580 Pflanzen (Botanik)
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The impact of pulsed light (PL) treatment on naturally occurring microorganisms, mycotoxins, and on physicochemical properties in red pepper powder was investigated. Powder samples were exposed to different PL treatments up to 61 pulses, with fluence ranging from 1.0 to 9.1 J/cm2. The highest fluence applied (9.1 J/cm2, 61 pulses, 20 s) resulted in 2.7, 3.1, and 4.1 log CFU/g reduction of yeasts, molds, and total plate counts (TPC), where initial microbial loads were 4.6, 5.5, and 6.5 log CFU/g, respectively. At the same fluence intensity, a maximum reduction of 67.2, 50.9, and 36.9% of aflatoxin B1 (AFB1), total aflatoxins (AF), and ochratoxin A (OTA) were detected, respectively. Proportional increase in temperature of the samples was observed from the absorbed PL energy, reaching maximum of 59.8°C. The inactivation of investigated microorganisms and mycotoxins followed first-order kinetics (R2 > 0.95). The fluence intensity at 6.9 and 9.1 J/cm2 did not cause degradation, but rather a significant (p < .05) and apparent increase of total phenols. Total color difference (ΔE*) revealed only “slight differences,” compared to the untreated sample. In conclusion, higher reduction of microbial load and mycotoxins in red pepper powder could be achieved, when higher treatment intensity was applied. This suggests the PL as a potential technology for decontamination of red pepper powder and other spice powders.
The kiwifruit processing industry is focused on product yield maximization and keeping energy costs and waste effluents to a minimum while maintaining high product quality. In our study, pulsed electric field (PEF) pretreatment enhanced kiwifruit processing to facilitate peelability and specific peeling process and enhanced valorization of kiwifruit waste. PEF optimization was applied to obtain the best treatment parameters. A 32 factorial design of response surface methodology was applied to find the effect of time elapsed after PEF treatment and the PEF-specific energy input on specific peeling force and kiwifruit firmness as response criteria. Under the optimized condition, the specific peeling force decreased by 100, and peelability increased by 2 times. The phenolic content and antioxidant capacity of PEF-treated kiwifruit bagasse were 5.1% and 260% richer than the control sample. Overall, the optimized PEF pretreatments incorporated into kiwifruit processing led to decreased energy demand and increased productivity.
Response of petunia to wood fibre amended peat substrate under ebb-and-flow irrigation (Abstract)
(2024)
Test von Schnellverfahren zur Bestimmung der Benetzungseigenschaften von Kultursubstraten (Abstract)
(2024)
Enhancing the nutritional value of pears through agronomic biofortification with iodine (Abstract)
(2024)
Water retention properties of wood fiber based growing media and their impact on irrigation strategy
(2024)
Distribution of water and air in growing media during ebb-and-flow irrigation depends on water storage properties (water retention curve) and water transport properties (hydraulic conductivity) of the materials. Growing media with their high number of coarse pores are known to exhibit strong hysteresis, i.e., differences in the water retention properties during drying and wetting cycles. To account for potential ecological disadvantages of peat, wood fibers are commonly used as substitutes for peat in growing media. However, the wood fibers generally have higher air capacities and hydraulic conductivities and lower water capacities compared to peat which may results in necessary adaptions of the irrigation strategy. Tools to optimize irrigation systems are physically based water transport models, such as HYDRUS-1D, which is commonly used to describe water transport in soils, but not often for growing media. In this study, white peat and pure wood fibers were used to describe differences in their water retention behavior. Water retention curves (drying cycles) and hydraulic conductivities were measured with standard analytical procedures. Hysteresis of the water retention curves was analytically determined based on their capillary rise properties. The results were used with a modified HYDRUS-1D model to test model quality against measured water contents during ebb-and-flow irrigation cycles and to optimize the irrigation strategy for the different materials. The results showed that the model quality was sufficiently good only if the strong hysteresis of the water retention curves was considered during the simulation process. Different strategies were tested to modify ebb-and-flow irrigation (irrigation frequency, irrigation duration and irrigation height) in that way that the water suction in the root zone was similar to that of the peat material. Simulation results showed that significant improvements could only be reached by increasing the flooding depth in ebb-and-flow systems to ensure an optimum water supply of plants in the wood fiber based growing media.
