bluuebunny/crossref_metadata_2025 huggingface dataset:
Knowledge of iodine nutrition in the South African adult population
Authors: Jooste PL , Upson N , Charlton KE
Published: June 2005

Objectives

To determine the level of knowledge regarding iodine nutrition and its relationship with socio-economic status in the South African population.

Design

A cross-sectional population survey collecting questionnaire information on knowledge of iodine nutrition and sociodemographic variables in a multistage, stratified, cluster study sample, representative of the adult South African population.

Setting

Home visits and personal interviews in the language of the respondent.

Subjects

Data were collected from one adult in each of the selected 2164 households, and the participation rate was 98%.

Results

Only 15.4% of respondents correctly identified iodised salt as the primary dietary source of iodine, 16.2% knew the thyroid gland needs iodine for its functioning, and a mere 3.9% considered brain damage, and 0.8% considered cretinism, as the most important health consequence of iodine deficiency. Compared with respondents from high socio-economic households, respondents from low socio-economic households were considerably less informed about aspects of iodine nutrition covered in this study.

Conclusions

The knowledge level of iodine nutrition is low among South Africans, particularly among the low socio-economic groups. These data suggest that the international emphasis on brain damage resulting from iodine deficiency has not been conveyed successfully to the consumer level in this country.
Consumer perception versus scientific evidence about health benefits and safety risks from fish consumption
Authors: Verbeke Wim , Sioen Isabelle , Pieniak Zuzanna , Van Camp John , De Henauw Stefaan
Published: June 2005

Objective

To investigate the gap between consumer perception and scientific evidence related to health benefits and safety risks from fish consumption.

Design

Consumer perceptions from a cross-sectional survey in March 2003 in Belgium were compared with scientific evidence based on a literature review.

Method

A quota sampling procedure was used with age as quota control variable. Subjects completed a self-administered questionnaire including health benefit beliefs from fish, fish content and effect beliefs for nutrients and harmful substances.

Subjects

Adults (n=429), who were the main person responsible for food purchasing in the household (284 women; 145 men), aged 18–83 years, from different regional, education, family size and income groups.

Results

Fish is predominantly perceived as a healthy food that reduces risk for coronary heart disease, which corroborates scientific evidence. This perception is stronger among women than among men. In contrast with scientific evidence, 46% of the consumers believe that fish contains dietary fibre, whereas less than one-third is aware that fish contains omega-3 fatty acids and that this nutrient has a positive impact on human health. The gap between perception and evidence is larger among consumers with lower education. In general, consumers are better aware of the content and effect of harmful substances than of nutrients in fish.

Conclusions

Despite conclusive evidence about the content and positive effect of omega-3 fatty acids in fish, related consumer awareness and beliefs are poor and often wrong. This study exemplifies the need for nutrition education and more effective communication about the health benefits of fish consumption.
Breast-feeding initiation and exclusive duration at 6 months by social class – results from the Millennium Cohort Study
Authors: Kelly YJ , Watt RG
Published: June 2005

Objectives

To assess breast-feeding initiation and rates of exclusive breast-feeding for the first 6 months after birth, and to examine social class differences in breast-feeding rates.

Design

First sweep of a longitudinal population-based survey, the Millennium Cohort Study.

Setting

Four countries of the UK.

Subjects

Subjects were 18 125 singletons born over a 12-month period spanning 2000–01. Data were collected by parental interview on the initiation of breast-feeding and exclusivity at 1, 4 and 6 months after birth.

Results

Overall breast-feeding was initiated for 71% of babies, and by 1, 4 and 6 months of age the proportions being exclusively breast-fed were 34%, 3% and 0.3%, respectively. There were clear social class differences and mothers with routine jobs with the least favourable working conditions were more than four times less likely (odds ratio (OR) 0.22, 95% confidence interval (CI) 0.18–0.29) to initiate breast-feeding compared with women in higher managerial and professional occupations. Women in routine jobs were less likely to exclusively breast-feed their infants at 1 month (OR 0.42, 95% CI 0.36–0.50) and 4 months (OR 0.5, 95% CI 0.31–0.77) compared with women in higher managerial and professional occupations.

Conclusions

Clear social class differences in breast-feeding initiation and exclusivity for the first 4 months were apparent in this large UK sample. By 6 months, less than 1% of babies were being exclusively breast-fed. A co-ordinated multi-faceted strategy is required to promote breast-feeding, particularly among lower-income women.
Mortality attributable to higher-than-optimal body mass index in New Zealand
Authors: Mhurchu Cliona Ni , Turley Maria , Stefanogiannis Niki , Lawes Carlene MM , Rodgers Anthony , Vander Hoorn Stephen , Tobias Martin
Published: June 2005

Objectives

To estimate the burden of mortality in New Zealand due to higher-than-optimal body mass index (BMI) in 1997, as well as mortality that could be avoided in 2011 with feasible changes in mean population BMI.

Setting

New Zealand.

Design

Comparative risk assessment methodology was used to estimate the attributable and avoidable mortality due to high BMI. Outcomes assessed were ischaemic heart disease (IHD), ischaemic stroke, type 2 diabetes mellitus, colorectal cancer and postmenopausal breast cancer.

