No description available.

Afin d’estimer la capacité de réponse du chêne sessile (Quercus petraea Matt. Liebl.) aux changements climatiques en cours, le potentiel d’adaptation de cette espèce pour le débourrement a été mesuré en populations naturelles. Ces populations sont situées le long d’un gradient altitudinal comprenant 12 populations entre 131 et 1630 m, et d’un gradient latitudinal comprenant 21 populations de l’ensemble de l’aire de répartition. Tout d’abord l’empreinte démographique sur les niveaux de diversité génétique a été estimée sur les populations du gradient altitudinal à partir de marqueurs neutre. Les résultats ont montré que la diversité est maintenue le long du gradient altitudinal grâce notamment à des forts flux de gènes entre populations. La variabilité génétique du débourrement à été mesurée en tests de provenances pour 10 populations du gradient altitudinal. Les résultats ont montré une forte différenciation ainsi qu’une héritabilité élevée du trait. Une variabilité génétique importante est maintenue à l’intérieur des populations et semble indiquer que de multiples pressions de sélection agissent de manière fluctuante et/ou opposée. La diversité de gènes candidats pour le débourrement a été étudiée sur les populations des deux gradients environnementaux. Un niveau de diversité nucléotidique relativement fort et un faible déséquilibre de liaison qui décroit rapidement avec la distance ont été observés. Des signatures de sélections ont été mises en évidence sur un ensemble de gènes candidats. Une étude d’association a été menée entre variabilité du caractère et polymorphisme au sein des gènes candidats sur les populations des deux gradients. Un total de 16 associations significatives a été observé impliquant 10 gènes candidats. Ces résultats suggèrent un potentiel d’adaptation important face aux changements climatiques et offrent des perspectives intéressantes pour la compréhension des processus évolutifs qui régissent l’adaptation du chêne sessile pour le débourrement. / In order to assess the capacity of sessile oak (Quercus petraea Matt. Liebl.) to withstand the ongoing climate changes, we estimated its adaptative potential for bud burst within natural populations. These populations are located along two steep temperature gradients: an altitudinal gradient comprising 12 populations located between 131 m 1630 m, and a latitudinal gradient including 21 populations from the species’ distribution range. First the demographic imprint on the overall genetic diversity was assessed on the altitudinal gradient populations using neutral markers. Results showed that genetic diversity was homogeneously distributed along the gradient and maintained at high altitudes. The genetic variability of bud burst was measured in provenance tests for 10 populations of the altitudinal gradient. We found a high level of genetic differentiation and a high heritability for the trait. A high variability was also observed within populations, indicating that selection pressures may fluctuate in natural conditions. Genetic diversity of candidate genes for bud burst was assessed on populations from both gradients. A high level of nucleotide diversity was observed, and linkage disequilibrium was low. Selective signatures were observed on few candidate genes. An association mapping study was performed between bud burst variability and polymorphism at the candidate genes on populations of both gradients separately. A total of 16 associations involving 10 genes were observed. These results suggest an important adaptive potential of sessile oak for bud burst in the face of climate change and provide interesting perspectives for the comprehension of evolutionary processes controlling bud burst adaptation of sessile oak.

