Fragile Plant Research Articles

Efecto del pastoreo sobre el banco de semillas en una estepa de halófitas de la Depresión del Salado

Rotational grazing, or even grazing cessation, improves soil and plant community structure on the halophytic steppe of the Flooding Pampa. However, no information exists about the effect of those grazing regimes on the soil seed bank of this fragile plant community. The objective of this work was to evaluate the effect of different grazing regimes on four attributes of the soil seed bank: 1) total size, 2) size and relative contribution of the functional groups of winter grasses (annual and perennial), summer grasses (annual and perennial), non-grass monocotyledonous, legumes and non-legume dicotyledonous, 3) diversity and 4) floristic composition. We studied five plots subjected to different grazing regimes for 14 years (two plots under continuous grazing; two plots under rotating grazing and one excluded from grazing), sampling in June and February to characterize the summer and winter soil seed bank. We found that continuous grazing reduced total seed bank size, and especially that of winter annual grasses and monocotyledonous, and also reduced floristic diversity, richness and evenness, especially in the summer seed bank. In addition, continuous grazing triggered important species replacements within each functional group, especially in the winter annual grasses, summer perennial grasses and dicotyledonous, the three groups explaining most proportion of the soil seed bank. Therefore, plots under continuous grazing were floristically different from those under rotational grazing or ungrazed. This work suggests that continuous grazing is a severe disturbance which can reduce the regeneration potential of the halophytic steppe.

Study of plant configuration pattern in guided vegetation restoration: A case study of semiarid underground mining areas in Western China

The large-scale and high intensity mining of coal resources has further worsened the already fragile plant ecosystem in Western China. On the basis of strictly following the developmental law of regional natural ecosystems, guiding the restoration of damaged vegetation is one of the important measures for ecological restoration in mining areas. However, there are still some problems to achieve the guided restoration of damaged vegetation in semiarid mining areas: how to configure different plant species, and what is the control threshold of vegetation coverage under different site conditions among others. In this paper, based on DEM, slope, aspect and soil type data, 12 different site conditions were obtained by using overlay analysis function of ArcGIS software. The trend of interannual variation of vegetation coverage was analyzed using Landsat Normalized Difference Vegetation Index (NDVI) time series data, and the spatial distribution of areas of degraded vegetation under 12 site conditions was identified. Based on the Fully Constrained Least Square (FCLS) unmixing algorithm, typical native plants were classified using Aerial Hyperspectral data. Finally, through the comparative analysis of plant composition and abundance under 12 site conditions, the control thresholds of vegetation coverage ranged from 36.60% to 45.30% in the early stage of vegetation restoration. The thresholds of steep slope are lower than that in gentle and flat slope, which is mainly related to the fact that steep slope is more prone to soil erosion and is not conducive to the conservation of soil water and nutrients. According to the calculation results of different plant allocation proportion under 12 site conditions, the proportion of herbs and shrubs is higher than that of trees. When selecting species for vegetation configuration, native herbs and shrubs with strong adaptability, fast growth and strong drought resistance should be preferred. It is suggested that trees should be planted properly after the site conditions of vegetation growth are effectively restored or the vegetation community structure tends to be stable. In the process of vegetation restoration in semiarid mining area, not only the appropriate threshold of vegetation coverage should be considered, but also the proportion of trees, shrubs, and herbs has an important impact on the effect of vegetation restoration. The results of this paper will provide guidance for the orderly restoration of damaged vegetation in semiarid mining areas.

