Animal pollination is responsible for the majority of the human food supply. Understanding pollination dynamics in agricultural systems is thus essential to help maintain this ecosystem service in the face of human disturbances. Surprisingly, our understanding of plant–pollinator interactions in widely distributed smallholder agricultural systems is still limited. Knowledge of pollination dynamics in these agricultural systems is necessary to fully assess how human disturbances may affect pollination services worldwide. In this study, we describe the structure of a plant–floral visitor network in a smallholder Cucurbitaceae agricultural system. We further identify the main floral visitors of these crops and tested their importance by simulating how their extinction affected network structure and robustness. The observed network was highly connected and generalized but it was neither nested nor compartmentalized. Our results suggest that the structure of agricultural plant–pollinator networks could be inherently different from those in natural communities. These differences in network structure may reflect differences in spatial distribution of floral resources between agricultural and natural systems. We identified Augochlora nigrocyanea and Peponapis limitaris as the two most frequent floral visitors. However, removal of these species did not affect network structure or its robustness, suggesting high levels of interaction rewiring. To our knowledge, this is one of the first studies to describe the structure of a plant–floral visitor network in diverse agricultural systems in the tropics. We emphasize the need for more studies that evaluate network structure in agricultural systems if we want to fully elucidate the impact of human disturbances on this key ecosystem service.

Made available in DSpace on 2016-08-12T19:15:24Z (GMT). No. of bitstreams: 1 ROBERTA KELIA B SILVA A.pdf: 784643 bytes, checksum: 092fd8f80edefb4e66110de6f8ed33b1 (MD5) Previous issue date: 2008-04-02 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The leafminer Liriomyza trifolii is nowadays the main pest of melon orchards in the region of Chapada do Apodi, Northeast of Brazil. In order of the high infestation level of this insect, the control based only in pesticides has not been plenty satisfactory. However, considerable parasitism levels occasioned by Opius sp. have been found in field, mainly in the beginning of the production. Because of this fact, the first studies with this parasitoid are been developed in the Entomology Laboratory of UFERSA. The present study had the objective of adapting a rearing technique to the parasitoid Opius sp. in laboratory conditions, and study the aspects of it s parasitism, aiming the future utilization of this parasitoid in the leafminer integrated management programs, in the Semi-Arid conditions of Rio Grande do Norte State. Initially, infested melon leaves with L. trifolii larvae were collected in field to obtain the parasitoids. From the first parasitoids obtained from field, a technique to multiply them in L. trifolii on melon plants was developed. In the observations of the parasitism aspects of Opius sp., was perceived that it prefer to oviposite in 2nd and 3rd instar larvae. In addition, was observed that females present the highest levels of parasitism in the first two days of life / A mosca-minadora Liriomyza trifolii (Diptera: Agromyzidae), é atualmente a principal praga do meloeiro Cucumis melo L., na região da Chapada do Apodi, nordeste brasileiro. Devido às altas infestações deste inseto, o controle baseado exclusivamente no uso de inseticidas não tem sido plenamente satisfatório. Por outro lado, índices consideráveis de parasitismo, ocasionados pelo parasitóide Opius sp. (Hymenoptera: Braconidae), têm sido constatado em campo, principalmente no início da safra. Em função deste fato, estudos básicos com este parasitóide estão sendo realizados no Laboratório de Entomologia da UFERSA, Mossoró, RN. Dessa forma, o presente trabalho objetivou descrever uma técnica para criação de Opius sp., em condições de laboratório, e estudar aspectos de seu parasitismo, visando sua utilização em futuros programas de manejo integrado da mosca-minadora do meloeiro, nas condições do semi-árido do Rio Grande do Norte. Inicialmente, folhas de meloeiro infestadas com larvas da mosca-minadora foram coletadas em campo para obtenção dos parasitóides. A partir dos primeiros parasitóides obtidos foi adaptada uma técnica para multiplicação destes sobre L. trifolii em plantas de meloeiro. Nas observações sobre os aspectos do parasitismo do Opius sp., constatou-se que estes preferem ovipositar em larvas de 2º e 3º ínstar. Além disso, foi observado que as fêmeas do Opius sp. apresentam maiores índices de parasitismo nos primeiros dois dias de vida

