Anther dehiscence is an important process taking place at the end of the plant life cycle. This process consists of various follow-up steps which result in anther opening and pollen grains exposure. Good timing of the anther dehiscence must be synchronized with pollen grains maturation and flower opening. Atmospheric precipitation is a high-risk factor for the anther dehiscence. Male fitness of plants can be reduced when anthers open during poor weather conditions. The aim of this study was to investigate the effect of atmospheric precipitation, rain and dew, on Arabidopsis arenosa anther dehiscence. We observed that rain and dew led to a postponed final stage of the anther dehiscence. This caused delayed pollen release. The effect of aqueous and nonaqueous environment on the anther dehiscence was also tested. Experiments with transformation of A. arenosa using Agrobacterium tumefaciens were performed. Key words: anther dehiscence, flower opening, rain, dew, Arabidopsis arenosa, Agrobacterium tumefaciens, transformation

It is well known that animals can exert strong selective pressures on plant traits. However, studies on the evolutionary consequences of plant–animal interactions have mainly focused on understanding how these interactions shape trait means, while overlooking its potential direct effect on the variability among structures within a plant (e.g. flowers and fruits). The degree of within-plant variability can have strong fitness effects but few studies have evaluated its role as a potential target of selection. Here we reanalysed data on Ipomoea wolcottiana stigma–anther distance to test alternate mechanisms driving selection on the mean as well as on intra-individual variance in 2 years. We found strong negative selection acting on intra-individual variation but not on mean stigma–anther distance, suggesting independent direct selection on the latter. Our result suggests that intra-individual variance has the potential to be an important target of selection in nature, and that ignoring it could lead to the wrong characterisation of the selection regime. We highlight the need for future studies to consider patterns of selection on the mean as well as on intra-individual variance if we want to understand the full extent of plant–animal interactions as an evolutionary force in nature.

