The big and the small: challenges of imaging the brain's circuits

The relation between the structure of the nervous system and its function is more poorly understood than the relation between structure and function in any other organ system. We explore why bridging the structure-function divide is uniquely difficult in the brain. These difficulties also explain the thrust behind the enormous amount of innovation centered on microscopy in neuroscience. We highlight some recent progress and the challenges that remain.     

Influence of herbage species, cultivar and cutting date on fatty acid composition of herbage and lipid metabolism during ensiling

The fatty acid (FA) concentration of herbage and lipid metabolism in silage, mainly oxidation and lipolysis, of different species (perennial ryegrass, red clover and white clover) and three cultivars of white and red clover at three cutting dates in the growing season (April, July and October) were studied. FA concentration and composition was strongly affected by species and cutting date. Perennial ryegrass had lower concentrations of C16:1, C18:0, C18:1 and C18:2 than red and white clover. Within red and white clover, the effect of cultivar was small. Oxidation of C18:3 during wilting was different between species and cutting date despite similar wilting conditions. Lipolysis in silage was also influenced by cutting date, species and to some extent by cultivar. Furthermore, in some cuts silages of red and white clover displayed a lower lipolysis than silage of perennial ryegrass. On average, over the three cutting dates proportionately 0·903, 0·864 and 0·857 of the membrane lipids in perennial ryegrass, red clover and white clover were hydrolysed during ensiling. In red clover this could be due to the lipid-protecting properties of polyphenol oxidase (PPO) activity. This was not observed in perennial ryegrass or white clover. Nevertheless, differences in lipolysis in silage between cultivars of red clover were not correlated with PPO activity.     

Data analyses with the WebGIS WaldIS

The forest monitoring in North Rhine-Westphalia consists of the forest condition evaluation, the foliar chemistry survey and the soil condition evaluation which are parts of the Germany-wide Level I network. Additionally, there are eight permanent sampling sites of the Europe-wide Level II network (UNECE ICP Forests). These data should be integrated and analysed by multivariate statistical methods. But there are problems regarding the access to data for scientific purposes. Accordingly, a Web-based geographical information system for compiling, management and analysis of forest monitoring data was implemented based on Open Source software to improve and harmonise data handling, visualisation and analysis.     

From marl to rock powder: On the history of soil fertility management by rock materials

The ancient practice of marling and the recent application of rock powder to soils are interventions into the orogenic energy budget of soils. Both are slow‐release, long‐term fertilizers or better, soil conditioners. Marls and their uses are reviewed by a study of knowledge and practices from the 1st century AD to the 1800s, for rock powders, a review of the recent theoretical and experimental literature is presented. Under pre‐industrial conditions, paucity of energy prevented the wide‐spread use of such materials, today they are marketed as by‐product of industrial operations. For marls and rock powders alike, their positive effect depends to a large extent on the soil matrix to which the minerals are applied, on the cultivar, and the specific type of applied material. Drawing parallels between the two materials, we suggest that the long‐term experience with marls could be used to study the effects of rock powders, as duration of experiments with these is most often too limited to allow conclusions.     

Phosphorus uptake by cowpea plants from sparingly available or soluble sources as affected by nitrogen form and arbuscular‐mycorrhiza‐fungal inoculation

In most plant species, nutrient uptake is facilitated upon root association with symbiotic arbuscular mycorrhizal (AM) fungi. The aim of the present experiment was to test how the form in which nitrogen (N) is supplied to the growth medium affects substrate pH, AM development, and contribution of the symbiosis to phosphorus (P) uptake from sparingly available or soluble resources. Cowpea (Vigna unguiculata L. Walp) plants inoculated or noninoculated with AM fungi (Glomus sp.) were grown in pots with a sand substrate supplied with nutrient solution. The nutrient solution was prepared either with a high or a low concentration of soluble P, and NO ‐N : NH ‐N ratios of 9:1 or 5:5. The substrate supplied with low‐P nutrient solution was either or not additionally amended with ground rock phosphate. Despite a high level of root colonization, AM fungi used in the present study did not appear to increase plant availability of rock phosphate. It cannot be excluded that the ability of AM root systems to acquire P from sparingly available resources differs depending on the plant and fungal genotypes or environmental conditions. The absence from the growth substrate of P‐solubilizing microorganisms able to associate with AM mycelia might also have been a reason for this observation in our study. Increased supply of NH relative to NO improved plant P availability from rock phosphate, but also had a negative effect on the extent of AM‐fungal root colonization, irrespective of the plant P‐nutritional status. Whether increasing levels of NH can also negatively affect the functioning of the AM symbiosis in terms of plant element uptake, pathogen protection or soil‐structure stabilization deserves further investigation.     

Genetic diversity analysis of Moroccan lentil (Lens culinaris Medik.) landraces using Simple Sequence Repeat and Amplified Fragment Length Polymorphisms reveals functional adaptation towards agro‐environmental origins

In the absence of previous molecular characterization, we assessed genetic diversity of 53 Moroccan lentil landraces including two local cultivars using simple sequence repeat (SSR) and amplified fragment length polymorphisms (AFLP). Nineteen SSRs yielded 213 alleles, and seven AFLP primer combinations gave 766 fragments of which 422 were polymorphic. Moderate to high genetic variation was observed. Several small groups of landraces were differentiated. Interestingly, one of the smallest groups contained short‐cycle landraces with high early vegetative growth. Landraces in that group were from the dry land location of Abda, where they were likely selected for adaptation to drought and heat stress over centuries. Another group contained two landraces from highland areas that may have been selected for specific adaptation to cold stress. A third group contained one landrace from the Zear region known for its seed quality and has been proposed for the protected designation of origin (PDO) quality mark. Both techniques gave evidence of differentiation of the latter landrace supporting the idea of PDO attribution. Functional grouping according to agro‐environmental origins, cycle duration and early vegetative vigour was observed.