Wood fibers can contribute to replacing peat in growing media and thus help to protect peatlands. As domestic, renewable raw materials, they represent a sustainable option for this purpose. To date, however, wood fibers are usually used as a peat substitute at a maxi-mum of 30% (v/v). A main reason for this limitation is the insufficient microbial stability of wood fibers, which favors nitrogen immobilization and can thus impair nitrogen supply of plants. To address this drawback, in this study wood fibers were subjected to different thermal or thermal-hydrolytic treatments. Seedling tests with napa cabbage were conducted to determine whether treated wood fibers were free of phytotoxic substances. Mixtures with 50% (v/v) wood fiber and white peat each were used. In addition, three wood fiber varieties were evaluated in the cultivation of petunia. Two wood fiber proportions (30 and 60% v/v) and two nitrogen fertilization rates (common and increased supply) were included in each case. In the seedling trial with napa cabbage, no phytotoxic effects were detectable in any of the wood fiber variants investigated. However, when cultivating petunias, both shoot mass growth and number of flowers decreased with increasing wood fiber content. In substrates with a wood fiber content of 60% (v/v), plant development was inhibited so severely that the petunias no longer achieved marketable quality. Increased nitrogen fertilization was able to compensate for this negative effect only in few cases. This suggests that other factors than nitrogen limited plant growth in wood fiber-rich substrates. Among others, physical proper-ties such as the lower water capacity of wood fibers may be a cause. More in-depth investigations are still required in this regard.
Dissertation zur Erlangung des Doktorgrades (Dr. rer. nat.)
Universität Osnabrück
Fachbereich Kultur- und Sozialwissenschaften
Institut für Geographie
in Kooperation mit der Hochschule Osnabrück
Fakultät Agrarwissenschaften und Landschaftsarchitektur
Das 23. gehölzkundliche Winterseminar der Arbeitsgruppe Junge Dendrologen in der DDG fand im Herzen Deutschlands in der Lutherstadt Wittenberg statt. Wie in den vergangenen Jahren war als Tagungsort eine Jugendherberge gewählt worden. Ursprünglich sollte Quartier in der Jugendherberge in der Bauhaus-Stadt Dessau bezogen werden. Da diese bereits ausgebucht war, wurde nach Wittenberg ausgewichen, was für die Programmgestaltung vorteilhaft war.
Den autochthonen Baumarten geht es unter den klimatischen Veränderungen des Klimawandels so- wohl in der freien Landschaft als auch im urbanen Raum zunehmend schlechter (vgl. fIetz & burger 2021; mlV.nrW 2022). Gleichzeitig können in natürlichen Waldökosystemen Anpassungsdynamiken an diese veränderten klimatischen Bedingungen im Rahmen der Laurophyllisierung beobachtet werden, bei dem sich die mitteleuropäischen sommergrünen Laubwälder in teilweise immergrünen Hartlaubwaldgesell- schaften entwickeln (s. frey et al. 2010: 41). Grund hierfür sind die klimatischen Veränderungen bedingt durch den Klimawandel und Gartentrends (s. berger 2008; deHnen-scHmutz et al. 2006). Der Klimawandel scheint daher günstige Bedingungen für wärmebedürftige und frostempfindliche Immergrüne zu bieten, die an die zu erwartenden Klimaten gut angepasst sind (s. WIttIg 2008: 20). Die Immergrünen, durch die der Prozess der Laurophyllisierung maßgeblich beeinflusst wird, haben ihr natürliches Verbreitungsgebiet überwiegend in der subtropischen vollhumiden Klimazone. Das Klimaxstadium dieser Klimate ist ein im- mergrüner Lorbeerwald, der als Zonobiom V zusammengefasst wird (s. brecKle & rafIqPoor 2019).
Auch in deutschen Städten ist eine solche Anpassung der Stadtbäume an sich ändernde klimatische Bedingungen notwendig. Neben dem Klimawandel spielt im urbanen Raum das Stadtklima eine wich- tige Rolle, welches die Standortbedingungen der Pflanzen zusätzlich beeinflusst und die Auswirkungen des Klimawandels verstärkt (s. HennInger & Weber 2020; WeIscHet & endlIcHer 2018; Kuttler 1998). Die vorlie- gende Arbeit soll daher untersuchen, inwiefern sich die Herkünfte der Arten, die am Prozess der Lauro- phyllisierung beteiligt sind, für die Verwendung im städtischen Raum eignen und somit beantworten, inwiefern die Laurophyllisierung eine Chance für die klimaresiliente Gehölzverwendung in der Stadt dar- stellen kann.
