Institute of Crop Science and Resource Conservation

Plant, Germany

Institute of Crop Science and Resource Conservation

Plant, Germany
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von Sperber C.,Stanford University | von Sperber C.,Institute of Crop Science and Resource Conservation | Chadwick O.A.,University of California at Santa Barbara | Casciotti K.L.,Stanford University | And 4 more authors.
Ecology | Year: 2017

The supply of nitrogen (N) constrains primary productivity in many ecosystems, raising the question “what controls the availability and cycling of N”? As a step toward answering this question, we evaluated N cycling processes and aspects of their regulation on a climate gradient on Kohala Volcano, Hawaii, USA. The gradient extends from sites receiving <300 mm/yr of rain to those receiving >3,000 mm/yr, and the pedology and dynamics of rock-derived nutrients in soils on the gradient are well understood. In particular, there is a soil process domain at intermediate rainfall within which ongoing weathering and biological uplift have enriched total and available pools of rock-derived nutrients substantially; sites at higher rainfall than this domain are acid and infertile as a consequence of depletion of rock-derived nutrients, while sites at lower rainfall are unproductive and subject to wind erosion. We found elevated rates of potential net N mineralization in the domain where rock-derived nutrients are enriched. Higher-rainfall sites have low rates of potential net N mineralization and high rates of microbial N immobilization, despite relatively high rates of gross N mineralization. Lower-rainfall sites have moderately low potential net N mineralization, relatively low rates of gross N mineralization, and rates of microbial N immobilization sufficient to sequester almost all the mineral N produced. Bulk soil δ15N also varied along the gradient, from +4‰ at high rainfall sites to +14‰ at low rainfall sites, indicating differences in the sources and dynamics of soil N. Our analysis shows that there is a strong association between N cycling and soil process domains that are defined using soil characteristics independent of N along this gradient, and that short-term controls of N cycling can be understood in terms of the supply of and demand for N. © 2017 by the Ecological Society of America

Kersting K.,Fraunhofer Institute for Intelligent Analysis and Information Systems | Xu Z.,Fraunhofer Institute for Intelligent Analysis and Information Systems | Wahabzada M.,Fraunhofer Institute for Intelligent Analysis and Information Systems | Bauckhage C.,Fraunhofer Institute for Intelligent Analysis and Information Systems | And 6 more authors.
Proceedings of the National Conference on Artificial Intelligence | Year: 2012

Pre-symptomatic drought stress prediction is of great relevance in precision plant protection, ultimately helping to meet the challenge of "How to feed a hungry world?". Unfortunately, it also presents unique computational problems in scale and interpretability: it is a temporal, large-scale prediction task, e.g., when monitoring plants over time using hyperspectral imaging, and features are 'things' with a 'biological' meaning and interpretation and not just mathematical abstractions computable for any data. In this paper we propose Dirichlet-aggregation regression (DAR) to meet the challenge. DAR represents all data by means of convex combinations of only few extreme ones computable in linear time and easy to interpret. Then, it puts a Gaussian process prior on the Dirichlet distributions induced on the simplex spanned by the extremes. The prior can be a function of any observed meta feature such as time, location, type of fertilization, and plant species. We evaluated DAR on two hyperspectral image series of plants over time with about 2 (resp. 5.8) Billion matrix entries. The results demonstrate that DAR can be learned efficiently and predicts stress well before it becomes visible to the human eye. Copyright © 2012, Association for the Advancement of Artificial Intelligence. All rights reserved.

Garcia A.,Federico Santa María Technical University | Angulo J.,Federico Santa María Technical University | Martinez M.M.,Federico Santa María Technical University | Martinez M.M.,Institute of Crop Science and Resource Conservation
Acta Horticulturae | Year: 2014

Compost is the product of the transformation from organic residues to stable organic matter by the action of several organisms, which provides nutrients, improves the structure, porosity and water retention of the soil and increases the plant resistance to diseases. The objective of this research was to determine the fertilization capacity of the compost in oil palm seedlings. For this, firstly, two treatments were set (addition of compost 2% (w/v) of compost/nursery bag, and 50% of its concentration with 50% of the chemical fertilization traditionally applied on the plantation) and a control (traditional chemical fertilization), evaluating for 8 months the physicochemical characteristics of the soil, the net height, the height to branch, bulb diameter, the plant nutrition by foliar analysis and the percentage of plants that reached the optimal selection characteristics to be transplanted into the field. After the evaluation, it was possible to determine that the compost can offer the plant required amounts of phosphorus (P) and boron (B), so it can substitute this element in the fertilizer, but not the nitrogen (N) fertilization because higher statistically significant values were obtained in the control for the net height: p=<0,0001, the height to branch: p=0,0002 and bulb diameter: p=0,0001; therefore, the final selection of control treatment plants had the lowest percentage of discarded plants (15%), followed by treatment of 50/50 of compost and traditional fertilization (39%) and finally, by the compost treatment alone (77%). Thus, it was possible to conclude that the evaluated compost did not provide all the nutritional elements necessary for optimal plant development and therefore, it becomes a complement but not a substitute for chemical fertilization in oil palms at nursery stage.