Thesis (MSc)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Only a limited number of systems involving anther-smut fungi have been studied, usually due to the economic significance of their crop plant hosts. A smut fungus of the genus Thecaphora has been discovered infecting Oxalis hosts in South Africa. This pathogenic fungus, Thecaphora capensis, produces dark-coloured spores in the anthers of host flowers, rendering it an anther-smut fungus. The host genus is the seventh largest plant genus in the Cape Floristic Region (CFR) and the largest geophytic genus of this region. Nine Oxalis species that host T. capensis have been identified across a wide distribution in the CFR of South Africa. A preliminary assessment of T. capensis infections of Oxalis was conducted in 2009, which provided a foundation for further research into the ecological and evolutionary consequences of hosting this fungus. In this study, a comprehensive host diversity assessment was conducted to determine the extent of infected Oxalis individuals within the CFR. Three new Oxalis host species for Thecaphora capensis were discovered. This brings the total number of known hosts to twelve. The morphological and reproductive effects of the fungus were assessed on two host species (O. incarnata and O. lanata) by comparing healthy and infected individuals of these species. Infection by Thecaphora capensis had a significantly negative effect on both of these factors. Host resources appear to be co-opted for fungal spore production, since floral morphological characters of infected individuals were reduced in size. Furthermore, infection by T. capensis ensured near-universal sterility in both hosts. Differences in floral characters and pollinator preferences for healthy Oxalis incarnata and O. lanata individuals from disease-free and diseased populations were compared to determine the evolutionary influence of Thecaphora capensis infections. It was shown that this pathogen can have a significant evolutionary influence on its hosts, showing its ability to shape flower size and pollinator activity in O. lanata, but not in O. incarnata. A need has therefore been identified to assess these evolutionary forces independently for each host and its pathogen before making erroneous assumptions for conservation practices. Plant pollinators play an integral role in plant fitness. Pollinator movements within a population are important when between-flower spore transfer by pollinators increases the likelihood of new infections. Pollinator movements may be influenced by host density and the frequency of diseased individuals, amongst other factors. Pollinators were found to mediate Thecaphora capensis spore transfers within diseased Oxalis populations. Host density and disease frequency affected the number of spores transferred under field and standardized conditions. More research is required to investigate confounding factors in these complex systems. This study highlighted the complexities of a fungal-plant-insect relationship, the evolutionary consequences of such fungal infections and the various factors influencing the likelihood of new infections. This research adds to the limited body of knowledge on multi-organismal interactions in the CFR and provides a base for more detailed future studies on this intriguing system. / AFRIKAANSE OPSOMMING: 'n Brandswam, wat deel is van die Thecaphora genus,is ontdek in 'n Oxalis blom waar dit die gasheer plant se blom gebruik om spore in te produseer. Die swam, Thecaphora capensis, produseer donker gekleurde spore in die helmknoppe van die blomme van gasheer plante, daarom word dit geklasifiseer as 'n brandswam van die helmknop. Die gasheer plante van die swam is deel van die genus Oxalis, die sewende grootste plant genus in die Kaapse Floristiese Streek (KFS) en die grootste geofitiese genus in die streek. Nege Oxalis species is al klaar identifiseer as gasheer plante van T. capensis. Hulle is versprei oor 'n groot area van die KFS van Suid Afrika. 'n Primêre ondersoek van T. capensis infeksies op Oxalis is in 2009 onderneem. Hierdie ondersoek het gelei tot meer vrae oor die sisteem en het 'n goeie fondasie geskep vir verdere navorsing rakende die ekologiese koste verbonde daaraan om as gasheer plant vir 'n swam op te tree. 'n Deeglike ondersoek is in die KFS aangepak om die Oxalis gasheer plante van die brand swam te identifiseer en om voort te bou op die basiskennis wat in die primêre ondersoek daargestel is. Drie nuwe Oxalis gasheer plante van Thecaphora capensis is ontdek. Die totale aantal gasheer plante staan nou op twaalf. Gesonde en geinfekteerde individuele gasheer plante is gebruik om die morfologiese en reproduktiewe effekte van die swam te toets in twee Oxalis spesies (O. incarnata en O. lanata). Die negatiewe gevolge om 'n gasheer plant van die brand swam te wees was duidelik toe gesonde en geinfekteerde individuele met mekaar vergelyk is. Dit kom voor asof gasheer plante se hulpbronne vir spoor produksie gebruik word, want hulle is morfologies kleiner en meestal steriel. Die evolusionêre effek van Thecaphora capensis op 'n populasie is getoets met gesonde individuele in populasies van twee Oxalis spesies. Blomkenmerke en insek bestuiwers van gesonde individue in gesonde en geinfekteerde populasies is ondersoek om die effekte van T. capensis op populasies te toets. Daar is suksesvol gedemonstreer dat swamme sterk evolusionêre kragte uitoefen, en die vermoë het om plantpopulasies te vorm en te verander, ofskoon nie in alle gevalle ewe sterk nie. Daarom is dit belangrik om die evolusionêre kragte vir elke gasheer plant en sy patogeen onafhanklik te assesseer, sonder om algemene aannames te maak in bewaringspraktyke. Plantbestuiwers speel 'n belangrike rol in die fiksheid van plante. Hulle kan hul fiksheid verbeter deur bestuiwers te lok met blomme en deur aspekte geassosieer met blomme. Die bewegingspatrone van plantbestuiwers is baie belangrik indien hulle helmknop-geproduseerde spore van brandswamme vervoer instede van stuifmeel, want dit vergroot die kanse vir nuwe infeksies. Die bewegingspatrone van plantbestuiwers word, onder andere, beinvloed deur die digtheid en frekwensie van geinfekteerde individue. Plantbestuiwers speel 'n belangrike rol in die vervoer van Thecaphora capensis spore in geinfekteerde Oxalis populasies. Die digtheid en frekwensie van geinfekteerde blomme het die vervoer van spore geaffekteer onder veld en gestandardiseerde kondisies, alhoewel baie veranderlikes so 'n komplekse natuurlike sisteem beinvloed. Hierdie studie beklemtoon die kompleksiteit van 'n fungus-plant-insek verhouding, die gevolge van so 'n interaksie en die verskeie faktore wat die waarskynlikheid van nuwe infeksies beinvloed. Tot dusver is daar 'n beperkte aantal sisteme soos hierdie bestudeer waarin 'n brandswam van die helmknop betrokke is, en die enkele beskikbare studies is onderneem meestal as gevolg van hulle ekonomiese effekte op landboukundig belangrike gasheer plante. Hierdie studie verteenwoordig 'n belangrike byvoeging tot die inter-organismiese studies in die KFS. 'n Holistiese ekologiese oorsig soos hierdie verskaf 'n belangrike basis vir toekomstige studies en bewarings- en bestuurspraktyke.

