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Experimental design considerations for developing spectroscopic calibration models of plant material
Get PDFInfluence of the pruning system on the fungal community of grapevine (Vitis vinifera)
Get PDF„Minimalschnitt im Spalier“ (MMS) ist ein neues Reben-Erziehungssystem, das den Winzern die Möglichkeit eröffnet, Einsparungen bei den Produktionskoste vorzunehmen. Bei diesem Erziehungssystem wird der zeit- und arbeitsaufwändige Winterschnitt, der normalerweise per Hand erfolgt, maschinell, mit Hilfe eines Laubschneiders, durchgeführt. Aufgrund dieses ökonomischen Vorteils erlebte der MMS eine erhöhte Popularität unter den Winzern in den letzten Jahren, Tendenz steigend. Jedoch fehlen wichtige Informationen zu einige Kultivierungsaspekten, da es kaum detaillierte Feldstudien zu diesem Erziehungssystem gibt. Einer dieser Aspekte betrifft das Vorkommen von pilzlichen Krankheiten und den entsprechenden Schutz der Reben. Aus diesem Grund war es Ziel dieser Arbeit, basierend auf Langzeitversuchen (2015–2018), den Einfluss des Schnittsystems auf die Pilzgemeinschaft der Rebe zu untersuchen, mit besonderem Hinblick auf phytopathogene Pilze.
Ein Teil dieser Arbeit verglich die Laubwandarchitektur und das Mikroklima von MMS-Reben mit Reben in der klassischen Bogenerziehung (BE). Zudem wurde das Auftreten der wichtigsten Pilzkrankheiten, nämlich Falscher Mehltau (FM), Echter Mehltau (EM) und Graufäule (GF), vier Jahre hintereinander in den beiden Erziehungssystemen untersucht. In diesem Zeitraum wurde festgestellt, dass MMS-Reben im Vergleich zu BE-Reben anfälliger sind gegenüber FM und EM. Es wird vermutet, dass das vergleichsweise langsamere Abtrocknen der MSS-Laubwand ein Mikroklima erzeugt, welches das Wachstum und die Verbreitung der Krankheiten begünstigt. GF betreffend waren MMS-Trauben weniger befallen als BE-Trauben, was vermutlich mit der lockeren Traubenarchitektur in MMS-Reben zusammenhängt.
Eine Analyse der zeitlichen Entwicklung der Pilzgemeinschaft in äußerlich gesunden Rebtriebe, von zwei Monate bis acht Jahre, ergab, dass schnell wachsende Pilze wie Alternaria spp., Aureobasidium pullulans, Botrytis cinerea, Cladosporium spp., Diaporthe spp., Epicoccum nigrum, Penicillium spp. und Truncatella angustata charakteristisch sind für junge Triebe (zwei Monate bis ein Jahr). In älteren Trieben (> ein Jahr) allerdings ist die Pilzgemeinschaft mehr durch grapevine trunk disease (GTD)-assoziierte Pilze geprägt, mit Cadophora luteo-olivacea, Diplodia seriata und Eutypa lata als vorherrschende Arten. Diese Daten zeigen, dass Reben mit älteren Trieben, wie bei MSS-Reben zu finden, stärker durch GTDs gefährdet sind als BE-Reben mit ausschließlich einjährigen Trieben.
In vier aufeinanderfolgenden Jahren wurde das Vorkommen von externen Esca-Blattsymptomen in zwölf Weinbergen, unterteilt in MMS und BE, untersucht, um herauszufinden, ob und inwieweit, dass Schnittsystem das Auftreten der Blattsymptome beeinflusst. Signifikante Unterschiede zwischen den zwei Erziehungssystemen hinsichtlich der Häufigkeit von Esca-Blattsymptomen wurden in drei von vier Jahren gefunden, jedoch sind die Ergebnisse widersprüchlich. Während in 2016 MMS-Reben häufiger Blattsymptome zeigten als BE-Reben, war es in den Jahren 2017 und 2018 das Gegenteil der Fall.