Changing Plant-based Subsistence Practices among Early and Middle Holocene Communities in Eastern Maghreb

ABSTRACT The eastern Maghreb is a key area for understanding environmental and cultural dynamics during the early and middle Holocene. Capsian populations from around 10000–7500 cal BP were among the last foragers in the region. Capsian sites are known as escargotières (land shell middens), and locally called rammadiyat (meaning ashy mound). As taphonomic conditions in Capsian open-air sites generally favour the preservation of resistant materials such as shells and bones rather than fragile plant remains, this study integrates macro-botanical and microfossil evidence from phytoliths, calcitic wood ash pseudomorphs and dung spherulites, since each is influenced by different formation and post-depositional processes. Archaeobotanical results from recent excavations in four Tunisian sites located across the lowland steppe, the Dorsale Mountains and the eastern coast display a wide range of wild plant resources, such as pine, oak, wild legumes, and grasses, in particular Alfa grass. These findings suggest that these plants could have played an important role in Capsian diet, whereas the presence of Alfa grass suggests the use of fibre sources for basketry, matting, building and fuel. Integrated macro-botanical and microfossil records contribute to a better understanding of changing subsistence practices on the threshold of early food-producing systems in north-west Africa.

Isolation of Plant Root Nuclei for Single Cell RNA Sequencing.

The characterization of the transcriptional similarities and differences existing between plant cells and cell types is important to better understand the biology of each cell composing the plant, to reveal new molecular mechanisms controlling gene activity, and to ultimately implement meaningful strategies to enhance plant cell biology. To gain a deeper understanding of the regulation of plant gene activity, the individual transcriptome of each plant cell needs to be established. Until recently, single cell approaches were mostly limited to bulk transcriptomic studies on selected cell types. Accessing specific cell types required the development of labor-intensive strategies. Recently, single cell sequencing strategies were successfully applied on isolated Arabidopsis thaliana root protoplasts. However, this strategy relies on the successful isolation of viable protoplasts upon the optimization of the enzymatic cocktails required to digest the cell wall and on the compatibility of fragile plant protoplasts with the use of microfluidic systems to generate single cell transcriptomic libraries. To overcome these difficulties, we present a simple and fast alternative strategy: the isolation and use of plant nuclei to access meaningful transcriptomic information from plant cells. This protocol was specifically developed to enable the use of the plant nuclei with 10× Genomics' Chromium technology partitions technology. Briefly, the plant nuclei are released from the root by chopping into a nuclei isolation buffer before purification by filtration then nuclei sorting. Upon sorting, the nuclei are resuspended in a low divalent ion buffer compatible with the Chromium technology in order to create single nuclei ribonucleic acid-sequencing libraries (sNucRNA-seq). © 2020 Wiley Periodicals LLC. Basic Protocol 1: Arabidopsis seed sterilization and planting Basic Protocol 2: Nuclei isolation from Arabidopsis roots Basic Protocol 3: Fluorescent-activated nuclei sorting (FANS) purification Support Protocol: Estimation of nuclei density using Countess II automated cell counter Alternate Protocol 1: Proper growth conditions for Medicago truncatula and Sorghum bicolor Alternate Protocol 2: Estimation of nuclei density using sNucRNA-seq technology.

Poly-l-lysine-based tissue embedding compatible with matrix-assisted laser desorption ionization-mass spectrometry imaging analysis of dry and fragile aristolochia plants

The integrity of tissue is crucial for a high-quality analysis of matrix-assisted laser desorption ionization-mass spectrometry image (MALDI-MSI). Various embedding media utilized in traditional tissue-sectioning techniques are generally not recommended for MALDI-MSI of dry and fragile plant tissues because of the ion suppression effect in MALDI ionization in the low-mass region as well as the undesirable structural deformation during the sample preparation. In this work, a novel poly-L-lysine (PLL)-based tissue embedding method was developed for MALDI-MSI analysis of dry and fragile aristolochia plant (AP) tissues. The practical application in fixation, embedding, cryosectioning, and mounting of the dry and fragile AP tissues demonstrated that the PLL-based embedding technique could provide good rigidity to the plant tissues analysis compared to that without embedding and gelatin embedding. With the assistance of the PLL embedding medium, high spatial resolution molecular ion maps of main compounds, including aristolochic acids I (AAI) and aristolochic acids II (AAII) in AP root tissue, could be achieved by MALDI-MSI with enhanced signal intensities and no obvious background interference. This work provides an alternative approach for embedding the dry and fragile plant tissues comparable with MALDI-MSI analysis.

