Stem Fragments Research Articles

Food for eternity? The analysis of a date offering from a 3rd millennium BC grave at Hili N, Abu Dhabi (United Arab Emirates)

Ever since the early 3rd millennium BC the date palm ( Phoenix dactylifera) has played an important role in eastern Arabia where its remains, in the form of seeds, fruits and stem fragments, are preserved on numerous archaeological sites. The recent discovery of a carbonised mass of pitted dates in a collective burial pit from the end of the Umm an-Nar period (ca. 2200–2000 BC) at Hili (United Arab Emirates) constitutes the earliest example of a food preparation involving this species. The present paper describes the discovery and identification of this unique offering before addressing the question of its significance in a funeral context in Bronze Age Arabia.

When sex is not enough: ecological correlates of resprouting capacity in congeneric tropical forest shrubs

In moist tropical forests resprouting may be an important component of life history, contributing to asexual reproduction through the clonal spread of individuals derived from shoot fragments. However, in contrast to other ecosystems where resprouting is common, the ecological correlates of resprouting capacity in tropical forests remain largely unexplored. In this study we characterized shade tolerance, resprouting capacity and sexual reproductive success of eight co-occurring Piper species from lowland forests of Panama. In field experiments we found that shade-tolerant Piper species had a higher capacity to regenerate from excised or pinned stem fragments than light-demanding species in both gap and understory light conditions. In contrast, shade-tolerant species had lower recruitment probabilities from seeds, as a consequence of lower initial seed viability, and lower seedling emergence rates. All Piper species needed gap conditions for successful seedling establishment. Of 8,000 seeds sown in the understory only 0.2% emerged. In gaps, seed germination of light-demanding species was between 10 and 50%, whereas for shade-tolerant species it was 0.5-9.8%. We propose that the capacity to reproduce asexually from resprouts could be adaptive for shade-tolerant species that are constantly exposed to damage from falling litter in the understory. Resprouting may allow Piper populations to persist and spread despite the high rate of pre-dispersal seed predation and low seed emergence rates. Across Piper species, we detected a trade-off between resprouting capacity and the annual viable seed production per plant but not with annual seed mass produced per plant. This suggests that species differences in sexual reproductive success may not necessarily result from differential resource allocation. Instead we suggest that low sexual reproductive success in the understory may in part reflect reduced genetic diversity in populations undergoing clonal growth, resulting in self-fertilization and in-breeding depression.

Alien Invasions, Ecological Restoration in Cities and the Loss of Ecological Memory

Abstract After a community or ecosystem is lost, it may leave behind an ecological memory. The site history, soil properties, spores, seeds, stem fragments, mycorrhizae, species, populations, and other remnants may influence the composition of the replacement community or ecosystem to varying degrees. The remnants may also hold the site to a trajectory that has implications for ecological restoration. This is true in urban situations in particular where repeated disturbance has masked the history of the site. The ecological memory remaining may be insufficient for a site to heal itself; restoration activities are required to direct the future of the site. Conversely, in light of climate change and other rapidly changing environments, the existing ecological memory may be poorly suited to the new conditions and restoration projects need to create new and perhaps novel ecosystems. The loss of ecological memory facilitates the establishment of foreign invasive species. These invasives may eventually create a new stability domain with its own ecological memory and degree of resilience. To be successful, invasive species control must address both internal within patch memory of invasives and external between patch memory. Further research is necessary to document and conserve ecological memory for ecological restoration in response to future ecosystem changes.

Estudo anatômico do xilema secundário da raiz e do caule de Maytenus guyanensis Klotzsch ex Reissek (Celastraceae)

Maytenus guyanensis é uma planta medicinal, conhecida popularmente por chichuá, possuindo ação analgésica, antiinflamatória, afrodisíaca e antireumática. O objetivo do presente trabalho foi analisar as características estruturais, da raiz e caule desta espécie como contribuição aos trabalhos anatômicos já realizados para o gênero. O material botânico foi coletado na Reserva Florestal Adolpho Ducke, Manaus/AM onde foram selecionados três indivíduos e de cada um deles retirados fragmentos de 1cm³ do caule e raiz. Amostras foram seccionadas em micrótomo de deslize e coradas com safranina e azul de astra. A análise estrutural revelou-se de acordo com o registrado pela literatura para o gênero. O xilema secundário da raiz e do caule apresentam parênquima axial apotraqueal, raios multisseriados, heterogêneos, vasos solitários, de distribuição difusa, uniforme, seção circular, com parede delgada, pontoações intervasculares alternas e areoladas.

