Biological control of brown rot (Moniliana laxa Ehr.) on apricot (Prunus armeniaca L. cv. Hacıhaliloğlu) by Bacillus, Burkholdria, and Pseudomonas application under in vitro and in vivo conditions

In 2002 and 2003, a study was conducted to determine the effect of bacterial strains, Burkholdria OSU 7, Bacillus OSU 142, and Pseudomonas BA 8, on biological control of brown rot disease (Monilinia laxa Ehr.) on apricot cv. Hacıhaliloğlu in Malatya province of Turkey. Apricot orchard at full blooming stage was inoculated with conidial suspension (1 × 10⁶ spores/ml) of M. laxa Ehr. After inoculation, two apricot trees for each application were treated with each of the three biological control agents (Burkholdria gladii OSU 7, Bacillus subtilis OSU 142, and Pseudomonas putida BA 8) by spraying (1 × 10⁹ cfu/ml) on inoculated branches. Disease incidence was evaluated for untreated (control 1) and four different treatment groups including commercial disease management (control 2, positive control: 3% Bourdox in fall, 50% Cupper at pink flower, 30 g/100 l Corus at first blooming, and 300 g/100 l Captan at last blooming stage) and treatments including each of the three bacterial strains (OSU 7, OSU 142, and BA 8). The results showed that disease incidence for negative control (control 1) was 9.94, which was significantly higher than disease incidence for commercial application (2.57%) or bacterial treatments (2.82–5.00%) in the first year. In 2003, the lowest disease incidence observed in OSU 7 treatment (6.80%), while disease incidence rate for positive control and negative control were 9.45% and 28.46%, respectively. This result may suggest that OSU 7 has potential to be used as biopesticide for effective management of brown rot disease on apricot.     

The effect of summer shading on flower bud morphogenesis in apricot (Prunus armeniaca L.)

The aim of this investigation was to assess whether imposed summer shading treatments in apricot (Prunus armeniaca L.) can affect the main phenological phases related to the floral morphogenesis (floral differentiation, xylogenesis), flower bud growth and quality in terms of bud capacity to set fruit. Experimental trials were carried out on fully-grown trees of ‘San Castrese’ and ‘Stark Early Orange’ cultivars characterized by different biological and agronomical traits to which shadings were imposed in July and August. Histological analysis was carried out from summer onwards in order to determine the evolution of floral bud differentiation, and the acropetal progression of primary xylem differentiation along the flower bud axis. Periodical recordings to evaluate the bud drop, blooming time, flowering and fruit set rates were performed also. These shade treatments determined a temporary shutdown of floral differentiation, slowed xylem progression up to the resumption of flower bud growth and a reduced entity of flowering and fruit set. These events were particularly marked in ‘San Castrese’ cultivar, which is well known for its adaptability to different climatic conditions. These findings suggest that adequate light penetration within the canopy during the summer season could be the determining factor when defining the qualitative traits of flower buds and their regular growth, and ultimately to obtain good and constant crops.     

The role of growth regulators in the differentiation of walnut buds (Juglans regia L.)

The character of endogenous regulators in walnut buds was followed by means of bioassays in the course of vegetation. It was ascertained that a rise in the level of gibberellin-like substances precedes the sprouting of buds. The origination of new buds in the axil of young leaves is accompanied by a fall in the level of auxins, by a low gibberellin content and by the presence of inhibitors. In this situation the primordia of staminate catkins are diferentiated in the basal buds. The vegetative buds which are formed in the axils of further leaves, stop developing because of the accumulating inhibitors. Towards the close of vegetation the primordia of pistillate flowers originate in terminal buds and their differentiation is accompanied by a substantial rise in the level of auxin-like substances, while some of the inhibitors keep asserting themselves. On the basis of these findings we have tested the possibility of affecting the differentiation of staminate primordia and of vegetative buds by the exogenous application of selected regulators. Spraying young leaves with IAA and MH solutions will increase the number of vegetative buds in the twigs. A later spray of other twigs by TIBA and GA₃ solutions will increase the number of staminate buds.     