Controls on seed dormancy

Plant Science![Figure][1] Seeds of the small mustard plant Arabidopsis thaliana in their pod CREDIT: DENNIS KUNKEL MICROSCOPY/SCIENCE SOURCE Herbivores and an inopportune cold snap can destroy fragile plant seedlings. Plants control the dormancy of their seeds in anticipation of more

Hedge mazes and landscape gardens as cultural boundary objects

Despite their obvious functional and stylistic differences, hedge mazes and English landscape gardens have salient symbolic and structural similarities which make them fruitful objects of comparative analysis. Both invert the norms expected of interior and exterior spaces, of human cultivation and “wilderness”, creating landscapes of semiotic uncertainty. Being at once natural and cultural, both types of space present a “problem to be solved” either by reaching a centre or understanding a layout. Both “play” with the notion of boundary by constructing uncrossable and at times oppressive walls from seemingly fragile plant matter or by hiding their boundaries. At the same time there are important differences which make this comparison of boundary spaces even more interesting: hedge mazes and landscape gardens are distinguishable by their respective structural levels, the presence or absence of a centre, their relation to other parts of gardens and connected human habitations.Using Juri Lotman’s notion of hybrid and transitional objects characteristic of boundary mechanisms, this paper explores the semiotically dense nature-culture boundary which these mazes and gardens both inhabit and create. The objects of our analysis are 17th-century English mazes and early English gardens dating from the beginning of the 18th century: mazes at Longleat and Hampton Court, and landscape gardens such as Rousham and Stowe.

Two parametric cell cycle analyses of plant cell suspension cultures with fragile, isolated nuclei to investigate heterogeneity in growth of batch cultivations.

Plant cell suspensions are frequently considered to be heterogeneous with respect to growth in terms of progression of the cells through the cell cycle and biomass accumulation. Thus, segregated data of fractions in different cycle phases during cultivation is needed to develop robust production processes. Bromodeoxyuridine (BrdU) incorporation and BrdU-antibodies or 5-ethynyl-2'-deoxyuridine (EdU) click-it chemistry are frequently used to acquire such information. However, their use requires centrifugation steps that cannot be readily applied to sensitive cells, particularly if nuclei have to be extracted from the protective cellular milieu and envelopes for DNA analysis. Therefore, we have established a BrdU-Hoechst stain quenching protocol for analyzing nuclei directly isolated from delicate plant cell suspension cultures. After adding BrdU to test Harpagophytum procumbens cell suspension cultures the cell cycle distribution could be adequately resolved using its incorporation for the following 72 h (after which BrdU slowed biomass accumulation). Despite this limitation, the protocol allows resolution of the cell cycle distribution of cultures that cannot be analyzed using commonly applied methods due to the cells' fragility. The presented protocol enabled analysis of cycling heterogeneities in H. procumbens batch cultivations, and thus should facilitate process control of secondary metabolite production from fragile plant in vitro cultures. Biotechnol. Bioeng. 2016;113: 1244-1250. © 2015 Wiley Periodicals, Inc.

Understanding the Molecular Signatures in Leaves and Flowers by Desorption Electrospray Ionization Mass Spectrometry (DESI MS) Imaging

The difference in size, shape, and chemical cues of leaves and flowers display the underlying genetic makeup and their interactions with the environment. The need to understand the molecular signatures of these fragile plant surfaces is illustrated with a model plant, Madagascar periwinkle (Catharanthus roseus (L.) G. Don). Flat, thin layer chromatographic imprints of leaves/petals were imaged using desorption electrospray ionization mass spectrometry (DESI MS), and the results were compared with electrospray ionization mass spectrometry (ESI MS) of their extracts. Tandem mass spectrometry with DESI and ESI, in conjunction with database records, confirmed the molecular species. This protocol has been extended to other plants. Implications of this study in identifying varietal differences, toxic metabolite production, changes in metabolites during growth, pest/pathogen attack, and natural stresses are shown with illustrations. The possibility to image subtle features like eye color of petals, leaf vacuole, leaf margin, and veins is demonstrated.

