The anatomy of the hypocotyls of Ceriops Arnott (Rhizophoraceae), Recent and fossil

Fragments of the hypocotyls of the fossil Ceriops cantiensis Chandler from the Lower Tertiary of southern England and the living Ceriops tagal (Perr.) C.B. Rob. and Ceriops decandra (Griff.) Ding How have been examined by SEM. The living material has also been studied by light microscopy. Great similarity has been revealed between homologous tissues of the Recent and fossil material: the palisade-like epidermis; a two-zoned cortex composed of an outer region of compact collenchymatous tissue and an inner region of aerenchyma; phloem fibres; a large number of small vascular bundles, only some of which have xylem; few xylem elements; similarity of xylem elements; pith region of roundish to shortly oblong cells forming long, bead-like rows in longitudinal view. Evidence is also presented of similarity between Recent and fossil starch grains.     

Fossil wood of the Juglandaceae: Some questions of taxonomy,evolution, and phylogeny in the family based on wood anatomy

Some problems in the taxonomy of the Juglandaceae are discussed based on wood anatomy; the identification of fossil juglandaceous wood is considered. Data on fossil wood of the Juglandaceae are summarized; a key for identification of wood anatomy in modern and fossil Juglandaceae is compiled. Wood anatomical characters in members of the family are discussed in the light of major evolutionary trends in the secondary xylem of dicots, and a comparative characterization of members of the family is developed. A hypothesis is proposed that the subfamily Engelhardioideae is the most primitive member of the Juglandaceae based on wood anatomy, the tribe Juglandeae and subfamily Platycaryoideae are slightly more highly specialized, and the tribe Hicorieae is the most advanced. Evolutionary relationships between the members of the Juglandaceae are reviewed based on wood anatomy.     

A potential novel source of information for screening and monitoring the impact of exotic plants on ecosystems

Exotic invasive species often affect the pools and fluxes of carbon, nutrient elements, and energy, but there are few sources of information that permit these effects to be anticipated. Some plant traits, such as growth rates and tissue nutrient content, are known to influence the ecosystem process, but information about these traits is often not available. I propose that plant secondary chemistry may be a useful trait for assessing the likelihood of ecosystem (and community) impacts. Information about such traits is readily available from several sources, rendering it a good candidate for screening and monitoring programs. Plant secondary chemicals affect a variety of ecosystem processes, largely through their direct and indirect impacts on soil microbial community composition and function. They also have well-known effects on human physiology, as evidenced in the numerous plant-derived bioactive compounds used for their medicinal and other physiological effects. There is a large amount of information available about plant secondary chemistry due to its role in herbal medicine, dietary supplements and the emerging field of nutraceuticals. This information includes databases and traditional texts in ethnobotany, plant chemistry, and alternative medicine. I review evidence that secondary compounds are widespread in invasive species and affect soil microbial communities and microbially-mediated ecosystem processes. Invasion ecology may profit from collaborations with a novel group of scientists, including those in ethnobotany, nutraceuticals, plant chemistry and alternative medicine.     

Siderophores of Pseudomonas putida as an iron source for dicot and monocot plants

Iron uptake from ferrated (⁵⁹Fe) pseudobactin (PSB), a Pseudomonas putida siderophore, by various plant species was studied in nutrient solution culture under short term (10 h) and long term (3 weeks) conditions. In the short term experiments, ⁵⁹Fe uptake rate from ⁵⁹FePSB by dicots (peanuts, cotton and sunflower) was relatively low when compared with ⁵⁹Fe uptake rate from ⁵⁹FeEDDHA. Iron uptake rate from ⁵⁹FePSB was pH and concentration dependent, as was the Fe uptake rate from ⁵⁹FeEDDHA. The rate was about 10 times lower than that of Fe uptake from the synthetic chelate. Results were similar for long term experiments.Monocots (sorghum) in short term experiments exhibited significantly higher uptake rate of Fe from FePSB than from FeEDDHA. In long term experiments, FePSB was less efficient than FeEDDHA as an Fe source for sorghum at pH 6, but the same levels of leaf chlorophyll concentration were obtained at pH 7.3.Fe uptake rates by dicots from the siderophore and FeEDDHA were found to correlate with Fe reduction rates and reduction potentials (E₀) of both chelates. Therefore, it is suggested that the reduction mechanism governs the Fe uptake process from PSB by dicots. Further studies will be conducted to determine the role of pH in Fe aquisition from PSB by monocots.     

Leaf anatomy and chloroplast ultrastructure of Mn-deficient orange plants

Leaf samples of Mn-deficient and Mn-sufficient (control) ‘Navelate’ orange plants grown in a greenhouse were taken to investigate the effects of Mn deficiency in leaf structure and chloroplast ultrastructure. Total leaf chlorophyll concentration was significantly lower in Mn-deficient plants than in control ones. Entire lamina thickness was not altered due to Mn deficiency. However, Mn deficiency resulted in disorganization of mesophyll cells, mainly of palisade parenchyma cells. The number of mesophyll chloroplasts per cellular area and their length were both affected negatively. The membranous system of chloroplasts was also disorganized. The percentages of starch grains and plastoglobuli per chloroplast of Mn-deficient leaves were significantly greater than those of control leaves.     