Researches Concerning In Vitro Conservation of the Rare Plant Species Dianthus Nardiformis Janka

ABSTRACTIn our work, we studied the possibility to use in vitro methods for the preservation of the rare species from the Red List of Romanian Flora-Dianthus nardiformis Janka.The plant material (whole plants and seeds) was collected from 3 populations from Natura 2000 sites.The in vitro cultures starting from single node stem fragments had to face with high contamination degree with fungi. Despite this fact, using different methods of disinfection, culture media and combination of growth factors, aseptic tissues cultures and micropropagation were successfully performed. The seeds were less infected and are most suitable for in vitro tissues cultures initiation.The rate of regeneration was evaluated after 2 months and the tissues cultures were used for the plant production and in the future for medium-term and long- term preservation approaches.

Gene flow and genetic structure of the aquatic macrophyte Sparganium emersum in a linear unidirectional river

Summary1. River systems offer special environments for the dispersal of aquatic plants because of the unidirectional (downstream) flow and linear arrangement of suitable habitats.2. To examine the effect of this flow on microevolutionary processes in the unbranched bur‐reed (Sparganium emersum) we studied the genetic variation within and among nine (sub)populations along a 103 km stretch of the Niers River (Germany–The Netherlands), using amplified fragment length polymorphisms.3. Genetic diversity in S. emersum populations increased significantly downstream, suggesting an effect of flow on the pattern of intrapopulation genetic diversity.4. Gene flow in the Niers River is asymmetrically bidirectional, with gene flow being approximately 3.5 times higher in a downstream direction. The observed asymmetry is probably caused by frequent hydrochoric dispersal towards downstream locations on the one hand, and sporadic zoochoric dispersal in an upstream direction on the other. The spread of vegetative propagules (leaf and stem fragments) is probably not an important mode of dispersal for S. emersum, suggesting that gene flow is mainly via seed dispersal. Realized dispersal distances exceeded 60 km, revealing a potential for long‐distance dispersal in S. emersum.5. There was no correlation between geographical and genetic distances among the nine S. emersum populations (i.e. no isolation by distance), which may be due to the occurrence of long‐distance dispersal and/or colonization and extinction dynamics in the Niers River.6. Overall, the genetic population structure and regional dispersal patterns of S. emersum in the Niers River are best explained by a linear metapopulation model. Our study shows that flow can exert a strong influence on population genetic processes of plants inhabiting stream systems.

Highly efficient in vitro adventitious shoot regeneration of peppermint (Mentha x piperita L.) using internodal explants

An in vitro regeneration system with a 100% efficiency rate was developed in peppermint [Mentha x piperita] using 5- to 7-mm-long second internode stem segments of 3-wk-old stock plants. Shoots developed at sites of excision on stem fragments either directly from the cells or via primary calluses. The optimal medium for maximum shoot initiation and regeneration contained Murashige and Skoog (MS) salts, B5 vitamins, thidiazuron (TDZ, 11.35 μM), ZT (4.54 μM), 10% coconut water (CW), 20 g l−1 sucrose, 0.75% agar, adjusted to pH 5.8. A frequency of 100% shoot initiation was achieved, with an average of 39 shoots per explant. This regeneration system is highly reproducible. The regenerated plants developed normally and were phenotypically similar to Black Mitcham parents.