English

Germination is a key event in plant life cycle and imbibition temperature is an important factor for the major reorganization pro- cesses in the germinating seeds. Sub-physiological temperature at this stage affects virtually all aspects of cellular function including protein folding, kinetic parameters of membrane fluidity, protein assembly, and general metabolic processes. In this article we will review the re- search which has been carried out to decipher the basic mechanisms of low temperature (LT) stress with special emphasis on germination. With the better understanding of LT tolerance in some plant species we will also discuss how these attributes can be transferred in the im- portant food crops to attain better germination stamina at sub-physiological temperatures. At germination stage, the cellular machinery in the embryo is not at its proper place and is going through reorganisation and any environmental severity has devastating effects on the fragile plant. But LT resistant species have evolved the ability to acclimatise, with the remodelling of cell and tissue structures and the reprogram- ming of metabolism and gene expression. Metabolic networks are redirected towards the synthesis of cryoprotectant molecules, which in association with other proteins bring about physical and biochemical restructuring of cell membranes through changes in the lipid composi- tion and induction of other non-enzymatic proteins that alter the freezing point of water. Genetic engineering of crops for enhanced seed germination performance will certainly help to achieve optimum agricultural yields..

Intoning the Male and Female Voices in a Novel by Eva Figes

AMY CHRISTINE PARKER University of Manitoba The book Light, with Monet at Giverny: A Novel is a story that imaginatively describes a day in the life of the Monet family. It is written by one of the feminist writers of the first wave which ended in the seventies, ‘‘Simone de Beauvoir, Betty Friedan, Eva Figes, Germaine Greer, Shulamith Firestone, and Kate Millett’’, as described by Susan Watkins in Twentieth Century Women Novelists: Feminist Theory into Practice. Watkins’ book describes these women as being opposed to contemporary interpretations of Freudian theory, and in particular to certain aspects of his description of the Oedipus complex which they see as patriarchal and arising from capitalist values and the hypothesis that hysteria is self-motived rather than a problem of sexuality. Yet what Sally Robinson recognizes in Engendering the Subject: Gender and Self-representation in Contemporary Women’s Fiction as the refreshing plurality of the voices of these feminist authors is characteristic as well of those who remain faithful to religion or Christianity, which are traditionally feminine voices. This paper searches for the developing voice of women in this work of fiction by Eva Figes and recognizes as well the presence of the continuing male voices. A positive aspect of Figes’ novels is the fact that she often finds a way for a character to thrive despite harsh conditions. Throughout the novel, exterior sounds such as a clock counting the hours, a nearby passing train, singing birds and galloping horses create some sonorous effects. As the land lies amongst hills and a river, echoes can also be heard. These sounds punctuate the dialogues and silences within which much of the meaning of the story is contained. In this novel about an artistic family, the auditory effects are enhanced by visual motifs of light and color. In another of her novels, The Knot, there is a similar recurrence of ‘[n]ot