Results

In 1997, 3154 deaths (11% of all deaths) in New Zealand were due to higher-than-optimal BMI (<21 kg m−2). This amounted to 83% of diabetes deaths, 24% of IHD deaths, 15% of ischaemic stroke deaths and 4% of all cancer deaths. If the projected increase in mean population BMI by 2011 was limited to 1.0 kg m−2rather than 1.3 kg m−2, approximately 385 deaths could be prevented annually, mainly from diabetes.

Conclusions

These results quantify the importance of higher-than-optimal BMI as a major modifiable cause of premature death in New Zealand. Intervention policies that would have only modest effects on slowing the rate of increase in mean population BMI by 2011 could still prevent hundreds of deaths annually.
The role of foreign direct investment in the nutrition transition
Authors: Hawkes Corinna
Published: June 2005

Objective

To examine the role of foreign direct investment (FDI) in the nutrition transition, focusing on highly processed foods.

Design

Data on FDI were identified from reports/databases and then compiled and analysed. A review of published literature on FDI into the food sector was conducted.

Setting

The nutrition transition is a public health concern owing to its connection with the rising burden of obesity and diet-related chronic diseases in developing countries. Global health leaders are calling for action to address the threat. Highly processed foods often have considerable fat, sugar and salt content, and warrant closer examination.

Results

FDI into food processing, service and retail has risen rapidly since the 1980s, mainly from transnational food companies (TFCs) in developed countries. As FDI has risen, so has the proportion invested in highly processed foods for sale in the host market. FDI has proved more effective than trade in generating sales of highly processed foods, and enables TFCs to cut costs, gain market power and obtain efficiencies in distribution and marketing. The amount of FDI targeted at developing countries is increasing; while a disproportionate share enters the larger developing economies, foreign affiliates of TFCs are among the largest companies in low- and low- to middle-income countries. The effect of FDI is to make more highly processed foods available to more people. FDI has made it possible to lower prices, open up new purchasing channels, optimise the effectiveness of marketing and advertising, and increase sales.

Conclusion

FDI has been a key mechanism in shaping the global market for highly processed foods. Notwithstanding the role of demand-side factors, it has played a role in the nutrition transition by enabling and promoting the consumption of these foods in developing countries. Empirical data on consumption patterns of highly processed foods in developing countries are critically needed, but since FDI is a long-term investment vehicle, it is reasonable to assume that availability and consumption of highly processed foods will continue to increase. FDI can, however, bring considerable benefits as well as risks. Through its position ‘upstream’, FDI would therefore be an appropriate entry-point to implement a range of public health policies to ‘redirect’ the nutrition transition.
Longitudinal changes in dietary intake in Scottish women around the menopause: changes in dietary pattern result in minor changes in nutrient intake
Authors: Macdonald Helen M , New Susan A , Reid David M
Published: June 2005

Objective

To examine dietary change that has occurred over 5 to 6 years.

Subjects

A cohort of Scottish women (n=898) with a mean age of 47.5 years (range 45–54 years) at baseline.

Design

Dietary intake was assessed by validated food-frequency questionnaire (FFQ) and analysed using the UK Composition of Foods database.

Results

Since the first dietary assessment, mean daily energy intake had decreased from 8.2±2.3 to 7.9±2.2 MJ. The degree of low energy reporting (defined as ratio of energy intake to basal metabolic rate >1.1) had increased from 18.7% at baseline to 25.6% at follow-up. Low energy reporters were significantly heavier than ‘normal’ energy reporters (mean weight at follow-up, 68.9±12.6 vs. 66.8±11.3 kg) and could be deliberately restricting intake rather than underreporting. Overall there were decreases in intakes of red meat, processed meat and cheese, but increases in poultry and non-oily fish consumption. Consumption of bread, biscuits and cakes had gone down and there was an increase in cereal and rice/pasta consumption. Intake of potatoes had decreased whereas fruit intake had increased. There were small but statistically significant differences in intakes for most nutrients (>8% change). Nutrient intakes at both visits were similar across menopausal status and usage groups of hormone replacement therapy. Modifications to the computer version of the McCance and Widdowson nutrient database, which differed from the published version, were noted. These changes altered the original baseline values for our study.

Conclusions

The menopauseper seis not a period of marked change in nutrient intake. Caution is advised when using computer databases of food compositions for longitudinal studies.
Public health implications of meat production and consumption
Authors: Walker Polly , Rhubart-Berg Pamela , McKenzie Shawn , Kelling Kristin , Lawrence Robert S
Published: June 2005

The high level of meat and saturated fat consumption in the USA and other high-income countries exceeds nutritional needs and contributes to high rates of chronic diseases such as cardiovascular disease, diabetes mellitus and some cancers. Affluent citizens in middle- and low-income countries are adopting similar high-meat diets and experiencing increased rates of these same chronic diseases. The industrial agricultural system, now the predominant form of agriculture in the USA and increasingly world-wide, has consequences for public health owing to its extensive use of fertilisers and pesticides, unsustainable use of resources and environmental pollution. In industrial animal production there are public health concerns surrounding feed formulations that include animal tissues, arsenic and antibiotics as well as occupational health risks and risks for nearby communities. It is of paramount importance for public health professionals to become aware of and involved in how our food is produced.
Agronomic performance of Pesticide Free Production under two crop rotations
Authors: Schoofs A. , Entz M.H. , Van Acker R.C. , Thiessen Martens J.R. , Derksen D.A.
Published: June 2005