Made available in DSpace on 2016-08-12T19:18:45Z (GMT). No. of bitstreams: 1 ROBERTA KELIA B SILVA A.pdf: 784643 bytes, checksum: 092fd8f80edefb4e66110de6f8ed33b1 (MD5) Previous issue date: 2008-04-02 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The leafminer Liriomyza trifolii is nowadays the main pest of melon orchards in the region of Chapada do Apodi, Northeast of Brazil. In order of the high infestation level of this insect, the control based only in pesticides has not been plenty satisfactory. However, considerable parasitism levels occasioned by Opius sp. have been found in field, mainly in the beginning of the production. Because of this fact, the first studies with this parasitoid are been developed in the Entomology Laboratory of UFERSA. The present study had the objective of adapting a rearing technique to the parasitoid Opius sp. in laboratory conditions, and study the aspects of it s parasitism, aiming the future utilization of this parasitoid in the leafminer integrated management programs, in the Semi-Arid conditions of Rio Grande do Norte State. Initially, infested melon leaves with L. trifolii larvae were collected in field to obtain the parasitoids. From the first parasitoids obtained from field, a technique to multiply them in L. trifolii on melon plants was developed. In the observations of the parasitism aspects of Opius sp., was perceived that it prefer to oviposite in 2nd and 3rd instar larvae. In addition, was observed that females present the highest levels of parasitism in the first two days of life / A mosca-minadora Liriomyza trifolii (Diptera: Agromyzidae), é atualmente a principal praga do meloeiro Cucumis melo L., na região da Chapada do Apodi, nordeste brasileiro. Devido às altas infestações deste inseto, o controle baseado exclusivamente no uso de inseticidas não tem sido plenamente satisfatório. Por outro lado, índices consideráveis de parasitismo, ocasionados pelo parasitóide Opius sp. (Hymenoptera: Braconidae), têm sido constatado em campo, principalmente no início da safra. Em função deste fato, estudos básicos com este parasitóide estão sendo realizados no Laboratório de Entomologia da UFERSA, Mossoró, RN. Dessa forma, o presente trabalho objetivou descrever uma técnica para criação de Opius sp., em condições de laboratório, e estudar aspectos de seu parasitismo, visando sua utilização em futuros programas de manejo integrado da mosca-minadora do meloeiro, nas condições do semi-árido do Rio Grande do Norte. Inicialmente, folhas de meloeiro infestadas com larvas da mosca-minadora foram coletadas em campo para obtenção dos parasitóides. A partir dos primeiros parasitóides obtidos foi adaptada uma técnica para multiplicação destes sobre L. trifolii em plantas de meloeiro. Nas observações sobre os aspectos do parasitismo do Opius sp., constatou-se que estes preferem ovipositar em larvas de 2º e 3º ínstar. Além disso, foi observado que as fêmeas do Opius sp. apresentam maiores índices de parasitismo nos primeiros dois dias de vida

Made available in DSpace on 2014-08-20T14:06:13Z (GMT). No. of bitstreams: 1 dissertacao_ daniela_ priori.pdf: 1667098 bytes, checksum: 34e76681ceb9a2d408f534549b9ee012 (MD5) Previous issue date: 2011-02-25 / Genetic resources conserved in genebanks have a great value in terms of conservation of rare types, when they are threatened by abandonment of farming or as a unique resource for plant breeding programs. Among the accessions conserved in genebanks important sources of genetic variability can be found for obtaining more productive genotypes tolerant to biotic and abiotic stresses and improved nutritional quality. To have success in that demand is necessary that the accessions contained in genebanks are characterized and evaluated in terms of both qualitative and quantitative characters. The characterization and evaluation of accessions conserved in genebanks must be priorities in the strategy for management of genetic resources, as they provide better knowledge of the germplasm available, is essential for use in breeding programs. In Brazil, there is little information on genetic resources of Cucurbits, especially