电视-显微成像系统在植物形态解剖学实验教学中的应用

介绍电视—显微成像系统在植物形态解剖学实验教学中的应用;并将其与计算机、数码投影仪、刻录机、影碟机等仪器进行组合应用,不仅提高了植物形态解剖学教学效果,而且提高了学生的综合素质。     

三种葱属植物花形态及花药解剖结构观察

蒙古韭(Allium mongolicum Regel)、细叶韭(Allium tenuissimum L.)、野韭(Allium ramosumL.)作为野生蔬菜近年来受到人们的青睐,一些学者对这三种葱属植物进行了初步研究,但对其解剖结构的研究未见报道.通过田间观察和石蜡切片法,对这三种葱属植物花的形态及花药解剖结构进行了观察,结果表明:三种葱属植物花的形态结构差异明显,花粉粒的形状及大小也有明显的差别:野韭花粉粒为长卵形,细叶韭为卵圆形,蒙古韭为近半圆形;从花粉粒大小来看,野韭最大,蒙古韭次之,细叶韭最小.通过以上研究揭示了三种葱属植物花药解剖学特征,从而为葱属植物分类标准、亲缘关系鉴定、生殖发育等方面的进一步研究提供理论依据.     

Siderophores sorbed on Ca-montmorillonite as an iron source for plants

Previous investigations have shown significant sorption of siderophores to the solid phase in soils, and clay surfaces in particular. The ability of plants to utilize Fe from this reservoir is therefore of great interest. This research focused on the ability of the hydroxamate siderophore ferrioxamine B (FOB) sorbed to Ca-montmorillonite – prevailing in soils – to supply Fe to peanuts (Arachis hypogeae L.). Remediation of Fe deficiency by the sorbed siderophore was found to be similar to that by the free (unsorbed) form. The concentration needed to achieve complete remediation of chlorosis was one order of magnitude higher than that of the optimal FeEDDHA [Fe-ethylenediamine-di(o-hydroxyphenylacetic acid)]. Using dialysis tubes, it was shown that Fe uptake from the sorbed siderophore is executed mainly via long-range pathways and does not require close proximity to the plant roots. It was hypothesized that the process involves chelating agents in solution, which transport the Fe from the immobilized siderophore and enable its uptake by the plant. Under calcareous conditions, the ability of the sorbed FOB to supply Fe was significantly impaired, probably as a result of inactivation of the bridging mechanism. Various possible shuttle compounds were examined. EDDHA was found to be a very efficient shuttle compound, which caused complete remediation of Fe deficiency, even under very harsh calcareous conditions. The findings support our hypothesis and imply the effectiveness of a ligand-exchange mechanism to strategy I plants (commonly attributed to strategy II plants). We suggest that the secretion of substances with chelating abilities, which is usually considered a less effective means of Fe acquisition mechanism, takes on more importance in this context.     

Systematic anatomy of Oceanopapaver, a monotypic genus of the Gapparaceae from New Caledonia

Evidence from vegetative anatomy, reproductive morphology, and palynology does not support a relationship of Oceanopapaver with Cistaceae, Cruciferae, Flacourtiaceae, Papaveraceae, and Tiliaceae, but suggests placement of the genus in Capparaceae. The apparent occurrence of myrosin cells, among other features, effectively excludes all of the aforenoted families except Capparaceae and Cruciferae. However, multicellular non-glandular trichomes, bracteate inflorescences, sepals and petals each occasionally other than four per flower, presence of an androgynophore, numerous stamens, tricolporate and binucleate pollen, the unilocular mature ovary, the stipitate fruit, and the exotegmic seed in Oceanopapaver favour Capparaceae over Cruciferae. Floral histology and vasculature provide no clues about the relationships of Oceanopapaver. A few features are anomalous, most notably the presence of secretory canals and secretory cells in the genus versus their absence in Capparaceae and their rarity in Cruciferae, the trichomic floral nectary in the genus versus the massive, non-trichomic nectaries in these two families, and the straight embryo in the genus versus the more or less curved or folded embryo in the two families. The fleshy endosperm in Oceanopapaver has counterparts in a few Capparaceae, contrary to previous claims that endosperm is absent or scanty in this family. The report of stamen fascicle traces for Oceanopapaver is the first for Capparaceae, but these should be sought elsewhere in the family. Within Capparaceae the genus fits best in Capparoideae compared to Cleomoideae or the nine other very restrictive subfamilies variously proposed for Capparaceae. There is no justification for the monotypic segregate Oceanopapaveraceae. The phylogenetic and functional anatomy of vegetative and reproductive structures is discussed.     

Colonization outwith the colon: plants as an alternative environmental reservoir for human pathogenic enterobacteria

Members of the Enterobacteriaceae have the capacity to adapt to a wide variety of environments and can be isolated from a range of host species across biological kingdoms. Bacteria that are pathogenic to animals, in particular humans, are increasingly found to be transmitted through the food chain by fruits and vegetables. Rather than simply contaminating plant surfaces, there is a growing body of evidence to show that these bacteria actively interact with plants and can colonize them as alternative hosts. This review draws together evidence from studies that investigate proven and potential mechanisms involved in colonization of plants by human pathogenic enterobacteria.     

