The overall aim of this PhD study was to develop protocols to improve the efficiency of eucalypt controlled pollinations (CPs) in order to make it more cost-effective for forestry companies to perform them on a commercial scale on small-flowered species. To achieve this, three research areas were explored, namely pollen handling, breeding systems and controlled pollination technique. Study species were Eucalyptus grandis, E. dunnii, E. smithii, E. nitens, E. urophylla and E. macarthurii. The first specific aim of the study was to identify a suitable liquid in vitro germination medium for reliably testing pollen viability of all six study species. Six levels of sucrose [0, 10, 20, 30, 40 and 50% (w/v)] were tested, both with (0.15 mg l-1) and without boric acid. The optimal sucrose concentration was found to be 30% (w/v), with boric acid stimulating pollen tube growth. A second aim was to determine temperatures suitable for the short-, medium- and long-term storage of E. smithii, E. nitens and E. grandis pollen. Pollen samples were stored at room (25oC), refrigerator (4oC), freezer (-10oC) and liquid nitrogen (-196oC) temperatures, and pollen viability tested every two months over a 12-month period. There was a rapid decline in the germination of pollen stored at 25oC, while temperatures cooler than 4oC appeared to maintain pollen viability for the duration of the 12-month study. Recommendations were thus to use a refrigerator for short-term (< 2 months), a freezer for medium-term (up to 10 months) and cryopreservation for longer-term storage. In the second part of the study, breeding systems of E. urophylla and E. grandis were examined by studying pollen-tube growth in the style after single-donor self- and cross-pollinations. Results showed that, in addition to both species exhibiting reduced seed yields following self-pollination, pollen tubes from self-pollen took significantly longer than those from cross-pollen to grow to the base of the style. This suggested the presence of both late-acting self-incompatibility and cryptic self-incompatibility (CSI) as possible mechanisms responsible for outcrossing in these two species. In a follow-up study, the siring ability of self- and cross-pollen was examined after single- and mixed-donor pollinations were performed on E. grandis. Once again, single-donor cross-pollinations resulted in a significantly higher number of seeds compared to self-pollinations. In addition, microsatellite molecular markers revealed that 100% of the progeny from mixed (self + outcross) pollinations were outcrossed, confirming the competitive advantage of cross-pollen. To date, CSI has never been associated with Eucalyptus, making this the first study to suggest its presence in the genus. For the final study area, three CP-techniques were compared, namely the Conventional method, One Stop Pollination (OSP) and Artificially Induced Protogyny (AIP), in E. grandis, E. smithii and E. macarthurii maternal parents. Although the AIP technique produced the highest seed yields in all three species, it also resulted in high self- and foreign-pollen contamination (determined using microsatellite markers). This necessitated exploration of different methods of isolating the pollinated flower, and this led to the identification of a novel method which uses sodium alginate gel. Flowers hand-pollinated and isolated with sodium alginate produced progeny that were 100% outcrossed with the applied pollen, confirming the superiority of this innovative isolation technique compared to the currently used exclusion bag. Sodium alginate isolation also increased the efficiency of CPs as the gel was naturally shed, removing the need for operators to return to the tree to remove the isolation material, and thereby reducing the cost per seed. Application of these results should make commercial CP-seed production of small-flowered eucalypts a practical reality. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2009.

Thesis (MScAgric (Horticulture))--Stellenbosch University, 2008. / Sweet cherries (Prunus avium L.) have a high chilling requirement and grow best in areas receiving >1 100 Utah chill units during winter. The main production areas in South Africa, and particularly the eastern Free State, frequently receive insufficient winter chilling and late spring frosts leading to problems of poor budburst, flowering, floral abnormalities and poor fruit set. Research was conducted on the cultivar ‘Bing’ to determine the main factors causing its low fruit set. Various trials were conducted to optimize the timing of rest breaking agents, identify suitable cross pollinizers that flower synchronously with ‘Bing’, and evaluate the influence of temperature and pollen-pistil interactions on fertilization and fruit set. Pollen biology studies using 2- to 3-year-old ‘Bing’ sweet cherry trees were conducted near Clarens, eastern Free State, during the 2005 and 2006 seasons to determine the most suitable cross pollinizer/s for ‘Bing’ and to assess the influence of temperature and pollen-pistil interactions on pollen tube growth and ovule longevity. Significant differences in pollen germination (‘rates’ deleted) occurred between pollinizers, although differences were noted in pollen performance on the stigma and style (in vivo) compared to the artificial media (in vitro), indicating a lack of correlation between in vitro germination and in vivo pollen-pistil interactions. Pollen tube