Pesticide Free Production (PFP) is a pesticide reduction system that removes in-crop pesticide use on a yearly basis. A long-term study was established in 2000 to investigate the effect of crop rotation and frequency of inclusion on the success of PFP, as well as the effect of PFP on subsequent crops in the rotation. The crop rotations being compared were linola–oat–canola–wheat and linola–oat–alfalfa–alfalfa. PFP occurred either once in the rotation (oat) or twice (linola–oat). Weed density and yield were measured in the crops that followed PFP. Oat was a more successful PFP crop than linola because it was better able to compete with weeds. Furthermore, PFP oat had a higher weed density when it followed PFP linola, but this did not influence PFP oat yield. Under the conditions of this study, PFP linola was more successful in the annual crop rotation. Inclusion of alfalfa hay crops in the crop rotation was not effective in lowering weed pressure and, in fact, may have contributed to an increase in weed density. It is concluded that weed species present influenced the effectiveness of alfalfa in facilitating PFP, because major weeds in the study are not effectively controlled by alfalfa. PFP did not have a negative effect on following crops in the rotation (i.e. canola–wheat or alfalfa), regardless of whether one or two consecutive years of PFP occurred in the rotation. No additional herbicide was necessary for weed control in the crops that followed PFP; however, alfalfa hay was weedier for the first year following PFP. This study indicates that PFP is a viable way to reduce herbicide use in a cropping system and that attention needs to be paid to PFP crop selection and crop rotation, particularly when the PFP crop is less competitive with weeds.
The use of human waste for peri-urban agriculture in Northern Ghana
Authors: Cofie O.O. , Kranjac-Berisavljevic G. , Drechsel Pay
Published: June 2005

In Ghana, studies on the use of organic materials to increase soil productivity have focused on crop-residue management, use of green and animal manures, and legume cover cropping. Few studies have assessed the use of human waste for agriculture, even though this is widely practiced by farmers in the northern part of the country. This study was carried out to investigate the stakeholders in the use of faecal sludge (FS) for crop production in Tamale and Bolgatanga municipalities in the guinea savanna agroecological zone of Ghana. The aim was to determine the driving factors, constraints and potentials for this practice. Field survey and focus group discussions were carried out among 90 farmers who use FS, and officials of the Municipal Sanitation Unit were interviewed. Sixty-four percent of farmers interviewed used FS as a cost-effective way to improve soil fertility and increase yields of maize and sorghum. Sludge is discharged by spreading it on the soil surface, or it is stored and dried in pits during the dry season and incorporated into the soil at the onset of the rainy season. The high temperatures of the savanna climate and this long period of drying allow sludge to be handled easily. Although this treatment is perceived to reduce the number of pathogens in dried sludge, 22% of farmers complained of itching feet and foot rot after working with FS, which is done without wearing protective foot covering. This constraint is coupled with the foul smell, transport problem and public mockery associated with the use of human waste for agriculture. In spite of these problems, there is competition for FS among farmers, due to benefits derived from its use. Further investigation is required to ascertain the causes of itching feet and foot rot, and there is a need for education on proper handling and appropriate hygiene practices when working with FS. Information regarding optimal FS application rates is also required.
Phytotoxicity factors and herbicide contamination in relation to compost quality management practices
Authors: Blewett T.Craig , Roberts David W. , Brinton William F.
Published: June 2005

The practice of composting mixed green wastes from community collection programs has been on the increase as a means to reduce organic debris to landfills. Recent reports of plant injury have appeared and were attributed to residues of the herbicide clopyralid in compost. Phytotoxicity issues with compost have been reported previously to result from other factors, including heavy metal content, soluble salts, organic acids and oxygen deprivation related to incomplete decomposition. The recent reports of plant injury due to clopyralid-contaminated compost were also associated with very heavy applications of compost, yet few of these reports included observations of herbicide symptomology. Since immature compost may contain sufficient degradation intermediates, soluble salts and other contaminants to cause phytotoxicity, particularly when applied at heavy rates, an effort must be made to distinguish confounding factors. Complete composting normally allows for the degradation of phytotoxic intermediates and synthetic compounds, such as herbicides, as well as allowing for leaching of salts. Absence of compost completeness standards within the compost industry leaves such factors to the guesswork of the end-user. Recommended compost use rates have established a relationship between compost maturity, application rate and use pattern, based on compost quality metrics. Greater attention to the use of high-quality compost, properly designated as to completeness of composting and applied at appropriate use rates, would minimize the potential for phytotoxic effects, irrespective of the contributing source.
Hydrothermal time analysis of seed dormancy in true (botanical) potato seeds
Authors: Alvarado Veria , Bradford Kent J.
Published: June 2005

