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Aachen, Germany

Dupuis J.,University of Bonn | Paulus S.,LemnaTec | Mahlein A.-K.,University of Bonn | Kuhlmann H.,University of Bonn | Eichert T.,University of Bonn
Photogrammetrie, Fernerkundung, Geoinformation | Year: 2015

Laser scanning devices used for plant phenotyping have shown their ability to penetrate the plant surface. This results in an interaction with the leaf tissue and in absorption of the emitted laser. The use of the intensity of reflection, measured from the backscattered laser ray, enables a more profound analysis of the geometric accuracy as well as an inspection of the plant's physiological condition. We show the comparison of two triangulation-based 3D laser scanners with different wavelengths, 658 nm (red) and 405 nm (blue), providing the intensity as additional information. By analysing the interaction of both laser sensors with separated leaf tissue contents it is possible to locate the origin of the measured signal and to evaluate the geometric accuracy of the point cloud. Furthermore, differences in the physiology of the plant as well as surface altering plant diseases like powdery mildew can be identified using the intensity of reflection. The use of the combination of a blue and a red laser scanner for high precision 3D imaging of the plant surface is shown, as well as its applicability for the analysis of plant tissue composition, the stage of leaf senescence and for a detection of plant diseases is demonstrated. Finally, the intensity of the red laser showed a high interpretability regarding the tissue composition while the blue laser provided a high geometric accuracy. © 2015 E. Schweizerbart'sche Verlagsbuchhandlung, Stuttgart, Germany.


Topp C.,Friedrich - Schiller University of Jena | Henke R.,Friedrich - Schiller University of Jena | Keresztes A.,Eotvos Lorand University | Fischer W.,Friedrich - Schiller University of Jena | And 2 more authors.
Plant Biology | Year: 2011

Lemna minor L. (duckweed) forms colonies through vegetative propagation because mother fronds remain connected for some time with their daughter fronds by stipes. The colony size is controlled by abscission of stipes at a specific preformed abscission zone. Application of silver ions (Ag+) enhances the rate of frond abscission, thus resulting in smaller colonies. The mechanism behind this process has not yet been identified. Silver caused an abscission response that saturated after 7h of treatment. The half-maximal effective concentration was 0.72μm Ag+ for the standard clone, L. minor St. Other clones of the same species show sensitivities that differ by one order of magnitude. Transmission electron microscopy revealed: (i) large numbers of vesicles close to the plasmalemma in cells adjacent to the abscission zone, which proves a vesicular type secretory activity; and (ii) a moderately electron-dense secretion accumulated in the enlarging intercellular spaces, and seemed to flow from the adjacent cells towards the abscission zone. We assume that increasing pressure causes this material to push apart the cells, thereby causing the break in the abscission zone of the stipe. This is a novel mechanism of abscission that has not previously been described. The same mechanism occurs in stipes of both control and Ag+-treated samples. Silver ions only accelerate the process leading to abscission of stipes, without affecting the mechanism involved. © 2010 German Botanical Society and The Royal Botanical Society of the Netherlands.


Bergstrasser S.,Julich Research Center | Fanourakis D.,Julich Research Center | Fanourakis D.,Technological Educational Institute of Crete | Fanourakis D.,Greek National Agricultural Research Foundation | And 6 more authors.
Plant Methods | Year: 2015

Background: Combined assessment of leaf reflectance and transmittance is currently limited to spot (point) measurements. This study introduces a tailor-made hyperspectral absorption-reflectance-transmittance imaging (HyperART) system, yielding a non-invasive determination of both reflectance and transmittance of the whole leaf. We addressed its applicability for analysing plant traits, i.e. assessing Cercospora beticola disease severity or leaf chlorophyll content. To test the accuracy of the obtained data, these were compared with reflectance and transmittance measurements of selected leaves acquired by the point spectroradiometer ASD FieldSpec, equipped with the FluoWat device. Results: The working principle of the HyperART system relies on the upward redirection of transmitted and reflected light (range of 400 to 2500 nm) of a plant sample towards two line scanners. By using both the reflectance and transmittance image, an image of leaf absorption can be calculated. The comparison with the dynamically high-resolution ASD FieldSpec data showed good correlation, underlying the accuracy of the HyperART system. Our experiments showed that variation in both leaf chlorophyll content of four different crop species, due to different fertilization regimes during growth, and fungal symptoms on sugar beet leaves could be accurately estimated and monitored. The use of leaf reflectance and transmittance, as well as their sum (by which the non-absorbed radiation is calculated) obtained by the HyperART system gave considerably improved results in classification of Cercospora leaf spot disease and determination of chlorophyll content. Conclusions: The HyperART system offers the possibility for non-invasive and accurate mapping of leaf transmittance and absorption, significantly expanding the applicability of reflectance, based on mapping spectroscopy, in plant sciences. Therefore, the HyperART system may be readily employed for non-invasive determination of the spatio-temporal dynamics of various plant properties. © 2015 Bergsträsser et al.; licensee BioMed Central.


