ultrastructural differentiation. The cytoplasmic vesicle is predominantly composed of starch-containing plastids. The main structural components of the sperm coil are a continuous mitochondrial band, an elongate nucleus, and a series of microtubules which separate the basal bodies from the nucleus and mitochondrion. A comparison of ultrastructural features common to Pteridium and Marsilea was made and factors affecting senescence discussed.     

中国新生代晚期的剑齿象(剑齿象科,长鼻目)及其扩散事件

对我国新生代晚期的剑齿象(Stegodon)进行再研究,提出了下列几点看法:1)依据Ste-godon的特征,可将已命名的中国剑齿象种分为3类。一类为有效的剑齿象种,包括晚中新世的S.licenti Teilhard & Trasseart,1937;上新世的S.zdanskyi Hopwood,1935和S.officinalis Hopwood,1935;上新世晚期至更新世早期的S.zhaotongensis Chow & Zhai,1962;更新世的S.chiai Chow & Zhai,1962,S.orientalis Owen,1870,S.sinensis Owen,1870和S.huananensis sp.n.等种。另一类是从剑齿象属中分出,归入到其他属或科的种。属于这一类的有可能置入真象类(Elephantoidae)的Stegodon parahypsilophus He,1984,S.guizhouensis Li & Wen,1986,Stegodon cf.S.hypsilophus和S.primitium Liu et al.,1973以及归入Stegolophodon的Ste-godon baoshanensis Yun,1975。第三类为属种分类位置未定的种,以S.wushanensis Huang et al.,1991为代表。2)南亚更新世的S.elephantoides(Clift),1828可能在我国不存在。3)我国的剑齿象化石相当丰富,发现于东经99°以东、北纬38°以南的广大地区(包括山西、陕西和甘肃以及华中、华南、西南和部分华东等地区),生存时代为晚中新世晚期至更新世。4)在新生代晚期我国的剑齿象可能经历了3次大的由北向南的扩散和迁移事件。第一次发生在晚中新世,第二次在晚中新世晚期至早上新世早期,第三次在更新世早期。5)剑齿象可能起源于亚洲。S.licenti是我国出现时代最早的剑齿象,也可能是剑齿象最原始的一种。     

ELECTRON MICROSCOPE OBSERVATIONS ON THE STRUCTURE AND DISCHARGE OF THE STENOTELE OF HYDRA

Sections of the stenotele type of nematocyst of Chlorohydra hadleyi have revealed that the stenotele, upon firing, completely everts its stylets and spines and the long, thin tubule, much as the eversion of the tubule of the nematocyst of the jewel anemone (Picken, 1953; Robson, 1953). Alternative mechanisms for supplying the energy necessary to forcefully discharge the stenotele contents are discussed as well as the possible significance of several regions containing highly ordered periodic structure. The origin of nematocysts as kinetosomal derivatives is discussed as a possibility suggested by the symmetry of the stenotele contents and the structure, location, and function of the cnidocil.     

草鱼出血病病毒人工感染稀有(鱼句)鲫出血病鱼主要器官组织的超薄切片观察

用电子显微镜观察了稀有(鱼句)鲫出血病(Hemorrhage of Gobiocypris rarus)鱼的病理切片及对照鱼的超薄切片。在对照鱼的鳃、肠道、肾脏、脾脏、肌肉和肝脏中没有见到任何病毒颗粒。在病鱼鳃血管内皮细胞质中观察到聚集的直径70nm左右的GCHV颗粒,说明鳃是GCHV侵袭的主要器官之一,并讨论了鳃对GCHV敏感在GCHV传播中的意义。还在病鱼肠道,肾脏中观察到成片的病毒颗粒,它们也是GCHV侵袭的主要组织。在病鱼脾脏的电子密度低的细胞质中观察到散在的病毒颗粒。很少见到病毒聚集体,脾脏中的病毒可能是脾脏的吞噬细胞吞噬而来。作者认为在病鱼组织中观察到的大小不同的病毒颗粒是处于不同成熟阶段的GCHV。     

OBSERVATIONS ON THE MICROBIOLOGY OF RAW AND HEAT-TREATED LIQUID EGG

SUMMARY: Factors influencing the hygienic quality of raw liquid egg have been inverstigated and bacterial counts obtained during the period January–October, 1952, have been summarized. As a commercial standard of quality, it is suggested that raw liquid egg with a total bacterial count in the region of 5 × 10⁶/g. at 22°, might be regarded as reasonably satisfactory, having regard to the quality of the raw material now permitted to be used.
A study of heat-treatment of Liquid egg has shown that a time-temperature combination slightly in excess of 2 min. at 146°F. may be regarded as satisfactory, as it gives a 99·99% kill of the initial flora without significantly imparing the functional properties of the final product. The residual flora in herat-treated egg has been found to be relatively inactive.
Salmonella organisms were found in 4·2% of raw hen egg and in 67·4% of raw duck egg. Under controlled conditions of heat-treatment, destruction of Salmonella species can be accomplished.     

OBSERVATIONS ON THE PROCAMBIUM AND PRIMARY PHLOEM OF PELARGONIUM DOMESTICUM

Carothers , Zane B. (U. Kentucky, Lexington.) Observation on the procambium and primary phloem of Pelargonium domesticum. Amer. Jour. Bot. 46(6): 397–404. Illus. 1959.—Stems of Pelargonium domesticum, a shrubby member of the Geraniaceae, were studied ontogenetically. It was found that a continuous cylinder of procambium is formed within the terminal millimeter of the young shoot. The pattern of trace procambium within this region is illustrated. Three traces are associated with each leaf; nodes are trilacunar. The prominent, sclerous “pericycle,” a diagnostic character of the family, actually consists of protophloem fibers. Commonly septate, these cells may contain as many as 4 nucleate protoplasts. The fibers average 1177 μ in length and 31 μ in diameter. Fiber walls average 5 μ in thickness, the inner pit apertures 6 μ in length. Metaphloem sieve tube elements averaged 203 μ in length.