Do Revised Giant Panda Population Estimates Aid in Their Conservation

Abstract The small number of giant pandas (Ailuropoda melanoleuca) in the world makes this the only species of bear classified as globally endangered on the IUCN red list. The latest rangewide population estimate was derived from scats (feces) found along transects throughout the geographic range of the species. Scats were differentiated into ∼1,600 individuals based on their geographical separation and the size of bamboo stem fragments contained within (reflective of bite-sizes). Recently, a team of researchers (Zhan et al. 2006) conducted genetic analysis of scats in a Chinese Nature Reserve (Wanglang). Their estimate of giant panda numbers there was double that obtained using the bite-size technique. Taking this to be representative of the entire range, they speculated that there could be 3,000 pandas in the wild. Many in the international conservation community heralded this as evidence that panda conservation is working well. Moreover, if the revised rangewide estimate is accepted as true, it could m...

Asexual spread versus sexual reproduction and evolution in Japanese Knotweed s.l. sets the stage for the “Battle of the Clones”

The invasion of NW Europe by a single clone of male-sterile Fallopia japonica var. japonica by purely vegetative reproduction has demonstrated that reproduction by seed and the genetic diversity associated with it may not be an essential feature of plant invasions, at least in the short term. What is less well known is that a significant proportion of the Japanese Knotweed s.l. involved is not F. japonica var. japonica, but the hybrid between it and F. sachalinensis–F. × bohemica. This hybrid is able to backcross to either parent with the potential to replace the missing male F. japonica; by the same process, the hybrid is generating the genetic diversity so conspicuously lacking in F. japonica. In terms of understanding the population structure in a particular country, it is important to be able to identify hybrids and putative back-crosses. We bring together a mixture of published and unpublished information to provide a comprehensive section on morphological and anatomical aids to identification. Regeneration of plants from stem and rhizome fragments varies by taxon, as do responses to control techniques, underlining the importance of correct identification of these plants. In this paper we look closely at this group of taxa, with special emphasis on the role played by hybridization, with an examination of the genetic make up of seedlings produced in the wild or by artificial hybridizations, and the implications that this will have on the future directions of the invasion process.

Spontaneous breakage and expulsion of a stem fragment of levonorgestrel intrauterine system (Mirena) following duplicate insertion

Removal and changing an intra-uterine device (IUD) involves good history taking, a proper examination and appropriate experience in fitting IUDs. We present a case of a woman who had two insertions of the levonorgestrel intrauterine system (LNG-IUS) which was diagnosed only at hysteroscopy when she presented with the spontaneous expulsion of a vertical stem of one of the devices. This is a unique case where two LNG-IUS were inserted in error and hence it teaches the clinicians the importance of good training and being aware of the possibility of the missing thread which deserves further investigations especially when such cases are encountered in a busy general practice.

Regeneration, colonisation and growth rates of allofragments in four common stream plants

Colonisation by stream plants occurs to a large extent from simple stem fragments. Allofragments are stem fragments formed by mechanical breakage. We studied regeneration, colonisation, and growth rates in four common stream plants: Elodea canadensis Michx., Myriophyllum spicatum L., Potamogeton perfoliatus L. and Ranunculus baudotii x pseudofluitans. The objectives of this study were to determine (1) if shoots with an apical tip have higher regeneration (growth of new shoots and rhizomes from allofragments) and colonisation (root attachment in sediment) abilities and higher relative growth rates (RGR) than shoots without an apical tip, and (2) if fragment size correlates with regeneration and colonisation abilities and with RGR of fragments. For all species, over 60% of fragments regenerated new shoots and colonised. Apical shoots and larger fragments generally had higher regeneration and colonisation abilities and higher RGR. Relative growth rate for E. canadensis and M. spicatum was between 0.06 and 0.09 d −1 whereas it was about half this rate for Ranunculus and P. perfoliatus (0.02–0.04 d −1).