growth, following cross pollination, was influenced by pollinizer genotype, temperature, and the number of pollen grains deposited on the stigma. The highest pollen tube growth rates in ‘Bing’ styles were recorded for the pollinizers ‘Black Tartarian’ (2006), ‘Lapins’ and ‘Rainier’ sweet cherry cultivars at temperatures of approximately 21°C. Temperature had the most significant influence on ovule longevity with the lower orchard temperatures extending ovule viability compared to the higher laboratory temperatures, although pollen tube growth rates were also reduced, thus shortening the effective pollination period. Cross pollination was also shown to extend ovule viability. The results indicate that ‘Black Tartarian’, ‘Lapins’ and ‘Rainier’ were the most suitable pollinizers for ‘Bing’. Hand-pollination with pollen from these donors resulted in a several-fold increase in seed set over naturally-pollinated control flowers. It appears that the principle factors causing poor fruit set in ‘Bing’ sweet cherry are premature abortion of the ovule before fertilization and inadequate transfer of sufficient viable pollen under orchard conditions. Rest breaking trials were conducted on 4-year-old ‘Bing’ sweet cherry trees on ‘Gisela® 5’ rootstock near Clarens (28°28’S; 28°19’E, 1860m) and Reitz (28°0’S; 28°28’E; 1717m) in the eastern Free State, South Africa, during the 2005 and 2006 seasons respectively. In 2005 five treatments were evaluated; viz. 1% and 2% Dormex® (hydrogen cyanamide, HCN); 1% Dormex® + 3% mineral oil; and 3% Lift® (thidiazuron and mineral oil) sprayed at three dates (29 July 2005, 5 August 2005 and 12 August 2005) preceding expected the “green-tip” stage of flower development, plus an unsprayed control. In 2006 four treatments were evaluated; viz. 1% Dormex®; 1% Dormex® + 3% mineral oil; 3% Lift® applied on three dates (26 July 2006, 7 August 2006 and 12 August 2006) and an unsprayed control. No interaction was observed between time of application and type of rest breaking agent (RBA). RBAs were effective at improving budburst and yield during both seasons with the time of application of RBAs having the most significant influence on budburst and production efficiency in ‘Bing’ sweet cherry trees. RBAs were most effective at improving vegetative budburst when applied 9 to 16 days before the (‘actual’ deleted) “green-tip” stage of flower development. Floral budburst and yield were increased by 1% Dormex® + 3% mineral oil and 3% Lift®, but results varied between seasons indicating that time of RBA application should be based on chilling accumulation and bud development stage and not based on calendar date. This current research suggests that ‘Bing’ sweet cherry is poorly suited climatically to the current production areas of the eastern Free State and short-term research needs to identify methods of improving chilling and fruit set by means of evaporative cooling and fruit set-enhancing plant growth regulators. Longer term work requires the identification of new, lower chill cultivars with improved climatic adaptation to South African conditions.

Made available in DSpace on 2016-06-02T18:55:27Z (GMT). No. of bitstreams: 1 5930.pdf: 2008307 bytes, checksum: d0e45679fd9d345a26733ef3c1512046 (MD5) Previous issue date: 2014-03-28 / Financiadora de Estudos e Projetos / It is estimated that approximately 73 % of the world crops are pollinated by a bees. The constant alteration of habitats has led to the decline of pollinators, which may reflect limitations in the quantity and quality of the fruits and seeds grown, becoming one of the biggest problems when it comes to agricultural production. Studies with agricultural crops and their pollinators may contribute in seeking proposals that combine agriculture and conservation of forest fragments. The general objective of this work was to study aspects of Solanum lycopersicum L. hybrid Pizzadoro pollination. The specific objectives were: 1) verify if the floral morphology influences the behavior of the pollinator visits, 2) evaluate the richness of pollinating bees and pollinators at different distances from the Legal Reserve area, 3) compare the efficiency of three species of bees pollination in two treatments: spontaneous self-pollination, and pollination under natural conditions. The study was conducted on a conventional tomato cultivation in the municipality of Estiva Gerbi, Sao Paulo. Flowers were collected and observed under a stereomicroscope and scanning electron microscope. Efficiency was compared between Apis mellifera, Augochloropsis sp. and Exomalopsis sp. by Spears index. Observations and sampling were made in situ at 50, 100 and 150 meters from the Legal Reserve. It was found that the anther dehiscence is longitudinal and that the efficiency of pollination by A. mellifera (0.72) was similar to Exomalopsis sp. (0.85) and greater than Augochloropsis sp. (0.22). It is considered that the success of A. mellifera is associated with the floral morphology. Eleven species of insects, of which 7 were considered pollinators were found. Fifty eight floral visits were recorded, out of which 24 in quadrant A (50 m), 13 in B (100 m) and 21 in C (150 m), with A. mellifera dominant with 62.1% of visits, followed by Augochloropsis sp. and Oxaea flavescens both with 10.3%, Exomalopsis sp. with 6.9 %, Allograpta sp. with 5.2 % ,Bombus sp. with 3.4 % and Xylocopa sp. 1.7 %. The data indicates that the Legal Reserve played a key