Schmittgen S.,Julich Research Center | Metzner R.,Julich Research Center | Van Dusschoten D.,Julich Research Center | Jansen M.,Julich Research Center | And 5 more authors.
Journal of Experimental Botany | Year: 2015

Cercospora leaf spot (CLS) infection can cause severe yield loss in sugar beet. Introduction of Cercospora-resistant varieties in breeding programmes is important for plant protection to reduce both fungicide applications and the risk of the development of fungal resistance. However, in vivo monitoring of the sugar-containing taproots at early stages of foliar symptoms and the characterization of the temporal development of disease progression has proven difficult. Non-invasive magnetic resonance imaging (MRI) measurements were conducted to quantify taproot development of genotypes with high (HS) and low (LS) levels of susceptibility after foliar Cercospora inoculation. Fourteen days post-inoculation (dpi) the ratio of infected leaf area was still low (∼7%) in both the HS and LS genotypes. However, during this period, the volumetric growth of the taproot had already started to decrease. Additionally, inoculated plants showed a reduction of the increase in width of inner cambial rings while the width of outer rings increased slightly compared with non-inoculated plants. This response partly compensated for the reduced development of inner rings that had a vascular connection with Cercospora-inoculated leaves. Hence, alterations in taproot anatomical features such as volume and cambial ring development can be non-invasively detected already at 14 dpi, providing information on the early impact of the infection on whole-plant performance. All these findings show that MRI is a suitable tool to identify promising candidate parent lines with improved resistance to Cercospora, for example with comparatively lower taproot growth reduction at early stages of canopy infection, for future introduction into breeing programmes. © 2015 The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.


News Article | March 3, 2015
Site: agfundernews.com

LemnaTec which has developed a high-throughput research platform and agricultural analysis software, has received a $5.6 million equity investment from Anterra Capital. This news arrives after a successful financing round led by DEWB, the German private equity firm. According to the company, they are now one of the largest providers of systems and software for image capture and data processing for agricultural use. LemnaTec plans to use the proceeds to fuel further growth and global market expansion. “The partnership between Anterra and LemnaTec will help accelerate our expansion, particularly in the USA, and allow us to extend our software and service capabilities,” said Dirk Vandenhirtz, CEO and founder of LemnaTec.  “We are now backed by two strong institutional investors and I am very confident that Anterra will energetically support our continued growth with their technology expertise and extensive industry contacts.” Founded in 1998, LemnaTec has developed a wide product line specializing in platforms and analysis software for Ag chemistry, plant cultivation, bio-tech and pharmaceutical research. It sells a specialized hardware and software designed to take and process digital images of plants in order to produce superior phenotypic data. The company uses it’s Scanalyzer product line to improve the performance of phenotyping results in research and development. Their line includes low throughput systems for lab monitoring and high throughput systems for monitoring large scale greenhouse and open field operations and uses a wide range of image acquisition and analysis platforms to suit most biological image analysis needs. The company also utilizes its LemnaLauncher, the main framework granting access to all LemnaTec software across the entire product range. All gathered research imagery and metadata are accessible through the customizable software platform provided by the company, providing a full circle implementation and data gathering workflow. The new influx of financing comes just after the company celebrates several benchmarks in the last few months such as opening an office in St. Louis, MO and breaking ground on the construction of a high output field based phenotyping facility in the UK.

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