bluuebunny/crossref_metadata_2025 huggingface dataset:
Variation in seed dormancy among mother plants, populations and years of seed collection
Authors: Andersson L. , Milberg P.
Published: September 2008

Variation in dormancy level was tested in seeds of four species, each collected from three populations in 1994 and 1995 (experiment 1). Germination was tested in light and darkness on recently-harvested seeds and on those after-ripened in dry storage for one year. In addition, seeds from each of eight individual plants within each of eight populations were tested for germination when recently harvested and after warm stratification or cold stratification followed by a drying period (experiment 2). Seeds from the two years differed in dormancy level in Silene noctiflora, Sinapis arvensis and Spergula arvensis. Germination percentage differed significantly among populations in Sinapis arvensis and Spergula arvensis in both experiments and in Thlaspi arvense in experiment 2. Furthermore, dormancy level in seeds from different mother plants also varied in the three species tested in experiment 2. Variations at the three levels tested (year, population and mother plant) indicate that these species have a random pattern of variation in dormancy level. It is concluded that variation in seed dormancy among mother plants, populations and years must be taken into account when testing the germination characteristics of a species and also when attempting to model weed seed bank dynamics.
The applicability of a seed ecological database (SEED) in botanical research
Authors: Csontos Péter
Published: September 2008

This is the first report on the SEed Ecological Database (SEED) being developed under the co-ordination of the author. In its first version the database will cover physical characteristics of seeds, such as: slenderness (length/width), flatness (thickness/width) and thousand-seed weight. The list of species encompasses all seed plants (gymnosperms and angiosperms) native or naturalized in Hungary (about 2450 species). Two examples to demonstrate the power of SEED are included. The significantly lower slenderness values of Hungarian C4 grasses (compared with C3 types), shown in the first example, is a new contribution to understanding the ecology of C4 grasses. In the second example heavier seed weights of shade plants are statistically demonstrated, compared to their heliophilous congeners with the same life forms. The 113 congeneric species pairs considered are derived from a wide range of plant families.
A comparative study of the seed germination biology of a narrow endemic and two geographically-widespread species ofSolidago(Asteraceae). 6. Seed bank
Authors: Walck Jeffrey L. , Baskin Jerry M. , Baskin Carol C.
Published: September 2008

Seeds of the geographically-widespreadSolidago altissimaandS. nemoralisand the narrow-endemicS. shortiiwere buried in pots of soil and placed in a glasshouse without temperature control. After 0.3–4.3 years of burial, some seeds (21–60%) of all three species were viable and they germinated to 75–100% during 2 weeks of incubation in light at 30/15°C. Soil samples collected from several population sites ofS. altissima, S. nemoralisandS. shortiiwere placed in the glasshouse and monitored for seedling emergence. During the first, second, third, fourth, fifth and sixth springs, the number ofS. altissimaseedlings m−2emerging was 108–1080, 8–494, 0–520, 0–69, 0–6 and 3, respectively, ofS. nemoraliswas 108–1122, 17–667, 0–42, 0–6, 0, 0 and 0, respectively, and ofS. shortiiwas 61–1753, 0–25, 0–6, 0, 0 and 0, respectively. More seedlings emerged from disturbed than from non-disturbed soil, but the differences were not significant. Thus, although some seeds of all three species buried in pots remained viable in soil throughout the 4.3-year burial period, longevity was greater and size of seed bank larger in field-collected soil samples containing seeds of the geographically-widespread species than in those containing seeds of the narrow endemic. Although 34 studies have reported seeds of 17 species ofSolidagopresent in soil seed banks, the present study is the first to show, conclusively thatSolidagocan form a persistent seed bank.
The regulation of secondary dormancy. The membrane hypothesis revisite
Authors: Hilhorst Henk W. M.
Published: September 2008

Secondary dormancy is predominantly associated with seed behaviour in soil seed banks. Periodic changes in secondary dormancy may explain seasonal emergence of weedy species. Temperature and possibly soil water potential appear to be the predominant factors that determine the annual cycling of dormancy. Dormancy cycling is paralleled by modulations of germination responsiveness to germination stimulants, such as light and nitrate and to the width of the germination temperature window. Membranes have been proposed to be the primary target for the perception of temperature. It is hypothesized that alterations in properties of cellular membranes are involved in the regulation of dormancy. Possible mechanisms are discussed.
Ecological aspects of seed dormancy loss
Authors: Allen Phil S. , Meyer Susan E.
Published: September 2008

