Der Einfluss veränderter Wintertemperaturverläufe auf die mikrobielle C und N Nutzung aus Ernterückständen und die Überlebensrate pilzlicher Phytopathogene

Die vorliegende Dissertation wurde im Rahmen des vom Niedersächsischen Ministerium für Wissenschaft und Kultur geförderten Forschungsverbundes „KLIFF – Klimafolgenforschung in Niedersachsen“ an der Universität Kassel im Fachbereich Ökologische Agrarwissenschaften im Fachgebiet Bodenbiologie und Pflanzenernährung angefertigt. Die Arbeit wurde von der Universität Kassel gefördert und ist mit dem DFG-Graduiertenkolleg 1397 assoziiert.

Antifungal activity of bacterium symbiotically associated with Steinernema abbasi towards Fusarium oxysporum

Fusarium oxysporum f.sp. lycopersici (Fol) is the causal agent of the Fusarium wilt disease of tomato. Soil fumigant (mainly methyl bromide) applications are in use for its control. With the increasing environmental awareness, biological control methods are under investigation for their effectiveness, including the use of antagonists. Pseudomonas oryzihabitans (=Flavimonas oryzihabitans), a symbiont of the entomopathogenic nematode Steinernema abbasi was investigated as an antagonism of a Fol isolate in two laboratory and two glasshouse experiments. Bacteria and cell-free filtrate antifungal activity were tested both in dual cultures and in broth culture. In pot experiments, suspensions of bacteria in five concentrations (106, 105, 104, 103 and 102 cells/ml) were tested for their ability to control the pathogen at 25±3°C. In all tests the bacterium significantly inhibited the growth of Fol mycelium in vitro. Similar results were obtained when the bacterium was also tested against Fusarium oxysporum f.sp. radicis lycopersici and against Rhizoctonia solani. Moreover, when it was introduced into the soil, it was able to suppress the Fusarium wilt of tomato.

Population performance of collembolans feeding on soil fungi from different ecological niches

The potential reproductive value of arbuscular mycorrhizal fungi (Gloinus intraradices and Glomus invermaium), root pathogenic fungi (Rhizoctonia solani and Fusarium culmorum) and saprotrophic fungi (Penicillium hordei and Trichoderma harzianum) were examined for the collembolans Folsomia candida Willem and Folsomia fimetaria L. Dried baker's yeast (Saccharomyces cerevisiae) was used as a reference standard food in laboratory cultures. Collembolan performance was determined as final size, fecundity and population growth rate after when fed the fungal food sources for 31 days. The mycorrhizal fungi gave the least growth and fecundity compared with the other fungi, but G. intraradices gave good fecundity for F. candida. In terms of growth, Baker's yeast was a high-quality food for both adults and juveniles of both species, but it was a poorer food in terms of fecundity of F. candida. Preference of the fungi in all possible pairwise combinations showed that although F. fimetaria did not perform well on Glomus spp. and F. candida did not grow well on Glomus spp. their preference for these fungi did not reflect this. The highest fecundity was seen with the root pathogen F. culmorum. Different quality indicators such as the C:N ratio of the fungal food sources as well as other biological parameters are discussed in relation to their reproductive value and Collembola preferential feeding. (c) 2007 Elsevier Ltd. All rights reserved.

Estudo etnofarmacológico e fitoquímico das espécies medicinais Cleome spinosa Jacq, Pavonia varians Moric e Croton cajucara Benth