as regards Cucurbita ficifolia, Cucurbita argyrosperma. Large number of Cucurbita landraces grown in the country could be better exploited as sources of genes for breeding programs, after genetic characterization. Much of the genetic diversity of different Cucurbita landraces grown in southern Brazil has been lost due to neglect of cultivation or its replacement by commercial hybrid varieties. This work was carried in order to contribute to general knowledge related to genetic resources of Cucurbita argyrosperma, Cucurbita ficifolia and Cucurbita pepo, and with specific objectives to assess the transferability of primers designed to C. pepo in C. argyrosperma and C. ficifolia and to evaluate the genetic variability within and among landraces of C. pepo grown in Rio Grande do Sul through analysis of microsatellite markers. Ten accessions of C. pepo, nine of C. argyrosperma and five of C. ficifolia belonging to the Active Germplasm Bank of Cucurbitaceae from Embrapa Temperate Agriculture were submitted to molecular characterization. The genetic distance between these accessions was determined. The transferability of SSR loci from C. pepo to C. argyrosperma and C. ficifolia was 85% and 80% respectively. The analysis of these 24 accessions with 35 loci generated a total of 105 SSR markers, ranging from one to four alleles per locus, of which 56 (53,33%) were polymorphic, showing that there is genetic diversity in the accessions analyzed. The presence and absence of markers allowed to find 100 loci, varying from one to five alleles per locus, with overall average of three alleles per marker analyzed. Among the 34 loci tested, 29 (85.2%) were polymorphic, showing that there is genetic variability among the accessions of C. pepo analyzed. Data evaluation was done by molecular analysis of molecular variance (AMOVA). It was observed that 54.60% of genetic variability is attributable to variation between accessions and 45.39% is attributed to differences within accessions. A comparative analysis was made between the ten accessions studied, analyzed two by two by AMOVA. From 45 comparisons between the ten accessions significant differences there were detected between 35 comparisons, with average of 57.10% of molecular variation attributed to differences between accessions. Genetic variation among counties where the accessions were collected was not significant, indicating that there is not population subdivision according to geographic region. Results indicate that the microsatellites were efficient for the characterization and molecular analysis of genetic divergence. These studies contributed to increase the knowledge related to these genetic resources. SSR primers developed for Cucurbita pepo can be used for molecular characterization of C. argyrosperma and C. ficifolia. Landraces of C. argyrosperma and C. ficifolia showed low genetic variation, while C. pepo shows great variability. The largest proportion of variability in C. pepo is distributed between accessions and not within accessions. / Os recursos genéticos conservados em bancos de germoplasma apresentam grande valor do ponto de vista da conservação de tipos raros, quando os mesmos são ameaçados pelo abandono do cultivo ou como recurso insubstituível para programas de melhoramento genético vegetal. Dentre os acessos contidos nos bancos de germoplasma podem ser encontradas importantes fontes de variabilidade genética para a obtenção de genótipos mais produtivos, tolerantes a estresses bióticos e abióticos e com melhor qualidade nutricional. Para que haja sucesso nessa demanda é necessário que os acessos contidos nos bancos de germoplasma sejam caracterizados e avaliados, tanto em termos de caracteres qualitativos quanto quantitativos. No Brasil, há pouca informação sobre os recursos genéticos de Cucurbitáceas, de modo especial no que se refere à Cucurbita argyrosperma e Cucurbita ficifolia. Grande número de variedades locais de Cucurbita cultivadas no país poderiam ser melhor exploradas como fontes de genes para programas de melhoramento, após a devida caracterização. Muito da diversidade genética das variedades locais de diferentes espécies de Cucurbita cultivadas no Sul do Brasil vem sendo perdida devido ao abandono do cultivo ou à sua substituição por variedades híbridas comerciais. Este trabalho foi realizado com o objetivo geral de contribuir para o conhecimento relacionado aos recursos genéticos de Cucurbita argyrosperma, C. ficifolia e C. pepo, e