As seed dormancy is released within a seed population, both the rate and percentage of germination increase progressively with increasing dose of a dormancy-breaking treatment or condition. Population-based models can account for this behaviour on the basis of shifting response thresholds as dormancy is alleviated. In particular, hydrothermal time analysis of germination sensitivity to water potential (Ψ) and temperature (T) can describe these features of seed behaviour. We used the hydrothermal time model to analyse the effects of dormancy-breaking treatments on germination of dormant true (botanical) potato (Solanum tuberosumL.) seeds (TPS). After-ripening (37°C and 4% seed moisture content) of TPS for 7 or 30 days partially or fully alleviated primary dormancy. The median base water potential required to prevent germination [Ψb(50)] decreased from –0.25 MPa in control seeds to –0.87 MPa and –1.83 MPa after 7 and 30 days of after-ripening, respectively. In contrast, the base temperature for germination (Tb) was relatively unaffected (0–3.3°C). Fluridone (50 μM), an inhibitor of abscisic acid (ABA) biosynthesis, also promoted germination of dormant TPS and lowered Ψb(50), indicating a role forde novosynthesis of ABA during dormancy maintenance. Moist chilling (3 days at 4°C) or gibberellin (100 μM) alleviated secondary dormancy and lowered Ψb(50) values from –0.08 MPa to –0.36 and –0.87 MPa, respectively. The hydrothermal time model allows quantification of dormancy levels and explains why changes in germination speed and percentage are closely correlated during dormancy alleviation.
Incubation under fluctuating temperatures reduces mean base water potential for seed germination in several non-cultivated species
Authors: Huarte Roberto , Benech-Arnold Roberto L.
Published: June 2005

Seeds ofCarduus acanthoides,Cynara cardunculus,Cirsium vulgare,Brassica campestris, andSisymbrium altissimumwere incubated at a range of decreasing osmotic potentials (Ψo) under fluctuating temperatures or the median temperature of the fluctuation cycle. Fluctuating temperatures promoted total seed germination in water and at reduced osmotic potential. Total germination was reduced as the Ψodecreased. However, this trend was smallest under fluctuating temperatures, signalling a higher tolerance of seeds to reduced osmotic potential. Effects of osmoticum and temperature were modelled with the hydrotime model. The parameters estimated from the model, the hydrotime constant (θH), the mean base water potential Ψb(50) and its standard deviation (σΨb) gave good descriptions of germination time courses. For all species, incubation under fluctuating temperatures shifted Ψb(50) values downwards without modifying their distribution substantially. This accounted for the greater tolerance of germination to reduced Ψounder fluctuating temperatures. To confirm that these effects were mediated by temperature fluctuationsper se, the behaviour ofC. acanthoidesandC. cardunculusincubated at the minimum, the mean and the maximum temperature of the fluctuation cycle was also analysed. Constant maximum and minimum temperatures of the cycle did not stimulate germination, nor did they shift Ψb(50) towards more negative values. The hydrotime model provides a physiologically based quantitative description for germination promotion due to fluctuating temperature.
Characterization of water status in primed seeds of tomato (Lycopersicon esculentum Mill.) by sorption properties and NMR relaxation times
Authors: Nagarajan Shantha , Pandita V.K. , Joshi D.K. , Sinha J.P. , Modi B.S.
Published: June 2005

The enhanced laboratory and field emergence characteristics of osmo- and halo-primed tomato seeds (cv. Pusa Ruby) were related to changes in hydration–dehydration kinetics, modified sorption properties and nuclear magnetic resonance (NMR) relaxation behaviour of humidified and imbibed seeds. Water sorption isotherms were constructed for primed and unprimed seeds by equilibrating to different water activities (aw) at 25°C. Analysis of the isotherms by the D'Arcy–Watt equation revealed that priming reduced the number of strong binding sites and the associated water content, and increased significantly the number of weak binding sites and the associated water content. This redistribution of water, which increased the availability of seed water, may be the reason for the higher speed of germination of primed seeds. The changes in transverse relaxation time (T2) of seed water and its components, measuredin vivousing nuclear magnetic resonance spectroscopy, showed interesting differences between primed and unprimed seeds. With an increase in humidification time, the T2of primed seeds could be resolved into three components with varying mobilities, while the control seeds had only two components until 10 d of humidification. During imbibition, the third component appeared after 2 and 6 h in primed and control seeds, respectively. This component disappeared after the germination process started in all treatments. The third fraction, with very low molecular mobility, which accounted for about 40% of the proton population, was assigned to hydration water of macromolecules. Hence, we propose that better performance of primed seeds may be attributed to the modifications of seed water-binding properties and reorganization of seed water during imbibition, so as to increase the macromolecular hydration water required for various metabolic activities related to the germination process.
Urban domestic gardens (VII): a preliminary survey of soil seed banks
Authors: Thompson Ken , Colsell Stephen , Carpenter Jennifer , Smith Richard M. , Warren Philip H. , Gaston Kevin J.
Published: June 2005

As part of a larger survey of biodiversity in private gardens in Sheffield, UK, we examined the composition and diversity of the soil seed banks in each of 56 gardens. Six soil cores from each garden revealed 2759 seedlings of 119 taxa, although the real species richness is likely to be much higher than this. By far the most abundant species were weedy natives, while the most common alien was Buddleja davidii. Seeds of perennial herbs were more abundant than hundreds of all other life forms combined. More frequent species were also more abundant, but the relationship was weak. Numbers of species in the seed bank and in the garden flora were positively but very weakly related. Seeds were quite evenly distributed between 0–5 cm and 5–10 cm soil layers, and most seeds were of species known to have persistent seed banks. Seeds of some species were largely confined to gardens in which the plant was growing, but others were not.
Effect of temperature on dormancy and germination of Eupatorium cannabinum L. achenes
Authors: Brändel Markus , Jensen Kai
Published: June 2005