M.Sc.(Agric) / Department of Horticultural Sciences

Thesis (M.Sc. (Horticulture)) --University of Limpopo, 2022 / Worldwide, water scarcity, land degradation and unavailability of agricultural lands have posed serious threats on food security and income generation. Hunger, micronutrient deficiencies and starvation are likely to go up in Africa due to increasing urbanisation and rise in global food prices. As a result, it is important to identify innovative vegetable growing-based strategies, which can increase access to food by utilising the limited space available in rural and urban areas. Therefore, sack gardening technology could be a solution to both the lack of arable land and water scarcity in urban and rural areas. The objective of the study was to determine whether axillary bud number will have an effect on agronomic parameters and yield of sweet potato cv. 'Blesbok' produced using the sack gardening technology. Treatments, namely, 1, 2, 3, 4, and 5 number of axillary buds per stem cutting, were arranged in randomised complete block design, with 10 replicates. One bud (1) was used as a control. Different stem cuttings measuring from 10 to 30 cm long with approximately one (1) to six (6) axillary buds were collected from mature sweet potato plantation at a certified nursery from cv. 'Blesbok'. A total of eight (8) stem cuttings were planted in sacks consisting of growing media mixture of steam pasteurised loam soil and compost (3:1 v/v), 4 on top side of the sack and the remaining four on the side-holes of the sack. Insect pests were scouted and monitored weekly, while diseases were managed using spraying programmes as in commercial sweet potato production systems. Two weeks after transplanting, each plant was fertilised with 5 g nitrogen (N), phosphorus (P), and potassium (K) 2:3:2 (26) + 0.5% Zinc (Zn) + 5% sulphur (S) and 5% calcium (Ca). Number of axillary buds had significant effects on vine length, fresh shoot mass, number of shoots and dry shoot mass contributing 59%, 58%, 45% and 58% in total treatment variation (TTV), respectively, whereas axillary bud numbers had no significant effects on fresh tuberous root mass, chlorophyll content, vine stem diameter, tuberous root diameter, tuberous root length, dry tuberous root mass and number of tuberous roots. Relative to control (one bud), two (2), three (3), four (4), five (5) number of axillary buds decreased vine length, fresh shoot mass and dry shoot mass by 8-37, 30-55 and 26-55%, respectively. However, relative to control (one bud), number of axillary buds increased number of shoots by 8-17%. The quadratic relationship models were explained by 95, 92, 96 and 98% of vine length (VL), number of shoots (NS), fresh shoot mass (FSM) and dry shoot mass (DSM), respectively. In conclusion, findings of the study demonstrated that a single (1) or two (2) axillary bud(s) on stem cuttings of sweet potato CV. „Blesbok‟ showed better results for both yield and growth parameters as compared to three (3), four (4) and five (5) buds. / AgriSETA

Thesis (PhD)--Stellenbosch University, 2008. / ENGLISH ABSTRACT: Introduced species displace native species and alter ecological communities, affect agriculture as well as human health and are economically costly to eradicate. Long term monitoring of introduced species including the documentation of levels of genetic variation is therefore of the utmost importance. This study investigated the distribution of genetic variation in two introduced species distributed across South Africa the bud gall-forming wasp Trichilogaster acaciaelongifoliae and the Argentine ant Linepithema humile. The bud gall-forming wasp was introduced into South Africa as a biological control agent to curb the spread of the invasive long-leaved wattle Acacia longifolia. In addition to the intended (target) host, the bud gall-forming wasp has also colonised A. floribunda, a noninvasive ornamental plant. Limited genetic variation was found across South Africa based on the mitochondrial DNA cytochrome oxidase subunit I (COI) gene. Only 3 haplotypes characterized 53 individuals collected from 23 localities (nucleotide diversity £k = 0.002 ¡Ó 0.001, haplotype diversity h = 0.482 ¡Ó 0.045). No significant partitioning of genetic variation was found across South Africa including between host plants (target host = A. longifolia, non target host = A. floribunda) or between the core (sites of introduction) and edge (naturally dispersed) sites (ƒ¶ST = 0.094, P = 0.288). The limited genetic variation and the absence of significant genetic structure are congruent with patterns described for many other introduced species and may suggest that propagule pressure plays only a minor role in species establishment and spread of the gall-forming wasp across South Africa. Mitochondrial and nuclear markers were used to describe the distribution of genetic variation within Argentine ants across their introduced range in South Africa. For the mitochondrial DNA, low genetic diversity was found for the COI gene with only five haplotypes, separated by single mutational changes, characterizing 101 specimens from 35 localities (nucleotide diversity π = 0.001 ± 0.001, haplotype diversity h = 0.151 ± 0.048). Notwithstanding the low levels of genetic diversity, mitochondrial variation was significantly structured (ST = 0.54, P < 0.001) across the landscape. In contrast, microsatellite analyses of 230 ants from 23 localities, employing six polymorphic microsatellite markers, revealed a relatively high amount of genetic diversity (HE = 0.51 ± 0.22). Significant population structure was similarly evident (RST = 0.14, P < 0.001) with the localities of Elim2, Porterville2 and Bloemfontein2 clustering as a distinct population from the remainder of the localities. Importantly, individuals from these localities also had a unique mitochondrial haplotype and, when taken with the nuclear results, may indicate the occurrence of more than one introduction event (and possibly more than one colony) in South Africa. This is further underscored by the presence of unique microsatellite alleles in these three populations. In an attempt to establish the source populations for the introduction of Argentine ants into South Africa, mitochondrial cytochrome b sequences were generated for a subset of ants representing the two major genetic clades across South Africa. A comparison with the published data from across the world including the native range of the Argentine ant in South America grouped Argentine ants from South Africa with three potential source populations namely Ocampo and Rosario in Argentina and Passo do Lontra in Brazil. The results of this study underscore the role of human-mediated dispersal in shaping the levels of genetic variation in both species. Human-mediated dispersal can lead to genetic homogenization across populations. / AFRIKAANSE OPSOMMING: Indringer spesies verplaas of verander ekologiese gemeenskappe, beinvloed landbou asook menslike gesondheid en is ekonomies duur om te verwyder. Langtermyn monitering van indringer spesies asook die dokumentasie van genetiese variasie is dus baie belangrik. Hierdie studie bestudeer die verspreiding van genetiese variasie in twee indringer spesies wat regoor Suid-Afrika voorkom, naamlik die kroongal-vormende wespe Trichilogaster acaciaelongifoliae en die Argentynse mier Linepithema humile. Die kroongal-vormende wesp is na Suid Afrika gebring as biologiese beheeragent om die verspreiding van indringer lang-blarige wattle Acacia longifolia te beveg. Die kroongalvormende wespe het sowel die teiken spesies, asook A. floribunda, ‘n nie-indringer ornamentele plant gekoloniseer. Beperkte genetiese variasie is gevind regoor Suid Afrika gebasseer op die mitochondriale DNA sitokroom-oksidasie subeenheid I (COI) geen. Slegs 3 haplotipes karakteriseer 53 indiviue van 23 bevolkings (nukleotied diversiteit π = 0.002 ± 0.001, haplotiep diversiteit h = 0.482 ± 0.045). Geen beduinde groepering van genetiese variase is gevind regoor Suid Afrika nie (ST = 0.094, P = 0.288). Hierdie bevinding geld onafhanklik van die gasheer plant (teiken gasheer = A. longifolia, nie-teiken gasheer = A. floribunda). Ook is geen beduidende genetiese groepering gevind tussen die sentrale (plek van inisiele blootstelling) en perifêre (natuurlik verspreide) lokaliteite nie. Die kleinskaalse genetiese variase en die afwesigheid van beduidende genetiese struktuur wat hier gevind is, verskil van die patrone wat voorheen vir baie ander indringer-spesies beskryf is. Dit mag daarop dui dat ‘propagule’ druk slegs ’n klein rol speel in spesies-vestiging en verspreiding van die