role in providing pollinators for tomato crops and therefore emphasizes the need for conservation and restoration of forest fragments to assist in increasing crop production. / Estima-se que aproximadamente 73% das plantas cultivadas mundialmente sejam polinizadas por alguma espécie de abelha. A constante alteração de habitats vem provocando o declínio de polinizadores, que pode refletir em limitações na quantidade e qualidade dos frutos e sementes cultivados, constituindo-se em um dos maiores problemas quando se trata de produção agrícola. Estudos com culturas agrícolas e seus polinizadores podem contribuir na busca de propostas que conciliem agricultura e conservação de fragmentos florestais. O objetivo geral do presente trabalho foi estudar aspectos relacionados com polinização de Solanum lycopersicum L. híbrido Pizzadoro. Os objetivos específicos foram: 1) verificar se a morfologia floral influencia no comportamento de visita do polinizador; 2) avaliar a riqueza de abelhas polinizadoras e visitantes florais em diferentes distâncias da área de Reserva Legal; 3) comparar a eficiência de três espécies de abelhas na polinização em dois tratamentos: kautopolinização espontânea, e a polinização em condições naturais. O estudo foi realizado numa área de cultivo convencional de tomate no município de Estiva Gerbi, São Paulo. Foram coletadas flores e observadas em estereomicroscópio e microscópio eletrônico de varredura. Foi comparada a eficiência de Apis mellifera, Augochloropsis sp. e Exomalopsis sp. pelo teste de Kruskal-Wallis. Observações e coletas foram feitas in situ a 50, 100 e 150 metros da RL. Verificou-se que a deiscência da antera é do tipo longitudinal e que não houve diferença entre as espécies de abelhas, ou seja, o número de sementes produzidas não depende da espécie de abelha. Considera-se que o sucesso de A. mellifera esteja associado à morfologia floral. Foram encontradas 11 espécies de insetos, das quais 7 foram consideradas polinizadoras. Foram registradas 58 visitas florais; dessas, 24 no quadrante A (50 m), 13 no B (100 m) e 21 no C (150 m), sendo A. mellifera dominante com 62,1% das visitas, seguida de Augochloropsis sp. e Oxaea flavescens ambos com 10,3%, Exomalopsis sp. com 6,9%, Allograpta sp. com 5,2%, Bombus sp. com 3,4% e Xylocopa sp. com 1,7%. Os dados indicam que a RL desempenhou um papel fundamental no fornecimento de polinizadores para a cultura de tomate e, por isso, enfatiza-se a necessidade de conservação e restauração de fragmentos florestais para auxiliar no aumento da produção da cultura.

Submitted by Geandra Rodrigues (geandrar@gmail.com) on 2017-12-22T14:54:33Z No. of bitstreams: 1 patriciasilvaneves.pdf: 1941458 bytes, checksum: 16ab3b743d0b75134d320f08de292905 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2018-01-22T18:33:39Z (GMT) No. of bitstreams: 1 patriciasilvaneves.pdf: 1941458 bytes, checksum: 16ab3b743d0b75134d320f08de292905 (MD5) / Made available in DSpace on 2018-01-22T18:33:39Z (GMT). No. of bitstreams: 1 patriciasilvaneves.pdf: 1941458 bytes, checksum: 16ab3b743d0b75134d320f08de292905 (MD5) Previous issue date: 2017-08-31 / O presente trabalho apresenta a aplicação conjunta de uma técnica de otimização bioinspirada e de um Algoritmo Heurístico Construtivo (AHC) na resolução do problema de planejamento estático da expansão de sistemas de transmissão de energia elétrica. O algoritmo bioinspirado utilizado é uma versão modificada do Flower Pollination Algorithm (FPA), no qual foi introduzido o operador de seleção clonal, oriundo do Algoritmo de Seleção Clonal (CLONALG), com o objetivo de potencializar o processo de busca local do FPA. A versão modificada proposta neste trabalho foi nomeada de Clonal Flower Pollination Algorithm (CFPA). O CFPA realiza a otimização da expansão de sistemas de transmissão de energia elétrica, determinando, entre um conjunto de linhas (circuitos) de transmissão previamente definidas, quais devem ser construídas de modo a minimizar os custos de investimento e de operação do sistema elétrico, suprindo a demanda prevista para um dado horizonte de planejamento. De modo a aumentar a eficiência do processo de busca pelo CFPA, fez-se o uso de informações provenientes de um Algoritmo Heurístico Construtivo. Tais informações heurísticas são utilizadas na inicialização do CFPA e também na seleção de um conjunto reduzido das rotas mais relevantes à expansão, reduzindo o espaço de busca. Para aferir os resultados da metodologia proposta foram simulados os sistemas Garver, IEEE 24 Barras e o equivalente da região Sul do Brasil. Diante dos resultados, pode-se verificar que tanto a inclusão do operador de seleção clonal quanto as informações heurísticas foram capazes de aumentar a eficiência do FPA na resolução do problema aqui em estudo. / This work presents the application of a bio-inspired algorithm, together with a Heuristic Constructive Algorithm (HCA) in the solution of a power system static transmission expansion planning problem. The algorithm used is a modified version of the Flower Pollination Algorithm (FPA) that includes a clonal selection operator, from the clonal selection algorithm (CLONALG) that aims to improve the FPA local search process. The modified version proposed is entitled Clonal Flower Pollination Algorithm (CFPA). The CFPA realizes the power system transmission expansion planning, that is, it determines between a set of predefined transmission lines (circuits), which of them must be constructed in order to minimize the power systems investments and operation costs, while meeting the forecast demand in a given planning horizon. In order to increase the efficiency of the search process by the CFPA, information from an HCA has been utilized. That heuristic information has been used in the initialization process of the CFPA and also in the selection of a reduced set of most relevant lines candidates to the expansion plan, thus reducing the search space. To evaluate the results of the proposed methodology, the Garver, IEEE 24 Buses and South Brazilian Systems were simulated. Considering the results it can be verified that both the inclusion of the clonal selection algorithm and the heuristic information were able to increase the efficiency of the FPA in solving this problem.