Submitted by Erika Demachki (erikademachki@gmail.com) on 2014-10-08T19:32:10Z No. of bitstreams: 2 Dissertação - Carlos de Melos e Silva Neto - 2013.pdf: 671422 bytes, checksum: 7774a52856834c1b8270fa6218029c99 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2014-10-09T11:23:41Z (GMT) No. of bitstreams: 2 Dissertação - Carlos de Melos e Silva Neto - 2013.pdf: 671422 bytes, checksum: 7774a52856834c1b8270fa6218029c99 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2014-10-09T11:23:41Z (GMT). No. of bitstreams: 2 Dissertação - Carlos de Melos e Silva Neto - 2013.pdf: 671422 bytes, checksum: 7774a52856834c1b8270fa6218029c99 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2013-09-16 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Pollinators provide an essential service to the ecosystem and bring numerous benefits to society, through its role in the production of food in agriculture and the conservation of biological diversity. In tomato, anthers are poricidal, thus the release of pollen grains requires the presence of pollinators that vibrate these anthers. Thus, pollinators of tomatoes are actually bees that perform buzz pollination. Here, we observed aspects of floral biology, quantity and viability of pollen grains and ovules, and pollinators behavior and richness. To evaluate the effects of pollination in the amount of pollen on the stigmas, we selected 37 plants and bagged an inflorescence and let another available to pollinators. Each marked inflorescence had three stigmas removed the pollen grains on their surfaces were quantified. For comparison of fruit production, fruit development were followed in inflorescences bagged and not bagged for 40 days, and then the fruits were counted, weighed, measured, and had their seeds counted. The anthesis is at 6:30 am. The flower remains open until 6:00 pm, closing and reopening in the next day at the same time, lasting up to 73 hours. The greatest amount of pollen in the anther is in the early hours of the flower opening, with reduction and stabilization of the number of pollen grains around noon, coinciding with increased pollinator visitation. We found 25 species of bees in pollinating tomato crops. The abundance of bees coinciding with hours of availability and depletion of pollen suggests efficient removal of pollen from the anthers by the native bees The amount of pollen on the stigma of flowers available to pollinators was higher than on the stigma of bagged flowers. Fruit production was higher in open inflorescences than in bagged inflorescences. Native bees pollinate tomato flowers, increasing the pollen load on the stigma and fruit production. / Os polinizadores fornecem um serviço essencial ao ecossistema e trazem inúmeros benefícios à sociedade, através do seu papel na produção de alimento na agricultura e na conservação da diversidade biológica. No tomateiro, as anteras têm abertura poricida, assim, para liberação dos grãos de pólen é necessária a presença de polinizadores efetivos que realizam a vibração dessas anteras. Sendo assim, os polinizadores de fato dos tomateiros são abelhas que realizam polinização vibrátil. Na realização deste trabalho, foram observados aspectos da biologia floral como duração da flor, a quantidade e viabilidade de grãos de pólen e óvulos, além dos aspectos ecológicos dos polinizadores, como observação e coleta dos visitantes florais. Para avaliar os efeitos da polinização na quantidade de pólen do estigma, selecionamos 37 plantas, ensacamos uma inflorescência e deixamos outra disponível aos polinizadores. De cada inflorescência marcada, retiramos três estigmas e quantificamos os grãos de pólen em suas superfícies. Para a comparação da produção de frutos, acompanhamos o desenvolvimento dos frutos nas inflorescências ensacadas e não ensacadas durante 40 dias, e posteriormente os frutos foram contados, pesados, medidos e tiveram suas sementes contadas. A antese floral inicia às 6h30 da manhã. A flor permanece aberta até às 18h, fechando e no dia seguinte reabrindo no mesmo horário, durando até 73h. A maior oferta de pólen é nas primeiras horas da abertura da flor, com redução e estabilização do número de grãos de pólen por volta do meio dia, coincidindo com o aumento da visitação dos polinizadores. Foram encontradas 25 espécies de abelhas polinizadoras nos cultivos de tomateiro. A abundância das abelhas coincidindo com os horários de disponibilidade e esgotamento do pólen sugere eficiência na retirada dos grãos de pólen das anteras, muitos dos quais se aderem provavelmente ao estigma da própria flor, ocorrendo o posterior desenvolvimento dos frutos. A quantidade de grãos de pólen no estigma das flores disponíveis para os polinizadores foi maior do que no estigma das flores ensacadas. A produção de frutos foi maior em inflorescências não ensacadas que em inflorescências ensacadas. Os frutos não ensacados apresentaram mais sementes que os ensacados. As abelhas nativas polinizam as flores do tomateiro, aumentando a carga de pólen no estigma e a produção de frutos.