Dafür werden die unterschiedlichen Baumstandorte einer Stadt anhand thermischer und hygrischer Verhältnisse zu schematischen Baumstandorttypen zusammengefasst. Während sich durch die ther- mischen Verhältnisse vor allem zentral und dezentral gelegene Baumstandorttypen differenzieren las- sen, trennen die hygrischen Verhältnisse naturnahe Baumstandorttypen von Baumstandorttypen mit eingeschränktem Wurzelraum. Für diese vier Baumstandorttypen wird dann für vier unterschiedliche Städte Deutschlands das zukünftige Mikroklima mithilfe des RCP8.5 in Form eines Klimadiagramms er- mittelt. Durch die differenzierte Auswahl der Untersuchungsgebiete Hamburg, Düsseldorf, München und Berlin können so Aussagen zu regionalen Auswirkungen des Klimawandels getroffen werden. Zudem dienen die Klimadiagramme der unterschiedlichen Baumstandorttypen als Grundlage für den klimati- schen Vergleich mit den Klimaten der Herkünfte der immergrünen Arten des Zonobiom V. Anhand die- ses Vergleiches können Subzonobiome ausfindig gemacht werden, die mehr oder weniger dem Klima der Baumstandorttypen entsprechen. Eines der Subzonobiome, welches eine gute klimatische Referenz darstellt, wird anschließend im Hinblick auf die prägnantesten immergrünen Arten näher betrachtet. Die Auswahl in dieser Arbeit ist auf das sommerregengeprägte Subzonobiom Ost-Asiens gefallen, aus dem insgesamt 20 immergrüne Laubbaumarten, neun Koniferen und eine Palmenart in Form von Steck- briefen näher beschrieben und auf die Eignung für die Verwendung innerhalb der Mirkoklimate der vier Baumstandorttypen eingeschätzt werden.
As allergy towards apples is widespread, the evaluation of various cultivation and postharvest influences on the allergenic potential is of great importance. Therefore, the analysis of the Mal d 1 content was the focus of this study, originally dealing with investigating the influence of a selenium biofortification on apple quality. The Mal d 1 content of apples was in most cases reduced when the fruits were biofortified with selenium. Apple variety and climatic conditions were identified as further influencing factors for the Mal d 1 content of the fruits. The separate analysis of the peel and the fruit flesh showed that the content of Mal d 1 in the fruit flesh was significantly lower in the biofortified samples than in the controls. In conclusion, the results indicate that the selenium biofortification of apples and biochemical mechanism behind can reduce the allergenic potential regarding the content of Mal d 1.
In dieser Arbeit soll an der Schnittstelle zwischen nachhaltiger Ernährung und nachhaltiger Landwirtschaft ein konkreter Planungsvorschlag eines AFS zur Anlage an der Hochschule (HS) Osnabrück entworfen werden. Auf diese Weise soll aufgezeigt werden, wie Agroforstsysteme zur Realisierung der Ziele der Planetary Health Diet beitragen können. Das so entstehende AFS soll zukünftig auch zu einem ernährungswissenschaftlichen Ort des Lehrens und
Lernens weiterentwickelt werden können – zum Beispiel einem Lehr- und Lerngarten. Auf diese Weise soll eine nachhaltige Ernährungsweise, die PHD in einem zukunftsweisenden Anbausystem, dem AFS pflanzenbaulich dargestellt werden. Hierzu sollen auch Standortfaktoren und Betriebsspiegel des Versuchsbetriebes der Hochschule geschickt einbezogen werden.