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / The purpose of this thesis was to investigate the feasibility of using the honey bee (Apis mellifera L.) for pollination and yield increment in Jatropha curcas L. crops. Therefore, the floral biology and pollination process of J. curcas were studied as well as the foraging behavior and pollination efficiency of A. mellifera in this crop by the introduction of four colonies in a hectare. The work was carried out in a five years-old commercial plantation comprising 10ha, in the state of PiauÃ, (08Â32â19,0âS and 43Â56â19,7âW, 220 meters above sea level), Brazil, from March to July, 2009. Flowers were presented in protogynous inflorescences and the anthesis and most of pollen presentation took place mainly in the morning shift. Inflorescences last, in average, 20 days, with female flowers concentrating in the first third of the period and male flowers predominating in the second third, in a relation of 18.1:1 male/ female flower. Although this may favor xenogamy, the stigma receptivity lasts for, at least, five days ensuring the flower to reach the period of most pollen release in its own inflorescence, facilitating the occurrence of geitonogamy. Flowers pollinated up to four days after anthesis did not differ (p>0.05) in fruit setting to those pollinated in the first, second or third day after anthesis. Foraging by A. mellifera occurs throughout the day and peaks between 13h00min and 15h00min and is characteristic of nectar harvesting both in male and female flowers. Only one visit by A. mellifera to J. curcas flowers set 100% producing results similar (p>0,05) to those from manual xenogamy (96%), manual geitonogamy (94%) and open pollination (93%). However, only one visit by a bee was not enough to maximize the oil content per seed (213mg) in comparison to the open pollination and geitonogamy treatments (both 250mg). Besides that, it was possible to observe that geitonogamy led to greater oil production than xenogamy (237mg). It is concluded that A. mellifera is an efficient pollinator of this crop. The introduction of four honey bee colonies per hectare maximize oil production and produce the best results for all parameters studied. Furthermore, only one visit by the honey bee to J. curcas flowers was enough to prevent pollination deficit in this crop. / O objetivo desta tese foi investigar a possibilidade da utilizaÃÃo de Apis mellifera L. na polinizaÃÃo e incremento de produtividade da cultura do pinhÃo manso (Jatropha curcas L.). Para tanto, foi estudado a biologia floral e a polinizaÃÃo do pinhÃo manso bem como o comportamento forrageiro e a eficiÃncia polinizadora de Apis mellifera. O trabalho foi realizado em 10ha de plantio comercial jà estabelecido, com cinco anos de idade, no estado do PiauÃ, (08Â32â19,0âS e 43Â56â19,7âW e 220 metros de altitude), entre os meses de marÃo e julho de 2009. A antese das flores do pinhÃo manso, distribuÃdas em cimos com carÃter protogÃnico, ocorre basicamente no perÃodo matinal, bem como a maior oferta de pÃlen. As inflorescÃncias duram, em mÃdia, 20 dias, com maior concentraÃÃo de flores femininas no terÃo inicial e de masculinas, no terÃo mÃdio, com relaÃÃo de 18,1 flores masculinas para cada feminina. Embora esse fato favoreÃa a xenogamia, a receptividade do estigma por, pelo menos, cinco dias, garante a flor alcanÃar o perÃodo de maior oferta de pÃlen no prÃprio cimo, oportunizando a geitonogamia. As flores polinizadas atà o quarto dia frutificam da mesma forma que aquelas polinizadas no primeiro, segundo e terceiro dias apÃs antese, nÃo havendo diferenÃas significativas. O forrageamento por A. mellifera ocorre durante todo o dia, com maior pico entre 13h00m e 15h00m e à tÃpico de coleta de nÃctar, tanto nas flores masculinas quanto nas femininas. Apenas uma visita da abelha Ãs flores acarreta em 100% de vingamento, mostrando resultado semelhante, (p>0,05), aos tratamentos de xenogamia manual (96%), geitonogamia manual (94%), e polinizaÃÃo aberta (93%). PorÃm, uma visita apenas, nÃo à suficiente para produzir maior quantidade de Ãleo por semente (213mg), em comparaÃÃo com o tratamento de polinizaÃÃo aberta, e por geitonogamia (250mg). AlÃm disto, foi possÃvel constatar que hà maior produÃÃo de Ãleo por geitonogamia e nÃo por xenogamia (237mg). Conclui-se que a Apis mellifera à um polinizador eficiente da cultura. Sua introduÃÃo, com quatro colÃnias por hectare, maximiza a produÃÃo de Ãleo e produz os melhores resultados para todos os parÃmetros avaliados. AlÃm disso, apenas uma visita da abelha melÃfera Ãs flores do pinhÃo manso à suficiente para prevenir dÃficit de polinizaÃÃo.

