Phytoextraction of cadmium and zinc by Salix from soil historically amended with sewage sludge

Short rotation coppice (SRC) such as Salix spp. can be grown as an energy crop and offers some potential for economic and practical phytoextraction of marginally contaminated arable soil. This study tested various soil amendments intended to increase soil metal availability to Salix, investigated the distribution of metal between different tree fractions and assessed the viability of phytoextraction using SRC on arable soils. Several Salix genotypes were grown in field trials over 4 years. Cd and Zn concentrations were generally ranked in the order leaves > bark > wood. Metal concentrations in wood increased towards the top of the willow stems, whereas concentrations in leaves showed the opposite trend. None of the amendments significantly increased uptake of Zn by willow. However, in response to a range of soil HCl treatments, mean Cd concentrations in stems and leaves were 112% and 130% of control values. Data from the current experiment, and previous studies, were combined to develop a predictive model of Cd and Zn stem uptake by Salix. The minimum biological concentration factor (BCF) required to achieve a prescribed soil metal target was also calculated based on typical proportions of bioavailable Cd in sludge-amended soils for a 25-year Salix rotation. The best Salix genotypes investigated achieved less than 20% of the uptake rate required to remove one third of the soil Cd content (equivalent to the average isotopically exchangeable Cd fraction in soils at the study site).     

Separating the determinants of phylogenetic community structure

The role of competition in forbidding similar species from co-occurring has long been debated. A difficulty in identifying this repulsion of similar species is that similar species share similar environmental requirements and hence show an attraction to communities where these requirements are met. To disentangle these opposing patterns, we use phylogenetic relatedness as an objective metric of species similarities. Studying 11 sunfishes (Centrarchidae) from 890 lakes, we first show no phylogenetic pattern in the raw community data. We then regressed sunfish presence/absence against seven environmental variables and show that lakes with similar water clarity and latitude likely contain closely related species. After statistically removing the environmental effects, phylogenetic repulsion was apparent, with closely related sunfishes less likely to co-occur. Thus, both phylogenetic attraction, driven by environmental filtering, and phylogenetic repulsion, possibly caused by competition, simultaneously occur and obscure one another in the overall phylogenetic structure of sunfish communities.     

Enhancing the Conservation of Crop Wild Relatives in England

Humans require resilient, rapidly renewable and sustainable supplies of food and many other plant-derived supplies. However, the combined effects of climate change and population growth compromise the provision of these supplies particularly in respect to global food security. Crop wild relatives (CWR) contain higher genetic diversity than crops and harbour traits that can improve crop resilience and yield through plant breeding. However, in common with most countries, CWR are poorly conserved in England. There is currently no provision for long-term CWR conservation in situ, and comprehensive ex situ collection and storage of CWR is also lacking. However, there is a commitment to achieve their conservation in England’s Biodiversity Strategy and the UK has international commitments to do so as part of the Global Plant Conservation Strategy. Here, we identify a series of measures that could enhance the conservation of English CWR, thereby supporting the achievement of these national and international objectives. We provide an inventory of 148 priority English CWR, highlight hotspots of CWR diversity in sites including The Lizard Peninsula, the Dorset coast and Cambridgeshire and suggest appropriate sites for the establishment of a complementary network of genetic reserves. We also identify individual in situ and ex situ priorities for each English CWR. Based on these analyses, we make recommendations whose implementation could provide effective, long-term conservation of English CWR whilst facilitating their use in crop improvement.     

Cytotaxonomic studies of Eastern MediterraneanVicia species (Leguminosae)

Collected material of rare and newVicia spp. was investigated from a cytotaxonomic point of view. Nineteen species were examined in total. The study includes 14 novel chromosome counts and measurements of DNA amount, as well as a comparison of chromosome morphology between species. The results of the cytological study support to an extent a recent taxonomical revision of subgenusVicia. To whom reprint requests should be addressed.     

Outbreak of idiopathic erysipelas in a psychiatric hospital.

In an outbreak of idiopathic erysipelas ten women patients, aged 42-74, in a long-stay unit of a psychiatric hospital were simultaneously affected. Group A streptococci M-type 1 were isolated from two isolated from two patients with erysipelas and 18 carriers, but subsequent serological tests for type-specific antibody, antistreptolysin O, and anti-deoxyribonuclease B showed that the infection had been widespread in the unit. Treatment with ampicillin proved ineffective and to prevent relapse it was substituted by a standard course of intramuscular penicillin. This seems to be the first epidemic of this type to be reported and certainly the first outbreak of idiopathic erysipelas to be investigated by modern serological techniques.     

