Swedish University of Agricultural Sciences

About: Swedish University of Agricultural Sciences is a education organization based out in Uppsala, Sweden. It is known for research contribution in the topics: Population & Soil water. The organization has 13510 authors who have published 35241 publications receiving 1414458 citations. The organization is also known as: Sveriges Lantbruksuniversitet & SLU.

Auxin: simply complicated

Abstract: Auxin is a plant hormone involved in an extraordinarily broad variety of biological mechanisms. These range from basic cellular processes, such as endocytosis, cell polarity, and cell cycle control over localized responses such as cell elongation and differential growth, to macroscopic phenomena such as embryogenesis, tissue patterning, and de novo formation of organs. Even though the history of auxin research reaches back more than a hundred years, we are still far from a comprehensive understanding of how auxin governs such a wide range of responses. Some answers to this question may lie in the auxin molecule itself. Naturally occurring auxin-like substances have been found and they may play roles in specific developmental and cellular processes. The molecular mode of auxin action can be further explored by the utilization of synthetic auxin-like molecules. A second area is the perception of auxin, where we know of three seemingly independent receptors and signalling systems, some better understood than others, but each of them probably involved in distinct physiological processes. Lastly, auxin is actively modified, metabolized, and intracellularly compartmentalized, which can have a great impact on its availability and activity. In this review, we will give an overview of these rather recent and emerging areas of auxin research and try to formulate some of the open questions. Without doubt, the manifold facets of auxin biology will not cease to amaze us for a long time to come.

Farmers and nature conservation: What is known about attitudes, context factors and actions affecting conservation?

Abstract: Farmers’ attitudes towards viability of specific conservation practices or actions strongly impact their decisions on adoption and change. This review of ‘attitude’ information reveals a wide range of perceptions about what conservation means and what the impacts of adoption will mean in economic and environmental terms. Farmers operate in a tight financial situation, and in parts of the world they are highly dependent on government subsidies, and cannot afford to risk losing that support. Use of conservation practices is most effective when these are understood in the context of the individual farm, and decisions are rooted in land and resource stewardship and long-term concerns about health of the farm and the soil. The attitudes of farmers entering agri-environmental schemes decide the quality of the result. A model is developed to show how attitudes of the farmer, the farming context and agri-environmental schemes interact and thus influence how the farming community affects nature and biodiversity. As new agri-environmental schemes are planned, agricultural development specialists need to recognize the complexity of farmer attitudes, the importance of location and individual farmer circumstances, and the multiple factors that influence decisions. We provide these insights and the model to conservation biologists conducting research in farming areas, decision makers who develop future agri-environmental schemes, educators training tomorrow’s extension officers and nature conservationists, and researchers dealing with nature conservation issues through a combination of scientific disciplines.

Variations in life-history traits in the common frog Rana temporaria (Amphibia: Anura): a literature review and new data from the French Alps

Abstract: Life-history traits of Rana temporaria were studied in an alpine French population and in the literature. In the living frogs, mean adult body length was greater in females than in males. Sexual dimorphism in body length was 0.109 using Lovich & Gibbon's (1992) formula, but tended to decrease with age. Age of adult frogs was assessed by skeletochronology, and age distribution was not significantly different between the sexes (range 4–15 years in males, 5–12 in females). Adult survival rate was about 0.80 in both sexes. Once maturity was reached, the total expected longevity was 6.1 years in males and 5.5 years in females. Age and body length were positively correlated in both sexes. The growth coefficient (K) was 0.47 in males, and 0.55 in females, mainly reflected as faster female growth between metamorphosis and maturation. Growth rate generally decreased before sexual maturity was reached. On average, females matured 1 year later than males. Newly metamorphosed froglets averaged 16.1 mm. When combined with published data from 12 European populations of R. temporaria, the following general patterns emerge. Mean adult body length is significantly greater in females than in males, and mean body length at maturity shows the same trend. Variation in mean age at maturity and in longevity are considerable among populations, but there is no consistent trend of difference between the sexes. Body length and age are correlated between males and females, i.e. populations with long and old males also have long and old females. Mean adult body length, mean body length at maturity, age at maturity, and longevity all increase with decreasing activity period. Adults exposed to a short activity period grow slower but attain a greater final length. Sexual dimorphism in body length generally increases as activity period gets shorter. Polygons describing norms of reaction for maturation in an age–body length space are similarly oriented in both sexes, but with a wider range in age for females. This is due to an older age at maturity for females in populations with a short activity season. Mean age and length at maturity are significantly correlated in females, but not in males, partly supporting the hypothesis that this species has a flexible pattern of development. Observed patterns are compared with predictions from life-history theory, paying attention to all life stages and environmental variation.