The spreading of the invasive plant Garden Lupine (Lupinus polyphyllus) has become a matter of national importance in Sweden, due to it posing a threat to native plant and pollinator diversity. The effective attraction of bumblebees (Bombus spp.) as pollinators facilitates the production of large numbers of seeds, which are key to the Garden Lupine’s success. Possible self-pollination could also provide a competitive edge for the plant. The objective of this study was to study the relationships between Garden Lupine color morphs, pollinator attraction and seeding. Inflorescences of three color morphs were studied during the flowering period, and bumblebee behavior was observed on the site. After seeding, any produced seeds were collected and analyzed, as well as experimentally germinated to provide insight into their viability. A subset of inflorescences of each color morph was prevented access to pollinators, to study potential self-pollination effects. Bumblebees preferred blue flowers over pink, but no difference in pollination between the color morphs was found. Flower color did not affect seed production or seed morphology. Self-pollinated inflorescences produced fewer seeds than those with access to pollinators, but no difference in seed morphology or germinative success between the pollination methods could be established. The results suggest that seed production and germination are less dependent on pollination than expected. The ability to germinate through self-pollination provides insight into the invasive potential of Garden Lupine, suggesting that further studies are needed to successfully counteract its spread. / Den invasiva växten blomsterlupin (Lupinus polyphyllus) har på senare år blivit en nationell angelägenhet i Sverige, där den hotar mångfalden av inhemska växter och pollinatörer. Blomsterlupinens framgångsrika tilldragning av framförallt humlor (Bombus spp.) som pollinatörer möjliggör det stora antalet frön som den producerar, vilket är nyckeln till dess invasiva etablering. Eventuell förmåga till självpollinering kan också utgöra en konkurrensfördel. Målet med studien var att utforska relationen mellan blomsterlupinens färgmorfer, pollinering samt fröbildning. Blomställningar av tre färgmorfer studerades under blomningsperioden. Humlornas beteende observerades också under perioden vid lupinlokalen. Efter frösättning samlades alla producerade frön upp och analyserades, varefter ett frögroningsexperiment utfördes för att belysa frönas grobarhet. I ett fältexperiment nekades en delmängd av blomställningarna tillgång till pollinatörer, för att studera eventuell självpollinering och dess effekter. Humlorna föredrog blåa blommor före rosa, men ingen skillnad i pollinering mellan färgmorferna kunde fastställas. Blommornas färg hade ingen effekt på fröproduktion eller -morfologi. Självpollinerade blomställningar producerade färre frön överlag än de med tillgång till pollinatörer, men ingen skillnad i frömorfologi eller grobarhet mellan pollineringsmetoderna kunde påvisas. Resultaten antyder att fröproduktion och frögroning hos blomsterlupin är beroende av pollinering i mindre grad än förväntat. Förmågan att gro genom självpollinering belyser blomsterlupinens invasiva potential, och antyder att fler studier behövs för att framgångsrikt motverka dess spridning.

Almost all conifer ovules produce a liquid secretion as part of reproduction. This secretion, termed an ovular secretion, is produced during ovule receptivity and is involved in pollen capture and transport. Historically, examinations of the ovular secretion have focused on how they are part of pollination mechanisms. As a result, the chemical composition of the ovular secretion has not been examined systematically. Investigations into the constituents of the ovular secretion were limited to analyses for simple water soluble compounds such as sugars, minerals, amino acids and organic acids. More recently, the protein component of the secretion has been investigated using mass spectrometry-based proteomics. Proteins involved in processes such as carbohydrate modification, proteolysis, and defence have been identified in conifer ovular secretions. This biochemical complexity suggests a broader view of the function of the ovular secretion is warranted. However, protein identifications only provide putative information on function. Functional characterization of these proteins is needed in order to fully understand how they contribute to ovular secretion function. The research outlined in this dissertation describes the first functional characterizations of proteins found in conifer ovular secretions. Three proteins - invertase, chitinase, and thaumatin-like protein - were characterized in the ovular secretions of Douglas-fir (Pseudotsuga menziesii) and hybrid yew (Taxus × media). The Douglas-fir ovular secretion is capable of converting sucrose to glucose and fructose, confirming that invertases present in the secretion are functional. The invertase activity was maximal at pH 4.0. Activity was 77% of maximal at pH 4.5, the physiological pH. This indicates that post-secretory hydrolysis of sucrose occurs in situ in the Douglas-fir ovular secretion. Invertases in the ovular secretion are likely involved in controlling the movement of carbohydrates to developing pollen and could facilitate pollen selection. Chitinases present in the Douglas-fir ovular secretion