This study investigated the effects of various temperature regimes on dormancy and germination inEupatorium cannabinum, a common wetland species in Central Europe. Germination of dry-stored achenes was tested at increasing amplitudes of temperature fluctuations, and stratified achenes were germinated at constant temperatures. Dormancy release was examined in the laboratory at constant temperatures of 3, 8, 12, 15 and 18°C. The effect of an increase in temperature during stratification from 5°C to 15, 18 or 20/10°C on dormancy was tested. Moreover, achenes were exposed to yearly seasonal temperature cycles in the soil in an experimental garden. Germination of dry-stored achenes was not promoted by fluctuating temperatures, while stratified achenes germinated (>5%) over a range of constant temperatures between 9 and 36°C. Dormancy was relieved at all stratification temperatures, but temperatures ≤12°C were more effective than higher temperatures, since germination occurred over a wider range of test conditions after these pretreatments. An induction of secondary dormancy occurred only if the temperature was increased during stratification. Annual dormancy cycles were apparent when achenes were germinated at 15°C, while at 25 and 15/5°C germination was always >60%. The germination behaviour ofEupatoriumis that of a typical wetland species. Thus, non-dormant achenes germinated at relatively high temperatures, and germination was promoted by fluctuating temperatures. The annual course of dormancy revealed that achenes can germinate throughout the growing season under favourable conditions. Achenes sown in an experimental garden germinated in spring, when daily mean temperatures were around 14°C. A decline in viability of achenes after 19 months' burial indicated thatEupatoriumdoes not form a long-term persistent seed bank.
Structural, physiological and molecular aspects of heterogeneity in seeds: a review
Authors: Matilla Angel , Gallardo Mercedes , Puga-Hermida María Isabel
Published: June 2005

Higher plants have several strategies to perpetuate themselves under adequate ecophysiological conditions. The production of heterogeneous seeds is one such strategy. That is, to ensure the survival of the next generation, an individual plant might produce seeds that are heterogeneous with respect to the extent of dormancy, dispersion and persistence within the seed bank. Heterogeneity can affect not only certain physiological and molecular properties related to seed germination, but also such characteristics as colour, size and shape, parameters commonly used to differentiate morphs within a heterogeneous seed population. In heterogeneous seeds, the above features determine seed behaviour and alter their mechanism of germination. In this work, emphasis is placed on the existence of seed mutants having major alterations in characteristics of the testa and hormonal response. These mutants constitute a valuable tool for elucidating the mechanism of dormancy, germination and perpetuation of seeds. Finally, ontogeny and heterogeneity are reviewed, providing the first data related to the possible hormonal control of heterogeneity in seeds. These results raise the hypothesis that one of the factors triggering differences in germination among heterogeneous seeds may be an alteration in the signalling and action mechanism of ethylene and abscisic acid (ABA).
Seed survival in Chilean Nothofagus in response to desiccation and storage
Authors: León-Lobos Pedro , Ellis Richard H.
Published: June 2005

Nothofagus alpina,N. obliqua,N. glauca,N. leonii,N. dombeyiandN. pumilioseeds exhibited consistent, albeit slight, sensitivity to extreme desiccation, but nevertheless maintained viability at low moisture contents and cool temperatures (–10° to –20°C) over 2 years.Nothofagus alpina,N. obliqua,N. glauca,N. leoniiandN. dombeyiconformed to the seed viability equation of Ellis and Roberts; sensitivity of longevity to temperature was quantitatively similar to that of crop seeds, sensitivity to moisture was somewhat less, and a low-moisture-content limit to the equation was detected at 4.8% moisture content in hermetic storage at 65 °C, and possibly similar moisture contents at 30–40°C. These five species show orthodox seed storage behaviour. Therefore,ex-situconservation of theseNothofagusspecies in seed banks is possible, but the quality of seed lots collected requires attention. Seed storage behaviour was not defined inN. pumilio: initial seed quality was poor and loss of viability was detected over 2 years at 0°, –10° and –20°C at 2.7% moisture content, but not at 5.2%. The results confirm that the economy of nature in seed storage physiology extends to forest tree seeds, but the repeated observation of reduced sensitivity of longevity to moisture in forest tree seeds requires further investigation.
Histological aspects of avocado embryo development and effect of developmental stages on germination
Authors: Perán-Quesada R. , Sánchez-Romero C. , Pliego-Alfaro F. , Barceló-Muñoz A.
Published: June 2005