Climate Change and Infectious Disease

Due to increasing CO2 emissions and other greenhouse gases, accelerated global warming is predicted by the Intergovernmental Panel on Climatic Change (IPCC). These climate changes are anticipated to have a long-term impact on marine and terrestrial ecosystems. Rising sea levels are predicted to flood low-lying coastal regions, and fresh water resources could become scarce leading to development of desert-like regions. This will greatly affect the survival of fragile plant species, wild animals, and other ecosystems all of which could directly or indirectly affect survival and or spread of pathogens and their vectors. Although these changes will undoubtedly have an impact on human health, the uncertainties in climate models, as well as predictive epidemiology, hamper accurate predictions on the impact of global warming on public health. In addition, the absence of experimental models that demonstrate dose dependent effects between climate change and disease gives ammunition to those in doubt. As a joint Institute of Medicine/National Academy of Science Committee concluded in 2001, we know that there is a relationship between climate change and infectious disease, but these links are disease specific and location specific, and we cannot yet predict these impacts at anything other than coarse temporal and spatial scales. Thus, the impact on human health is still unclear, and climate change may increase the prevalence of particular infectious diseases in some regions, while decreasing the prevalence in others. There are currently 137 publications in PubMed using the keywords “infectious diseases” and “global warming.” The majority of which were published in the last few years, and this attests to the increasing interest in this aspect of public health. However, most data so far are observational, and the predictive understanding of the impact of disease is based on mathematical modeling. Other sources of data include retrospective time-series analyses in specific locations, or use the periodic El Nino Southern Oscillation (ENSO) phenomenon as a surrogate for long-term change. Since controls are usually historical and data are now collected in a more biased fashion than before, there is a concern that some of our conclusions reflect an observational bias that is common when data collection is initiated on new problems that were not previously under rigid observation. To tackle global warming, coordinated efforts will have to be taken that do not only span countries and cultures but also require many fields of scientific expertise. Effects of global warming are multifactorial and occur at a time when many other important confounding variables constantly change. Beyond global warming, increasing global mobility, genetic modification of agricultural products, and usage of reagents that inhibit pathogens can all have a significant impact on spread and prevalence of infectious diseases. This will make it difficult to establish causality between global warming and impact of infectious diseases. Rigorous scientific conclusions call for experimental models that examine impact of temperature under controlled conditions. Finally, global warming occurs in the general setting of climate change—temperature is not the only variable that is changing. Rather, rainfall patterns, wind patterns, and other climatologic variables are changing at the same time. As much as we all wish to act fast, and as much as we cry out for an enlightened public consciousness that would be required to press for policy changes that ameliorate the effects of global warming and limit the emission of greenhouse gases, our most imminent problem is that we do not have a true scientific understanding of the matter yet. In this special issue, Interdisciplinary Perspectives on Infectious Diseases solicited cross-cutting interdisciplinary articles that took new and broad perspectives ranging from what we might learn from previous climate changes on disease spread to integrating evolutionary and ecologic theory with epidemiologic evidence in order to identify key areas for study in order to predict the impact of ongoing climate. These studies present interesting results and analysis of available data. They also highlight how difficult it is to interpret data at present. Future studies should increase retrospective surveys of museum specimens from previous times, long lasting unbiased data mining and true experimental work on disease manifestation under higher temperatures. Moreover, predictive climate models and predictive epidemiology both need to advance, and become coupled together. This research will likely not meet current output criteria of short-term grant proposals. This problem needs meticulous patient intelligent researches like Darwin to devote their life to answering these pressing questions. Without such efforts, the current generation will inevitably benefit at the cost of generations to come. Bettina C. Fries Jonathan Mayer

Human Health Risk Assessment due to Global Warming – A Case Study of the Gulf Countries