The relationship between Spirogyra (Zygnematophyceae, Streptophyta) filament type groups and environmental conditions in Central Europe

Species identification of the common filamentous green alga Spirogyra is mainly based on the conjugation process and zygospores. However, this genus is mostly found in its vegetative stage, which complicates studies on the ecological demands for individual species. We therefore used a different approach by assessing the relationship between vegetative Spirogyra filament type groups (morphotypes) and environmental conditions (mainly ions, nutrients, light supply and water temperature). Sampling was done at 133 sites in Central Europe and in total 333 different filament types were classified. Spirogyra was found at pH values between 6.2 and 9.1, while total alkalinity ranged from 0.6 to 7.9 mequiv l⁻¹. The genus is colonizing habitats with a specific conductivity between 75 and 1500 μS cm⁻¹. Total phosphorus amounts varied between 1 and 2240 μg l⁻¹ with a median value of 34 μg l⁻¹, indicating meso- to eutrophic conditions as optimal growth range. Filament type grouping by means of cluster analysis was based on cell cross walls (plane or replicate), average cell widths and average chloroplast numbers and resulted in 10 groups with plane cross walls and three with replicate cross walls. Canonical correspondence analysis revealed nutrients to be the key factor for morphotype occurrence: filaments with increased cell widths preferred elevated nutrient conditions. Other environmental variables (ions, buffer capacity, light supply and water temperature) had no significant effects on morphotype occurrence.     

Proteome analysis of Norway maple (Acer platanoides L.) seeds dormancy breaking and germination: influence of abscisic and gibberellic acids

Background  

Seed dormancy is controlled by the physiological or structural properties of a seed and the external conditions. It is induced as part of the genetic program of seed development and maturation. Seeds with deep physiological embryo dormancy can be stimulated to germinate by a variety of treatments including cold stratification. Hormonal imbalance between germination inhibitors (e.g. abscisic acid) and growth promoters (e.g. gibberellins) is the main cause of seed dormancy breaking. Differences in the status of hormones would affect expression of genes required for germination. Proteomics offers the opportunity to examine simultaneous changes and to classify temporal patterns of protein accumulation occurring during seed dormancy breaking and germination. Analysis of the functions of the identified proteins and the related metabolic pathways, in conjunction with the plant hormones implicated in seed dormancy breaking, would expand our knowledge about this process.     

Genetic relationship between Salix exigua and other North American willows (Salix L.): Evidence from allozyme variation

Starch gel electrophoresis was used to examine the allozyme variation and the genetic relationship between Salix exigua and other North American willows. A total of 149 clonal collections comprising six willow species were analyzed for 26 putative isozyme loci. Genetic distances between species were estimated and used for distance analysis of species relationships. Individual alleles were used as characters for cladistic analysis of phylogenetic inference. Distance analysis indicates that S. exigua has approximately equal divergence to both subgenus Salix and Vetrix. Results of cladistic analysis suggest that S. exigua may be a separate group isolated from all other willows. Based on evidence of allozyme variation, it is suggested that the taxonomic placement of S. exigua within subgenus Salix need to be revised.     

The role of life history in the relationship between population dynamics and environmental variability in two Mediterranean stream fishes

Chub Squalius torgalensis and nase Chondrostoma lusitanicum , in a Mediterranean stream, showed important differences in life-history traits and population dynamics. Both species reached mean maturity at age 2 years. Chub lived up to age 5 years, spawned in March to June, grew at a maximum rate of 0·59 mm mm⁻¹ year⁻¹ and showed a low reproductive allocation, with fecundity and egg size increasing with body size. Nase lived up to age 4 years, spawned in January to April, grew at a maximum rate of 0·46 mm mm⁻¹ year⁻¹ and showed a high reproductive allocation, with egg size independent of body size. Both chub and nase showed moderate fluctuations in population size during 1991–1998, but differed in factors driving density at age. Density of age 1 year juvenile chub decreased following severe summer droughts and proportionate survival prevailed thereafter. Density of age 2 year adult nase decreased following severe spring floods, but neither environmental nor parental stock effects were detected for juveniles and older fishes. The results illustrated the interplay between life history and environmental variability in driving fish population dynamics, with impacts of both summer droughts and spring floods being contingent on species-specific patterns of spawning and reproductive investment.     

