A forage grass and small grain legume plant collecting expedition in South East Poland, 1990

Summary The Plant Genetic Resources Unit (PGRU) of the Institute of Grassland and Environmental Research, Welsh Plant Breeding Station (IGER, WPBS), UK, and the Plant Genetic Resources Section of the Plant Breeding and Acclimatization Institute (PBAI), Poland, carried out a joint collecting expedition in Poland between 25 August and 7 September 1990. The expedition was unique in that it was the first time that vegetative sampling had been applied to the perennial forage grass and legume populations of south east Poland. The expedition focused on seminatural vegetation in agriculturally managed situations and detailed collection site data on management systems was obtained from landowners.Samples were collected from 62 sites. Vegetative collections of Lolium spp. (37 populations) and Trifolium spp. (56 populations), and seed collections of Festuca spp. (32 populations) were made by the IGER team (Table 2). The PBAI team made 59 separate seed collections, mainly of Leguminosae.The expedition covered four geographical subregions of south east Poland. (See Fig. 1). These were the Nizina Mazowiecka south of Warszawa, the Wyzyna Malopolska with the town of Kielce at its centre and the Beskidy Zachodnie and Beskidy Wschodnie regions of the Carpathian mountains.A diverse range of habitats was sampled covering a broad range of altitude agricultural management systems and ecological conditions. Polish agriculture is faced with the problems of a rapid orientation to a market economy and it is likely that the diverse range of habitats encoutered will be reduced as agricultural practices change. This will lead to genetic erosion of the unique forage grass and legume populations to be found in Poland.Abbreviations ECP/GR European Co-operative Programme on Crop Genetic Resources - IGER Institute of Grassland and Environmental Research - PBAI Plant Breeding and Acclimatization Institute - PGRU Plant Genetic Resources Unit - WPBS Welsh Plant Breeding Station     

Analysis of beta-casein-monopalmitin mixed films at the air-water interface

The surface pressure (pi)-area (A) isotherms and Brewster angle microscopy (BAM) images of monopalmitin and beta-casein mixed films spread on buffered water at pHs 5 and 7 and at 20 degrees C were determined as a function of the mass fraction of monopalmitin in the mixture (X). The structural characteristics and morphology of monopalmitin-beta-casein mixed films are dependent on surface pressure, pH, and monolayer composition. The prevalence of monopalmitin in the interface increases with the amount of monopalmitin in the mixture and at higher pi. At the monopalmitin monolayer collapse the mixed film is practically dominated by the presence of monopalmitin. However, some degree of interactions exist between monopalmitin and beta-casein in the mixed film, and these interactions are more pronounced as the monolayer is compressed at the highest surface pressures.     

Nitrosation of phenolic compounds: inhibition and enhancement

The nitrosation of phenol, m-, o-, and p-cresol, 2,3-, 3,5-, and 2, 6-dimethylphenol, 3,5-di-tert-butylphenol, 2,4,6-trimethylphenol, o-chlorophenol, and o-bromophenol was studied. Kinetic monitoring of the reactions was accomplished by spectrophotometric analysis of the products at 345 nm. At pH > 3, the dominant reaction was C-nitrosation through a mechanism that appears to consist of an attack on the nitrosatable substrate by NO(+)/NO(2)H(2)(+), followed by a slow proton transfer. The finding of an isokinetic relationship supports the idea that the same mechanism operates throughout the series. The observed sequence of nitrosatable substrate reactivities is explained by (i) the preferred para-orientation of the hydroxyl group for the electrophilic attack of nitrosating agents, (ii) steric hindrance of alkyl substituents, which reduces or prevents attack by nitrosating agents, and (iii) the hyperconjugative effect of the methyl substituent, which causes electronic charge to flow into the aromatic nucleus, as well as the opposite electronic withdrawing effect induced by halogen substituents. The results show that potential nitrosation of widespread environmental species such as chlorophenols is negligible, but more attention should be paid to polyphenols with strongly nucleophilic carbon atoms.     