Advances in seed biology include progress in understanding the ecological significance of seed dormancy mechanisms. This knowledge is being used to make more accurate predictions of germination timing in the field. For several wild species whose seedlings establish in spring, seed populations show relevant variation that can be correlated with habitat conditions. Populations from severe winter sites, where the major risk to seedlings is frost, tend to have long chilling requirements or to germinate very slowly at low temperatures. Populations from warmer sites, where the major risk is drought, are non-dormant and germinate very rapidly under these same conditions. Seed populations from intermediate sites exhibit variation in dormancy levels, both among and within plants, which spreads germination across a considerable time period. For grasses that undergo dry after-ripening, seed dormancy loss can be successfully modelled using hydrothermal time. Dormancy loss for a seed population is associated with a progressive downward shift in the mean base water potential, i.e., the water potential below which half of the seeds will not germinate. Other parameters (hydrothermal time requirement, base temperature and standard deviation of base water potentials) tend to be constant through time. Simulation models for predicting dormancy loss in the field can be created by combining measurements of seed zone temperatures with equations that describe changes in mean base water potential as a function of temperature. Successful validation of these and other models demonstrates that equations based on laboratory data can be used to predict dormancy loss under widely fluctuating field conditions. Future progress may allow prediction of germination timing based on knowledge of intrinsic dormancy characteristics of a seed population and long-term weather patterns in the field.
Methods for dehydration-tolerance: Depression of the phase transition temperature in dry membranes and carbohydrate vitrification
Authors: Oliver Ann E. , Crowe Lois M. , Crowe John H.
Published: September 2008

Anhydrobiosis, or life without water, is the remarkable ability of certain types of plants and animals to survive almost total dehydration. This phenomenon requires a coordinated series of events within the cells of anhydrobiotes that protect their cellular components, particularly proteins and lipid membranes, from damage caused by the removal of water. Much of what is now understood about preserving biological samples during drying was learned by studying naturally desiccation-tolerant organisms and extended using model systems such as phospholipid vesicles. Most anhydrobiotic organisms accumulate disaccharides in their cells and tissues during the dehydration process. These carbohydrates, usually sucrose or trehalose, satisfy two criteria that appear to be necessary for protecting membranes during desiccation and during storage in the dry state. These requirements include: (1) depression of the gel-to-liquid crystalline phase transition temperature (Tm) in the dehydrated lipid to a temperature at or near that of the hydrated lipid, a process that appears to require a direct interaction between the carbohydrates and the lipid molecules of the membrane; and (2) formation of a carbohydrate glass with a relatively high glass transition temperature, leading to inhibition of fusion between the vesicles.
Genetic engineering with α-amylase inhibitors makes seeds resistant to bruchids
Authors: Chrispeels Maarten J. , Fatima Grossi de Sa M. , Higgins T. J. V.
Published: September 2008

Seeds of the common bean,Phaseolus vulgaris, contain two inhibitors of mammalian and insect α-amylases (αAls) that show specificity towards the amylases of different insect species. Expression in pea (Pisum sativum) and azuki bean (Vigna angularis) of a chimeric gene consisting of the cDNA of bean αAl-1 and a seed-specific promoter makes the seeds of these legumes resistant to three species of Old World bruchids whose amylases are inhibited by αAl-1. This was the first successful genetic engineering of insect resistance in seeds. To understand the basis of the specificity between amylases and inhibitors we cloned a second bean inhibitor (αAl-2) with different specificity, and we cloned the cDNA of the New World bruchid,Zabrotes subfasciatus. The amylase of this bruchid is inhibited by αAl-2, but not by αAl-1. Knowledge of the amino acid sequences and of the three-dimensional structure of the pancreatic α-amylase–αAl-1 complex allows us to predict the peptide domains and amino acids of the proteins that are important for protein–protein recognition and inhibition of enzyme activity.
Seed quality assessment
Authors: McDonald Miller B.
Published: September 2008

Growers expect high-quality, genetically pure seed. As a result, seed companies maintain quality control programmes that monitor seed from harvest to purchase. An array of ‘traditional’ seed quality tests, including mechanical tests and tests of genetic purity, seed germination and vigour, and seed health tests, is used, and seed quality assessment techniques continue to evolve. Advances in molecular genetics are allowing the release of new varieties differing essentially in one gene. New molecular biology approaches offer the potential to identify these subtle genetic differences. Advances in seed enhancements, such as pelleting, priming and pregermination, require increased scrutiny of seed quality before and after the enhancement process. New developments in computer imaging for improved purity and germination/vigour analyses are being developed. These novel approaches to seed quality assessment become important as new genetic improvements are conveyed in the seed at increased cost to the grower.
Implications of new technologies for seed health testing and the worldwide movement of seed
Authors: Maddox Darrell A.
Published: September 2008