Immunolocalization of two ligninO-methyltransferases in stems of alfalfa (Medicago sativa L.)

Summary Caffeic acid 3-O-methyltransferase (COMT) and caffeoyl CoA 3-O-methyltransferase (CCOMT) catalyze parallel reactions that are believed to be involved in the biosynthesis of lignin monomers. Antisera specific for alfalfa (Medicago sativa L.) COMT or CCOMT were raised against the enzymes expressed inEscherichia coli, and were used for immunolocalization studies in lignifying alfalfa stem tissue. Both COMT and CCOMT were localized to xylem parenchyma cells, as assessed by light microscopy and immunocytochemistry. Electron microscopy revealed that both enzymes were located in the cytoplasm of xylem parenchyma cells, and to a lesser extent, in the cytoplasm of phloem cells. There was no significant difference in the localization pattern of COMT and CCOMT, suggesting that the two enzymes may be part of a metabolic grid leading to production of lignin monomers in lignifying tissue of mature alfalfa stem internodes.     

The influence of size on domoic acid concentration in king scallop, Pecten maximus (L.)

Concentrations of domoic acid (DA), the biotoxin responsible for amnesic shellfish poisoning (ASP), exceeding the regulatory limit of 20 μg g⁻¹ have caused restricted harvesting and closures of wild king scallop fisheries. Toxin monitoring programmes have reported significant inter-animal variation in DA concentration between scallops from the same area. For the development of reliable sampling and management protocols an understanding of the magnitude and causes of inter-animal variation in toxin concentration are important. Ten samples were collected from an aquaculture site in Clew Bay, Co. Mayo off the west coast of Ireland between February 2003 and February 2004, each sample comprising 12 scallops of each of the following size groups: small (70–85 mm), medium (85–100 mm), large (100–115 mm) and very large (>115 mm). DA concentration in each hepatopancreas and in composite samples of both gonad and adductor muscle from each size group on each sampling occasion were measured. High inter-animal variability in DA concentration in hepatopancreas was recorded; CVs ranging from 12.5% to 82.5%. One negative correlation (R² = 0.7079) between DA concentration in hepatopancreas and scallop shell length, three positive but weak correlations (R² = 0.4536, 0.3459 and 0.4665) and six no correlations were exhibited. Negative correlations were attributed to faster DA uptake by smaller scallops, positive correlations to faster DA depuration by smaller scallops. If only scallops greater than or equal to 100 mm shell length, the minimum commercial size of this species were considered, no correlation occurred on any of the 10 sampling occasions.     

Perch (Perca fluviatilis L.) parasites reflect ecosystem conditions: a comparison of a natural lake and two acidic reservoirs in Finland

Parasite communities of perch were studied in a natural lake (Vetämäjärvi) and two reservoirs (the Kyrkösjärvi and Liikapuro reservoirs) located in Western Finland. All water bodies studied are small, shallow and humic. However, the reservoirs are more acidic than the lake (pH 5.9 and 5.3 vs. 6.4). Altogether, 18 parasite species were found, but the component communities were reduced in the harsh conditions of the reservoirs (12 and six species) as compared with the lake (17 species). In addition, the mean number of metazoan parasite specimens per fish was markedly lower in the reservoirs (64.3 and 14.3 specimens) than in the lake (116.1 specimens). Our prediction on the depauperation of parasite communities in reservoirs as compared with the lake was confirmed. Many ectoparasite groups were rare and most of the digenean parasites using molluscs as their intermediate host were absent from the reservoirs due to the inability of molluscs to tolerate the acidic water. The only digenean parasite found in the less acidic reservoir was Bunodera luciopercae. There were also species that preferred reservoirs as was expected. The protozoan ciliate Capriniana piscium benefiting acidic water and Acanthocephalus lucii, due to the abundance of its intermediate host, were most prevalent in the reservoir conditions.     