are functional at physiological conditions. All three modes of chitinolytic activity, i.e. endochitinase, chitobiosidase and β-N-acetylglucosaminidase, were detected at physiological pH. β-N-acetylglucosaminidase activity was 80 % of maximal at physiological pH. Chitinases are pathogenesis-related proteins capable of hydrolysing chitin in fungal cell walls. These results suggest the ovular secretion is capable of defending the ovule against infection by phytopathogens. Thaumatin-like protein was immunolocalized to the cell wall and amyloplasts in Douglas-fir and yew nucellar tissue in a pattern consistent with a defensive role. It was also localized to the cell wall of fungal spores and germinating hyphae that were present in the micropyle of a yew ovule. These results provide additional evidence for an antifungal role for the ovular secretion. Functioning enzymes involved in pollen-ovule interactions and ovule defence are present in the conifer ovular secretion. The ovular secretion has functions beyond pollen capture. A revised functional model for the conifer ovular secretion is proposed. / Graduate / 2021-08-17

Thesis (MSc (Botany and Zoology))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: It is thought that a large proportion of the great variety of floral structures in flowering plants reflect adaptations to different biotic pollen vectors. Divergence in flower traits and pollinators is linked to speciation. Pollinator-driven speciation is thought to have played a large role in the spectacular floral diversity found in South African Iridaceae and the genus Tritoniopsis is a particularly good example of this. This study focuses on Tritoniopsis revoluta, a pink irid occurring in the Swartberg and Langeberg Mountains, as well as Potberg Mountain. I tested the hypothesis that variation in flower tube-lengths of Tritoniopsis revoluta are related to the geographic distribution of pollinators and the variation of their tongue lengths. It was determined that this species is highly variable in respect to corolla tube-length and is pollinated by different fly species across its range. Also, the tongue-lengths of the fly pollinators corresponded almost exactly with the tube-length of the flowers they were pollinating in each population. In some populations, where long-proboscid flies were absent, bees were observed visiting T. revoluta flowers. This presents evidence for pollinator-driven floral variation within a single plant species, and most of this vast diversification in floral morphology has probably been driven by morphological variation found within a single fly family. In one population I found variable tube-lengths which appeared to exhibit a bimodal distribution of corolla tubelengths. I hypothesized that the two Tritoniopsis revoluta ecotypes at this population are pollinated by two different pollinators, leading to assortative mating, and ultimately strong inter-ecotype incompatibility. Tritoniopsis revoluta is self-incompatible and exists as two discrete entities (morphotypes) at the Gysmanshoek Pass site, and these entities differ in tubelength, color, nectar volume and sugar content. These morphotypes were not pollinated by long-proboscid flies, but seems to represent a recent shift to pollination by Amegilla bees. However, ecotypes are not reproductively isolated as short and long flowers can produce offspring, rather tube-length differences are possibly maintained through spatial separation. To compliment the correlatory data between flower tube-lengths and pollinator tongue-lengths, I used molecular tools (chloroplast markers and AFLPs) to elucidate the patterns of tube-length evolution in Tritoniopsis revoluta. I aimed to determine the directionality and frequency of transitions between tube-length categories. Tube-length transitions would be suggestive of flower morphology being labile, and together with the tube-tongue length correlation it suggests pollinator shifts may drive the changes in tube length. Character state reconstructions using tube-length as character determined that four evolutionary transitions to shorter tube-length categories and two transitions to longer categories occurred. I also tested whether morphological divergence between populations corresponds to patterns of divergence from neutral genetic markers. Population genetic structure in this system showed that the different populations of T. revoluta are vicariant and tube-length differences between them could have evolved through selection. / AFRIKAANSE OPSOMMING: Dit is ‘n algemene gedagte dat die groot verskeidenheid blom strukture in die angiosperme dui op aanpassings tot verskillende biotiese stuifmeel draers. Die diverse blom strukture in baie van die groot Kaapse genera kan verduidelik word deur aanpassings tot veranderinge in bestuiwings-sisteme. ‘n Aantal studies hieroor stel voor dat bestuiwers nie net die veranderinge in blom morfologie bewerkstellig nie, maar ook ‘n rol speel in die aanpassende uiteenlopendheid van blomplant kenmerke. Spesiasie bewerkstellig deur bestuiwers het moontlik ‘n groot rol gespeel in die blom-diversiteit wat gevind word in die Suid-Afrikaanse Iridaceae familie, en die genus Tritoniopsis is ‘n baie goeie voorbeeld hiervan. Hierdie studie fokus spesifiek op Tritoniopsis revoluta, ‘n pienk iris wat voorkom in die Swart- en Langeberge, asook by Potberg. Die hipotese dat die variasie in