In this present work an ethnographic research was performed with 84 native medicinal specimens from the Litoral Norte Riograndense, from which two plants Cleome spinosa Jacq e Pavonia varians Moric were submitted to ethnobotanic, phytochemistry and pharmacologic investigations. Additionally, a phytopharmacological research of the medicinal specimen Croton cajucara Benth ( native plant of the Amazon region of Brazil) was improved. The obtained phytochemical results of the C. spinosa and P. varians showed the presence of flavonoids constituents, among other components. The two flavonoids (2S)-5-hydroxy-7,4 -dimethoxy-flavanone and 5,4 -dihydroxy-3,7,3 -trimethoxy-flavone were isolated from C. spinosa. The antioxidant activity of the hydroalcoholic extracts of C. spinosa and P. varians solubilized in the microemulsion systems SME-1 and SME-4, was evaluated in the DPPHmethod. The used SME systems [obtained with Tween 80: Span 20 (3:1) and isopropyl myristate (IPM)] improved the dissolution of those tested polar extracts, with higher efficacy to the SME-1 system (in which ethanol was included as cosurfactant). The CE50 values evidenced for P. varians were 114 [g/mL (SME-1) and 246 [g/mL (SME-4); for C. spinosa it was 224 [g/mL (SME-1) and 248 [g/mL (SME-4), being the system SME-1 more effective for both tested extracts. The hydroalcoholic extracts of P. varians (HAE-PV) was also submitted to pharmacological screening for antinociceptive activity in animal models. The oral administration of this extract (100, 300 and 1000 mg/kg) inhibited the acetic acid-induced writhing in mice. The higher inhibition (74%) was evidenced to the 1000 mg/kg administered dose. Its effect on the central nervous system (CNS) was investigated by tail flick and formalin-method and reveled that it has negligible antinociceptive action on the CNS. After taking consideration of HAE-PV interaction, Pavonia varians Moric could be used as a potent analgesic agent in case of peripheral algesia, without affecting the CNS. The phytochemical study of the stem bark of Croton cajucara Benth lead to the isolation of 19-nor-clerodanetype diterpenes, as well as to the separation of its fixed oil FO-CC. This non polar oil material reveled to be rich in sesquiterpenes and 19-nor-clerodanes components. The biologic effect of OF-CC was evaluated in the development in vitro of the fungis phytopatogens such as Fusarium oxysporum, Rhizoctonia solani and Sclerotium rolfsii. Significant inhibitory effect of the tested fungis (at 0,2 mg.mL-1 dosage) were comproved. A Mass Spectrometry study of clerodane-type diterpenes was developed in order to identify characteristic fragments on mass spectrometra of both clerodane and 19-nor-clerodane presenting an α,β-insaturated carbonyl moiety at ring A of the decalin-system. For that study, mass spectroscopy data were analysed for 19-nor-clerodanes [trans-dehydrocrotonin (DCTN), trans-crotonin (CTN), cis-cajucarin B (c-CJC-B), and cajucarinolide (CJCR)] and for clerodanes [isosacacarin (ISCR) and transcajucarin A (t-CJC-A)] obtained from the stem bark of C. cajucara, and also clerodane-type from other species. The trans-junction of the enone-system clerodanes was clear correlated with the presence of the characteristic ions at m/z 95, 121 e 205. Meanwhile, the characteristics ions at m/z 122 e 124 were correlated to cis-junction. The trans-junction of the enone-system 19-nor-clerodanes showed characteristics ions at m/z 161, 134 e 121. This study could be successful employed for identification of clerodane constituents from other specimens without any additional spectroscopic analyses, as well as a previously phytochemical analyzes in clerodane project search

Solarização em microcosmo: efeito de materiais vegetais na sobrevivência de fitopatógenos de solo e na produção de voláteis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeitos da simulação da solarização do solo com materiais vegetais sobre o crescimento micelial de fungos fitopatogênicos habitantes do solo

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

TRATAMENTO DE SEMENTES DE ARROZ, TRIGO, FEIJÃO E SOJA COM UM PRODUTO FORMULADO À BASE DE CÉLULAS E DE METABÓLITOS DE Bacillus subtilis

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Diversidade de bactérias de solo sob vegetação natural e cultivo de hortaliças

The microorganisms are essential components in the maintenance of the biological and physicochemical balance of the soil. They exert important function including the degradation of residues of plants and animals and the release of nutrients in the alimentary chain. This work had as objective to compare the microbiota of a soil under bush covering (SMS) and other cropped with vegetables (SHC), suppressive or not it Rhizoctonia solani. Total microbial community DNA was extracted of soils, amplification for PCR of the genes 16S rDNA, inserted into pGEM (R)-T cloning vector and sequencing of the genes of the ribosomal RNA. The analysis of the results demonstrated that this methodology was efficient for evaluation of bacteria in ground. In the bush soil suppressive the microorganisms more found belonged to the phyla of the Acidobacterias, Verrucomicrobia and Actinobacterias and in the soil cultivated with vegetables the biggest frequency was of organisms pertaining to the phyla of the Proteobacterias, Firmicutes and Bacteroidetes.

Efeito de biofertilizantes sobre o crescimento micelial e a germinação de esporos de alguns fungos fitopatogênicos

The biofertilizer was produced through anaerobic fermentation of cow manure adding milk, sugar, salts, cow liver parts and bone powder. After 73 days of fermentation it was evaluated the effect on micelial growth of Pythium aphanidermatum, Alternaria solani, Stemphylium solani, Septoria licopersici, Sclerotinia sclerotiorum, Botrytis cinerea, Rhizoctonia solani, Fusarium oxysporum f. sp. phaseoli and spores germination of B. cinerea, A. solani, Hemileia vastatrix and Coleosporium plumierae. In relation to micelial growth inhibition, the growth rate was calculated and it was found that, in general, concentrations over 10% caused a total inhibition of growth for the majority of fungi assayed. In case of spores germination, biofertilizer concentration over 20% has inhibited completely the germination of B. cinerea, over 10% inhibited A. solani, 5 and 1% of C. plumierae and H. vastatrix, respectively. Three different biofertilizers were also tested and one of them was less effective, which was the one produced with manure from confined cows opposed to the others produced with grazing cows.

Controle químico de doenças de Eucalyptus spp. em viveiros e seus efeitos morfo-fisiológicos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Enxertia e podridão de raízes e colo em cucurbitáceas

Pós-graduação em Agronomia (Produção Vegetal) - FCAV

Performance da aplicação de polímero no tratamento de sementes de amendoim

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Solarização em microcosmo: efeito de materiais vegetais na sobrevivência de fitopatógenos e na produção de voláteis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Produção e preservação de estruturas de resistência de fungos fitopatogênicos habitantes do solo

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeito do lodo de esgoto sobre a atividade microbiana e fitopatógenos habitantes do solo

Pós-graduação em Agronomia (Proteção de Plantas) - FCA