New techniques for the accurate and feasible detection of many seedborne pathogens have been developed over the last 25 years. These include conducive environmental incubation and identification (many seedborne fungi), liquid plating assay (seedborne bacteria), enzyme-linked immunosorbent assay (seedborne viruses) and polymerase chain reaction (PCR) technology. Regardless of the detection methodology, the specificity, sensitivity, reliability, efficiency of the assay and an understanding of pathogen tolerance in a seedlot need to be considered before a technique is an acceptable clinical seed health test. Acceptable seed health tests are tools for disease risk-management and routinely used in seed quality assessment. Seed health issues are increasingly important in international seed trade. With the advent of free trade, many countries are redefining their phytosanitary requirements with the goal of preventing introduction of a devastating pathogen into their country. However, many phytosanitary regulations are implemented without fully understanding the economic threat of a pathogen or a complete scientific analysis of a pathogen's presence in that country. This has led to confusing regulations, unnecessary tests or inspection requirements and unjustified trade barriers. To provide a means to answer scientifically the problems encountered in the worldwide movement of seed, an international movement has emerged to standardize seed health tests and inspection practices for international seed trade. The impact of standardization on the free trade of seed and the goals of the International Seed Health Initiative (ISHI) will be discussed.
Genetic purity and testing technologies for seed quality: a company perspective
Authors: Smith J. S. C. , Register III J. C.
Published: September 2008

A high level of genetic purity in crop varieties must be achieved and maintained for agronomic performance as well as to encourage investment and innovation in plant breeding and to ensure that the improvements in productivity and quality imparted by breeders are delivered to the farmer and, ultimately, to the consumer. Traditionally, morphological comparisons have formed the basis for genetic purity evaluations. However, replicated field observations are time-consuming, expensive and unreliable. Morphology cannot provide information on the purity of specific genetic attributes that relate to grain quality or to pest or herbicide resistance bred into varieties. Biochemical assays, including isozymes, can distinguish varieties within several species. Isozymes have been routinely used in checking seed-lot purity in maize (Zea maysL.) for the past 20 years. Newer DNA-based technologies such as restriction fragment length polymorphisms and more recently developed methods that use the polymerase chain reaction can allow even more discriminative and faster identification of varieties. However, none of the DNA methods have replaced biochemical methods for seed purity assays, other than in a relatively select group of crops with very high seed value, due to their high datapoint cost. It will require further miniaturization, automation and enhanced capabilities to process numerous samples simultaneously before newly developed methods supplant biochemical methods for routine usage in purity testing. New varieties that have major genes for herbicide or insect resistance incorporated within them require purity assays during product development and following seed production of the commercial variety. Immunological or DNA sequence assays can be developed and automated systems are required to process hundreds of thousands of individuals. Ultra-high, micro-array technologies and single-molecule detection systems are now under development. These technologies offer the promise that adequate distinction and high sample throughput will be combined. New methods may eclipse the capabilities of biochemical methodologies, thereby potentially raising genetic purity standards and enabling farmers and consumers better to utilize and benefit from increasingly productive varieties that are bred from a more diverse base of genetic resources.
Vegetative plant development and seed production in cool-season perennial grasses
Authors: Chastain Thomas G. , Young William C.
Published: September 2008

The literature suggests that the establishment of seed yield potential in cool-season perennial grasses is based on developmental processes that take place before floral induction. The relationship between vegetative plant development to flowering and seed yield can be influenced by numerous factors, such as genotype, stand age, post-harvest regrowth environment, pests, management practices and juvenility. The objectives of our investigations and survey of literature were to identify characteristics of vegetative plant development present before floral induction (autumn regrowth period) that were related to flowering (yield potential) and seed yield (utilization of seed yield potential). The number of fertile tillers present at anthesis is a function of the number and developmental state (or biological age) of vegetative tillers present prior to floral induction. The number and size of vegetative tillers before induction was correlated with flowering and seed yield in young stands of orchardgrass (Dactylis glomerataL.) and tall fescue (Festuca arundinaceaSchreb.) (r= 0.93 and 0.95 for first-year stands of orchardgrass and tall fescue, respectively), but older stands did not exhibit this relationship. The basal diameter of vegetative tillers in autumn was related to flowering and seed yield in young stands of Kentucky bluegrass (Poa pratensisL.) and creeping red fescue (F. rubraL) As stands aged, basal diameter was not a primary indicator of subsequent flowering and seed yield. Tiller height at the end of the regrowth period was consistently related to flowering and seed yield in Kentucky bluegrass(r= −0.81,P< 0.01) and creeping red fescue (r= −0.87,P< 0.01), regardless of stand age. Increasing the rhizome:root ratio caused reduction of flowering in creeping red fescue. Vegetative characteristics were not related to flowering and seed production in perennial ryegrass (Lolium perenneL.) and dryland bentgrass (Agrostis castellanaBoiss. and Reut.). Green leaf number was a poor indicator of flowering and seed yield potential in all species tested. Ethylene production during autumn vegetative development has been implicated as a potential cause of reduced flowering in creeping red fescue. As much as 92% of the seed yield potential in several cool-season perennial grasses is set before the onset of conditions favouring vernalization of the crop. An increased understanding of developmental gateways in the formation of flowering and seed yield potential may be key to enhancing the economic and environmental sustainability of seed production enterprises.
Phytochromes and seed germination
Authors: Casal Jorge J. , Sánchez Rodolfo A.
Published: September 2008