First macrofossil evidence of a pre-Holocene thorny bamboo cf. Guadua (Poaceae: Bambusoideae: Bambuseae: Guaduinae) in south-western Amazonia (Madre de Dios — Peru)

Three fossil stem fragments collected from the banks of the Madre de Dios river in the south-western Peruvian Amazon are described and identified as Guadua sp. from their anatomical structure and gross morphology. These fossil monocots are stem fragments corresponding to a nodal region with i) circular sheath scars, ii) monopodial ramifications, iii) thorny or spiny buds or complex branches, and iv) a hollow stem structure. According to C 14 radiodating and to their stratigraphic position, these fossils are older than 45,790 yr BP (Late Pleistocene) and younger than 3.12 ± 0.02 My (Late Pliocene) indicating that Guadua was present in south-western Amazonia before the first human occurrence in America, and before the Last Glacial Maximum (LGM). Since little is known regarding the origin of Guadua Kunth, a bamboo native to Central and South America and questions remain regarding the history of Guadua-dominated forests within the Amazonian lowland tropical rainforest, this work suggests an alternate interpretation for the Poaceae-rich palynological assemblages of Amazonia and may contribute to an understanding of the evolutionary history and present diversity of the vegetation of Amazonia.

인삼 잿빛곰팡이병균 Botrytis cinerea의 균학적 특성

A total of 29 Botrytis were isolated from ginseng gray mold at 8 locations in Korea from June to July, 2004 and 2005. The causative agent of them was identified as Botrytis cinerea based on morphological characteristics of conidia and RPB2 gene sequence analysis. In inoculation experiments with sclerotia, one isolate was pathogenic to ginseng plant whereas two isolates were non-pathogenic. Scanning electron microscopy revealed that the sclerotia of pathogenic isolate has rough surface and that of non-pathogenic isolate very smooth surface. Optimum temperature and culture conditions for sclerotia production were and darkness, respectively. The number of sclerotia was increased tenfold on media added with 0.5% old stem fragment of ginseng.

Estudo anatômico de folha e caule de Elephantopus mollis Kunth (Asteraceae)

Conhecida comumente como erva-de-colégio, erva-grossa e sussuaiá, Elephantopus mollis Kunth (Asteraceae) é uma espécie herbácea perene, de base sublenhosa, ramos curtos e flores arroxeadas. Suas folhas são empregadas como emoliente, resolutivo, sudorífico e no tratamento de bronquite, tosse e gripe na medicina popular. O objetivo deste trabalho foi estudar caracteres anatômicos foliares e caulinares, a fim de fornecer subsídios aplicáveis à identificação da planta medicinal. Folhas adultas e fragmentos de caules foram fixados, seccionados e corados com azul de astra/fucsina básica ou com azul de toluidina. Testes microquímicos e análise ultra-estrutural de superfície foram também executados. A folha possui epiderme uniestratificada, recoberta por cutícula estriada e, em vista frontal, tem células com contorno ondulado. Ocorrem tricomas tectores e glandulares. Os primeiros são eretos, pluricelulares e unisseriados. Os tricomas glandulares são capitados e bisseriados. O mesofilo é dorsiventral e a nervura central é percorrida por feixes vasculares colaterais dispostos em arco aberto. O caule, em estrutura secundária inicial, possui epiderme unisseriada com cutícula estriada e tricomas semelhantes aos da folha. No córtex, observam-se colênquima anelar alternado com clorênquima e endoderme com estrias de Caspary. Calotas esclerenquimáticas apõem-se ao floema. Este é formado pelo câmbio vascular em direção à periferia e o xilema é gerado de modo centrípeto. A medula é parenquimática. Pequenos cristais de oxalato de cálcio estão presentes na folha e no caule.

Water dispersal as an additional pathway to invasions by the primarily wind-dispersed tree Ailanthus altissima