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.

Made available in DSpace on 2015-03-26T13:42:26Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1076965 bytes, checksum: 39f371186cedd4587ea0ad27b341a26b (MD5) Previous issue date: 2012-07-16 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / The anther culture has been applied in tomato as an attempt to induce callogenesis followed by regeneration of haploid and doubled haploid plants. By this technique, homozygous lines can be obtained, which has been considered relevant to breeding programs and molecular techniques. The androgenetic response can be influenced by several factors, especially the development stage of microsporogenesis. In this perspective, this study adapted a protocol by associating of flow cytometry and cytogenetic techniques in order to relate the development stages of microsporogenesis in tomato anthers to their size, aiming to select anthers profiles to be inoculated into culture medium. After a flow cytometry protocol was adapted for calli obtained in vitro, in order to monitor the DNA ploidy level. The nuclear suspensions analyzed by flow cytometry were obtained from digestion of anther cells and further homogenization using a mini mixer. The histograms showed low CV s, being considered suitable for cytometric analysis. Thus, anthers small (0.5 0.7 mm), showing cells in interphase/prophase I, exhibited a histogram profile similar to that observed in diploid leaf, and anthers large (1.6 1.9 mm), containing tetrad and microspores, showed an haploid peak and a G2 peak enlarged due to the presence of tetrads. From these analyzes, anthers of flower buds 1 5 mm, with size corresponding to those analyzed by flow cytometry and cytogenetics (0.5 1.9 mm), were inoculated in the callogenesis induction medium, to identify the phases more responsive to the condition in vitro. The basal MS medium supplemented with 2 mg L-1 AIA and 1 mg L-1 2 ip, induced 21.7% of callogenesis, and the highest percentage of calli was obtained from anthers of flower buds 2.0 3.9 mm, corresponding to the phases prophase I to anaphase II. The calli were analyzed by flow cytometry to identify the DNA ploidy. The chopping performed on calli afforded the nuclei isolation, and histograms with CV s considered suitable were obtained. The cytometric analysis revealed that the all calli were multiploids, each of which presented one of five classes of DNA ploidy levels, namely: 2C-4C-8C-16C; 2C-4C-8C-16C-32C; 4C-8C; 4C-8C-16C; 8C-16C-32C. A total of 44.4% of calli analyzed showed five levels of DNA ploidy. A statistical test of interaction showed that the size of flower buds had no effect on polyploidization occurred in the calli. These data evidence the somaclonal variation occurrence, which, probably, results from the interaction of genotype with growth regulators added to the induction medium. / A cultura de anteras tem sido aplicada em tomate como tentativa à indução de calogênese seguida da regeneração de plantas haplóides e duplo-haplóides. Por meio desta técnica, linhas homozigóticas podem ser obtidas, o que tem sido considerado relevante para programas de melhoramento e técnicas moleculares. A resposta androgenética pode ser influenciada por diversos fatores, destacando-se, dentre eles, o estádio de desenvolvimento da microsporogênese. Nesta perspectiva, este estudo adaptou um protocolo associando técnicas de citometria de fluxo e citogenética para relacionar as fases de desenvolvimento da microsporogênese em anteras de tomate com o tamanho das mesmas. O objetivo desta associação foi selecionar perfis de anteras a serem inoculadas em meio de cultura. Posteriormente, adaptou-se um protocolo de citometria de fluxo para os calos obtidos in vitro, a fim de monitorar o nível de ploidia de DNA. As suspensões nucleares analisadas pela citometria de fluxo foram obtidas com digestão das anteras e posterior homogeneização das células usando um mini mixer. Os histogramas obtidos mostraram baixos CV s, sendo considerados adequados para a análise citométrica. Dessa forma, anteras pequenas (0,5 0,7 mm), na fase de intérfase/prófase I, apresentaram um perfil de histograma semelhante ao observado em folha diplóide, e anteras grandes (1,6 1,9 mm) na fase de tétrades e micrósporos apresentaram um pico haplóide e um aumento em G2 em função da presença de tétrades. A partir destas análises, as anteras de botões florais de 1 5 mm, com tamanho correspondente aos daquelas analisadas por citometria de fluxo e citogenética (0,5 1,9 mm) foram inoculadas em meio de indução de calogênese, visando identificar as fases mais responsivas a esta condição in vitro. O meio MS basal, suplementado com 2 mg L-1 de AIA e 1 mg L-1 de 2 ip, induziu 21,7% de calogênese, e o maior percentual de calos foi obtido a partir de anteras de botões florais com 2,0 3,9 mm, correspondendo às fases prófase I a anáfase II. Os calos foram analisados pela citometria de fluxo a fim de identificar a ploidia de DNA. O chopping realizado nos calos proporcionou o isolamento dos núcleos, e histogramas com CV s considerados adequados foram obtidos. A análise citométrica evidenciou que todos os calos eram multiplóides, sendo que cada um apresentou uma das cinco classes de níveis de ploidia de DNA, a saber: 2C-4C-8C-16C; 2C-4C-8C-16C-32C; 4C-8C; 4C-8C-16C; 8C-16C-32C. Um total de 44,4% dos calos analisados apresentaram cinco níveis de ploidia de DNA. Um teste estatístico de interação mostrou que o tamanho dos botões florais não influenciou na poliploidização ocorrida nos calos. Estes dados evidenciam a ocorrência de variação somaclonal que, provavelmente, é resultado da interação do genótipo com os reguladores de crescimento acrescidos ao meio de indução.