objetivos específicos de avaliar a transferibilidade de loci de microssatélites de C. pepo para C. argyrosperma e C. ficifolia; e avaliar a variabilidade genética entre e dentro de variedades locais de C. pepo cultivadas no Rio Grande do Sul por meio da análise de marcadores microssatélites. Foram analisados dez acessos de C. pepo, nove de C. argyrosperma e cinco de C. ficifolia do acervo do Banco Ativo de Germoplasma de Cucurbitáceas da Embrapa Clima Temperado. A distância genética entre esses acessos foi determinada. A transferibilidade de locos SSR de C. pepo para C. argyrosperma e C. ficifolia foi de 85% e 80%, respectivamente. A análise dos 24 acessos de Cucurbita por meio de 35 loci SSR gerou um total de 105 marcadores SSR, com variação de um a quatro alelos por loco, dos quais 56 (53,33%) foram polimórficos, evidenciando que há diversidade genética entre os acessos analisados. Através dos dados de presença e ausência de marcadores obtidos com 34 combinações de primers, foram encontrados 100 locos com variação de um a cinco alelos por loco, com média geral de três alelos por marcador analisado. Dentre os 40 locos analisados, 29 (85,3%) foram polimórficos, evidenciando que há variabilidade genética entre os acessos de C. pepo analisados. A avaliação dos dados moleculares foi feita pela análise molecular da variância (AMOVA). Deste modo, foi possível verificar que 54,60% da variabilidade genética é atribuída à variação entre acessos e 45,39% é atribuída a diferenças dentro dos acessos. Foi feita a análise comparativa entre os dez acessos estudados, analisados dois a dois, pela análise AMOVA. Das 45 comparações entre os dez acessos, foram significativas as diferenças entre 35 delas, com média de 57,10% da variação molecular atribuída às diferenças entre acessos. A variação genética entre os municípios onde os acessos foram coletados não foi significativa, indicando que não ocorre subdivisão de populações em função da região geográfica. Os resultados obtidos indicam que os microssatélites foram eficientes para a caracterização molecular e a análise da divergência genética. É possível utilizar primers de microssatélites desenvolvidos para C. pepo na caracterização molecular de C. argyrosperma e C. ficifolia. Variedades locais de C. argyrosperma e C. ficifolia apresentam pouca variabilidade genética, enquanto que C. pepo evidencia grande variabilidade genética. A maior proporção da variabilidade em C. pepo encontra-se distribuída entre os acessos, e não dentro dos acessos.

Momordica foetida Schum. & Sond. (Cucurbitaceae), locally known as iNtshungu, is widely used by the Zulu people of Natal-KwaZulu for the treatment of a variety of ailments. The dried leaves leaves and stems of this plant was subjected to soxhlet extraction by refluxing with hexane, chloroform and methanol successively. Thin layer chromatography of the chloroform extract of the leaves revealed a multiplicity of compounds. The chloroform extract was further partitioned with sodium hydroxide resulting in an organic and aqueous phase. The organic phase, containing extract A, afforded two compounds, viz. compounds 1 and 2. The basic aqueous fraction was neutralised and re-extracted with chloroform to give extract B, affording five compounds, viz. compounds 3,4,5,6 and 7. Structural elucidation was accomplished by techniques such as IH and 13C NMR spectroscopy, HETCOR, COSY, FTIR and High Resolution Mass Spectrometry. Compounds 1 and 2 were identified as cucurbitane triterpenoids known as momordicines which had been previously discovered in the related species of this plant, Momordica charantia L. The remaining five compounds were identified as novel compounds, although natural derivatives of compounds 6 and 7 had been isolated previously from Momordica charantia L. Compounds 3-7 were each isolated as an epimeric mixture but it was possible to select the resonances corresponding to the major epimer. These five epimers were respectively identified as 5, 19-epoxy-19(R)-hydroxy-25-methoxy-5β- cucurbita-6,23-diene-3β-ol [102], 5,19-epoxy-19(R),25-dihydroxy-5β-cucurbita- 6,23-diene-3β-ol [103], 5,19-epoxy-19(R)-methoxy-25-hydroxy-5β-cucrbita- 6,23-diene-3β-ol [104], 5,19-epoxy-25-methoxy-5β-cucurbita-6,23diene- 3β-ol [105] and 5,19-epoxy-19(R),25-dimethoxy-5β-cucurbita-6,23diene- 3β-ol [106]. Appropriate reactions were performed, where possible, on the compounds isolated in order to confirm their identity. / Thesis (M.Sc.)-University of Natal, Durban, 1994.

