Institution
University of Hohenheim
Education•Stuttgart, Germany•
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.
Papers published on a yearly basis
Papers
More filters
••
TL;DR: Recommendations for planning of QTL mapping experiments and allocation of experimental resources are given, and cross-validation performed well with respect to yielding asymptotically unbiased estimates of the genotypic variance explained by QTL.
Abstract: From simulation studies it is known that the allocation of experimental resources has a crucial effect on power of QTL detection as well as on accuracy and precision of QTL estimates. In this study, we used a very large experimental data set composed of 976 F 5 maize testcross progenies evaluated in 19 environments and cross-validation to assess the effect of sample size ( N ), number of test environments ( E ), and significance threshold on the number of detected QTL, the proportion of the genotypic variance explained by them, and the corresponding bias of estimates for grain yield, grain moisture, and plant height. In addition, we used computer simulations to compare the usefulness of two cross-validation schemes for obtaining unbiased estimates of QTL effects. The maximum, validated genotypic variance explained by QTL in this study was 52.3% for grain moisture despite the large number of detected QTL, thus confirming the infinitesimal model of quantitative genetics. In both simulated and experimental data, the effect of sample size on power of QTL detection as well as on accuracy and precision of QTL estimates was large. The number of detected QTL and the proportion of genotypic variance explained by QTL generally increased more with increasing N than with increasing E . The average bias of QTL estimates and its range were reduced by increasing N and E . Cross-validation performed well with respect to yielding asymptotically unbiased estimates of the genotypic variance explained by QTL. On the basis of our findings, recommendations for planning of QTL mapping experiments and allocation of experimental resources are given.
267 citations
••
TL;DR: Observations suggest that PIC1 functions in iron transport across the inner envelope of chloroplasts and hence in cellular metal homeostasis.
Abstract: In chloroplasts, the transition metals iron and copper play an essential role in photosynthetic electron transport and act as cofactors for superoxide dismutases. Iron is essential for chlorophyll biosynthesis, and ferritin clusters in plastids store iron during germination, development, and iron stress. Thus, plastidic homeostasis of transition metals, in particular of iron, is crucial for chloroplast as well as plant development. However, very little is known about iron uptake by chloroplasts. Arabidopsis thaliana PERMEASE IN CHLOROPLASTS1 (PIC1), identified in a screen for metal transporters in plastids, contains four predicted α-helices, is targeted to the inner envelope, and displays homology with cyanobacterial permease-like proteins. Knockout mutants of PIC1 grew only heterotrophically and were characterized by a chlorotic and dwarfish phenotype reminiscent of iron-deficient plants. Ultrastructural analysis of plastids revealed severely impaired chloroplast development and a striking increase in ferritin clusters. Besides upregulation of ferritin, pic1 mutants showed differential regulation of genes and proteins related to iron stress or transport, photosynthesis, and Fe-S cluster biogenesis. Furthermore, PIC1 and its cyanobacterial homolog mediated iron accumulation in an iron uptake–defective yeast mutant. These observations suggest that PIC1 functions in iron transport across the inner envelope of chloroplasts and hence in cellular metal homeostasis.
266 citations
••
TL;DR: In this article, the authors present the current knowledge on nitrogen (N) rhizodeposition, including techniques for 15N labelling of agricultural plants, amounts of N rhizoposition and its fate in soil.
Abstract: The objective of the present review was to present the current knowledge on nitrogen (N) rhizodeposition, including techniques for 15N labelling of agricultural plants, amounts of N rhizodeposition and its fate in soil. Rhizodeposition is the process of release of organic and inorganic compounds from living plant roots. It is often quantified in terms of carbon (C) and less often as N derived from rhizodeposition (NdfR). Rhizodeposition of N can be estimated by labelling plants with 15N and following its fate in soil. Most methods used for labelling plants with 15N can only be applied after appearance of the first leaf and only allow pulse or multiple pulse labelling. Only the split-root technique and the application of gaseous 15N allow continuous labelling. All methods available at present have their flaccidities mostly due to the fact that the application of N is not following its physiological pathway of assimilation or by using artificial conditions. In the studies reviewed, amounts of N rhizodeposits ranged from 4% to 71% of total assimilated plant N. In legumes the median was 16% and in cereals it was 14%. Rhizodeposits were 15–96% of the below-ground plant biomass (BGP). In legumes the median was 73% and in cereal it was 57%. The high variability of these results shows the need for more investigations on N rhizodeposition looking especially on the factors influencing the amounts released in different plant species under field conditions.
265 citations
••
TL;DR: Two bacteriocin producing strains,one of Lactobacillus curvatus and one of L. sake, have been isolated employing a catalase-containing bacteriOCin-screening-medium for lactobacilli, and were not only active against closely related lactOBacilli but also against the opportunistic food pathogens Listeria monocytogenes and Enterococcus faecalis.
264 citations
••
University of Minnesota1, University of Oxford2, University of California, Davis3, Charles Darwin University4, Imperial College London5, Utah State University6, Panthera Corporation7, University of Cape Town8, Rhodes University9, Ezemvelo KZN Wildlife10, University of Kent11, Alberta Biodiversity Monitoring Institute12, University of KwaZulu-Natal13, Michigan State University14, University of California, Berkeley15, Tshwane University of Technology16, University of Johannesburg17, Leiden University18, University of Antwerp19, Kenya Wildlife Service20, African Wildlife Foundation21, Mammal Research Institute22, University of Hohenheim23, Wildlife Conservation Society24, Field Museum of Natural History25, National University of Benin26, University of Pretoria27
TL;DR: This work relates African lion population densities and population trends to contrasting management practices across 42 sites in 11 countries to show that lions in unfenced reserves are highly sensitive to human population density in surrounding communities, and unfenced populations are frequently subjected to density-independent factors.
Abstract: Conservationists often advocate for landscape approaches to wildlife management while others argue for physical separation between protected species and human communities, but direct empirical comparisons of these alternatives are scarce. We relate African lion population densities and population trends to contrasting management practices across 42 sites in 11 countries. Lion populations in fenced reserves are significantly closer to their estimated carrying capacities than unfenced populations. Whereas fenced reserves can maintain lions at 80% of their potential densities on annual management budgets of $500 km 2 , unfenced populations require budgets in excess of $2000 km 2 to attain half their potential densities. Lions in fenced reserves are primarily limited by density dependence, but lions in unfenced reserves are highly sensitive to human population densities in surrounding communities, and unfenced populations are frequently subjected to density-independent factors. Nearly half the unfenced lion populations may decline to near extinction over the next 20–40 years.
262 citations
Authors
Showing all 8665 results
Name | H-index | Papers | Citations |
---|---|---|---|
Robert J. Lefkowitz | 214 | 860 | 147995 |
Patrick O. Brown | 183 | 755 | 200985 |
Mark Stitt | 132 | 456 | 60800 |
Wolf B. Frommer | 105 | 345 | 30918 |
Muhammad Imran | 94 | 3053 | 51728 |
Muhammad Farooq | 92 | 1341 | 37533 |
Yakov Kuzyakov | 87 | 667 | 37050 |
Werner Goebel | 85 | 367 | 26106 |
Ismail Cakmak | 84 | 249 | 25991 |
Reinhold Carle | 84 | 418 | 24858 |
Michael Wink | 83 | 938 | 32658 |
Albrecht E. Melchinger | 83 | 398 | 23140 |
Tilman Grune | 82 | 479 | 30327 |
Volker Römheld | 79 | 231 | 20763 |
Klaus Becker | 79 | 320 | 27494 |