buis-lengtes van T. revoluta verwant is aan die geografiese verspreiding van bestuiwers en die variasie in hul tong-lengtes is hier getoets. Dit is bepaal dat hierdie spesie groot variasie toon in terme van buis-lengtes en bestuif word deur verskillende vlieg spesies regoor sy verspreiding. Die tong-lengtes van hierdie vlieë korrespondeer ook met die buis-lengtes van die blomme wat hul bestuif in elkeen van die T. revoluta populasies. In sommige van die populasies, waar lang-tong vlieë afwesig was, is bye wat die T. revoluta blomme besoek, opgemerk. Hierdie resultate lewer bewyse vir die hipotese dat bestuiwers blom morfologie kan beïnvloed; die interessante hiervan is dat die variasie in buis-lengtes in hierdie spesie heel moontlik te danke is aan die morfologies variasie wat gevind word in ‘n enkele lang-tong vlieg familie. In een van die populasies het ek ‘n bimodale verspreiding van buis-lengtes gevind. ‘n Logiese afleiding is dat hierdie twee verskillende buislengtes – ekotipes – deur twee verskillende bestuiwers besoek word, en dat dit lei tot sterk onversoenbaarheid tussen ekotipes. Tritoniopsis revoluta is nie instaat tot self-bestuiwing nie en die twee ekotipes verskil in terme van buis-lengtes, kleur, nektar volume en suiker inhoud. Kort- en lang-buis blomme word nie eksklusief bestuif deur lang-tong vlieë in die Gysmanshoek Pas nie, maar word in die algemeen ook bestuif deur bye van die genus Amegilla. Die twee ekotipes is in staat om te reproduseer met mekaar, so die buis-lengte verskille word moontlik in stand gehou deur hul geografiese skeiding. Om die korrelasie analise tussen blom buislengtes en vlieg tong-lengtes te komplimenteer, het ek molekulêre tegnieke (chloroplast merkers en AFLPs) gebruik om die patrone van buis-lengte evolusie in Tritoniopsis revoluta duidelik te maak. Ten eerste het ek bepaal of verkortings en verlengings van buis-lengtes een keer in die verlede gebeur het, of as meermalige gebeurtenisse. Meermalige veranderinge in buis-lengtes kan moontlik dui op verskuiwings tussen verskillende bestuiwers, asook taksonomiese verdelings wat korrespondeer met bestuiwer veranderinge. Ek het ook bepaal of die buis-lengte verskille in die verskillende populasies toegeskryf kan word aan seleksie prosesse. Deur buis-lengte as karakter te gebruik, het ek karakter-status rekonstruksies gedoen en bepaal dat vier ewolutionêre transisies na korter buis-lengte kategorieë, en twee transisies na langer kategorieë plaasgevind het. Populasie genetiese struktuur in die sisteem dui daarop dat T. revoluta populasies geïsoleer is deur afstand. Die konklusie wat ek trek gebasseer op hierdie resultate is dat verskille in buis-lengtes in hierdie sisteem moontlik ontstaan het as gevolg van die verskillende bestuiwers wat aktief is in die verskillende T. revoluta populasies, en dat natuurlike prosesse nie die hoofrol spelers in hierdie sisteem is ten opsigte van buis-lengte evolusie nie.

Thesis (MScConsEcol (Conservation Ecology and Entomology)--University of Stellenbosch, 2009. / Apiculture in the Western Cape is a well-developed industry based on honey production and pollination services to agriculture. Apart from Eucalyptus trees, fynbos vegetation serves well as bee forage to managed honeybee colonies outside the agricultural pollination season. Eucalyptus trees are cleared as invasive plant species while fynbos are rigorously protected as one of the 34 Biodiversity Hotspots identified worldwide. Thus, bee forage is in short supply and is most probably the only limitation to the number of honeybee colonies that beekeepers can feasibly maintain. The impact of a collection of commercially managed honeybee colonies on other floral resource-dependent species in the Cape Floristic Region is unknown. This is one of the first studies on the topic in South Africa and specifically in the Western Cape. Managed hives were introduced to near pristine fynbos habitat in De Hoop Nature Reserve and Marine Protected Area during July. The aim was to induce stronger competition for floral resources through greater resource exploitation by managed honeybee colonies and record the change in foraging behaviour for several insect guilds on specific plant species. The results suggest that eight hives per site proved insufficient to increase honeybee density above the natural density of honeybees. Honeybee abundance did not increase during the presence of the managed hives, while honeybee visitation frequency was significantly greater during the presence of the managed hives. Neither the abundance nor the visitation frequency of non-Apis bees and wasps differed significantly between treatments. Honeybees were the most abundant foragers on the three focal plant species during all three treatments and also made the most visits to flowers. Honeybee abundance and visitation frequency increased with distance from the managed hives. The significant increase in honeybee visitation frequency during hive presence, coupled with a significant decrease in the time honeybees spent per flower extracting nectar, were an indication of a lower standing crop of nectar during that treatment. Nevertheless, no competition for floral resources was obvious, as the number of honeybees did not increase the abundance and visitation frequency of all other insect guilds (except for a significant decrease in Muscidae, which could be ascribed to changes in weather conditions).