Anatomical differentiation and storage product accumulation were studied during avocado (Persea americana Mill.) zygotic embryo development using histological techniques. The results were correlated with the germination capacity under in vitro conditions. The histodifferentiation phase, characterized by active cell division and differentiation, was accomplished by 100 d after pollination (DAP), when embryos reached 16–18 mm in length. After a phase in which there were no morphological changes, the maturation phase commenced at 125 DAP in embryos 24–26 mm in length. Accumulation of starch granules and the appearance of protein bodies occurred at this time. Germination was significantly influenced by the embryo developmental stage. Different parameters used as indicators of germination quality (germination percentage, germination speed and recovery of complete plantlets) showed a positive correlation with the age of the embryos. However, germination in vitro was not achieved fully until the end of zygotic embryo development, when the embryo reached physiological maturity.
Spatial coherence between seasonal seed banks in a semi-arid gypsum community: density changes but structure does not
Authors: Caballero I. , Olano J.M. , Luzuriaga A.L. , Escudero A.
Published: June 2005

Seed banks play a crucial role in arid plant communities because they confer stability and long-term persistence. However, seed banks have high temporal and spatial variability, with dramatic changes in density and composition. The aim of this study was to test whether seasonal change affected seed bank community structure and spatial pattern. Moreover, we wanted to know if the effect driven by environmental factors on the seed bank was constant year round. We sampled the seed bank at 188 points along seven parallel transects through a gypsum system in central Spain. Soil samples were taken twice (September and April) in contiguous plots. In each plot we measured environmental parameters, including micro- and macroslope, vegetation band, shrub cover, lichen crust cover and landform. A nearly threefold decrease in seed bank density occurred between September (16,230 seeds m–2) and April (5960 seeds m–2). Seasonal changes in density varied widely among species; however, a seed bank was present for most species at both sampling dates. For several well-studied species (Lepidium subulatum and Helianthemum squamatum), seed losses were within the range of losses by emergence reported in the literature. In both seasons, seed bank composition was controlled mainly by community band and microslope. Sampling season had a significant, but minor effect on seed bank composition. Moreover, a high spatial correlation existed in terms of seed density and richness through the two studied seasons. These results show that the seed bank keeps a constant structure even under substantial variation in density.
Trait stasis versus adaptation in disjunct relict species: evolutionary changes in seed dormancy-breaking and germination requirements in a subclade of Aristolochia subgenus Siphisia (Piperales)
Authors: Adams Christopher A. , Baskin Jerry M. , Baskin Carol C.
Published: June 2005

There are two ideas regarding changes in the physiological and ecological tolerances and requirements within plant lineages through geological time. One is that these attributes have changed very little, or not at all (trait stasis), and the other is that they have undergone considerable change (adaptation), as plants shifted to new climatic and vegetation zones. We tested these ideas for seed dormancy-breaking and germination requirements of four species in a subclade ofAristolochiasubgenusSiphisia: the three temperate species,A. macrophyllaandA. tomentosa(the basal species in the subclade) of eastern USA andA. manshuriensisof East Asia, and the Mediterranean-climate speciesA. californica endemic to California, USA. A long period at cold-stratifying temperatures was required for growth of the underdeveloped embryo and seed germination inA. californica, whereas embryos grew and seeds germinated in the other three species at warm temperatures, either before or after they were cold stratified. Thus, seeds ofA. californicahave either intermediate or deep complex morphophysiological dormancy (MPD), whereas those of the three temperate species have either morphological dormancy or non-deep simple MPD. Further, there were quantitative differences in temperature requirements for dormancy-break and germination between the AppalachianA. macrophylla, which did not differ from its sister speciesA. manshuriensis, and the lowlandA. tomentosa. Thus, within this lineage there has been both trait stasis and divergence (adaptation) in the physiology and ecology of seed dormancy and germination.
Isolation of a Protein Interacting with Vfphot1a in Guard Cells of Vicia faba
Authors: Emi Takashi , Kinoshita Toshinori , Sakamoto Koji , Mineyuki Yoshinobu , Shimazaki Ken-ichiro
Published: June 2005

A recent study has demonstrated that phototropins act as blue light receptors in stomatal guard cells. However, the downstream components responsible for phototropin signaling are largely unknown. In this study, using a yeast two-hybrid system, we isolated a Vicia faba protein that has a high similarity to dynein light chain in the C terminus, which interacts with Vicia faba phototropin 1a (Vfphot1a). Protein-blot and two-hybrid analyses revealed that Vfphot1a interacting protein (VfPIP) bound to the C-terminal region of Vfphot1a but did not bind to Vfphot1b. The interaction between VfPIP and Vfphot was indicated by a pull-down assay. Northern analysis revealed that the transcription level of VfPIP gene was more abundant in guard cells than in other tissues or cell types. The transiently expressed fusion protein of VfPIP-green fluorescent protein was localized on cortical microtubules in Vicia guard cells. Microtubule-depolymerizing herbicides partially inhibited both blue light-dependent H+ pumping in Vicia guard cell protoplasts and stomatal opening in the Vicia epidermis. From these results, we conclude that VfPIP may act as a downstream component of phototropin (Vfphot1a) in blue light signaling in guard cells. The possible role of VfPIP in blue light signaling of guard cells is discussed.
Differences in Cell Death Induction by Phytophthora Elicitins Are Determined by Signal Components Downstream of MAP Kinase Kinase in Different Species of Nicotiana and Cultivars ofBrassica rapaandRaphanus sativus
Authors: Takemoto Daigo , Hardham Adrienne R. , Jones David A.
Published: June 2005