The control of seed germination by red and far-red light is one of the earliest documented phytochrome-mediated processes Phytochrome is now known to be a small family of photoreceptors whose apoproteins are encoded by different genes Phytochrome B (phyB) is present in dry seeds and affects germination of dark imbibed seeds but other phytochromes could also be involved Phytochrome A (phyA) appears after several hours of imbibition and mediates very-low-fluence responses PhyB and other phytochromes different from phyA mediate the classical low-fluence responses The phytochrome involved in high-irradiance responses of seed germination (inhibition of germination under continuous far-red) has not been unequivocally established, although phyA is the most likely candidate Phytochrome can affect embryo growth capacity and/or the constraint imposed by the tissues surrounding the embryo At least in some species, gibberellins participate in the signalling process In the field, phyA has been implicated in the perception of light during soil cultivations, and phyB would be involved in the perception of red/far-red ratios associated with the presence of gaps in the canopy This review describes recent advances in phytochrome research, particularly those derived from the analysis of germination in specific mutants, and their connection with traditional observations on phytochrome control of seed germination
Assimilate uptake and the regulation of seed development
Authors: Weber Hans , Heim Ute , Golombek Sabine , Borisjuk Ljudmilla , Wobus Ulrich
Published: September 2008

Seed development is a series of events involving cell division, followed by cell differentiation and storage activity In legume cotyledons, cell differentiation starts in certain regions and gradually spreads to other parts, thereby building up developmental gradients The entire process appears to be subject to metabolic control The high hexose state of the premature legume embryo as controlled by seed coat-specific invertases favours cell division Differentiation is initiated when hexose decreases and sucrose increases Seed development occurs in a close interaction with seed metabolism and transport processes Movement of photoassimilates from the sieve tubes to the unloading region of the maternal seed tissue is symplasmic and controlled by plasmodesmal passage Sucrose uptake intoVicia fabacotyledons is mediated by a H+-sucrose symporter located in the outer epidermis which generates transfer cells Formation of the sucrose uptake system is induced during the early to mid-cotyledon stage by tissue contact with the maternal seed coat and is controlled by carbohydrate availability In contrast, a hexose transporter gene is also expressed in epidermal cells covering younger, mitotically active regions of the cotyledons The sucrose uptake system apparently generates the high sucrose state immediately preceding the storage phase Sucrose specifically induces storage-associated differentiation processes indicating a specific sucrose-dependent signalling pathway operating in maturing cotyledons Moreover, the mode of sucrose uptake — apoplasmic movement into the epidermal cells with subsequent symplasmic transfer to the storage parenchyma cells — appears to control coordinated cotyledon development Unlike sucrose, amino acid transport into legume cotyledons is passive during early development but at later stages when large amounts of storage proteins are synthesized an additional active uptake system is established to ensure a sufficient supply
Responses of tomato seeds to osmoconditioning as related to temperature and oxygen
Authors: Ozbingol N. , Corbineau F. , Côme D.
Published: September 2008

Untreated (control) tomato seeds germinated at temperatures ranging from 15 to 35°C. There was a positive linear relationship between the rate of germination (expressed as the reciprocal of time to obtain 50% germination) and temperature up to the thermal optimum. At higher temperatures, the negative relationship was also linear. The thermal optimum for seed germination was 27–28°C and the lower and maximal temperatures were around 9 and 40°C, respectively. Germination was strongly reduced in atmospheres containing less than 10% oxygen. After pretreatment at 15°C in a polyethylene glycol-8000 solution at –1.0 MPa, seeds germinated faster in a wider range of temperatures, and this stimulatory effect remained after drying back the seeds. Such a pretreatment did not change the optimal and maximal temperatures of germination, but decreased the lower temperature to about 6°C. The beneficial effect of osmoconditioning increased as the duration of the treatment increased and was maximal after 5–7 days. Osmotic pretreatment also reduced the sensitivity of seeds to oxygen deprivation; 50% of the seeds germinated within 7 days in 5% oxygen. The range of temperatures and the concentrations of oxygen which were effective in osmoconditioning were very similar to those which allowed the germination of untreated seeds. In particular, the optimal temperature (27–28°C) and oxygen concentrations (more than 10%) for osmoconditioning and germination were the same. These results confirm that the beneficial effect of osmotic pretreatment (priming) corresponds to the realization of germinationsensu stricto(phase II of the germination process).
Seed development, testa structure and precocious germination of Chinese cabbage (Brassica rapasubsp.pekinensis)
Authors: Ren Chengwei , Bewley J. Derek
Published: September 2008