Sporenfallen wurden in einem Weinberg an Trieben von MMS- und BE-Reben befestigt, um das Vorkommen des mit Esca assoziierten Pilzes Phaeomoniella chlamydospora im Jahresverlauf zu erfassen. Neben P. chlamydospora wurden dabei auch andere Arten der Phaeomoniellales isoliert; eine bereits bekannte Art, Neophaeomoniella zymoides, und sechs unbekannte Arten, die neu beschrieben wurden. Die Anzahl an Pilzstämmen und Arten von Phaeomoniellales war tendenziell höher für Sporenfallen, die an Ästen von MMS-Reben befestigt waren. Ein Pathogenitätstest mit Topfpflanzen im Gewächshaus ergab, dass von den acht isolierten Arten der Phaeomoniellales nur P. chlamydospora signifikante Läsionen im Holz verursachen kann.
Die Daten, welche in dieser Arbeit generiert wurden, sollen helfen, ein an MMS-Reben angepasstes Pflanzenschutzregime zu entwickeln.The novel grapevine training system “semi minimal pruned hedge” (SMPH), enables farmers to reduce their production costs by replacing the time and labour intensive winter pruning, usually done by hand, with a mechanical pruning approach. Due to its economic benefits, SMPH became more popular in Germany over the last decade and the number of SMPH vineyards is still increasing. However, due to the lack of extended monitoring in the field, some cultivation aspects of SMPH are poorly understood. One important issue is related to the incidence of fungal grapevine diseases and the respective protection of the vines. Therefore, it was the aim of this study to investigate on a long term basis (2015–2018) the influence of the pruning system on the fungal community of grapevine, with special regard to phytopathogenic fungi.
One part of this study compared the canopy architecture and microclimate of SMPH and “vertical shoot positioning” (VSP) trained vines. The incidence of major fungal grapevine diseases, i.e. Downy Mildew (DM), Powdery Mildew (PM) and Botrytis Bunch Rot (BR) was surveyed over four consecutive years. Within this time frame it was noted that SMPH trained vines were more susceptible to DM and PM compared to VSP trained vines. It is assumed that the comparatively slower drying process of SMPH canopies produces a microclimate that favours growth and spread of these diseases. By contrast, SMPH bunches were less susceptible to BR compared to VSP bunches, which is probably linked to the more loose bunch architecture.
An analysis of the temporal development of the fungal community in healthy grapevine branches covering two months to eight years old branches revealed that fast growing fungi like Alternaria spp., Aureobasidium pullulans, Botrytis cinerea, Cladosporium spp., Diaporthe spp., Epicoccum nigrum, Penicillium spp., and Truncatella angustata are characteristic for young branches (two months to one year old). However, in older branches (> one year) the fungal community is more characterized by grapevine trunk disease (GTD) associated fungi, with Cadophora luteo-olivacea, Diplodia seriata and Eutypa lata as predominant species. These data show that grapevines with older branches, as found in SMPH trained vines, are more threatened by GTDs than grapevines with only annual branches, as in VSP trained vines.
In four consecutive years a monitoring for Esca related foliar symptoms was performed in twelve vineyards each subdivided in SMPH and VSP trained sections to investigate the influence of the training system on symptom occurrence. Significant differences between the two training systems regarding the incidence of Esca foliar symptoms were found in three out of the four years. However, overall the results are inconsistent. While in 2016 SMPH trained vines expressed more symptoms than VSP trained vines, the opposite was the case in 2017 and 2018.
Spore traps were placed in a vineyard subdivided into SMPH and VSP trained sections to monitor the incidence of the Esca associated fungus Phaeomoniella chlamydospora over the year. Besides P. chlamydospora also other species of the Phaeomoniellales were isolated, including one known species, Neophaeomoniella zymoides, and six unknown species, which were newly described. The number of fungal strains and species of the Phaeomoniellales tend to be higher for spore traps attached to SMPH trained vines. A pathogenicity test made with potted plants in the greenhouse revealed that of the eight isolated species of the Phaeomoniellales only P. chlamydospora was able to induce significant lesions in the wood.