Elicitins are small, secreted proteins produced by species of the plant-pathogenic oomycete Phytophthora. They induce hypersensitive cell death in most Nicotiana species and in some cultivars of Brassica rapa and Raphanus sativus. In this study, two true-breeding Fast Cycling B. rapa lines were established that showed severe necrosis (line 7-R) or no visible response (line 18-NR) after treatment with elicitin. Unexpectedly, microscopic examination revealed localized cell death in line 18-NR plants, and expression levels of various defense-marker genes were comparable in both lines. These results suggested that both “responsive” and “nonresponsive” plants responded to elicitin but differed in the extent of the cell death response. Expression of a constitutively active form of Arabidopsis (Arabidopsis thaliana) MAP kinase kinase 4 (AtMEK4DD) also induced rapid development of confluent cell death in line 7-R, whereas line 18-NR showed no visible cell death. Similarly, elicitin-responsive Nicotiana species and R. sativus cultivars showed significantly stronger cell death responses following expression of AtMEK4DD compared with nonresponsive species/cultivars. Line 7-R also showed higher sensitivity to toxin-containing culture filtrates produced by Alternaria brassicicola, and toxin sensitivity cosegregated with elicitin responsiveness, suggesting that the downstream responses induced by elicitin and Alternaria toxin share factors that control the extent of cell death. Interestingly, elicitin responsiveness was shown to correlate with greater susceptibility to A. brassicicola (a necrotroph) in B. rapa but less susceptibility to Phytophthora nicotianae (a hemibiotroph) in Nicotiana, suggesting a more extensive cell death response could cause opposite effects on the outcomes of biotrophic versus necrotrophic plant-pathogen interactions.
Thermodynamic Battle for Photosynthate Acquisition between Sieve Tubes and Adjoining Parenchyma in Transport Phloem
Authors: Hafke Jens B. , van Amerongen Jan-Kees , Kelling Frits , Furch Alexandra C.U. , Gaupels Frank , van Bel Aart J.E.
Published: June 2005

In transport phloem, photoassimilates escaping from the sieve tubes are released into the apoplasmic space between sieve element (SE)/companion cell (CC) complexes (SE/CCs) and phloem parenchyma cells (PPCs). For uptake respective retrieval, PPCs and SE/CCs make use of plasma membrane translocators energized by the proton motive force (PMF). Their mutual competitiveness, which essentially determines the amount of photoassimilates translocated through the sieve tubes, therefore depends on the respective PMFs. We measured the components of the PMF, membrane potential and ΔpH, of SE/CCs and PPCs in transport phloem. Membrane potentials of SE/CCs and PPCs in tissue slices as well as in intact plants fell into two categories. In the first group including apoplasmically phloem-loading species (e.g. Vicia, Solanum), the membrane potentials of the SEs are more negative than those of the PPCs. In the second group including symplasmically phloem-loading species (e.g. Cucurbita, Ocimum), membrane potentials of SEs are equal to or slightly more positive than those of PPCs. Pure sieve tube sap collected from cut aphid stylets was measured with H+-selective microelectrodes. Under our experimental conditions, pH of the sieve tube saps was around 7.5, which is comparable to the pH of cytoplasmic compartments in parenchymatous cells. In conclusion, only the membrane potential appears to be relevant for the PMF-determined competition between SE/CCs and PPCs. The findings may imply that the axial sinks along the pathway withdraw more photoassimilates from the sieve tubes in symplasmically loading species than in apoplasmically loading species.
Vitamin B1 Functions as an Activator of Plant Disease Resistance
Authors: Ahn Il-Pyung , Kim Soonok , Lee Yong-Hwan
Published: June 2005

Vitamin B1 (thiamine) is an essential nutrient for humans. Vitamin B1 deficiency causes beriberi, which disturbs the central nervous and circulatory systems. In countries in which rice (Oryza sativa) is a major food, thiamine deficiency is prevalent because polishing of rice removes most of the thiamine in the grain. We demonstrate here that thiamine, in addition to its nutritional value, induces systemic acquired resistance (SAR) in plants. Thiamine-treated rice, Arabidopsis (Arabidopsis thaliana), and vegetable crop plants showed resistance to fungal, bacterial, and viral infections. Thiamine treatment induces the transient expression of pathogenesis-related (PR) genes in rice and other plants. In addition, thiamine treatment potentiates stronger and more rapid PR gene expression and the up-regulation of protein kinase C activity. The effects of thiamine on disease resistance and defense-related gene expression mobilize systemically throughout the plant and last for more than 15 d after treatment. Treatment of Arabidopsis ecotype Columbia-0 plants with thiamine resulted in the activation of PR-1 but not PDF1.2. Furthermore, thiamine prevented bacterial infection in Arabidopsis mutants insensitive to jasmonic acid or ethylene but not in mutants impaired in the SAR transduction pathway. These results clearly demonstrate that thiamine induces SAR in plants through the salicylic acid and Ca2+-related signaling pathways. The findings provide a novel paradigm for developing alternative strategies for the control of plant diseases.
Fatty Acid Hydroperoxides and H2O2 in the Execution of Hypersensitive Cell Death in Tobacco Leaves
Authors: Montillet Jean-Luc , Chamnongpol Sangpen , Rustérucci Christine , Dat James , van de Cotte Brigitte , Agnel Jean-Pierre , Battesti Christine , Inzé Dirk , Van Breusegem Frank , Triantaphylidès Christian
Published: June 2005