O melão-de-São-Caetano (Momordica charantia L) é uma cucurbitácea que ocorre em todas as regiões geográficas brasileiras. A espécie apresenta duas \"variedades\" distintas, comumente conhecidas por \"variedade silvestre\" e \"variedade cultivada\", esta última caracterizada por plantas de maior tamanho. Plantas da \"variedade selvagem\" são hospedeiras de um fitoplasma do grupo 16SrIII-J, que causa superbrotamento de ramos, nanismo generalizado, clorose, redução no tamanho de folhas e frutos. No entanto, não há informação da \"variedade cultivada\" ser hospedeira de fitoplasmas. Assim, no presente estudo, plantas sintomáticas desta \"variedade\" foram analisadas quanto à presença de fitoplasmas em seus tecidos, visando associar este tipo de patógeno à doença. Neste mesmo trabalho, os isolados do fitoplasma encontrados nas plantas sintomáticas da \"variedade cultivada\" foram molecularmente analisados em relação ao gene secY, atualmente usado como um marcador que permite identificar variações genéticas sutis. Buscou-se, com isto, identificar possíveis variantes entre os isolados. Amplificações de fragmentos de DNA a partir dos genes 16S rRNA (1,2Kb) e secY (1,6Kb) demonstraram a associação de fitoplasma do grupo 16SrIII com as plantas sintomáticas de melão-de-São-Caetano da \"variedade cultivada\". Nestas plantas, corpúsculos pleomórficos, típicos de fitoplasmas, foram visualizados no floema dos tecidos doentes, confirmando os resultados dos testes moleculares. Análises de RFLP virtual, conduzidas com o fragmento genômico correspondente ao gene secY e diversas enzimas de restrição, permitiram identificar o referido fitoplasma como pertencente ao subgrupo 16SrIIIJ. A análise filogenética evidenciou que o fitoplasma padrão do subgrupo 16SrIII-J emergiu do mesmo ramo que o fitoplasma identificado no melão-de-São-Caetano, confirmando que ambos estão estritamente relacionados. O emprego do gene secY como marcador para diferenciação fina entre fitoplasmas não apontou variabilidade genética entre os isolados do fitoplasma detectado tanto nas plantas da \"variedade cultivada\" como naquelas pertencentes à \"variedade selvagem\". Como conclusão, a \"variedade cultivada\" de M. charantia é hospedeira do mesmo fitoplasma encontrado na \"variedade selvagem\", o qual é afiliado ao subgrupo 16SrIII-J; por sua vez, o gene seY não distinguiu geneticamente os isolados do fitoplasma pertencente ao subgrupo 16SrIII-J, presentes nas plantas de melão-de-São- Caetano. / Momordica charantia is a species of the family Cucurbitaceae that occurs in all Brazilian geographic regions. This species presents two distinct \"varieties\", commonly called \"wild variety\" and \"cultivated variety\", whose plants are bigger than those belonging to the \"wild variety\". Plants of the \"wild variety\" are hosts of a phytoplasma of the group 16SrIII-J, which is associated with shoot proliferation, stunting, chlorosis, and small leaves and fruits. However, there is no information about the occurrence of phytoplasmas in plants of the \"cultivated variety\". Thus, in the present study, symptomatic plants belonging to this \"variety\" were analysed in order to associate phytoplasmas with the disease. In addition, strains of the phytoplasma found in symptomatic plants of the \"cultivated variety\" were molecularly analyzed in relation to the gene secY, which is currently used as a marker for identification fine of genetic diversity, aiming provide elements for construction of new schemes for classification of phytoplasmas. The objective was to identify distinct strains among the strains present in plants of the wild and cultivated varieties. Amplifications of DNA fragments from the genes 16Sr rRNA (1.2Kb) and secY (1.6Kb) demonstrated the association of a phytoplasma of group 16SrIII with the symptomatic plants belonging to \"cultivated variety\". These plants revealed the presence of pleomorphic bodies, typical of phytoplasmas, which was visualized in the phloem vessel from diseased tissues, confirming the results obtained by molecular assays. Virtual RFLP analysis, performed with the genomic fragment corresponding to the gene secY and various restriction enzymes, allowed to identify this phytoplasma as a member of the subgroup 16SrIII-J. Phylogenetic analysis revealed that the phytoplasma used as reference for 16SrIII-J subgroup and the phytoplasma identified in plants of M. charantia emerged from the same branch, confirming that both phytoplasmas are closely related. The gene secY, used as marker for fine differentiation of phythoplasmas, did not show genetic variability among the strains of the phytoplasma detected both plants belonging to \"cultivated variety\" and \"wild variety\". In conclusion, plants of the \"cultivated variety\" are hosts of the same phytoplasma found in the \"wild variety, which is affiliated with the 16SrIII-J subgroup; in addition, the gene secY did not distinguish isolates of the phytoplasma belonging to 16SrIII-J subgroup, present in plants of M. charantia.

