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Edyta Wojciechowska Christoph H. Weinert Björn Egert Bernhard Trierweiler Markus Schmidt-Heydt Bernd Horneburg Simone Graeff-Hönninger Sabine E. Kulling Rolf Geisen 《European journal of plant pathology / European Foundation for Plant Pathology》2014,139(4):735-747
Tomato fruits can be contaminated by saprophytic strains of Alternaria alternata which is the reason for the frequent occurrence of Alternaria toxins like alternariol, alternariol monomethylether or tenuazonic acid in these types of products. It was shown earlier that alternariol is a colonization factor for tomatoes. In the current analysis two different tomato genotypes were analysed by untargeted comprehensive two-dimensional gas chromatography mass spectrometry (GC×GC-MS). This analysis revealed clear differences in the metabolic profiles which were paralleled by differences in resistance towards Alternaria colonization. One of the genotypes was more resistant against A. alternata infection and contained high amounts of chlorogenic acid in contrast to the other genotype which was sensitive against infection. In in vitro analysis, chlorogenic acid reduced alternariol biosynthesis during the first days of growth of A. alternata. Expression analysis of the alternariol polyketide synthase gene, a key gene in the biosynthesis of alternariol, also revealed a temporal reduction in its expression in the first phases of growth. However by chromatographic analysis it could be demonstrated that chlorogenic acid was degraded over time. This degradation leads to a relief of inhibition resulting in an only temporal inhibition of alternariol biosynthesis. In vivo colonization experiments revealed that chlorogenic acid reduces colonization of tomatoes by A. alternata in a concentration dependent manner, which however is partly counteracted by the addition of alterariol. 相似文献
44.
Narcisa Urgiles Paúl Loján Nikolay Aguirre Helmut Blaschke Sven Günter Bernd Stimm Ingrid Kottke 《New Forests》2009,38(3):229-239
Most tree species in tropical mountain rain forests are naturally associated with arbuscular mycorrhizal fungi. Previous studies
in southern Ecuador of 115 tree species revealed that only three species were not associated with arbuscular mycorrhizal fungi.
Seedlings of tropical tree species raised in the nursery may need to be associated with arbuscular mycorrhizal fungi to survive
transplantation shock in higher numbers. Methods for establishing plantations with native tree species are not yet established
for Ecuador. Thus, we investigated the feasibility of using mycorrhizal roots of seedlings of Inga acreana, Tabebuia chrysantha, Cedrela montana and Heliocarpus americanus that had trapped mycorrhizal fungi from forest humus in the nursery to inoculate C. montana and H. americanus with native arbuscular mycorrhizal fungi. Inoculation with either a mixture of mycorrhizal roots from the four species or
only with mycorrhizal roots from the same tree species were compared with effects of moderate fertilization. Assessment of
plant growth and mycorrhizal status of 6-months-old Cedrela montana and Heliocarpus americanus revealed an improvement in growth and diverse associated fungi through mycorrhizal root inoculation in comparison with moderate
fertilization. Moderate fertilization did not suppress mycorrhization. 相似文献
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The use of camera vision to automatically detect head blight (scab) on wheat ears could provide information about the severity of this dangerous disease and help meet future food traceability requirements. Fusarium spp. is dangerous for both human and animal consumption and the ability to monitor symptom location and severity before the harvested product is further processed or stored could help determine whether the grain is fit for human/animal consumption, for bio-conservation, or is completely unusable.To generate various infection levels, field trials were conducted in 2008 and 2009 using wheat varieties with differing levels of susceptibility to the disease; plots were artificially infected with a spore suspension. A color (red, green, and blue) and a multispectral (red, infrared) camera system with real-time image analysis software were developed and compared to detect disease symptoms in the plots.The chlorophyll defect of the infected wheat ears was classified against the image background by setting binarization thresholds. The result was a black and white image. Single pixels or tiny clusters of pixels not belonging to the symptoms were eliminated by setting an area threshold. For both systems, a linear correlation was found between the camera and the visually detected disease levels of the wheat ears in the plots.In the non-infected control plots without disease symptoms, the multispectral system accurately measured “no disease” even though the digital color system detected too much infection (i.e., a false positive). The multispectral system showed a superior calibration capacity. While the color system had to calibrate for each variety, the multispectral system used only one calibration step before starting the measurements. 相似文献