We initially compared lipid peroxidation profiles in tobacco (Nicotiana tabacum) leaves during different cell death events. An upstream oxylipin assay was used to discriminate reactive oxygen species (ROS)-mediated lipid peroxidation from 9- and 13-lipoxygenase (LOX)-dependent lipid peroxidation. Free radical-mediated membrane peroxidation was measured during H2O2-dependent cell death in leaves of catalase-deficient plants. Taking advantage of these transgenic plants, we demonstrate that, under light conditions, H2O2 plays an essential role in the execution of cell death triggered by an elicitor, cryptogein, which provokes a similar ROS-mediated lipid peroxidation. Under dark conditions, however, cell death induction by cryptogein was independent of H2O2 and accompanied by products of the 9-LOX pathway. In the hypersensitive response induced by the avirulent pathogen Pseudomonas syringae pv syringae, both 9-LOX and oxidative processes operated concurrently, with ROS-mediated lipid peroxidation prevailing in the light. Our results demonstrate, therefore, the tight interplay between H2O2 and lipid hydroperoxides and underscore the importance of light during the hypersensitive response.
Interacting Proteins and Differences in Nuclear Transport Reveal Specific Functions for the NAP1 Family Proteins in Plants
Authors: Dong Aiwu , Liu Ziqiang , Zhu Yan , Yu Fang , Li Ziyu , Cao Kaiming , Shen Wen-Hui
Published: June 2005

Nucleosome assembly protein 1 (NAP1) is conserved from yeast to human and facilitates the in vitro assembly of nucleosomes as a histone chaperone. Inconsistent with their proposed function in the nucleus, however, many NAP1 proteins had been reported to localize in the cytoplasm. We investigated the subcellular localization of tobacco (Nicotiana tabacum) and rice (Oryza sativa) NAP1 family proteins first by identification of interacting partners and by direct examination of the localization of green fluorescent protein-tagged proteins. Through treatment of tobacco cells with leptomycin B and mutagenesis of nuclear export signal, we demonstrated that Nicta;NAP1;1 and Orysa;NAP1;1 shuttle between the cytoplasm and the nucleus. Together with the demonstration that tobacco NAP1 proteins bind histone H2A and H2B, our results support the current model and provide additional evidence that function of NAP1 as histone chaperones appears to be conserved in plants. In addition, we show that tobacco NAP1 proteins interact with tubulin and the mitotic cyclin Nicta;CYCB1;1, suggesting a role for NAP1 in microtubule dynamics. Interestingly, in spite of their high homology with the above NAP1 proteins, the other three tobacco proteins and Orysa;NAP1;2 did not show nucleocytoplasmic shuttling and were localized only in the cytoplasm. Moreover, Orysa;NAP1;3 that lacks a typical nuclear localization signal sequence was localized in both the cytoplasm and the nucleus. Finally, we show that only Orysa;NAP1;3 could be phosphorylated by casein kinase 2α in vitro. However, this phosphorylation was not responsible for nuclear import of Orysa;NAP1;3 as being demonstrated through mutagenesis studies. Together, our results provide an important step toward elucidating the molecular mechanism of function of the NAP1 family proteins in plants.
Specificity in Ecological Interactions. Attack from the Same Lepidopteran Herbivore Results in Species-Specific Transcriptional Responses in Two Solanaceous Host Plants
Authors: Schmidt Dominik D. , Voelckel Claudia , Hartl Markus , Schmidt Silvia , Baldwin Ian T.
Published: June 2005

Model systems have proven enormously useful in elucidating the biochemical function of plant genes. However their ecological function, having been sculpted by evolutionary forces specific to a species, may be less conserved across taxa. Responses to wounding and herbivore attack differ among plant families and are known to be mediated by oxylipin, ethylene, and systemin-signaling networks. We analyzed transcriptional responses of two native Solanaceous species to the attack of an herbivore whose elicitors are known not to be influenced by diet. With The Institute for Genomic Research 10k-cDNA potato (Solanum tuberosum) microarray, we compared the transcriptional responses of Nicotiana attenuata with those of black nightshade (Solanum nigrum) when both were attacked by the Solanaceous generalist herbivore, Manduca sexta. Based on an NADH dehydrogenase subunit F phylogeny, S. nigrum is more closely related to potato than N. attenuata but responded significantly less to M. sexta attack. Apart from transcriptional differences anticipated from their differences in secondary metabolism, both species showed distinct transcriptional patterns (with only 10% overlap in significantly regulated genes), which point to fundamental differences in the signaling cascades and downstream genes mediating herbivore resistance. The lackluster transcriptional response of S. nigrum could not be attributed to its inability to respond to elicitation, because methyl jasmonate elicitation of S. nigrum resulted in a strong transcriptional response. Given that attack from the same herbivore elicits profoundly different responses in two Solanaceaous taxa, we conclude that blueprints for commonly regulated responses to plant-herbivore interactions appear unlikely.