On the basis of embryo and seed colour, morphology, accumulation of fresh and dry weight, seed development of Chinese cabbage (Brassica rapasubsp.pekinensis) can be divided into 10 discrete but contiguous stages. Precocious germination (PG) occurs in the seeds of a Chinese cabbage mutant on the parent plant mainly during the maturation period (from stage 5 to 8), with either the radicle or the cotyledon protruding out of the testa. All plants of the mutant line produce some PG seeds, but among the seeds, only 18% (maximum) germinate precociously. The developing mutant seeds have higher water contents and lower dry weights than those of the wild-type and are less tolerant of desiccation. The testa structure of Chinese cabbage seed is similar to that of otherBrassicaspecies. In developing seeds, it consists of the epidermis, subepidermis, palisade layer and pigmented layers, while in the mature dry seeds, all the cell layers except the palisade layer are crushed into non-cell structures and are stacked on the outer and inner faces of the palisade layer; the aleurone layer is fused to the testa. An alteration in testa structure of the mutant seeds (both non-germinated and precociously-germinated seeds) is probably related to PG. The secondary cell wall materials are less, or not deposited on the radial and basal walls of the palisade cells on the adaxial side of the testa, which could result in a weaker mechanical restraint, thus leading to PG.
Soybean seed pectinesterase
Authors: Markovič Oskar , Obendorf Ralph L.
Published: September 2008

Methanol accumulates in axis tissues of maturing soybean seeds, correlating with preharvest seed deterioration. Accumulation of methanol appears to be associated with the enzymic demethylation of pectin methyl esters by pectinesterase (PE; EC 3.1.1.11). To characterize PE in developing and maturing soybean (Glycine max (L.) Merrill) seeds, enzyme activity was assayed in axis and cotyledon tissues. Activity per g fresh weight was 20–25 times higher in axes than in cotyledons with highest activities between 45 and 60 days after flowering (DAF). Twenty to 33% of the total PE activity was in the ‘soluble’ form (extracted with water, 0.5 M sucrose, 1 M sucrose and water). Soluble and cell-wall-bound PE (subsequently extracted with 1 M NaCI) were purified and characterized from axes of seeds at 45–60 DAF. Purification of PE was achieved through concentration of extracts by ultra-filtration, precipitation with ammonium sulfate (30–80% saturation), dialysis, gel filtration on Sephadex G-75 columns, and ion exchange chromatography on CM Sepharose CL-6B. Further purification of both soluble and bound PE was by isoelectric focusing (IEF) on ultrathin layers of polyacrylamide gel with simultaneous detection of protein and PE activity. It was possible to follow seven bands exhibiting PE activity with pl values between 6.0 and 9.5 in 1 M NaCI-extracts of total homogenates. Differences in the IEF patterns of bound and soluble PE were observed. Whereas the bound enzyme exhibited more basic PE bands (pl 8–9.5), the soluble enzyme had more active bands at pl 6.5, 7.0 and 7.5. The Mr was close to 33 000 and the pH optimum was 7.8 for both soluble and bound PE.
Effects of differential drying rates on viability retention of recalcitrant seeds of Ekebergia capensis
Authors: Pammenter N. W. , Greggains Valerie , Kioko J. I. , Wesley-Smith J. , Berjak Patricia , Finch-Savage W. E.
Published: September 2008

The drying rate of whole seeds of Ekebergia capensis (Meliaceae) was shown to influence the response to desiccation, with rapidly dried seeds surviving to lower water contents. Short-term rapid drying (to water contents higher than those leading to viability loss) actually increased the rate of germination. The form of the time course of decline of axis water content varied with drying rate; slow drying could be described by an exponential function, whereas with rapid drying initial water loss was faster than predicted by an exponential function. These observations suggest that slow drying brought about homogeneous dehydration and that the rapid drying was uneven across the tissue. This raised the possibility that the different responses to dehydration were a function of different distributions of water in the axis tissue under the two drying regimes. However, ultrastructural observations indicated that different deleterious processes may be occurring under the different drying treatments. It was tentatively concluded that a major cause of viability loss in slowly dried material was likely to be a consequence of aqueous-based processes leading to considerable membrane degradation. Uneven distribution of tissue water could not be rejected as a contributory cause of the survival of rapidly dried seeds to low bulk water contents. The differential response to dehydration at different drying rates implies that it is not possible to determine a ‘critical water content’ for viability loss by recalcitrant seeds.
A multifactorial study of conditions influencing longevity of neem (Azadirachta indica) seeds
Authors: Sacandé Moctar , Hoekstra Folkert A. , van Pijlen Jaap G. , Groot Steven P. C.
Published: September 2008