galvormende wespe regoor Suid-Afrika. Mitochondriale asook kern merkers is gebruik om die verspreiding van genetiese variasie in Argentynse miere in Suid Afrika te beskryf. Vir die mitochondriale DNA is lae genetiese variase gevind vir die COI geen, met slegs 5 haplotipes, gedifferensieer deur enkele mutasie veranderinge wat 101 monsters van 35 lokaliteite karakteriseer (nukleotied diversiteit π = 0.001 ± 0.001, haplotiep diversiteit h = 0.151 ± 0.048). Desondanks die lae genetiese variasie, is gevind dat mitochondriale variasie beduidend gestruktureerd is (ST = 0.54, P < 0.001) oor die landskap. Hierteenoor het mikrosatelliet analises van 230 miere van 23 lokaliteite, deur gebruik te maak van ses polimorfiese mikrosatelliet merkers, ’n relatiewe hoë hoeveelheid genetiese diversiteit aangedui. Beduidende bevolkingstruktuur was ook gevind (RST = 0.14, P < 0.001) in die areas Elim2, Porterville2 en Bloemfontein2 wat saam groepeer as eiesoortige bevolkings vergeleke met die res van die areas. Ook van belang is dat individue van die areas ’n unieke mitochondriale haplotipe besit, en in kombinasie met die kern resultate, mag dit die voorkoms van meer as een blootstellingsgeleentheid (en moontlik meer as een kolonie) in Suid Afrika aandui. Hierdie bevinding word verder beklemtoon deur die teenwoordigheid van unieke mikrosatelliet allele in die drie bevolkings. In ‘n poging om die oorsprong van die oorsprong-bevolking vir die blootstelling van Argentynse miere in Suid Afrika vas te stel, is mitochondriale sitokroom b volgordes gegenereer vir ’n substel miere wat die twee hoof genetiese klades in Suid Afrika voorstel. Vergelyking met gepubliseerde data van regoor die wêreld, insluitende die endemiese gebied van die Argentynse mier in Suid Amerika, het die Argentynse mier van Suid Afrika met drie potensiele oorsprong-bevolking verbind, naamlik Ocampo en Rosario in Argentina en Passo do Lontra in Brazil.

A transformação genética possibilita a introdução de genes de interesse agronômico no genoma das plantas e pode ser empregada na tentativa de obter plantas resistentes a doenças. No entanto, para se obter uma planta transgênica é necessário primeiramente estabelecer um procotolo eficiente de regeneração de plantas in vitro. Assim, o objetivo desse trabalho foi estudar a organogênese in vitro e a transformação genética de limão Volkameriano e laranja azeda com um fragmento do gene da capa protéica do CTV. Para a organogênese in vitro utilizou-se, como explante, segmento internodal, obtido de planta cultivada em casa-de-vegetação, segmento de epicótilo, coletado de plântula cultivada in vitro e segmento de cotilédone associado ao hipocótilo obtido de semente introduzida in vitro. Esses explantes foram mantidos em meio de cultura EME suplementado com 6-benzilaminopurina (BAP 0,0; 0,5; 1,0; 1,5; 2,0 mg L- 1), sendo incubados sob fotoperíodo de 16 h de luz ou em condições de escuro por 30 dias e então transferidos para fotoperíodo de 16 h de luz. A avaliação foi realizada após 45 dias de cultivo, determinando-se o número de explantes responsivos e o número de gemas por explante. A caracterização anatômica do processo de regeneração foi realizada por meio de cortes histológicos. Pela análise dos dados foi possível verificar que a organogênese in vitro ocorreu a partir dos três tipos de explantes testados, sendo que, nas duas espécies em estudo, os melhores resultados foram obtidos com o cultivo de segmento de cotilédone associado ao hipocótilo. As concentrações de BAP que estimularam as melhores taxas de regeneração foram de 1,0 e 1,5 mg L-1, para limão Volkameriano, e 0,5 e 1,0 mg L-1 para laranja azeda. A incubação dos explantes em ausência de luz favoreceu a regeneração in vitro. Pela análise histológica foi possível observar que o processo de regeneração, a partir dos três tipos de explantes testados, ocorreu por meio de organogênese indireta. O protocolo de desenvolvimento estabelecido durante os experimentos de organogênese in vitro foi utilizado para a transformação genética dessas espécies via Agrobacterium, contendo o plasmídeo pCAMBIA 2201, com um fragmento do gene da capa protéida do CTV, em uma construção gênica do tipo hairpin. As gemas de limão Volkameriano e laranja azeda identificadas como transgênicas pelo teste histoquímico GUS foram enxertadas in