Wood and stem anatomy of Lardizabalaceae, with comments on the vining habit, ecology and systematics

CARLQUIST, S., 1984. Wood and stem anatomy of Lardizabalaceae, with comments on the vining habit, ecology and systematics. Qualitative and quantitative data, based mostly upon liquid-preserved specimens, are presented for Akebia, Roquila, Decaisnea, Holbodia, Lardizabala, Sinofranchetia and Stauntonia . Because Decaisnea is a shrub whereas the other genera are vines, anatomical differences attributable to the scandent habit can be considered. These include exceptionally wide vessels, a high proportion of vessels to tracheids (or other imperforate trdcheary elements) as seen in transection, simple perforation plates, multiseriate rays which are wide and tall, and pith which is partly or wholly sclerenchymatous. With respect to ecology, two features are discussed: spirals in narrower vessels may relate to adaptation to freezing in the species of colder areas, and crystalliferous sclereids seem adapted in morphology and position to deterrence of phytophagous insects or herbivores. The wood may provide mechanisms for maintaining conduction even if wider vessels are deactivated temporarily by formation of air embolisms. Wood and stem anatomy of Lardizabalaceae compare closely to those of Berberidaceae and of Clematis (Ranunculaceae), as well as to other families of Berberidales. Decaisnea is more primitive than these in having consistently sralariform perforation plates and in having scalariform pitting on lateral walls of vessels. A tentative listing of anatomical features which may correspond to generic limits is given.     

Comparative anatomy of the heart of mammals

Hearts from 20 mammalian orders were examined according to a fixed protocol to determine if the gross differences of shape and internal anatomy could be explained. Three generalizations can be made: firstly differences are most closely related to taxonomic position, secondly some features, such as the prominence of the conus of the right ventricle in animals that leap, dig or sprint regularly as part of their defence mechanism and a long, narrow left ventricle in endurance performers may be more closely related to activity than ancestry, and lastly some characteristics may be pleiotropic effects of thoracic morphogenesis.     

高师《人体解剖生理学》教学改革研究与实践

分析了高师人体解剖生理学教学现状,提出人体解剖生理学知识体系的构建途径,从教学内容、教学方法、教学手段等方面进行改革与实践。     

Albumin preservation in fossil bones and systematics of Malpaisomys insularis (Muridae,Rodentia), an extinct rodent of the Canary Islands

Collagen and albumin were extracted from subfossil bones of the extinct rodent Malpaisomys insularis; the radiocarbon age of the sample was at least 1.73 Ka. Electrophoretic and immunological techniques indicate the preservation of albumin while collagen is revealed as degraded fragments. Immunological comparisons between Malpaisomys albumin and albumin antisera of four extant rodents indicate that Malpaisomys is more closely related to Mus than to Acomys and Uranomys and that Cavia is the most divergent taxon studied. The branching order of the fossil and the extant rodents is discussed with respect to the relationships derived from morphological criteria.     

Genetic consequences of glacial survival and postglacial colonization in Norway spruce: combined analysis of mitochondrial DNA and fossil pollen

Norway spruce (Picea abies [L.] Karst.) is a broadly distributed European conifer tree whose history has been intensively studied by means of fossil records to infer the location of full‐glacial refugia and the main routes of postglacial colonization. Here we use recently compiled fossil pollen data as a template to examine how past demographic events have influenced the species’ modern genetic diversity. Variation was assessed in the mitochondrial nad1 gene containing two minisatellite regions. Among the 369 populations (4876 trees) assayed, 28 mitochondrial variants were identified. The patterns of population subdivision superimposed on interpolated fossil pollen distributions indicate that survival in separate refugia and postglacial colonization has led to significant structuring of genetic variation in the southern range of the species. The populations in the northern range, on the other hand, showed a shallow genetic structure consistent with the fossil pollen data, suggesting that the vast northern range was colonized from a single refugium. Although the genetic diversity decreased away from the putative refugia, there were large differences between different colonization routes. In the Alps, the diversity decreased over short distances, probably as a result of population bottlenecks caused by the presence of competing tree species. In northern Europe, the diversity was maintained across large areas, corroborating fossil pollen data in suggesting that colonization took place at high population densities. The genetic diversity increased north of the Carpathians, probably as a result of admixture of expanding populations from two separate refugia.     

Functional anatomy of the tarsier foot

Tarsiers possess a very odd musculoskeletal foot anatomy that goes beyond their acknowledged specialized leaping adaptations. Tarsius has evolved a fundamentally different method of bone rotation to achieve an inverted foot position during grasping and has developed an unusual muscular system for holding onto vertical supports. Although galagos and tarsiers possess elongated foot bones as adaptations for leaping, galagos utilize many more types of movements, have specialized osteological surface for inversion, and have a more common type of muscle development in the foot and leg than tarsiers possess. Likewise, the Omomyidae, the ancestral lineage of Tarsius, exhibit a lack of morphological similarity with Tarsius in the known foot joints.