Long-distance dispersal is a key process in biological invasions. Previous research has emphasized the role of nonstandard dispersal vectors, but consequences of a change in dispersal vector for the establishment of invasive plant species have received less attention. We analyzed how water-mediated dispersal rather than the more expected wind-mediated dispersal can affect the establishment of the invasive tree Ailanthus altissima in riparian corridors by changing the germination rate and velocity and by providing the option of a new pathway of vegetative propagation. We analyzed the potential of different types of propagules (fruits that have floated or been submerged, current- and second-year stem fragments) to establish new individuals after contact with water for 0, 3, 10, and 20 days. Length and type of seed contact with water led to divergent germination responses. Seeds that had floated for 3 days had an increased level of seed germination (87%), while a 20-day stay in water water-curbed germination to 32% compared to 53% in control. After floatation, the maximum number of emerged seedlings was achieved more than 3 weeks earlier than in all other treatments. In general, the germination was enhanced in floating compared to submerged fruits. Experiments with stem fragments revealed the option of a novel pathway for long-distance dispersal in river corridors: Except for stem fragments that floated for 20 days, 33–75% of buried stem fragments produced adventitious shoots, 10% also set roots. The results suggest that both generative and vegetative propagules of A. altissima can be dispersed at regional scales in river corridors. Hence, water as an additional dispersal vector is expected to enhance invasions by species with wind-dispersed seeds. Our findings suggest the importance of control of initial colonizations in riparian habitats and emphasize the need to include consequences of secondary dispersal when modeling the spread of invasive species.

HORSETAILS AND SEED FERNS FROM THE MIDDLE TRIASSIC (ANISIAN) LOCALITY KÜHWIESENKOPF (MONTE PRÀ DELLA VACCA), DOLOMITES, NORTHERN ITALY

Abstract: Well‐preserved floras from the Alpine Early–Middle Triassic are rare, and thus our understanding of the vegetation in this area during this period of time continues to be incomplete. As a result, every new find represents a significant piece of information that deserves thoughtful consideration. Anisian (Middle Triassic) sphenophytes and pteridosperms have recently been recovered from the Kühwiesenkopf locality (Monte Prà della Vacca) in northern Italy. The sphenophytes are represented by stem fragments, strobili and isolated sporangiophore heads of Equisetites, as well as by a few specimens of Neocalamites sp. and Echinostachys sp. The pteridosperms include abundant remains of the peltasperm foliage type Scytophyllum bergeri. A second Scytophyllum species in this flora, S. apoldense, is regarded as conspecific with S. bergeri based on epidermal anatomy; the two morphotypes are interpreted as sun and shade leaves of a single biological species. The seed‐bearing disc Peltaspermum bornemannii sp. nov. probably represents the female reproductive structure of S. bergeri. Additional pteridosperm remains include foliage assignable to Sagenopteris sp. and Ptilozamites sp., in both cases perhaps the earliest records of these genera.

The Biology of Invasive Alien Plants in Canada. 7. Cabomba caroliniana A. Gray

The freshwater aquatic plant Cabomba caroliniana, or fanwort, was recently reported in a lake northeast of Peterborough, Ontario, where it has successfully established and survived winter conditions since at least 1991. This is the first documented occurrence of fanwort becoming naturalized in Canada. Fanwort is a popular aquarium plant that is native to South America and possibly the southeastern United States and has been introduced in several Asian, Pacific and European countries through the discarding or deliberate planting of aquarium plants in natural waterways. It is particularly invasive in China, Japan and Australia, and in parts of the United States, where its range is spreading. Fanwort grows rapidly and forms dense stands that clog waterways, impeding flow, obstructing navigation, altering fish habitat and excluding other vegetation. It does not produce mature seed in the northern parts of its North American range, but can multiply clonally and spread quickly by stem fragmentation. It produces turion-like stems at the end of the growing season, which assist in over-wintering under adverse conditions. Fanwort is difficult to control with herbicides and is resistant to mechanical management techniques as populations can quickly re-establish from plant fragments. Populations near the Trent-Severn Waterway in Canada are extensively established and management tools are not available to attempt eradication. An integrated management plan that focuses on early detection and rapid response in surrounding water bodies may succeed in mitigating the economic and environmental impacts and limiting the spread of fanwort. Key words: Cabomba caroliniana, fanwort, cabomba de Caroline, CABCA, aquatic plant, weed biology, invasive alien