Dynamic Controlled Atmosphere-Chlorophyll Fluorescence storage (DCA-CF) uses a fluorescence-based measurement method to detect fermentation in apples (Malus × domestica BORKH.) caused by low-oxygen levels at an early stage. In recent years, it has been observed that individual apples of the same variety and origin can exhibit different fermentation behavior when stored under completely identical conditions. The causes of the different fermentation behavior must be found in order to be able to use DCA storage optimally. This study aimed to find the causes of the different fermentation behaviors of individual apples. Our results show that fruit ripeness can affect the lower oxygen limit (LOL), especially immediately after harvest, when the starch degradation in the fruit is not yet complete. A significant increase in the LOL was observed in ‘Elstar’ (2020: 0.3 kPa, 0.6 kPa, 0.9 kPa; 2021: 0.3 kPa, 0.4 kPa, 0.6 kPa). ‘Braeburn’ also exhibited this behavior regarding the LOL at a lower level. The LOL could not be identified for some of the fruit (varying from 12.5% to 41.7% of the examined apples) previously stored in Ultra Low Oxygen (ULO) storage for 4 months. Also, the chlorophyll content in the apple skin influences the fluorescence measurement method. Within 2 weeks, the chlorophyll content in the apple skin was halved. If the chlorophyll content drops, the reliability of the fluorescence measurement also decreases. It turned out that apples with an Fv/Fm < 0.7 were unsuitable for valid LOL identification.
Within the frame of the EU Common Agricultural Policy, most countries subsidise the establishment and maintenance of perennial flower strips on arable land within Agri-Environmental Schemes to provide foraging habitats and refuges for wildlife.
In a replicated field experiment, we studied the effects of different types of seed mixtures on the establishment and maintenance of perennial flower strips on fertile arable land in the federal state of Saxony-Anhalt, Germany over seven years. The seed mixtures were commonly applied within recent Common Agricultural Policy funding periods: (1) a low-diversity cultivar standard seed mixture (CULTIVAR), (2) a high-diversity cultivar and native plant mixture (MIX), and (3) a high-diversity native plant mixture (WILDFLOWER). All plots were mulched every year in March and at the beginning of August.
The low success of CULTIVAR triggered the massive encroachment of spontaneously established perennial grasses. In MIX, too, cultivars have disappeared after the first year. Both wildflower variants were successful in maintaining a high cover of sown perennial native forbs and a high ratio of established sown species, even after seven years. WILDFLOWER always tended to show better values than MIX. Furthermore, spontaneously establishing species began to spread their cover in MIX in the fifth year, with a very strongly increasing tendency, whereas in WILDFLOWER cover of spontaneously immigrating species stayed satisfyingly low.
Using native wildflowers to establish perennial wildflower strips was very effective in maintaining high species diversity within the Agri-Environmental Schemes funding period of five years and beyond. WILDFLOWER was especially successful. On the other hand, CULTIVAR failed completely. On fertile soils in regions with rather low yearly precipitation, mulching twice a year supported the maintenance of perennial wildflower strips.
Extensive green roofs (EGRs) offer several beneficial ecosystem services for sustainable urban development. However, most standard green roofs have been designed with species-poor plant mixtures containing non-native species. Aiming to increase the nature conservation values of EGRs, we developed and tested a vascular plant seed mixture including regionally occurring native sandy dry grassland species in experimental miniature roofs in Northwestern Germany (temperate oceanic climate) over 4 years. We tested the mixture at two seed densities (1 and 2 g/m2). Additionally, we tested seeding at 1 g/m2 and introducing raked plant material collected from an ancient dry grassland. The total establishment rates of sown species reached 92–96% in the first year, but dropped to 40–60% in the last 2 years, with the highest values for the plots with raked material. Twenty-four additional species (11 vascular, 7 lichen, and 6 moss species, including 7 red-list species) typical of sandy dry grasslands were introduced through the raked material. Vascular plants reached 60–70% cover in the second year. Severe drought periods in the third and the fourth year led to a strong decline of vascular plant cover then. As this cover was higher in the plots with raked material, we assume facilitative effects through the well-developed cryptogam layer containing a mix of pleurocarpous and acrocarpous mosses and lichens. Spontaneously establishing acrocarpous mosses in sown plots did not seem to provide this same function. We conclude that EGRs designed with regionally occurring sandy dry grassland plant species and especially the application of raked plant material from ancient grassland is a fruitful approach to increase the value of green roofs for native phytodiversity.
Entstehung der Rasentypen
(2018)