Na flora brasileira, Cucurbitaceae representa uma importante família entre a sinúsia de trepadeiras, com aproximadamente 180 espécies nativas, distribuídas em 30 gêneros, poucos dos quais são monografados para o Brasil. Esta tese tem como objetivo o estudo taxonômico e morfológico de sete destes gêneros, distribuídos em quatro tribos: Anisosperma e Fevillea (Zanonieae), Apodanthera e Melothrianthus (Coniandreae), Melothria (Benincaseae) e, Cyclanthera e Sicyos (Sicyeae). Anisosperma é monotípico e Fevillea está representado por sete espécies de distribuição bicêntrica no neotrópico. Verificou-se a ocorrência de distintos padrões de distribuição geográfica para as espécies destes gêneros: Padrão amplo neotropical (F. cordifolia), Padrão amplo atlântico (F. trilobata), Padrão restrito amazônico (F. anomalosperma, F. pedatifolia e F. pergamentacea), Padrão restrito atlântico (A. passiflora) e Padrão higrófilo sul bahiano (F. bahiensis). Apodanthera está representada no Brasil por 11 espécies (10 delas endêmicas), distribuídas em duas secções: Apodanthera (A. argentea, A. glaziovii, A. laciniosa, A. sagittifolia var. villosa e A. ulei) e Pseudoapodanthera (A. congestiflora, A. hindii, A. pedisecta, A. succulenta, A. trifoliata e A. villosa). O gênero Melothria compreende oito espécies na flora brasileira (M. candolleana, M. cucumis, M. dulcis, M. hirsuta, M. pendula, M. schulziana, M. trilobata e M. warmingii), assim como Cyclanthera (C. eichleri, C. hystrix, C. multifoliola, C. oligoechinata, C. pedata, C. quinquelobata, C. tenuifolia e C. tenuisepala). Sicyos possui somente três espécies: S. martii na secção Atractocarpus, e S. polyacanthus e S. warmingii em Sicyos. O estudo taxonômico apresenta uma revisão e atualização nomenclatural, descrições, ilustrações e chaves analíticas para os gêneros e espécies, bem como dados sobre distribuição geográfica, ecologia e aspectos fenológicos. As características da morfologia polínica revelaram- se extremamente úteis na identificação dos gêneros estudados. No entanto, a diferenciação entre espécies de um mesmo gênero requer uma análise mais acurada. Fevillea apresenta grãos típicos de Nhandiroboideae, pequenos, tricolporados e estriados. Os gêneros representativos de Coniandreae (Apodanthera e Melothrianthus) e de Benincaseae (Melothria) são predominantemente de tamanho médio, tricolporados, reticulados e/ou microreticulados. Dentre as tribos estudadas, Sicyeae apresenta os maiores tamanhos de grãos de pólen, sendo Cyclanthera estes são 4-8-colporados e punctitegilados, e em Sicyos estefanocolpados e supra-microreticulados equinados. Os grãos foram descritos com base em microscopia óptica e eletrônica de varredura e, em cada gênero, as espécies foram comparadas. / In the Brazilian flora, Cucurbitaceae represents an important family among the climbing synusia, comprising ca. 180 native species, distributed in 30 genera, few of which are already reviewed in Brazil. The object of this thesis is to carry out a taxonomic and morphological study concerning seven of these genera: Anisosperma and Fevillea (Zanonieae), Apodanthera and Melothrianthus (Coniandreae), Melothria (Benincaseae), Cyclanthera and Sicyos (Sicyeae). Anisosperma is monotypic and Fevillea is represented by seven species whit bicentric distribution in the Neotropics. We verified the occurrence of distinct geographic distributional patterns for the species of these genera: Wide Neotropical pattern (F. cordifolia), Wide Atlantic pattern (F. trilobata), Restricted Amazonian pattern (F. anomalosperma, F. pedatifolia e F. pergamentacea), Restricted Atlantic pattern (A. passiflora) and South-Bahian hygrophilous pattern (F. bahiensis). Apodanthera is represented by 11 species in Brazil (10 of which are endemic), distributed in two sections: Apodantera (A. argentea, A. glaziovii, A. laciniosa, A. sagittifolia var. villosa and A. ulei) e Pseudoapodanthera (A. congestiflora, A. hindii, A. pedisecta, A. succulenta, A. trifoliate and A. villosa). The genus Melothria encompasses eight species in the Brazilian flora (M. candolleana, M. cucumis, M. dulcis, M. hirsuta, M. pendula, M. schulziana, M. trilobata and M. warmingii) as well as Cyclanthera (C. eichleri, C. hystrix, C. multifoliola, C. oligoechinata, C. pedata, C. quinquelobata, C. tenuifolia and C. tenuisepala). Sicyos presents only three species: S. martii in Atractocarpus section and S. polyacanthus and S. warmingii in Sicyos section. The taxonomic study presents nomenclatural revision and updating, descriptions, illustrations and analytical keys for genera and species, as well as data concerning geographic distribution, ecology and phenological aspects. Characters concerning pollen morphology were extremely useful for the identification of the studied genera. However, differentiation between congeneric species demands more acurate analyses. Fevillea presents typical Nhandiroboideae grains, small, tricolporate and striate exine. Representative genera of Coniandreae (Apodanthera and Melothrianthus) and Benincaseae (Melothria) are predominantly medium-sized, tricolporate, reticulate and/or micro-reticulate exine. Among the studied tribes, Sicyeae presents the largest pollen grains, 4-8-colporate and punctitegillate exine in Cyclanthera and stephanocolpate and supra-microreticulate echinate exine in Sicyos. Grains descriptions were based in light microscopy and scanning microscopy and, within each genus, species were compared.