Demaurex N.,University of Geneva | Schwarzlander M.,Institute of Crop Science and Resource Conservation
Antioxidants and Redox Signaling | Year: 2016

Transient changes in the physiology of individual mitochondria have recently drawn much interest. The use of a circular permuted yellow fluorescent protein (cpYFP) to monitor mitochondrial flashes and their interpretation as superoxide bursts has added confusion, however. Reviewing mitochondrial flashes in this Forum, Wang et al. again deem cpYFP to be a specific and reversible superoxide indicator, dismissing evidence that purified cpYFP is insensitive to superoxide. This interpretation lacks reproducible evidence and conflicts with the parsimony principle. We offer a constructive, transparent pathway to reach definitive clarification of contradictory reports. Antioxid. Redox Signal. 25, 550-551. © Nicolas Demaurex and Markus Schwarzlander.

Goertz A.,Institute of Crop Science and Resource Conservation | Zuehlke S.,TU Dortmund | Spiteller M.,TU Dortmund | Steiner U.,Institute of Crop Science and Resource Conservation | And 4 more authors.
European Journal of Plant Pathology | Year: 2010

High year-to-year variability in the incidence of Fusarium spp. and mycotoxin contamination was observed in a two-year survey investigating the impact of maize ear rot in 84 field samples from Germany. Fusarium verticillioides, F. graminearum, and F. proliferatum were the predominant species infecting maize kernels in 2006, whereas in 2007 the most frequently isolated species were F. graminearum, F. cerealis and F. subglutinans. Fourteen Fusarium-related mycotoxins were detected as contaminants of maize kernels analyzed by a multi-mycotoxin determination method. In 2006, a growth season characterized by high temperature and low rainfall during anthesis and early grain filling, 75% of the maize samples were contaminated with deoxynivalenol, 34% with fumonisins and 27% with zearalenone. In 2007, characterized by moderate temperatures and frequent rainfall during the entire growth season, none of the 40 maize samples had quantifiable levels of fumonisins while deoxynivalenol and zearalenone were detected in 90% and 93% of the fields, respectively. In addition, 3-acetyldeoxynivalenol, 15-acetyldeoxnivalenol, moniliformin, beauvericin, nivalenol and enniatin B were detected as common contaminants produced in both growing seasons. The results demonstrate a significant mycotoxin contamination associated with maize ear rots in Germany and indicate, with regard to anticipated climate change, that fumonisins-producing species already present in German maize production may become more important. © 2010 KNPV.

Menzel W.,Leibniz Institute DSMZ | Hamacher J.,Institute of Crop Science and Resource Conservation | Winter S.,Leibniz Institute DSMZ
Acta Horticulturae | Year: 2015

During investigation of Gaillardia aristata breeding material several plants reacted strongly (DAS-ELISA) with a commercially available Chrysanthemum virus B (CVB) antiserum. In order to confirm the identity of the virus, a part of its replicase gene was sequenced, showing just 26% amino acid sequence identity to CVB. This prompted us to determine the entire genome of this virus isolate. The complete genome was 8659 nt in length (excluding poly-A tail) and contained six open reading frames. The genome organisation resembled that of typical carlaviruses. The replicase (70%) and CP (71%) showed the highest aa sequence identities to Phlox virus S (PhVS), being well below the species demarcation threshold of 80%. The remaining ORFs (TGB1-3, NABP) also showed the highest aa sequence identities to PhVS, ranging from 59 (TGB3) to 77% (NABP). In addition, the CVB antiserum was tested with other Carlavirus isolates available at the DSMZ plant virus collection. Besides CVB and the new Carlavirus from Gaillardia, it showed a strong cross-reaction (DAS-ELISA) with isolates of Kalanchoe latent virus, Potato virus S, Passiflora latent virus and Helenium virus S.

Menzel W.,DSMZ | Hamacher J.,Institute of Crop Science and Resource Conservation | Weissbrodt S.,Institute of Crop Science and Resource Conservation | Winter S.,DSMZ
Journal of Phytopathology | Year: 2012

The complete sequence of the RNA 3 of a virus causing chlorosis in Impatiens in Germany was determined and identified as an isolate of Bacopa chlorosis virus (BaCV, genus Ilarvirus). BaCV has previously only been reported from bacopa in the USA, but no coat protein (CP) sequence has been previously available. Both RNA 3 encoded proteins, CP and movement protein, showed highest sequence identity to Parietaria mottle virus, a subgroup 1 ilarvirus. Attempts to purify BaCV failed, so an antiserum was raised against a recombinant CP. The polyclonal antiserum so produced allowed specific detection of BaCV but showed no serological cross-reaction with other ilarviruses and was unsuitable for immunoelectron microscopy. The host range includes many important flowering plant species, highlighting the potential threat BaCV might pose for the horticultural industry. This is the first report of BaCV occurring in Germany and outside the US. © 2012 Blackwell Verlag GmbH.

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