Accelerated global warming is predicted by the Intergovernmental Panel on Climatic Change (IPCC) due to increasing anthropogenic greenhouse gas emissions. The climate changes are anticipated to have a long-term impact on human health, marine and terrestrial ecosystems, water resources and vegetation. Due to rising sea levels, low lying coastal regions will be flooded, farmlands will be threatened and scarcity of fresh water resources will be aggravated. This will in turn cause increased human suffering in different parts of the world. Spread of disease vectors will contribute towards high mortality, along with the heat related deaths. Arid and hot climatic regions will face devastating effects risking survival of the fragile plant species, wild animals, and other desert ecosystems. The paper presents future changes in temperature, precipitation and humidity and their direct and indirect potential impacts on human health in the coastal regions of the Gulf countries including Yemen, Oman, United Arab Emirates, Qatar, and Bahrain. The analysis is based on the long-term changes in the values of temperature, precipitation and humidity as predicted by the global climatic simulation models under different scenarios of GHG emission levels. Monthly data on temperature, precipitation, and humidity were retrieved from IPCC databases for longitude 41.25°E to 61.875°E and latitude 9.278°N to 27.833°N. Using an average of 1970 to 2000 values as baseline, the changes in the humidity, temperature and precipitation were predicted for the period 2020 to 2050 and 2070 to 2099. Based on epidemiological studies on various diseases associated with the change in temperature, humidity and precipitation in arid and hot regions, empirical models were developed to assess human health risk in the Gulf region to predict elevated levels of diseases and mortality rates under different emission scenarios as developed by the IPCC. The preliminary assessment indicates increased mortality rates due to cardiovascular and respiratory illnesses, thermal stress, and increased frequency of infectious vector borne diseases in the region between 2070 and 2099.

Phenotypic Characterization, Genetic Analysis and Gene‐mapping for a Brittle Mutant in Rice

Plant mechanical strength is an important agronomic trait of rice. An ethyl methane sulfonate (EMS)-induced rice mutant, fragile plant 2 (fp2), showed morphological changes and reduced mechanical strength. Genetic analysis indicated that the brittle of fp2 was controlled by a recessive gene. The fp2 gene was mapped on chromosome 10. Anatomical analyses showed that the fp2 mutation caused the reduction of cell length and cell wall thickness, increasing of cell width, and the alteration of cell wall structure as well as the vessel elements. The consequence was a global alteration in plant morphology. Chemical analyses indicated that the contents of cellulose and lignin decreased, and hemicelluloses and silicon increased in fp2. These results were different from the other mutants reported in rice. Thus, fp2 might affect the deposition and patterning of microfibrils, the biosynthesis and deposition of cell wall components, which influences the formation of primary and secondary cell walls, the thickness of cell walls, cell elongation and expansion, plant morphology and plant strength in rice.

Getting Away with Murder on the Texas Frontier: Notorious Killings and Celebrated Trials (review)