The longevity of neem,Azadirachta indica, seeds from African Sahelian (Burkina Faso) and Asian (Sri Lanka) provenances was studied over two years of storage under different conditions of moisture and temperature. After drying to equilibrium moisture content (MC) at different relative humidities at 20°C, seeds were placed in open storage at 20°C or hermetically sealed in packets at temperatures ranging from −20 to +20°C. There was hardly any difference in storage behaviour between seed batches / lots, whatever their provenance. Seeds originating from mature yellow fruits lived longer than seeds from green or brown fruits. In all storage experiments with seeds having MCs ≥ 10%, viability was preserved best at 10−15°C, indicating that neem seed is chilling (and freezing) sensitive. There was no survival longer than 2 years under these conditions. At MCs of 4–8%, seeds were considerably more tolerant of low temperature storage and had 40–60% viability after 2 years at all temperatures tested (−20 to +20°C). However, the seeds were sensitive to imbibitional stress, which could be alleviated by imbibition at temperatures of 25–30°C or above. The difficult storage behaviour of neem seed seems to stem from: (1) the sensitivity to low temperatures at MCs ≥ 10%; (2) the extreme sensitivity to imbibitional stress after storage at ≤ 8% MC; (3) underestimation of the water activity due to the high oil content of the neem seeds, causing unexpected metabolic stress in the higher MC and temperature range.
Development of soil seed banks beneath synthesized meadow communities after seven years of climate manipulations
Authors: Akinola M. Olatunde , Thompson Ken , Hillier Susan H.
Published: September 2008

Meadow microcosms were established from seed on low-fertility soil of known seed bank composition, and subjected to manipulations of simulated grazing, cutting date, temperature and fertility for seven years. The composition and density of the seed bank was then determined in five 2-cm soil layers (0–2, 2–4, 4–6, 6–8 and 8–10 cm). The seed bank contained three distinct groups of species: species present in the original soil, sown species, and ‘others’. The seed bank was little affected by the experimental treatments, presumably because the sown species made only a small contribution to the seed bank. Nearly all the species in the original soil are known to possess persistent seed banks and had survived, although at reduced density, for seven years. Density of the most abundant species in this group, Sagina procumbens, had changed very little over seven years, confirming the well-documented longevity of the seeds of this species. Seeds of sown species made up only about a quarter of the seed bank, despite accounting for virtually all the above-ground vegetation. Of the sown meadow species, only Plantago lanceolata and Alopecurus pratensis were relatively abundant in the seed bank. These results strongly support the conclusion of other authors that most meadow species, once lost owing to the effects of fertilizers or inappropriate management, will not reestablish from the seed bank. Among species which were neither sown nor present in the original soil, the majority possessed adaptations for wind dispersal and had presumably dispersed into the experimental plots from outside. The most abundant member of this group, Betula pendula, had dispersed from a nearby tree. Density of Betula seeds declined sharply with depth, consistent with the view that seeds on the soil surface are rapidly lost, mainly through germination, but seeds that become buried survive much better. Seeds of Betula appear to be persistent but not particularly long-lived.
Post-dispersal seed predation and seed bank persistence
Authors: Hulme P. E.
Published: September 2008

This study examines whether post-dispersal seed predators could be an important selective force in determining the seed bank strategies of grassland plants. It tests the hypothesis that species with persistent seed banks should sustain proportionally less predation of buried seeds than species which have transient seed banks and that this should be true irrespective of seed size. Results are drawn from a field experiment examining the relative susceptibility of surface versus buried seeds for 19 herbaceous taxa exhibiting different degrees of seed bank persistence. The data were consistent with the hypothesis that seed predators (rodents) influence the seed bank characteristics of seeds. Rodents removed proportionally more large seeds than small seeds and removed a smaller proportion of seeds with persistent rather than transient seed banks, independently of seed size. On average, burial reduced seed removal by almost 50%. The decrease in rates of seed removal following burial was marked for seeds with persistent seed banks but negligible for seeds with transient seed banks. Herbaceous plants with relatively large seeds (seed mass > 1 mg) that form persistent seed banks were either completely avoided or only consumed in small quantities by rodents. In contrast, large-seeded species with transient seed banks suffer high rates of seed predation. Models of life-history evolution predict trade-offs between seed dormancy and seed mass since dormancy and seed size are correlated traits that both reduce risk in variable environments and thus will show patterns of negative covariation. This paper presents an alternative explanation for this trade-off based on experimental evidence of a negative relationship between seed bank persistence and predation risk.
Stuff and Nonsense in the Treatment of Older People: Essential Reading for the Over-45s
Authors: James Ian Andrew
Published: September 2008

There is a lot of nonsense talked about how to adapt therapy for older people. This is because often authors fail to define the types of populations they are tailoring their therapy for. Such definitions are important with such a diverse patient group, some of whom were “in-service” during the first world war, while others were “doing drugs and dropping out” in the 1960s. To guide our thinking regarding specific adaptations, this paper presents a framework for clarifying therapeutic need. The second section of the paper illustrates ways in which working psychotherapeutically with older patients has helped inform mainstream CBT theory and practice, with particular reference to competence and schema work.
Cognitive Behavioural Therapy for Mood Disorders
Authors: Meyer Thomas D. , Scott Jan
Published: September 2008

This paper provides a selected review of recent studies highlighting key aspects of mood disorders research. Cognitive models and clinical trials of cognitive therapy of depression are evolving and adapting to increase applicability to the spectrum of depressive symptoms and syndromes experienced by clients, as well exploring beyond acute phase treatment to relapse prevention. In contrast, cognitive models of bipolar disorders and the effectiveness of the therapy are unclear and there are more questions than answers for researchers in this area.
Investment, uncertainty, and production games
Authors: FLÅM S. D. , ERMOLIEV Y. M.
Published: September 2008