Thesis (M.Sc. (Biochemistry)) --University of Limpopo, 2017 / Cancer is a broad group of various diseases characterised by unregulated cell proliferation which leads to the formation of tumours (Vickers, 2004). Some tumours remain confined to their site of origin while some gain the ability to spread to other parts of the body, a process known as metastasis (Weiss, 1990). The burden of cancer continues to rise, due to inefficient prevention strategies and serious side effects, as well as the cost of cancer regimens (Sondhi et al., 2010). Medicinal plants represent a reservoir of bioactive compounds that can be useful in the management of cancer with less or no side effects (Wong et al., 2012). The aim of this study was to investigate the anti-cancer effects of M. balsamina leaf extract in breast MCF-7 cancer cells. In this study, M. balsamina leaves powder was extracted using acetone. The biological effect of the extract was assessed on the viability of MCF-7 cells using the MTT assay. The extract’s ability to induce apoptosis was assessed using the Hoechst/propidium iodide dual staining method. Its anti-metastatic potential was investigated by determining its effect on MCF-7 cell migration, attachment and invasion using wound healing, adhesion, invasion assay, respectively. The human apoptosis antibody and human angiogenesis antibody array kits were used to determine the effect of the extract on the expression levels of proteins involved in apoptosis and metastasis, respectively. Treatment of MCF-7 cells with different concentrations of the extract showed a significant decrease in cell viability after 48 h incubation at 10 - 20 µg/ml. The decrease in cell viability was associated with the induction of apoptosis as seen by nuclear condensation and loss of membrane permeability in cells treated with the extract. Inhibition of migration, adhesion and invasiveness of the MCF-7 cells was seen in the treated cells. The extract also modulated proteins implicated in cell apoptosis, adhesion, migration and invasion such as Bcl-2 family of proteins, IGFBP, uPA, MMPs. In conclusion, based on the results, the extract show pro-apoptotic and anti-metastasis potential. Thus M. balsamina can be considered as a potential source of compounds with anti-cancer activity

Cucurbits (i.e. squash, melons, pumpkins, gourds) are high value crops of global importance. Insect pests in these systems are often controlled by chemical insecticides, which are not always effective and can be damaging to the environment. Many integrated pest management (IPM) techniques have been developed for the control of pests in these systems, with a goal of improving system stability and reducing chemical inputs. The overarching goal of my research was to investigate the impact of select IPM techniques on arthropod populations and yield in organic and conventional cucurbit systems. This dissertation can be divided into three major projects which were conducted between 2013 and 2017. First, an investigation was conducted to understand the impact of two commonly used IPM practices (tillage regime and the use of row covers) on pest insect populations, beneficial arthropod populations, and plant yield. By developing studies in both organic and conventionally managed squash and melon production, four independent studies were conducted and analyzed to provide a broad understanding of these IPM strategies. In all systems, plant yields and pests were greatest in the plasticulture systems, but reduced tillage had a positive impact on the natural enemy arthropods within these crops. Row cover use resulted in larger plants and increased yields, but had an inconsistent influence on arthropods in the systems studied. From these initial studies, an additional investigation was developed to better understand the impacts of cultivation on the specialist pollinator Peponapis pruinosa [Hymenoptera: Apidae]. Nesting site selection was examined in two independent experiments. By conducting choice studies to allow P. pruinosa to select preferred nesting sites, we determined that P. pruinosa prefer to build nests in loose soils and show reduced nest making in compact soils. This poses interesting management challenges since less-compact soils are within high tillage zones. This research supports the need for the development of cultivation management plans that consider of pollinator habitat and reproduction needs. A multi-year, multi-farm study was developed for the comparison of parasitism in cucumber beetles (Acalymma vittatum and Diabrotica undecimpunctata) in organic and conventional growing systems. Parasitoids were reared from beetles collected from working organic and conventional cucurbit farms in central Kentucky. Our results show that there is some seasonal variation in parasitism, but that there is no significant difference between organic and conventional production. We conclude that IPM techniques can be effective in contributing to the control cucurbit pests in agroecosystems and the improvement of crop yields. These studies show that natural enemies and pollinators react differently to IPM practices, which should be considered when developing IPM plans in cucurbit production. By researching these management techniques we are able to develop production systems that have increased stability.