Data collected in this study shall help to developing a plant protection regime adapted to SMPH
DNA barcoding to trace Medicinal and Aromatic Plants from the field to the food supplement
Get PDFThe global market of food supplements is growing, along with consumers demand for high-quality herbal products. Nevertheless, substitution fraud, and adulteration cases remain a common safety problem of global concern. In the last years, the DNA barcoding approach has been proposed as a valid identification method and it is now commonly used in the authentication of herbal and food products. The objective of this study was to evaluate whether DNA barcoding can be applied to trace the plant species from the starting raw material to the finished commercial products. We selected a panel of 28 phytoextracts obtained through three different extraction methods (i.e., maceration, percolation and sonication) with different solvents (i.e., ethanol, deionized water and glycerol). Furthermore, we chose six plant species for which we collected and analysed all the intermediates of the industrial production. We sequenced and analyzed the sequence variability at DNA barcoding (psbA-trnH, ITS) and minibarcoding (rbcL 1-B) marker regions. Phytoextracts obtained through hydroalcoholic treatment, with the lower percentage of ethanol (<40%), and aqueous processing, at the lowest temperature, had major rate of sequencing and identification success. This study proves that DNA barcoding is a useful tool for Medicinal and Aromatic Plants (MAPs) traceability, which would provide consumers with safe and high-quality herbal products
Variation in fruit chemical and mineral composition of Kenyan guava (Psidium guajava L.): Inferences from climatic conditions, and fruit morphological traits
Get PDFThere is limited knowledge about the impact of climatic conditions and fruit morphological traits on the nutritional composition of the guava fruit. Fruits were gathered from 128 guava trees across four geographically diverse regions of Kenya. The fruits were morphologically characterized and analysed for their chemical and mineral composition. The ascorbic acid content correlated positively only with total annual precipitation, while total soluble solids (TSS) correlated positively with mean annual temperature. TSS correlated negatively with pulp weight and was higher in white-fleshed fruits than in the red-fleshed types. The mineral content of the fruits correlated negatively with most of the fruit weight- and size-based morphologicaltraits, as well as with the total annual precipitation, but positively with fruit seed proportion. This information could act as a guide in the selection of specific regions for upscaling guava production and aid in the selection of accessions for improvement programmes that enhance guava fruit nutritional composition
Cryopreservation of sorghum seeds modifies germination and seedling growth but not field performance of adult plants
Get PDFClimate change poses risks to both wild and crop plant biodiversity, which can be mitigated by cryopreservation (usually at -196 °C in liquid nitrogen [LN]) of crop germplasm. Cryopreservation is widely regarded as a reliable method for the ex situ conservation of plant genetic resources but its effects on subsequent field performance of popular crop species such as sorghum are largely unknown. This hampers the large-scale implementation (i.e. germplasm banks) of cryostorage for such species. This short communication describes the early stages of germination and field performance of plants derived from cryopreserved sorghum seed. Compared with the control, cryopreservation significantly increased seed electrolyte leakage and from 24 to 120 hours, percentage of germination of the control was ~2.6 folds higher than cryopreserved seeds. At 0 days, chlorophyll a/b rate was ~1.7 folds higher in the control and at 7 and 14 days, chlorophyll a level (~1.5 folds) and chlorophyll a/b rate (~1.8-1.9 folds) were higher in the control. Contrastingly, at 7 days, seedlings derived from cryopreserved seeds (treatment seedlings) showed ~1.5 folds more superoxide dismutase activity and ~1.9 folds more peroxidase activity. In contrast, treatment and control adult plants were statistically comparable in terms of chlorophylls, proteins, superoxide and peroxidase activities, plant architecture, and yield components. The fact that differences in biochemical indicators observed between control and treatment seedlings did not persist in adult plants validates the use of seed cryopreservation for the conservation of sorghum genetic resources
Effect of harvest date on yield and secondary compounds of lemon balm (Melissa officinalis L.)
