Mineral nutrition, soil factors and growth rates of Gmelina arborea plantations in the humid lowlands of northern Costa Rica

The purpose of this study was to determine the factors which are responsible for clearly visible growth irregularities in Gmelina arborea stands by relating growth rates to soil and site properties. All Gmelina plantations under study, established on degraded pasture soils in the Atlantic lowlands of Costa Rica, showed the same growth pattern: very poor growth and chlorotic foliage of trees in mid-slope positions, and fast growth and healthy leaves of trees on hilltops and hillbases. The variation in site and soil properties and tree growth rates was analysed, investigating 24 plots in eight different plantations. Leaf samples were taken from 120 trees (five trees per site). Foliar analysis revealed that the tree growth is highly dependent on the supply of N, P, K and S, indicating that poorly growing trees suffer from a multiple nutrient disorder. To identify the most restricting soil factor, simple correlations between growth rates and soil chemical and physical properties were applied to the entire data set. The best correlation was obtained with exchangeable soil K (r=0.78, P<0.001). Subdivision of the data set into plots on brown soils (eight) and plots on red soils (16) and subsequent correlation analysis resulted in much stronger relationships. Growth depressions in mid-slope positions had other causes on brown soils than on red soils. On the acid brown soils the combination of the variables Al saturation and bulk density could explain 82% of the variation of tree growth. Al saturation of up to 80% in brown soils inhibits nutrient uptake, particularly of N and P. The red soils dominate on Ca---Mg-enriched, alluvial terraces and were among the first soils to be cultivated in the region. During the agricultural use and at the establishment of the tree plantations, they received dolomitic lime to reduce Al toxicity. Here, very low K/Mg ratios (less than 0.03) may induce K deficiency. Therefore, the best multiple regression model for tree growth rates on red soils is obtained with K/Mg ratio and thickness of the humic A-layer (r²=0.75, P<0.001). Inclusion of the variable bulk density resulted in a clear improvement of the model, explaining 91% of the growth variability.     

Möglichkeiten zum Nachweis von autochthonen Hochlagenbeständen der Fichte (Picea abies) in den Berchtesgadener Alpen

Zusammenfassung Bedingt durch Mangel an Wissen und zum Teil auch geeignetem Saat- und Pflanzgut wurden vor ca. 130 Jahren manche Best?nde in den Hochlagen der Berchtesgadener Alpen mit nicht angepa?ten Fichten-Herkünften (Picea abies) aus mittleren und tieferen Lagen begründet. Um den autochthonen Charakter und damit die Angepa?theit an die Umwelt von solchen Hochlagenbest?nden des Nationalparks einzusch?tzen, wurde mit Hilfe biochemisch-genetischer Methoden deren genetische Struktur an drei Enzym-Genloci bestimmt. An einem weiteren Enzym-Genlocus wurden Beziehungen zwischen dem jeweiligen Genotyp und dem Gesundheitszustand der B?ume überprüft Als Versuchsmaterial dienten Samenproben von 30 Einzelb?umen aus Best?nden unterschiedlicher H?henlage und eine Mischprobe von einem Tieflagenbestand nahe München. W?hrend die Daten von zwei Enzym-Genloci, an denen arealspezifische Allele vorkommen, zeigten, da? das untersuchte Fichtenmaterial nicht aus einem anderen Refugialgebiet stammt, ergaben die Genotyph?ufigkeitsverteilungen am dritten Genlocus (SAP-B), an dem bereits h?henlagen-abh?ngige Allelverteilungen nachgewiesen worden waren, da? Restbest?nde der h?chsten Gebirgslagen nur SAP-Hochlagentypen enthalten und damit, wie vermutet, als autochthon zu betrachten sind. Demgegenüber weisen die Best?nde der Tallagen überwiegend die SAP-Tieflagentypen, die Best?nde der mittleren Lagen jedoch alle SAP-Typen in unterschiedlicher H?ufigkeit auf, wobei in einem Fall die Vermutung der künstlichen Begründung gestützt werden konnte. Für einen weiteren Genlocus (GRD-A) wurde zudem beim Vergleich zwischen gesunden und immissionsgesch?digten B?umen festgestellt, da? bestimmte heterozygote Genotypen weitaus h?ufiger bei den gesunden Individuen vorkommen, was frühere Ergebnisse bei jüngeren Best?nden und Klonmaterial voll best?tigte. Generell zeigen die Ergebnisse dieser Untersuchung auf, wie die Autochthonie von Hochgebirgs-Fichtenbest?nden eingesch?tzt werden kann; ein Weg, der für waldbauliche und Generhaltungsma?nahmen von gro?er Bedeutung ist.