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Krengel Sandra Richter Christel Freier Bernd Stangl Gabriele I. Brandsch Corinna 《植物病害和植物保护杂志》2013,120(5-6):218-226
Journal of Plant Diseases and Protection - An analysis of existing data gained in a set of climate chamber experiments was conducted to compare food conversion efficiencies of young Coccinella... 相似文献
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Gebhard Bufler Bernd Horneburg 《The Journal of Horticultural Science and Biotechnology》2013,88(6):756-761
SummaryLow-temperature sweetening of parsnip (Pastinaca sativa L.) roots, which may occur both pre-harvest and post-harvest, is a well-known phenomenon, but is poorly understood. ‘White King’ parsnip roots were analysed over two seasons (2008 and 2009) during field growth and over six months cold storage at 1ºC for their dry matter content, as well as their starch, sucrose, glucose, fructose, and malto-oligosaccharide (MOS) concentrations and for their changes in amylolytic enzyme activities (2009 only). In 2008, when the air temperature fell below 5ºC for 12 d in the last 8 weeks before harvest, the concentration of starch decreased significantly (P ≤ 0.05) and the concentration of total sugar increased significantly. In 2009, when temperatures did not fall below 5°C during the last 8 weeks before harvest, the concentrations of starch (339 + 17 mg g–1 DW) and total sugars (168 + 12 mg g–1 DW) did not change significantly. However, in both years, during 24 weeks in cold storage at 1ºC, starch levels were almost completely depleted, whereas sucrose concentrations and, to a lesser extent, MOS concentrations increased at least two-fold. Glucose and fructose concentrations also increased significantly during 24 weeks in cold storage, but to a much lower level than sucrose or MOS. Total amylolytic activity and α-amylase activity doubled during the first 8 weeks in cold storage, whereas β-amylase activity did not change significantly. As products of α-amylase activity, changes in MOS concentration paralleled the changes in α-amylase activity. The accumulation of sucrose and MOS may raise the culinary quality of cold-stored parsnip. 相似文献
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Within the southern Ecuadorian Andes, landslides have an impact on landscape development. Landslide risk estimation as well as hydrological modelling requires physical soil data. Statistical models were adapted to predict the spatial distribution of soil texture from terrain parameters. For this purpose, 56 soil profiles were analysed horizon-wise by pipette and laser method. Results by pipette compared to laser method showed the expected shift to higher silt and lower clay contents. Linear regression equations were adapted. The performance of regression tree (RT) and Random Forest (RF) models was compared by hundredfold model runs on random Jackknife partitions. Digital soil maps of sand, silt and clay percentage mean and standard deviation indicate model variability and prediction uncertainty.RF models performed better than RT models. All terrain factors considered in the analysis influenced soil texture of the surface horizon, but altitude a.s.l. was assigned the highest variable importance during model construction. Shallow subsurface flow is considered responsible for increasing sand/clay ratios with increasing altitude, on steep slopes and with overland flow distance to the channel network by removing clay particles downslope. Deeper soil layers are not influenced by this process and therefore, did not show the same texture properties. However, the influence of parent material and landslides on the spatial distribution of soil texture cannot be neglected. Model performance, most probably, could be improved by a bigger dataset. 相似文献
49.
Cadmium (Cd) is toxic to plants, animals, and humans. However, different plant species growing on the same soil may have very different shoot Cd concentrations depending on properties such as size of the root system, Cd net influx, shoot‐growth rate, Cd translocation from root to shoot, and the ability to affect Cd availability in the soil. To investigate possible reasons for different shoot Cd concentrations maize, sunflower, flax, and spinach were grown on an acid sandy soil (pH<$>_{{\rm{(CaCl}}_{\rm{2}} {\rm)}<$> 4.5, and Corg 2.8%) in a growth chamber with Cd additions as Cd(NO3)2 of none, 14, and 40 μmol (kg soil)–1 resulting in Cd soil‐solution concentrations of 0.04, 0.68, and 2.5 μM. Only the high Cd addition caused a significant growth reduction of flax and spinach. The shoot Cd concentration was up to 30 times higher in spinach than in maize; the other species were intermediate. Of the plant properties studied only the variation of the Cd net influx explained the differences in shoot Cd concentrations. This was due to a decreased (maize, sunflower) or increased (flax) Cd concentration in soil solution or more effective uptake kinetics (spinach). 相似文献
50.