354Southwestern Historical QuarterlyJanuary GettingAway with Murderon tL· TexasFrontier: Notorious Killings and Celebrated TriaL·. By Bill Neal. (Lubbock: Texas Tech University Press, 2006. Pp. 320. Illustrations, maps, notes, bibliography, index. ISBN 0896725790. $27.95, cloth.) Bill Neal, a longtime district attorney and criminal defense lawyer, has painstakingly researched some of West Texas's most celebrated trials during the late nineteendi and early twentiedi centuries. With an ear for a good story, he organizes his inquiry around the central question of how some defendants, in spite of evidence, routinely avoided guilty verdicts for their crimes. He concludes diat the explanation lies in the southern roots of many West Texas migrants, whose code of honor did not rule out self-help, coupled with a cultural context in which there was generally a high toleration for violence. Moreover, a "reverse minded" appeals court in the state paid close attention to technicalities in reviewing convictions, seeking to assert its power as an institution in the state. As Neal asserts, an increasingly professional bench and bar succeeded in "transplanting" legal culture toWest Texas where, as he notes in his conclusion, "the fragile plant ofjustice under duly enacted law finally took root and matured. Judge Blackstone finally oustedJudges Lynch and WincL·stef (p. 244). Chapters focus on such cases as die trial of Thomas Fulcher for die murder of"Old Man Beemer," the 1896 Wichita Falls bank robbery and murder of cashier Frank Dorsey, as well as some rather "funny" pardons from the Texas governor's office. "Off the Record" conclusions in each chapter—where Neal brings his legal training to bear on die interpretations of historical proceedings—are especially interesting. While entertaining reading, this study does not address the larger historiographical issues it raises. For example, do famous trials really help us understand the day-to-dayworkings ofcriminaljustice in WestTexas? Are diey typical? Moreover, Neal's transplantation thesis suggests an empty legal vessel into which good men bring impartialjustice dirough die establishment offormal legal systems, struggling against mob rule,jury nullification, or simply the outrageous personalities drawn to the frontier. Neal's own evidence, in fact, suggests the very political nature of those same transplanted institutions—whether law enforcement, die professional bar, the bench, or even the governor's office. What I think Neal misses here is an opportunity to situate die imposition of a certain kind of law and criminaljustice in relationship to die larger U.S. colonial project, a process so well documented by many recent historians of the U.S. West. In die final analysis, the appeal to personality over systemic explanation is a real limitation of diis study. The afterword illustrates this nicely. Here Neal analogizes notorious trials profiled in die book to contemporary examples such as the O. J. Simpson trial and the trials ofthe police officers accused ofbeating Rodney King. Illustrating how "racism, emotion and bias trumped overwhelming evidence and the law, enabling guilty defendants to get away with their crimes" (p. 245), these cases suggest to Neal that die problem is not with the system but in the "human frailties of those who operate die system" (p. 246). I was left wondering whether such analogies are fair, given the vast historical differences among these cases. Moreover, all these cases raise real structural questions about howjustice, fairness, 2??8Book Reviews355 and process operate in practice in a wider social, economic, and political context. Despite these limitations, I enjoyed GettingAway with Murder. It certainly reminds us that what counts as justice was as negotiated in late-nineteenth-century West Texas as it is today. California State University Monterey BayDavid A. Reichard Brokers ofCulture: ItalianJesuits in tL·American West, 1848-içiç. By Gerald McKevitt. (Palo Alto, Calif.: Stanford University Press, 2006. Pp. 448. Illustrations, notes, glossary, index. ISBN 0804753571. $60.00, clodi.) "Whether [San Francisco] should be called a villa, a brothel, or Babylon, I am at a loss to determine," wrote Jesuit missionary Michele Accolti during his labors in California during the mid-nineteenth century (p. 116). His disapproval of the city notwithstanding, Accolti gained a reputation for his tireless work among San Francisco's disparate communities. A Protestant minister recalled: Wheuier it was a dying foreigner in the sandhills...

Novel tissue preparation method and cell-specific marker for laser microdissection of Arabidopsis mature leaf

Laser microdissection (LMD) is a powerful tool to isolate pure cell populations from heterogeneous tissues. This system has been successfully used for animal research; however, the reports of its application to plant tissues remain limited. One of the challenges of LMD for plant material is the tissue preparation. Although cryosectioning is commonly used for animal tissues, this is not a desirable method for fragile plant material with large central vacuoles. While paraffin preparation provides high histological quality and stability, the procedure is highly time consuming and may result in degradation of molecules of interest. In addition, conventional fixation and paraffin preparation methods do not preserve the structural integrity of very delicate plant tissues such as mature Arabidopsis thaliana leaves. Here, we used the rapid microwave paraffin preparation method with no fixative for preparation of Arabidopsis leaf tissue for LMD. This method resulted in Arabidopsis leaf sections with excellent preservation of leaf internal structure as evidenced by well-defined vascular bundles, phloem, and chloroplasts, and expanded and rounded epidermal cells. RNA extracted from leaf epidermal and mesophyll cells was of sufficient yield and specificity to use in downstream applications such as microarray analysis of the amplified mRNA. We employed the mesophyll cell-specific molecular marker, chloroplastic carbonic anhydrase, and developed an epidermal cell-specific marker, the very-long-chain fatty acid-condensing enzyme, CUT1, to assess specificity of harvested Arabidopsis leaf cell types by reverse transcription polymerase chain reaction. The described method is also likely to be superior for the preparation of other fragile botanical tissue for LMD and downstream applications.