This paper explores a few cooperative aspects of investments in uncertain, real options. By hypothesis some production commitments, factors, or quotas are transferable. Cases in point include energy supply, emission of pollutants, and harvest of renewable resources. Of particular interest are technologies or projects that provide anti-correlated returns. Any such project stabilizes the aggregate proceeds. Therefore, given widespread risk aversion, a project of this sort merits a bonus. The setting is formalized as a two-stage, stochastic, production game. Absent economies of scale, such games are quite tractable in analysis, computation, and realization. A core imputation comes in terms of shadow prices that equilibrate competitive, endogenous markets. Such prices emerge as optimal dual solutions to coordinated production programs, featuring pooled commitments, or resources. Alternatively, the prices could result from repeated exchange.
A Jew on Java, a Model Malay Rabbi and a Tamil Torah Scholar: Representations of Abdullah Ibnu Salam in theBook of One Thousand Questions
Authors: RICCI RONIT
Published: September 2008

In contrast to many regions of the Middle East, where Jewish communities existed at the time of the Prophet and throughout the centuries following his death, the Tamil region of south India and the Indonesian-Malay world lacked such populations. The absence of Jewish communities did not, however, imply a complete unfamiliarity with Jews and Judaism. Rather, their image emerged from a variety of textual sources in lieu of direct encounters. In addition to their depictions in the Qur'an and hadith literature, Jewish figures occasionally appeared in texts produced in these regions' local languages. TheBook of One Thousand Questions, composed in Arabic and translated thereafter into many languages – including Javanese, Malay and Tamil – offers a glimpse to portrayals of Jews and Judaism in lands where their actual presence was virtually unknown.
Report of the Honorary Treasurer to the Annual General Meeting 8 May 2008
Authors: Mundy Brampton
Published: September 2008

Ladies and Gentlemen, Fellows of the Society. I am pleased to present the Annual Report for 2007.
Composite Noise Reduction of ERPs Using Wavelet, Model-Based, and Principal Component Subspace Methods
Authors: Cutmore Tim R.H. , Celka Patrick
Published: September 2008

This paper used three theoretically different algorithms for reducing noise in event-related potential (ERP) data. It examined the possibility that a hybrid of these methods could show gains in noise reduction beyond that obtained with any single method. The well-known ERP oddball paradigm was used to evaluate three denoising methods: statistical wavelet transform (wavelet-Z), a smooth subspace wavelet filter (wavelet-S), and subspace PCA. The six possible orders of serial application of these methods to the oddball waveforms were compared for efficacy in signal enhancement. It was found that the order was not commutative, with the best results obtained from applying the wavelet-Z first. Comparison of oddball and frequent trials in the grand average and in individual averages showed considerable enhancement of the differences. It was concluded that denoising to remove variance caused by rare sizeable artifacts is best done first, followed by state space PCA and a light-bias model-based wavelet denoising. The ability to detect and distinguish the effects of variables (such as task, drug effects, individual differences, etc.) on ERPs related to human cognition could be considerably advanced using the denoising methods described here.
Electrophysiological Evidence for a Syntactic but Not a Semantic Deficit in Patients with Major Depression
Authors: Ruchsow Martin , Groen Georg , Spitzer Manfred , Hermle Leopold , Buchheim Anna , Kiefer Markus
Published: September 2008

Cognitive deficits are common in patients with major depression. The present study investigated whether these impairments also comprise language processes such as sentence comprehension. We studied four language-related evoked potentials (early left anterior negativity [ELAN], N400, left anterior negativity [LAN], and P600) in 14 patients with major depressive disorder (MDD) in partial remission and 14 matched healthy controls using a sentence paradigm with correct, semantic mismatching, and syntactic mismatching sentences. In contrast to controls, patients showed no significant P600 effect when comparing syntactic mismatching and correct sentences. No group differences could be observed for the ELAN, N400, and LAN components. The missing P600 effect may indicate deficits in the cognitive domain of language processing in depressive patients or impairment of a more general process to detect deviances from regularities. How this result integrates into the concept of a general cognitive deficit in major depression remains a goal for future studies.
No Effect of Training State on Ambulatory Measures of Cardiac Autonomic Control
Authors: Goedhart Annebet D. , de Vries Marije , Kreft Jeroen , Bakker Frank C. , de Geus Eco J.C.
Published: September 2008