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Possibilities of detecting indigenous high-elevation Norway spruce (Picea abies) stands in the Berchtesgadener Alps

Summary The lack of sufficient seed and planting stock from high-elevation provenances of Norway spruce (Picea abies) led to the introduction of poorly adapted seed sources from low and middle elevations into the higher, elevations of the Berchtesgadener Alps. In order to evaluate the indigenous character and thus the adaptability of tree stands located at high elevations, their genetic structures using three enzyme gene loci were determined by means of biochemical-genetic methods. For another enzyme gene locus, the relationship between certain genotypes and the extent of pollution-caused damage of trees was examined. The test material consisted of seed lots from 30 single trees from stands at different elevations and from a bulk seed collection from a lowland stand near Munich. While the data of two enzyme gene loci possessing areal-specific alleles revealed that the investigated spruce stands do not originate from other distribution area,, the genotype frequencies of the third gene locus (SAP-B), for which elevational gradients in allele frequencies have already been established, were found to vary markedly among the spruce stands. Some tree groups from the highest altitudes in these Alps exhibited only those SAP genotypes which characterize high-elevation stands (high-elevation types) thus confirming their indigenous character. In contrast, the spruce stands from the valleys mainly consisted of low-elevation types and rarely of heterozygotes of both SAP types. The stands from middle- and higher-elevation sites, however, contained all three SAP types in different proportions, whereby in one case the assumption of an artificial regeneration with low elevation types was supported. For another enzyme gene locus (GRD-A), a comparison between healthy trees and such damaged by air pollution showed that certain heterozygotes occur more frequently among the healthy trees, which surprisingly well confirms the results from earlier studies on younger spruce stands and fumigated clone material. In general, the results of this study indicate possibilities of evaluating the indigenous character of high-elevation stands, which should be of value especially for silvicultural and gene conservation measures.

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Herrn Prof.H. Schmidt-Vogt zum 70. Geburtstag gewidmet.     

Pathology and mass mortality of Pacific oysters, Crassostrea gigas (Thunberg), in 2005 at the East Frisian coast, Germany

In 2005, Pacific oysters, Crassostrea gigas , were collected from May to September along the East Frisian coast and processed for histology. Because of mass mortalities in September, additional samples of moribund oysters and apparently healthy blue mussels, Mytilus edulis , were subjected to virological and ultrastructural investigation. The oysters displayed a variety of pathological conditions including viral gametocytic hypertrophy which is reported here for the first time from the German coast. Haemocyte aggregations in the digestive tract, in the intestinal mucosa and submucosa, in the mid-gut gland and in the ventricle of the heart were commonly observed at some stations. In association with mass mortalities, severe gill necrosis occurred which may have contributed to the high mortality rates. Total mortality rates of up to approximately 60% were seen. All size classes and thus age classes of oysters were affected, with highest mortality rates within the youngest age classes which had just reached sexual maturity (shell lengths <40 mm). The smallest dead oysters had shell lengths of 10 mm. The phenomenon was mainly restricted to C. gigas stocks in harbours, probably because of favourable conditions for infection, i.e. limited water exchange, less food availability, reduced oxygen content and higher pollution levels.     

Detection of weed algae in open pond cultures of <Emphasis Type="Italic">Cyanobacterium aponinum</Emphasis> using PAM

The potential use of non-arable land in the al-Wusta region of the Sultanate of Oman for the production of algae biomass was examined. Brackish cleaned production water from oil production supplemented with commercial fertilizer was used as growth medium. The indigenous isolate Cyanobacterium aponinum WP7(1) was grown in open ponds using batch or semi-continuous cultivation. Biomass production rates of 15–24 g/m²/day were achieved. The change of salinity due to evaporation, which was thought to be a major challenge, did not exceed 35 ppt. All cultures showed contaminations with weed algae. Contaminations with green algae or diatoms were detectable using fluorescence pattern excited by four different wavelengths using a pulse-amplitude-modulation chlorophyll fluorometer (PAM). It is possible to estimate the health level and the mayor groups of which a culture is composed using the PAM method. Therefore, the fluorescence of the photosynthetically inactive sample is compared with the fluorescence after all copies of photosystem II were closed by exposing the sample to a high-intensity light beam. A detection limit of one weed algae cell in a hundred cells was achieved.     

Histological and electron microscopy studies on the adenocarcinomatosis of laying hens]

Histological examination of 187 tumours from 98 hens (laying hybrids of various lines, age 80-123 weeks) showed that highly-differentiated tubulo-alveolar adenocarcinoma was present in 95% of the birds; in 20% it had a scirrhus structure. Histological and ultrastructural features of these carcinomas and their tendency to form secretory granules pointed to an origin from the protein-secreting part of the oviduct (magnum). In the remaining 5% of birds there were non-specific adenocarcinomas (probably ovarian carcinoma) and mesotheliomas.