Gottfried Jetschke

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Correlates between genetic diversity at intra- and interpopulation levels and the species diversity in plant communities are rarely investigated. Such correlates may give insights into the effect of local selective forces across different communities on the genetic diversity of local plant populations. This study has employed amplified fragment length(More)
Two duckweed species, Spirodela polyrhiza and Lemna minor, were used to measure the toxicity of chromate (100 microM) at three levels of sulphate (13 microM, low sulphate=LS; 410 microM, normal sulphate=NS; 10,000 microM, high sulphate=HS). Growth rates calculated on the basis of dry weight, chlorophyll and carotenoid content were all reduced by chromate.(More)
Many plants live in habitats that are becoming increasingly rare and fragmented due to human disturbance. Studies of genetic diversity are necessary for understanding and evaluating the impact of habitat fragmentation, and land-use change on the dynamics of rare species to help in setting priorities for their management. We used AFLP markers to study(More)
The subtropical plant species Cyphostemma digitatum, Vitaceae, is used in central Yemen in traditional medicine, as a culinary herb, and as a source of food flavoring. The contents of vitamin C, vitamin E, and carotenoids and changes caused by common processing were investigated. Carotenoids were determined by reversed phase C30-high-performance liquid(More)
Formation of turions, the vegetative perennation organs, plays an important role in the survival strategy of Spirodela polyrhiza (L.) Schleiden. Turion formation [quantified as number of turions formed per frond; specific turion yield (SY)] was investigated in 27 clones collected from a wide geographical range. The Pearson correlation was tested with (1)(More)
A trade-off between the parameters of Lotka-Volterra systems is used to give verifications of relations between intrinsic growth rate and limiting capacity and the stability type of the resulting dynamical system. The well known rock-paper-scissors game serves as a template for toxin mediated interactions, which is best represented by the bacteriocin(More)
A variety of statistical techniques has been used in predictive vegetation modelling (PVM) that attempt to predict occurrence of a given community or species in respect to environmental conditions. We compared the performance of three profile models, BIOCLIM, GARP and MAXENT with three nonparametric models of group discrimination techniques, MARS, NPMR and(More)
In a few insect groups, males pierce the female's integument with their penis during copulation to transfer sperm. This so-called traumatic insemination was previously confirmed for Strepsiptera but only in species with free-living females. The more derived endoparasitic groups (Stylopidia) were suggested to exhibit brood canal mating. Further, it was(More)
We have developed a stochastic model to explore the common effect which genetics and demography have on the extinction risk of endangered populations. The dynamics is formulated as a MARKOVian birth and death process (in continuous time), whereby selection acts through different mortalities of each genotype. With the help of this model we are able to show(More)
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