Acute toxicity of zinc and arsenic to the warmwater aquatic oligochaete <Emphasis Type="Italic">Branchiura sowerbyi</Emphasis> as compared to its coldwater counterpart <Emphasis Type="Italic">Tubifex tubifex</Emphasis> (Annelida,Clitellata)

Purpose

This study aimed at evaluating the acute effects of arsenic and zinc to the warmwater aquatic oligochaete Branchiura sowerbyi. Relative sensitivity with the coldwater species Tubifex tubifex was compared. Implications for the use of B. sowerbyi in the risk assessment of sediments in the tropics are discussed.

Materials and methods

Water-only (96 h) and sediment (14 days) toxicity tests were conducted with both species evaluating a concentration series of arsenic and zinc. The tests were conducted considering the environmental conditions in the natural habitat of T. tubifex (predominantly temperate) and B. sowerbyi (predominantly tropical). Both lethal and sublethal endpoints (autotomy of the posterior body parts, abnormal behavior and appearance) were determined in the tests. The lethal (LC₁₀ and LC₅₀) and effect (EC₁₀ and EC₅₀) concentrations were also determined to assess metal sensitivity for both species.

Results and discussion

Both test species were more sensitive to Zn than As in water-only tests, which is in agreement with previous studies evaluating the toxicity of these metals to aquatic oligochaetes. Sublethal effects were generally noted at concentrations lower than those leading to mortality. The warmwater oligochaete B. sowerbyi was more sensitive to both metals tested than the coldwater species T. tubifex.

Conclusions

Study findings support the need for using indigenous tropical species in risk assessments in the tropics. In addition, sublethal effect parameters should be included in toxicity testing with aquatic oligochaetes.

     

Immediate Impact of the Flood (Bohemia, August 2002) on Selected Soil Characteristics

In August 2002 extreme floods affected Bohemia a part of the Czech Republic, along Vltava and Labe rivers. After the flood had culminated, soil samples of arable and meadow soil (flooded and control-non-flooded) have been collected in the surroundings of the cities of ?eské Budějovice (CB, South Bohemia, the Vltava river, the upper flood stream) and Ústí nad Labem (UL, the Labe river, the lower flood stream). Different parameters of arable soils have been affected more significantly than those of meadow soils. Soil texture e.g. has been shifted from sandy loam to loam (CB) and clay loam (UL). Organic carbon, total phosphorus and nitrogen contents have been increased as well as the content of some hazardous elements such as arsenic. A shift of soil pH from 6.1 to 4.8 has been noticed in CB and an opposite one from 5.1 to 7.1 was measured in UL. Available phosphorus decreased in CB by 56% while a four-fold increase was measured in UL. Chlorinated organic pesticides level was significantly reduced, but that of polycyclic aromatic hydrocarbons (PAH) increased up to the maximum values of legal limits. The UL arable soil also became heavily contaminated by PAH. The CB arable soil demonstrated high microbial activity, while UL arable soil suffered under stress conditions in this respect. The flooded meadow soils became covered with a layer of drifted soil sediment, which retained enhanced content of the PAH's different hazardous elements, and, in addition, the soil aeration was reduced.     

Influence of micelles on the basic degradation of carbofuran

The effect of micellar aggregates upon the stability of carbofuran in basic media has been studied. The effect of the presence of micelles upon the basic hydrolysis of carbofuran is a function of the nature of the surfactant monomer. Important catalysis of basic hydrolysis of carbofuran in the presence of colloid aggregates with positive surface charge has been reported. On the other hand, the presence of anionic and nonionic surfactants implies a large inhibition of the basic hydrolysis of carbofuran. Both catalysis and inhibition are due to the association of carbofuran with the micellar core. The kinetic constants for the basic hydrolysis of carbofuran in these microheterogeneous media have been obtained on the basis of a micellar pseudophase model. No significant changes in the intrinsic reactivity of HO- against carbofuran have been observed.     