A comparative study of the bacterial cell wall,protoplast membrane and L-form envelope ofStreptococcus pyogenes

The chemical composition of the cell wall, protoplast membrane and L-form envelope of Group A streptococci has been studied. The L-form envelope could not be identified with either the cell wall or the protoplast membrane. Although both the induced structures were mainly lipo-protein in nature, the protein/lipid ratio was much higher in the protoplast membrane (4 : 1) than in the L-form envelope (1.7 : 1). The L-form envelope differed from the bacterial cell wall in that it had a very small amount of mucopeptide which carried relatively fewer peptide chains, and also very little reducing sugar. Electrokinetic measurements in the presence of sodium dodecyl sulphate revealed that none of the lipid material was present on the surface of the L-form or protoplast. pH-mobility curves of all three structures indicated the presence of surface protein, and the absence of surface phosphate groups associated with the phospholipids found in the L-form envelope and the protoplast membrane.     

New approaches for establishing conservation priorities for socio-economically important plant species

The establishment of priorities among species is a crucial step in any conservation strategy since financial resources are generally limited. Traditionally, priorities for conservation of plant species have been focused on endemicity, rarity and particularly on their threatened status. Crop wild relatives (CWR) and wild harvested plants (WHP) are important elements of biodiversity with actual or potential socio-economic value. In this study, eight prioritisation criteria were used along with different prioritisation systems and applied to the Portuguese CWR and WHP. The top 50 species obtained by each of these methods were identified. The final top CWR were those that occurred as a priority in most methods. Twenty CWR were identified as the highest priorities for conservation in Portugal and they include wild relatives of the crop genera Allium, Daucus, Dianthus, Epilobium, Festuca, Herniaria, Narcissus, Quercus, Plantago, Trifolium, and Vicia. Eighteen WHP were recognised as priorities for conservation and include several Narcissus and Thymus species, among others. The advantages, limitations and level of subjectivity of each of the methods used in this exercise are discussed.     

The relative significance of environmental and anthropogenic factors affecting zooplankton community structure in Southeast Wisconsin Till Plain lakes

Zooplankton community composition can be related to natural environmental factors such as lake morphology, lake landscape position, and water chemistry as well as anthropogenic factors such as agricultural and urban land-use. We hypothesized that within-lake factors, such as water chemistry, lake morphology, and human land-use would each be related to zooplankton community structure, but that watershed land-use would be the strongest correlate in southeast Wisconsin lakes. Zooplankton samples, collected every 3 months over a year, from 29 lakes were used to determine how lake and watershed morphology, water quality, and land-use were related to zooplankton community structure in the heavily developed Southeast Wisconsin Till Plain Ecoregion. Forward selection and a variation partitioning procedure were used to determine relative and shared contributions of each suite of variables in predicting zooplankton community structure. Redundancy analysis was used to characterize dominant gradients in pelagic zooplankton communities and related environmental factors and land-use. The major correlates of community structure included summer phosphorus, lake depth and surface area and urban and natural land. Variation partitioning illustrated that phosphorus alone accounts for the greatest part (12%) of community structure. Urban land-uses (residential, commercial and paved land) and lake morphology partially explain zooplankton community variation through combined effects with phosphorus. Small cladocerans and Skistodiaptomus pallidus were associated with higher phosphorus, shallow depth and higher urban land-use, while Daphnia pulicaria dominates in deep lakes with lower phosphorus and less urban land-use. This study contributes to the understanding of factors affecting zooplankton community structure in a largely human developed region and illustrates the importance of eutrophication in structuring zooplankton community composition.     

A multivariate and cladistic study of Vicia L. ser. Vicia (Fabaceae) based on analysis of morphological characters

 Vicia ser. Vicia, which includes the Vicia sativa aggregate, was studied by observing morphological variation. The study is an attempt to resolve the taxonomic relationships within the Vicia sativa aggregate by novel investigations along with a synthesis of the results obtained by previous researchers. The study has included some accessions and characters used previously, but has drawn accessions from a wider geographical range than has been attempted previously. Cluster analysis on the basis of 53 morphological characters justified the delimitation of four species within the series and six subspecies within the Vicia sativa aggregate. Accessions from South Asia could easily be incorporated in the classification, but some of the accessions from North Africa showed morphological differences. The morphometric data were coded using the gap weighting method of Thiele (1993) and used in a phylogenetic analysis to study the relationships between the taxa. The phylogenetic analysis, using 33 variables, showed Vicia pyrenaica closely related to Vicia sativa subsp. amphicarpa. A dichotomous key and a multi-access key to aid the identification of the taxa in the series are presented. Received January 21, 2002; accepted November 8, 2002 Published online: March 20, 2003