Detrital stocks and dynamics of the seagrass Posidonia oceanica (L.) Delile in the Spanish Mediterranean

Previous studies have shown that most leaf production (>90%) of the seagrass Posidonia oceanica is shed after senescence and that a substantial percentage (up to 80%) may thereafter be exported off the seagrass meadows by waves and currents. It has also been reported that P. oceanica meadows can accumulate large stocks of belowground detritus due to slow decomposition rates. However, the generality of these results across broad spatial scales is poorly known. In this report, we examine the fate of leaf production and the magnitude and dynamics of belowground detritus in 16 P. oceanica meadows distributed along the Spanish Mediterranean. Herbivores removed a small percentage of leaf production in all the meadows (≤13%), with most leaf production (>85%) being shed after senescence. Most shed leaves (>90%) were exported off the meadows by physical agents, such as waves and currents. The amount of belowground detritus stored within 10–15 cm from the sediment surface varied from ca. 70 to 7500 g DW m⁻² among the meadows examined, and they accumulated at rates ranging from ca. 65 to 650 g DW m⁻² per year. These values are large when compared to other communities of aquatic and terrestrial macrophytes. Our results show that P. oceanica meadows in the Spanish Mediterranean support high values of secondary production in other systems by exporting large amounts of leaf detritus as well as acting as substantial carbon sinks by accumulating large reservoirs of belowground detritus. Therefore, the increasing anthropogenic threats on P. oceanica could entail an important loss of secondary production and carbon storage in Mediterranean coastal ecosystems.     

Molecular mapping of two semidwarf genes in an indica rice variety Aitaiyin3 (Oryza sativa L.)

Genetic analysis established that Aitaiyin3, a dwarf rice variety derived from a semidwarf cultivar Taiyin1, carries two recessive semidwarf genes. By using simple sequence repeat (SSR) markers, we mapped the two semidwarf genes, sd-1 and sd-t2 on chromosomes 1 and 4, respectively. Sd-t2 was thus named because the semidrawf gene sd-t has already been identified from Aitaiyin 2 whose origin could be traced back to Taiyin1. The result of the molecular mapping of sd-1 gene revealed it is linked to four SSR markers found on chromosome 1. These markers are: RM297, RM302, RM212, and OSR3 spaced at 4.7 cM, 0 cM, 0.8cM and 0 cM, respectively. Sd-t2 was found to be located on chromosome 4 using five SSR markers: two markers, SSR332 and RM1305 located proximal to sd-t2 are spaced 11.6 cM, 3.8 cM, respectively, while the three distally located primers, RM5633, RM307, and RM401 are separated by distances of 0.4 cM, 0.0 cM, and 0.4 cM, respectively. __________ Translated from Acta Genetica Sinica, 2005, 32 (2) [译自: 遗传学报, 2005,32(2)]     

The influence of spawning and nursery grounds on the distribution of sole Solea solea (L.) in the Irish Sea, Bristol Channel and adjacent areas

In the coastal waters of west England and Wales, sole, Solea solea (L.), are found in greatest abundance in the north-east Irish Sea and the Bristol Channel. Data from research and charter vessel surveys in these areas showed differences in the spatial distribution of age-groups between the two regions. Juvenile sole (0-group, 1-group and 2-group) were found almost exclusively in the shallow (<20 m deep) parts of the north-east Irish Sea and adults (3-group and older) were also found in the same area and in deeper water. In contrast, while juvenile sole in the Bristol Channel were abundant in and around Carmarthen Bay, Swansea Bay and the Severn estuary, they also occurred frequently in deeper areas of the Bristol Channel down to depths of 40 m. Adult sole in the Bristol Channel were also relatively more abundant at depths >40 m than adults in the Irish Sea. The movements of sole which produce these patterns of distribution in the two areas are also shown by the recaptures of sole tagged in the respective nursery areas. The differences in the distribution of sole in the two areas may be related to the depths of their spawning grounds and the distances that maturing fish must travel to reach them.