Isolation and genetic characterization of a fragile plant mutant in rice (itOryza sauva) L.

The fragile rice mutant was isolated from an M2 population of indica variety Shuang Ke Zao (SKZ) treated with γ-rays, and designated asfpl (fragile plant 1) because of its fragile leaves and culms. To mapFP1 locus, an F2 mapping population was derived from a cross between thefpl and C-bao, a polymorphic japonic variety. The primary mapping result places theFP1 locus in an interval between two molecular markers, microsatellite marker RM16 (3.1 cM proximal toFP1) and STS marker G144a (9.1 cM distal toFP1) in the centromere region of chromosome 3. A CAPS marker C524a was further developed between RM16 and G144a, with 0.4 cM genetic distances to theFP1 locus, providing a practical starting point for constructing a BAC contig spanning theFP1 locus and cloning thefpl gene. Allelism test demonstratedthat fpl is allelic tobcl, a fragile rice mutant reported previously.

Reservoir ages in Baltic Sea sediment—a case study of an isolation sequence from the Litorina Sea stage

In order to quantify the reservoir age in Baltic Sea sediment, one sedimentary sequence from an isostatically isolated basin was subject to high-resolution AMS radiocarbon dates. Diatom analysis confirmed deposition during the Litorina Sea stage and later, in a freshwater lake. Macrofossils from well preserved seeds and other remnants from terrestrial plants were used for AMS datings. It is assumed that these fragile plant remains are not redeposited or affected by internal ages. The ages obtained from the macrofossils range from 6460±125 to 5580±75 14C yr BP. By comparing these radiocarbon ages with those obtained by bulk sediment dates, it was obvious that the bulk samples were affected by reservoir ages, resulting in too old ages. The reservoir ages varied within the sediment column; during the most saline phase, the reservoir age was approximately 750 yr, shortly after the isolation ca 400 yr and in the freshwater lake, the age differences between the two series were neglectable.

Vegetation changes in the Northern Russian far East as a result of human activity

Abstract At first glance, the vast expanses of the North appear incapable of withstanding the pressure of a modern industrial society. However, this paper, through a detailed examination of the interrelationship between nature and humanity along the northern reaches of the Russian Far East, documents that any form of human economic activity entails the destruction of fragile northern plant communities. It demonstrates the extent of human modification of the vegetation cover and discusses the various aspects of its restoration and preservation. The authors argue that the special conditions of the North require a long‐term strategy for rational utilization of the environment, including a program of measures for protection of native vegetation and development of environmentally benign technologies for industrial and agricultural production.

Determination of mass transfer parameters in surface aerated bioreactors with bubble entrainment

The volumetric oxygen mass transfer coefficient k L a is a critical design parameter for most bioreactors and has been extensively studied. However, few reliable correlations are available for its estimation. In this context, the k L a and specific interfacial area a of 3.5 1 and 16 1 surface-baffled and aerated double-helical-ribbon impeller (HRI) bioreactors were evaluated. The bioreactor configuration is characterized by significant surface bubble generation and entrainment into the liquid phase and has been shown to be highly efficient in the culture of fragile plant, mammalian and insect cells. The k L a and a parameters were determined independently using the dynamic gassing-in method and a modified sulphite method respectively. A second order model with proper validity criteria was developed to account for the effect (up to 90% underestimation) of headspace gas mixing dynamics on the k L a determination of surface-aerated bioreactors. For a 3.5 bioreactor stirred at 250 rev min −1 a surface k L a value of 52 h − was observed while the value for the 16 1 bioreactor mixed at 150 rev min −1 was 44 h −1. The liquid mass transfer coefficients k L obtained by dividing the measured k L a by the corresponding measured specific interfacial area are within the ranges reported in the literature for surface aerated (2.0–3.2×10 −5 m s −1) and sparged (9/23;7×10 −5 m s −1) conventional systems.