Apodanthera es un género americano de Cucurbitaceae con distribución disyunta en áreas áridas y semiáridas de Norteamérica y Sudamérica; cuenta en la actualidad con un total 45 nombres en el nivel de especie y otros 6 en el de variedad. Hasta el presente trabajo, el tratamiento más integral del género correspondía al publicado por A. Cogniaux en 1916; en este trabajo se incluyeron las 25 especies publicadas hasta ese momento y se estructuró al género en tres secciones: Apodanthera (de los Andes de Perú y Bolivia, hasta el noroeste de la Argentina, y algunos representantes de zonas costeras de Ecuador y el este de Brasil), Pseudoapodanthera (endémica del nordeste de Brasil) y Cucurbitopsis (del sur de Estados Unidos de América y México). Numerosos autores advirtieron sobre la necesidad de realizar una revisión moderna del género, debido a la gran variabilidad interespecífica e intraespecífica observada, tanto sobre estructuras florales como foliares, y a la mencionada distribución disyunta de sus secciones. El presente trabajo comprendió una exhaustiva recopilación bibliográfica, observación de numerosos especímenes de herbario en instituciones nacionales e internacionales (incluyendo todo el material tipo localizado), trabajo de campo, estudios morfológicos y taxonómicos. Adicionalmente, se llevó a cabo un estudio filogenético, mediante un análisis cladístico sobre la base de caracteres morfológicos y moleculares, que permitió definir grupos monofiléticos y ajustar los límites de Apodanthera frente a sus géneros afines dentro de la tribu Coniandreae. Pudo comprobarse que Apodanthera, tal como estaba circunscripto, no resultaba un género monofilético, debiendo acotarse, en sentido estricto, a sólo 7 especies de filiación andina. Las antiguas secciones de Apodanthera fueron segregadas y consideradas como géneros independientes; así, se fundaron Cucurbitopsis (con 3 especies de zonas áridas de América del Norte) y Pseudoapodanthera (con 4 especies del nordeste de Brasil). Se transfirió una especie de Apodanthera al género Doyerea y otras tres a Melothrianthus; por cuanto se amplió la circunscripción de los mismos, hasta el presente estudio considerados como monoespecíficos. Otras cinco especies sudamericanas se consideran como “incerta saedis” dentro de Apodanthera, hasta tanto puedan aclararse sus relaciones. En la presente contribución se reconocen como independientes a 23 taxones, todos en el nivel de especie, dentro de los géneros antes mencionados; se establecen 15 nuevas sinonimias, se proponen 11 nuevas combinaciones y, en relación con el trabajo nomenclatural, se realizan 23 lectotipificaciones. Para cada género y especie se brindan descripciones botánicas detalladas, mapas de distribución, ilustraciones de pluma y, en algunos casos fotografías de campo; adicionalemente, se proveen claves dicotómicas para distinguir los géneros y las especies dentro de cada uno de ellos. Finalmente, se incluyen comentarios biogeográficos y se evalua la correspondencia entre el patrón filogenético obtenido y la distribución geográfica de los géneros tratados.