In the north-east Irish Sea, sole spawning grounds are generally in waters of <40 m depth and within an extensive area of relatively shallow and gently shelving sediments close to the coastal nursery grounds. The bottom topography of the Bristol Channel is more steeply shelving and the spawning grounds of sole are at a depth of 40–75 m off Trevose Head, ≈100 km from the main nursery areas. The hydrographic conditions in the two areas are described, and it is concluded that one of the more important requirements of a successful spawning ground is the presence of suitable hydrographic conditions to transport eggs and larvae to nursery areas.     

The influence of environmental conditions on the body mass of Barn Swallows (Hirundo rustica) during spring migration

The present study examines the effects of seven microclimatic factors on the arrival body mass of migrant Barn Swallows (Hirundo rustica) in the Aiguamolls de l’Empordà Natural Park, a site located in northeastern Spain. We used principal component analysis, followed by a general linear model procedure, to create a model that examines the relationships between body mass and weather-related events recently experienced during the spring migration. Our results suggest that local weather variation during the migratory flight clearly affects the body mass of Barn Swallows on a short time scale. This effect demonstrates the importance of the environmental conditions en route for migrating swallows and how these conditions might influence diverse events of the life cycle, such as the arrival time at the breeding grounds or the reproductive success.     

The length-weight relationship, condition factor and gut contents of the dolphin-fish Coryphaena hippurus (L.) in the Mediterranean

The length-weight relationship and condition factor of 420 dolphin-fish ( Coryphaena hippurus ) collected in Malta in 1974 were determined. The length-weight relationship for the size range investigated was similar to that reported for the fish from North America. The main food items were flying fish and other fish and crabs.     

Inter-specific variation in the concentration of two iridoid glucosides in Avicennia L. (Avicenniaceae Endl.)

Concentrations of two iridoid glucosides (2′-cinnamoyl mussaenosidic acid and 2′-caffeoyl mussaenosidic acid) were measured in different populations of several Avicennia species. The results obtained for 2′-cinnamoyl mussaenosidic acid seem to confirm the recognition of infraspecific taxa in A. marina and also in A. germinans (africana (palaeotropic) and germinans (neotropic)).     

Asymmetric fusion between protoplasts of tomato (Lycopersicon esculentum Mill.) and gamma-irradiated protoplasts of potato (Solanum tuberosum L.): the effects of gamma irradiation

This paper describes the aggregation of nuclei in heterokaryons of tomato and unirradiated or irradiated potato protoplasts and the effects of gamma irradiation of potato and tomato protoplasts on single- and double-stranded DNA fragmentation, DNA repair and DNA synthesis as revealed by alkaline and pulsed field gel electrophoresis and an immunocytochemical technique. The prospects for obtaining highly asymmetric somatic hybrids of tomato and gamma-irradiated potato are discussed.     

The respiratory responses of Carcinus maenas (L.) to changes in environmental salinity

Exposure of Carcinus to a reduction in salinity is accompanied by an increase in oxygen consumption. The highest rates of oxygen consumption are found during the first 2–3 h after a reduction in salinity, after which oxygen consumption then declines, but to a higher than ‘normal’ level which is maintained throughout the period of exposure to low salinity. This augmented rate of oxygen consumption persists even after 3–4 days in water of reduced salinity and indicates that the respiratory rate of Carcinus does not acclimate rapidly to reduced salinity. The increased oxygen consumption is associated with an increase in ventilation volume resulting from an increase in the rate of beating of the scaphognathites, while oxygen utilization remains at a low level. Since the oxygen-transporting properties of the blood of Carcinus show little change under conditions of reduced salinity, the increased oxygen demand of the tissues is met by a rise in cardiac output resulting mainly from an increase in heart rate.