vitro em citrange Carrizo. A confirmação da transformação genética foi realizada pela análise de PCR, a qual mostrou a amplificação de um fragmento de 671 pb, correspondente a parte do gene amplificada. / Genetic transformation permits the introduction of agronomically important genes in plant genome and can be utilized in order to produce disease resistant plants. However for the recovery of transgenic plants is required to establish an efficient in vitro plant regeneration protocol. In this work the aim was to study an in vitro organogenesis and the genetic transformation of Volkamer lemon and sour orange with a sequence of the CTV coat protein gene. For in vitro organogenesis explant internodal segments collected from plants cultivated in greenhouse, epicotyl segments obtained from in vitro cultivated seedlings and cotyledon fragment with hypocotyl attached obtained from in vitro germinated seed were used as explant. These explants were cultured in EME medium supplemented with benzilaminopurine (BAP 0,0; 0,5; 1,0; 1,5; 2,0 mg L-1). Cultures were maintained under a 16 h photoperiod or in the dark for 10 d and then transferred to a 16 h photoperiod. The evaluation was performed 45 d after the incubation determining the number of responsive explant and the number of buds per explant. The anatomical characterization of in vitro regeneration process was carried out through histological analyses. The in vitro organogenesis occurred in the three types of explant tested, however cotyledon fragment with hypocotyl attached showed higher morphogenetic potential in both species. The best responses of regeneration were obtained when the medium was supplementation with 1,0 e 1,5 mg L-1 BAP for the Volkamer lemon and 0,5 e 1,0 mg L-1 BAP for the sour orange. The incubation in darkness favored the in vitro regeneration. The histological analyses showed that the regeneration process occurred through indirect organogenesis in the three types of explants tested. The developed protocol was use for genetic transformation of Volkamer lemon and sour orange with Agrobacterium, containing pCAMBIA 2201 plasmid with a sequence of CTV coat protein gene, in a hairpin construction. Volkamer lemon and sour orange shoots identified as transgenic by histochemical test GUS were micrografted into Carrizo citrange. PCR analysis were performed after micrografted showing the presence of the 671 pb fragment of the transgene.

A perda do parênquima hepático, induzida por tratamento agudo, cirúrgico ou químico, desencadeia um processo regenerativo até que a massa hepática seja completamente restaurada. A regeneração hepática, após a hepatectomia parcial de 70%, é um dos modelos mais adequados de regeneração de células, órgãos e tecidos mais estudados. No fígado, ainda que sejam atribuídas propriedades regenerativas, muitas das lesões são tão prejudiciais que este mecanismo de reparação é insuficiente, tornando o transplante a única opção. As células derivadas do broto hepático de ratos apresentam uma boa alternativa para tratamento de doenças hepáticas devido ao seu alto índice proliferativo e da expressão de marcadores de pluripotência, sendo sua aplicabilidade viável em modelos experimentais. O objetivo deste trabalho foi analisar as diferentes vias de administração das células derivadas do broto hepático de ratos com 12,5 dias de gestação visando a melhor regeneração do órgão. Foram realizados experimentos de hepatectomia parcial de 70% (N=50 animais), PET Scan MSFX PRO In-Vivo RX e fluorescência, índice hepatossomático, análise de marcadores solúveis (GH, AFP, CEA, IGF-1), análises hematológicas, microscopia de luz (coloração HE, Tricômio de Masson), análise de marcadores por citometria de fluxo (CD90, STRO-1, Nanog, Oct3/4, Ki-67, Caspase 3) e ciclo celular por citometria de fluxo. Nossos dados demonstraram que as células do broto hepático administradas na via endotraqueal apresentaram melhor equilíbrio entre proliferação e morte celular, com maior expressão dos marcadores de pluripotência, melhor organização celular e regeneração tecidual, em contraste com outras vias, incluindo endovenosa, intraperitoneal e oroenteral. Isto a torna mais segura e de maior viabilidade na regeneração celular em relação às demais vias, sendo mais eficiente nos modelos de hepatectomia parcial / The restoration