Sulfometuron resistance as a genetic marker for yeast populations in wine fermentations

Winemaking with selected yeasts requires simple and cheap techniques to monitor the yeast population dynamics. We obtained new sulfometuron (smr) resistant mutants, easy to detect by replica-plate assay, from selected wine yeasts. The mutations were dominant and were located at the ilv2 locus that encodes for acetolactate synthase enzyme. The mutants were genetically stable and maintained the killer phenotype of the parent yeast strain. They were genetically improved by elimination of recessive growth-retarding alleles followed by spore clone selection according to the must fermentation kinetics and the organoleptic quality of the wine. Some mutants were tested in industrial winemaking and were easily monitored during must fermentation using a simple plate assay. They accounted for more than 95% of the total yeasts in the must, and the resulting wine had as good a quality as those made with standard commercial wine yeasts.     

The effect of sample storage on the extraction of Cu,Zn, Fe,Mn and organic material from oxidized estuarine sediments

Concentrations of extractable Cu, Zn, Fe and Mn in oxidized estuarine sediment are influenced by the manner and time of storage between collection and extraction. No storage method tested completely preserves the initial chemical and physical characteristics of the sediment. Freezing or (for some extractions) drying are adequate methods of storage if sediments are to be extracted only with acids. However, if a variety of extractants is to be used, extractions should be conducted as soon as practical after collection.     

Conservation in a changing world: <Emphasis Type="Italic">in situ</Emphasis> conservation of the giant maize of Jala

Using survey data from Jala, Mexico, this case-study evaluates in situ maize conservation of the variety ‘Jala’ (Zea mays L.). Though historically ‘Jala’ was the dominant variety grown in the valley of Jala, today less than 20% of farmers grow it on only 5% of the maize area. Younger growers of the ‘Jala’ variety specialize in it, growing relatively large amounts for niche markets. Older, diversified farmers grow small areas for household use and to compete in a local contest. Conservation of the ‘Jala’ variety has been heavily influenced by shifting ideal concepts of maize, as determined by market and consumption demands and by a contest designed to promote in situ conservation. The current move away from nationalized purchasing may favor ‘Jala’s’ continued conservation.     

Diversity in White Lupin (<Emphasis Type="Italic">Lupinus albus</Emphasis> L.) Landraces from Northwest Iberianplateau

All the accessions (35) of white lupin (Lupinus albus L.) landraces collected from northwest Iberian plateau and maintained at the Spanish germplasm collection (CRF of INIA), were studied with the general objective of assessing the biodiversity of these landraces and to ascertain their value as genetic resources for the development of germplasm adapted to the areas where they were collected with long and chilly winters. The characterization study comprised 51 qualitative and 50 quantitative characters. Quantitative parameters were analyzed by Principal Components Analysis (PCA). The 2-dimensional plot (49.3% of cumulative variability) formed a main group of accessions and 4 outliers (#1, #9, #27 and #28) separated in the first PC. The characters with a higher contribution to the first PC were inflorescence length, leaf petiole length and leaf central foliole area. The presence of alkaloids, the percentage of plants killed by soil borne fungal diseases, the phenology, the yield per plant and yield components were also assessed. Twenty six accessions (the main group in the PCA plot) showed high homogeneity, with the following highlights: bitterness, indeterminate growth habit, early ripeness and spring sowing with the exception of #18, in which seeding date is unknown and it had a later phenology. By contrast accessions #9 and #27 were bitter of autumn sowing with determinate growing habit and they had the longest values of primary inflorescence length and a later phenology when they were sown in spring. Average values for yield and yield components showed a broad range of variation between accessions. The main yield component was the number of pods per plant. Accession #22 had the highest mean seed mass, although this had not significant influence in yield. Accession #17 showed the highest yield and #1 the lowest. This last also had the lowest values of inflorescence length, leaf petiole length and leaf central foliole area. No significant differences of resistance to soil-borne fungi were found between accessions. The year had a significant effect in the phenology, yield and yield components except for number of seeds per pod. The studied material might be of interest for the development of spring sowing germplasm adapted to north Iberian peninsula.