Thesis (MScConsEcol)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Apis mellifera, the honeybee, is regarded as the most crucial insect pollinator to South African agriculture as it is the only managed pollinator used in the pollination of commercial agricultural crops. Essential to sustaining managed honeybees is the supply of adequate and sustainable forage resources upon which managed honeybee colonies can forage throughout the year. In most instances agricultural pollination services are only required for a brief period of the year, and consequently managed honeybee colonies need to be sustained on a variety of alternate forage resources for the remaining months of the year. As an essential resource in maintaining managed honeybee colonies, honeybee forage can subsequently be linked to the maintenance of agricultural crop pollination. Exotic honeybee forage species have always been an important part of managed honeybee foraging patterns, however recent pressure to control exotic plant species in South Africa has put this type of honeybee forage under threat. This studies’ first aim was focused on identifying the historic honeybee forage use pattern in South Africa, thereby identifying which forage species have maintained managed beekeeping up until this point. A comprehensive literature review of the South African Bee Journal, dating back to the journals first publication in the 1910’s documented both the exotic and indigenous forage species that have sustained the beekeeper industry in the past. Significance ratings of individual species were determined according to the number of times a species was cited in the literature throughout the review period. Although indigenous species where cited in the literature, the predominately used forage species was found to be exotic, highlighting the role these species played in the development of South African beekeeping. Secondly, this study identifies and highlights the current honeybee forage usage pattern in South Africa. By means of a country wide honeybee forage questionnaire, honeybee forage usage patterns were determined based on forage species usage by beekeepers in different provincial regions. Important forage species were highlighted in each region on the basis of number of colonies using individual forage species. In addition to identifying current forage usage, this questionnaire was able to help estimate the number of managed honeybee colonies in South Africa at present, given that census data is not yet available. Even though there is currently a greater awareness and usage of indigenous forage species, it remains that the predominantly used forage source are exotic forage species. Whilst there appears to be a movement and awareness towards the use of indigenous forage species across South Africa, forage species usage patterns have not shift dramatically in the last century. In order to fulfill their foraging requirements, managed honeybee colonies remain heavily dependent on exotic species, especially that of Eucalyptus and certain agricultural crop species. The removal of Eucalyptus should thus just be done in sensitive environments, while all woodlots should be demarcated and managed to ensure continued forage availability. In turn growers of forage crops should be made aware of their contribution to provincial honeybee forage resources. / AFRIKAANSE OPSOMMING: Apis mellifera, die heuningby, word beskou as die belangrikste insek bestuiwer vir kommersiële boerdery in Suid Afrika, aangesien dit die enigste bestuurde bestuiwer is wat vir kommersiële landbou-gewasse gebruik word. Die beskikbaarheid van voldoende en volhoubare voedselbronne vir bestuurde heuningby kolonies is noodsaaklik vir hul voortbestaan. Bestuiwing deur hierdie insekte is in die meeste gevalle net nodig vir ʼn kort tydperk elke jaar, dus benodig bestuurde heuningby kolonies ʼn verskeidenheid van alternatiewe voedselbronne vir die oorblywende maande. Heuningby voedselbronne is noodsaaklik vir die handhawing van heuningby kolonies, en dus kan die beskikbaarheid van hierdie bronne gekoppel word aan die onderhouding van landbougewas bestuiwing. Uitheemse heuningby voedsel spesies is belangrik vir die voortbestaan van die heuningby, maar ’n toename in uitheemse plant spesies bestuur bedreig hierdie heuningby voedselbronne. Die eerste doel van hierdie studie was om die historiese heuningby voer gebruik patrone in Suid Afrika te identifiseer, om vas te stel watter plant spesies tot nou toe belangrik was vir byboerdery. ʼn Omvattende literatuuroorsig van die South African Bee Journal, vanaf die eerste publikasie in die 1910’s, het bevestig watter inheemse en uitheemse spesies belangrik was vir die voortbestaan van byboerdery in die verlede. Betekenis gradering van individuele spesies was bepaal volgens die aantal kere wat ʼn spesies aangehaal is in die literatuur binne die oorsigtydperk. Alhoewel inheemse plant spesies aangehaal was in die literatuur, was die meerderheid van die spesies uitheems. Dit dui dus die belangrikheid van uitheemse spesies aan vir die ontwikkeling en voortbestaan van Suid Afrikaanse byboerdery. Die tweede doel van hierdie studie was om die huidige kos soek patrone van die heuningby in Suid Afrika aan te wys. Die heuningby voer gebruik patrone is bepaal deur ʼn landwye vraelys, wat die voedselbron spesies van byeboere in die verskillende provinsies ondersoek het. Belangrike voedselbron spesies in elke streek was uitgelig in terme van die aantal by kolonies wat daardie spesie gebruik. Hierdie vraelys was ook gebruik om vas te stel hoeveel bestuurde heuningby kolonies daar tans in Suid Afrika is, aangesien sensus data nog nie beskikbaar is nie. Alhoewel daar tans ʼn groter bewustheid is van die gebruik van inheemse spesies as ʼn voedselbron, word uitheemse spesies steeds die meeste gebruik. In die laaste eeu was daar nie ʼn dramatiese verskuiwing vanaf uitheemse na inheemse spesies nie, ten spyte van die toeneemde bewustheid. Ten einde hul voedsel vereistes te voldoen, bly bestuurde heuningby kolonies afhanklik van uitheemse spesies, veral Eucalyptus spesies en sekere landbou-gewasse. Eucalyptus moet net in sensitiewe omgewings verwyder word, en bebosde gebiede moet afgebaken en bestuur word om te verseker dat hul as volhoubare voedselbronne beskikbaar bly. Verder moet produsente van gewasse wat byeboere kan gebruik bewus gemaak word van hul bydrae tot die voedselbronne van bestuurde heuningbye in hul streek.