Anther smuts (Microbotryum violaceum s.l.) represent a well-known system for studying pathogens of wild plants and coevolution between pathogens and hosts. Infected plants produce sterile flowers with anthers filled with fungal spores which are transmitted to other host plants by pollinators. Data from existing research come mainly from the genus Silene. However, the applicability of these findings to other host plants of anther smuts is largely unknown. Therefore, this thesis focuses on a different host species - Dianthus carthusianorum. First, the pattern of disease was surveyed in natural populations of D. carthusianorum in a small area in Střední Povltaví. Most populations were infected to various degrees and only a few populations remained completely healthy. The prevalence of disease was positively correlated with size and density of host populations. On the other hand, environmental factors and the degree of connectedness had very little effect on disease prevalence. Second, additional data were collected from a subset of populations to determine plant resistance and densities of pollinators. Differences in resistance among populations (as inferred from flower inoculations) were not significant. Populations differed in densities of pollinators, but there was no correlation between densities...

Genotypes of rapeseeds producing yellow seeds were not found in nature. Breeders yellow-seeded rapeseeds have been developed applying different combinations of interspecific crosses. In the Laboratory of Genetics-Biotechnology at the Lithuanian Agricultural University, yellow-seeded spring rapeseeds were developed for the first time without interspecific crosses (Burbulis, 2001). All cultivars of yellow-seeded rapeseed have one essential drawback – unblocking of pigmentation takes place in other generations and seeds of different colours (yellowish brown, brown or black) are formed. Breeders, working with the cultivars of yellow-seeded rapeseed, admit that environmental temperature is one of the factors limiting the manifestation of the trait.

Natural plant growth regulators (phytohormones) are a group of organic compounds which, in very small amounts, act as regulators of physiological processes in plants.Methods were developed for the analysis of phytohormones in samples from Norway spruce (Picea abies (L.) Karst.) and Scots pine (Pinus sylvestris (L.) Karst»). Identification of abscisic acid, 3-indoleacetic acid, gibbe-rellin Ag and the conjugate N-(3-indoleacetyl)aspartic acid was performed by GC-MS as their methyl esters. A quantitative determination of abscisic acid was made by GC-ECD and this method was also applied to anther samples of Anemone canadensis. 3-Indole-acetic acid and N-(3-indoleacetyl)aspartic acid were quantified by reversed-phase HPLC and spectrofluorimetric detection. Dichlorophene, used as a growth regulator in containerized seedlings of pine and spruce, was analysed by GC-MID in peat and paper. / digitalisering@umu

No description available.