Plant remains from the Kreftenheye Formation (Eemian) at Raalte, The Netherlands

The Kreftenheye Formation is a fluviatile deposit occurring in the central part of the Netherlands. The present study deals with the plant remains found in suction-dredged bulk samples from its largely Eemian Zutphen Member, a clayey sediment formerly known as the clay–peat bed or the Salvinia bed. It reports the discovery of a large number of galls induced by the asexual generation of the currently southeast European oak gall wasp Andricus hungaricus. The associated plant remains include seeds, fruits, conifer cones, wood, spines, leaf fragments, buds, bud scales, stem fragments, bryophytes, sporangia, oospores, palynomorphs, galls, jet and amber. The palynomorph samples indicate the Late Eemian pollen zone E5b of the Carpinus phase as the origin of the galls, but the other macrofossils may have a wider stratigraphic range, including possibly also material from (a part) of the zones E3–E5a. Several elements, such as Celtis, Chamaecyparis, Juglans, Magnolia and Pterocarya, date almost certainly from earlier interglacials. The list of plant remains is dominated by fresh water plants, riparian elements and ancient woodland taxa, which reflects the ecological range of the IJssel valley and adjacent ice-pushed ridges very well. Thermophilous elements include Brasenia schreberi, Buxus sempervirens, Cornus mas, Najas minor, Salvinia natans, Trapa natans and possibly also Andricus hungaricus. Quercus cerris, the probable host of the sexual generation of A. hungaricus was not found.

Biomechanical comparison of extended trochanteric osteotomy and slot osteotomy for femoral component revision in total hip arthroplasty

Depending upon the clinical presentation and need for exposure in revision hip arthroplasty, an extended trochanteric osteotomy or slot osteotomy could be used for removal of an inaccessible distal cement mantle, infected material, or distal fragment of a broken stem. This study is a biomechanical comparison of these two osteotomy techniques. A press-fit femoral component with a 20-cm straight stem was implanted in each of ten synthetic femurs. The stiffness of these components implanted in the femurs was measured for a compressive load condition simulating the stance phase of level walking. Half of the femurs then received an extended trochanteric osteotomy, and the other half a slot osteotomy. Stiffness testing was repeated both after the osteotomized bone was removed, and after it was fixed back in place by cerclage wiring. The stiffness of the femoral component/synthetic femur constructs in the slot osteotomy group was significantly greater than in the extended trochanteric osteotomy group. This study demonstrated that in the laboratory setting, the slot osteotomy was significantly stiffer than the more traditional extended trochanteric osteotomy. However, the clinical implications of this increased stiffness are unknown. The ultimate choice of the type of osteotomy depends upon the exposure requirements for a given clinical situation.

Localization of Ruminal Cellulolytic Bacteria on Plant Fibrous Materials as Determined by Fluorescence In Situ Hybridization and Real-Time PCR

To visualize and localize specific bacteria associated with plant materials, a new fluorescence in situ hybridization (FISH) protocol was established. By using this protocol, we successfully minimized the autofluorescence of orchard grass hay and detected rumen bacteria attached to the hay under a fluorescence microscope. Real-time PCR assays were also employed to quantitatively monitor the representative fibrolytic species Fibrobacter succinogenes and Ruminococcus flavefaciens and also total bacteria attached to the hay. F. succinogenes was found firmly attached to not only the cut edges but also undamaged inner surfaces of the hay. Cells of phylogenetic group 1 of F. succinogenes were detected on many stem and leaf sheath fragments of the hay, even on fragments on which few other bacteria were seen. Cells of phylogenetic group 2 of F. succinogenes were often detected on hay fragments coexisting with many other bacteria. On the basis of 16S rRNA gene copy number analysis, the numbers of bacteria attached to the leaf sheaths were higher than those attached to the stems (P<0.05). In addition, R. flavefaciens had a greater tendency than F. succinogenes to be found on the leaf sheath (P<0.01) with formation of many pits. F. succinogenes, particularly phylogenetic group 1, is suggested to possibly play an important role in fiber digestion, because it is clearly detectable by FISH and is the bacterium with the largest population size in the less easily degradable hay stem.