We examined the effect of training state on cardiac autonomic control in a naturalistic setting. Twenty-four vigorous exercisers were compared to age- and sex-matched sedentary controls. The regular exercisers were subjected to a 6-week training program after which they were randomized to 2 weeks of continued training or 2 weeks of detraining. Cardiac autonomic control was measured over a 24-h period by ambulatory recording, using the preejection period (PEP) and respiratory sinus arrhythmia (RSA). Nonexercising controls had a significantly higher ambulatory heart rate (HR) compared to the regular exercisers but comparable 24-h levels of PEP and RSA. In regular exercisers, 2 weeks of detraining did not significantly change the 24-h levels of HR, PEP, or RSA. We conclude that the bradycardia in healthy regular exercisers is the result of a lower intrinsic heart rate rather than a shift in cardiac autonomic balance from sympathetic to vagal control.
Does Autonomic Arousal Distinguish Good and Bad Decisions?
Authors: Jenkinson Paul M. , Baker Sarah R. , Edelstyn Nicola M.J. , Ellis Simon J.
Published: September 2008

The somatic marker hypothesis (SMH) proposes that physiological feedback to the brain influences cognitive appraisal and human decisions, however, the strength of evidence in support of the SMH is equivocal. We examined the validity of the SMH by measuring physiological arousal in a population of healthy individuals playing the Iowa Gambling Task (IGT), which is a computerized card game designed to assess real-life decisions. We also examined the influence of reinforcer type on IGT performance and physiological reactivity. Skin conductance level (SCL) reactivity was measured in 41 participants performing the IGT using either facsimile or real money. Participants were categorized as normal (i.e., nonimpaired) or impaired on the basis of their IGT performance, and differences in performance and physiological reactivity between groups were examined. No differences in SCL were found between normal and impaired groups. However, greater SCL rises were borderline significant when anticipating choices from bad decks compared with good decks, and a significantly greater SCL rise followed a reward from a bad deck. The effect of reinforcer type also revealed marginally greater performance when using facsimile money. This was corroborated physiologically by Deck × Reinforcer Type interactions, showing a marginally significant tendency for a greater SCL rise when anticipating a choice from a bad deck using facsimile but not real money, and a significantly greater SCL rise following a reward from a bad deck when using facsimile but not real money. Findings constrain the SMH, suggesting that autonomic activity may discriminate between good and bad decks (i.e., good vs. bad decision-making) by reflecting the magnitude of gains and losses, but is independent of long-term consequences and does not discriminate between overall good and bad performance (i.e., normal vs. impaired decision-makers).
Personal Interaction in the Vegetative State
Authors: Dolce G. , Riganello F. , Quintieri M. , Candelieri A. , Conforti D.
Published: September 2008

Background and purpose: Brain processing at varying levels of functional complexity and emotional reactions to relatives are anecdotally reported by the caregivers of patients in a vegetative state. In this study, computer-assisted machine-learning procedures were applied to identify heart rate variability changes or galvanic skin responses to a relative’s presence. Methods: The skin conductance (galvanic skin response) and heart beats were continuously recorded in 12 patients in a vegetative state, at rest (baseline) and while approached by a relative (usually the mother; test condition) or by a nonfamiliar person (control condition). The cardiotachogram (the series of consecutive intervals between heart beats) was analyzed in the time and frequency domains by computing the parametric and nonparametric frequency spectra. A machine-learning algorithm was applied to sort out the significant spectral parameter(s). For all patients, each condition (baseline, test, control) was characterized by the values of its spectral parameters, and the association between spectral parameters values and experimental condition was tested (WEKA machine-learning software). Results and comments: A galvanic skin response was obtained in two patients. The machine-learning procedure independently selected the nu_LF spectral parameter and attributed each nu_LF measure to any of the three experimental conditions. 69.4% of attributions were correct (baseline: 58%; test condition: 75%; control. 75%). In seven patients, attribution changed when the subject was approached by the test person; specifically, sequential shifts from baseline to test condition (“the Mom effect”) to control condition were identified in four patients (30.0%); the change from test to control was attributed correctly in seven patients (58%). The observation of heart rate changes tentatively attributable to emotional reaction in a vegetative state suggest residual rudimentary personal interaction, consistent with functioning limbic and paralimbic systems after massive brain damage. Machine-learning proved applicable to sort significant measure(s) out of large samples and to control for statistical alpha inflation.
Stream discharge using mobile large‐scale particle image velocimetry: A proof of concept
Authors: Kim Y. , Muste M. , Hauet A. , Krajewski W. F. , Kruger A. , Bradley A.
Published: September 2008

The authors describe a mobile large‐scale particle image velocimetry–based system (MLSPIV) that allows real‐time visualization and quantitative estimation of instantaneous and averaged flow characteristics at the river free surface with minimum preparation from the banks of the river. High spatial resolution and the remote, real‐time, and fully digital nature of MLSPIV make it well suited to work as either a stand‐alone instrument, as presented in the paper, or an integrated system in large‐scale networks for monitoring ungauged river basins. Preliminary tests with the mobile LSPIV configuration demonstrate that the technique has the potential to efficiently support research and monitoring of riverine systems. Discharge measurements obtained with MLSPIV show good agreement with discharge measured by the U.S. Geological Survey stream gauging station and other measurement methods.