University of Hohenheim

About: University of Hohenheim is a education organization based out in Stuttgart, Germany. It is known for research contribution in the topics: Population & Soil water. The organization has 8585 authors who have published 16406 publications receiving 567377 citations.

Ten things to know about oomycete effectors

Abstract: Long considered intractable organisms by fungal genetic research standards, the oomycetes have recently moved to the centre stage of research on plant-microbe interactions. Recent work on oomycete effector evolution, trafficking and function has led to major conceptual advances in the science of plant pathology. In this review, we provide a historical perspective on oomycete genetic research and summarize the state of the art in effector biology of plant pathogenic oomycetes by describing what we consider to be the 10 most important concepts about oomycete effectors.

Effects of anaerobic digestion on soil carbon and nitrogen turnover, N emissions, and soil biological activity. A review

Abstract: Sustainability in agriculture means the inclusion of several aspects, as sustainable agriculture systems must not compromise not only their ability to satisfy future needs by undermining soil fertility and the natural resource base but also sustainable agriculture has had to address a range of other issues including energy use, efficient use, and recycling of nutrients, the effects on adjacent ecosystems including the effects on water bodies and climate change. Organic manures are an important factor to keep the soil fertility level of soils. However, their management is often related to large emissions. In this context, anaerobic digestion is—similarly to composting—a treatment option for stabilization of biogenic wastes leading to a residual product called digestates, enabling the sanitation and the recycling and use as fertilizer. It is also a means to obtain energy from wastes as well as from dedicated energy crops. Therefore, anaerobic digestion potentially addresses several aspects of agricultural sustainability. This review discusses the current state of knowledge on the effects of anaerobic digestion on organic compounds in digestates and the most important processes influencing N emissions in the field, as well as the possible long-term effects on soil microbial biomass and soil fertility. The main findings are that (1) the direct effects of anaerobic digestion on long-term sustainability in terms of soil fertility and environmental impact at the field level are of minor relevance. (2) The most relevant effects of anaerobic digestion on soil fertility as well as on N emissions will be expected from indirect effects related to cropping system changes such as changes in crop rotation, crop acreage, cover cropping, and total amounts of organic manures including digestates. Furthermore, (3) the remaining organic fraction after anaerobic digestion is much more recalcitrant than the input feedstocks leading to a stabilization of the organic matter and a lower organic matter degradation rate after field application, enabling a similar reproduction of the soil organic matter as obtained by direct application of the feedstock or by composting of the feedstock. (4) Regarding emissions, the main direct effect of anaerobic digestion on a farm level is the influence on gaseous emissions during manure or digestate treatment and handling, whereas the direct effects of anaerobic digestion on a field level on emissions (NH3 − and N2O− emissions, NO3 - leaching) are negligible or at least ambiguous. (5) The main direct effects of anaerobic digestion on the field level are short-term effects on soil microbial activity and changes in the soil microbial community. Therefore, in terms of the effects on agricultural sustainability, potential cropping system-based changes induced by introduction of biogas plants are probably much more relevant for the overall performance and sustainability of the cropping system than the direct effects triggered by application of digestates in comparison to the undigested feedstocks. Furthermore, to get the full potential advances from implementation of biogas plants in terms of improvement of the nutrient use efficiency and reduction of greenhouse gas emissions, there is the need to introduce more sophisticated techniques to avoid counteracting effects by pollution swapping, e.g., by gas-tight closure of the digestate stores and direct soil incorporation of the field-applied digestates.

Abscission and thinning of young fruit and thier regulation by plant hormones and bioregulators

Abstract: Natural abscission of young fruit and its regulation by plant hormones isconsidered and compared to the generally accepted model of “senescencetriggered” abscission of, for example, leaves or mature fruit It isconcluded that abscission of young fruit cannot be explained by this modelAlternatively, it is suggested that the senescence triggered initial step inthe classical abscission model should be replaced by a “correlativelytriggered” step Polar basipetal IAA transport with its autostimulation andautoinhibition components is the main regulating signal in this correlativeacting system and replaces ethylene as the initial driving force from thesenescence triggered modelResults supporting this model are presented and tested against existingresults from the literature Finally, this hypothesis is tested as a possibleexplanation of the “mode of action” of some thinning chemicals orbioregulators It is speculated how a thinning chemical should be designedto function in a more reliable way, at least as far as its interference with the endogenous hormone system is concerned