Get PDFThe quality of the drug of lemon balm (Melissa officinalis L.) is influenced by several factors, among which the effect of ontogenesis has practically not been studied before. Five varieties (‘Lorelei’, ‘Lemona’, ‘Quedlinburger Niederliegende,’, ‘Gold Leaf’, ‘Soroksár’) were sampled at vegetative, budding, full flowering and after flowering phases at two locations (Budapest and Poznań) and their dried leaves analysed.The accumulation of volatile compounds showed maximum values (0.08-0.46 ml/100 g dry weight) in budding phase (Budapest) or during flowering (Poznań). The content of total phenolics was highest (226-431 mg gallic acid equivalent/g dry weight) in vegetative stage and in some cases similar values were measured until budding. After a sharp decrease at flowering time in several cases, a second peak was detected at the end of the vegetation period. Similarly to the total phenolics, also the total flavonoid content reached the highest level (0.239-1.152% dry weight) at the first half of the vegetation period however, with characteristic differences between habitats.In cultivation, the highest essential oil content may be reached later than highest polyphenol content, however harvesting at budding time may assure a good quality from both aspects with advantageous fresh and drug yields. The described dynamics of the accumulation of the investigated secondary metabolites was depending more on the habitat and less from the cultivar
Autotetraploid plant production in endemic Onobrychis elata with colchicine treatments
Get PDFThis study aimed to induce autotetraploidy in endemic Onobrychis elata plants by colchicine treatment of seeds or seedlings. Colchicine was applied to O. elata directly on germinated seeds, pre-germinated seeds (root length of 3-8 mm), and apical regions (using cotton) under in vivo conditions. Out of a total of 1,210 colchicine-treated seeds that were evaluated, only 203 survived. There was an inverse relationship between the number of surviving plants and colchicine concentration and exposure time. The highest percentage of tetraploidy in surviving plants (50%) was obtained by applying 0.2% colchicine for 6 hours to pre-germinated seeds. No significant tetraploidy was achieved by colchicine application to seedlings. Flow cytometry observations indicated that DNA content varied between 0.99 and 1.06 pg in diploid plants (controls), while DNA content varied between 2.22 and 2.48 pg in tetraploid plants. It was concluded that tetraploid plants were induced successfully only in seedlings obtained from pre-germinated seeds, with their ploidy level confirmed via flow cytometry analysis
Die Beurteilung des Anbauwertes französischer Rotkleesaaten
Get PDFDie erste und wichtigste Grundlage einer erfolgreichen Pflanzenkultur ist die Verwendung guten, einwandsfreien Saat gutes. Die Eigenart des heimischen Pflanzenbaues, einmal die kulturellen und klimatischen Verhältnisse, dann die Notwendigkeit des gesteigerten Anbaues von Getreide und Hackfrüchten sowie von Futterpflanzen machen es unmöglich, den gesamten Bedarf an Saatgut für alle Pflanzenarten im Inlande selbst zu erzeugen: in weitgehendem Maße sind und bleiben wir auch für die Folge auf den Bezug vom Auslande angewiesen. Ganz besonders behält dies Geltung für unsere wichtigste Futterpflanze, den Rotklee.
Nun ist aber gerade für diesen die Anbauwürdigkeit eines Saat gutes in hohem Grade abhängig von seiner Herkunft. Praktische Erfahrungen und zahlreiche Anbauversuche haben längst die Tatsache erwiesen, daß die inländischen Rotkleesorten und unter diesen besonders die östlichen Herkünfte, die schlesischen, ost- und westpreußischen an erster Stelle stehen, denen sich als zweifellos hochwertig russische und österreichische (Böhmen, Steiermark), Saaten anschließen. Bezüglich des Wertes der west- und südeuropäischen Provenienzen gehen die Meinungen jedoch stark auseinander, ..