of liver parenchyma after partial hepatectomy or chemical treatments represents appropriate models to study regeneration mechanisms. The most appropriate model for liver regeneration is partial hepatectomy of 70%, however, organ repair properties are insufficient, suggesting the transplantation the best alternative to treat liver diseases. Cells derived from liver buds of rats show a high proliferative index and the expression of pluripotency markers; thus their significance for regeneration purposes can be tested experimentally. We here investigated different routes to administer cells derived from rat live buds of 12.5 days of gestation to adult individuals (N=50 animals) suffering from partial hepatectomy (70%). Applied methods included PET Scan MSFX PRO In-Vivo RX, fluorescence hepatossomatic index, analysis of soluble markers (GH, AFP, CEA, IGF-1), hematological analysis, light microscopy (staining HE, and Masson trichrome) as well as flow cytometry for cell cycle analysis and CD90, STRO-1, Nanog, OCT3/4, Ki-67, Caspase 3 expression. Our data showed that administration via the tracheal route resulted as favorite in regard to the balance between proliferation and cell deaths, of pluripotency marker expression, cellular organization and tissue regeneration, in contrast to other routes including: intravenous, intraperitoneal and oroenteral. Consequently, the tracheal route showed safer and more efficient treatment to enhance cell regeneration after partial hepatectomy

As células-tronco são capazes de se diferenciarem em praticamente todos os tipos celulares, podendo ser utilizadas em terapias de substituição em várias doenças. Células de linhagens hepáticas embrionárias e fetais pode ser uma fonte importante para a terapia celular em indivíduos com doenças hepáticas, pois possuem um alto índice de diferenciação em hepatócitos e células do ducto biliar. O objetivo deste trabalho foi avaliar o potencial e o controle da resposta proliferativa de células do broto hepático de ratos Fischer 344 em cultura. A obtenção das células do broto hepático foi realizada nos períodos 12,5; 14,5 e 16,5 dias de gestação e os fragmentos foram cultivados em meio DMEM-F12. A caracterização morfológica foi realizada em microscopia invertida de luz e eletrônica de varredura. A caracterização dos marcadores de células mesenquimais, do citoesqueleto, progressão e fases do ciclo celular, morte celular, e do potencial elétrico mitocondrial foram realizadas por citometria de fluxo. A função bioquímica foi realizada pela análise das transaminases hepáticas e pela produção de radicais livres lipoperoxidados. Os resultados encontrados no acasalamento dos ratos isogênicos da linhagem Fischer 344 seguiu o protocolo de 12 h de luz, alcançando o índice reprodutivo satisfatório e reprodutível. O isolamento e separação do broto hepático desta linhagem de ratos permitiu a obtenção, expansão e caracterização de uma cultura primária nos diferentes dias de gestação 12,5; 14,5 e 16,5. Os aspectos morfológicos encontrados foram de células fusiformes do tipo fibroblast-like para todos os períodos de gestação em cultura. As análises das transaminases hepáticas TGO e TGP, mostraram se em concentrações menores no período 12,5 dias de gestação. A expressão dos marcadores de células-tronco de origem mesenquimais (CD90, Nanog, Oct ¾ e STRO1), marcadores do citoesqueleto (CK8, CK18 e Desmina), marcadores envolvidos na checagem e progressão do ciclo celular (P53, P21, P27 e Ciclina D1) e marcadores envolvidos na morte celular (Anexina V/PI, Caspase 3, Bax, Bad e Bcl2) mostraram diferencialmente expressos, nos diferentes períodos gestacionais. A análise do potencial elétrico mitocondrial nos períodos de gestação de 14,5 e 16,5 dias, foi maior na proporção de células inativas com menor capacidade funcional ou metabólica, quando comparada ao período de 12,5 dias ou mesmo em relação ao hepatócito normal de um rato adulto. Análise das fases do ciclo celular observou-se uma concentração de célula na fase G0/G1, repercutindo na modulação da capacidade de proliferação e aumento na proporção de células com DNA fragmentado, nas CBH no período de 16,5 dias em comparação aos demais períodos e ao hepatócito normal. O aumento da fragmentação do DNA em média de 3,5 e 2,3 vezes, respectivamente nos períodos de 12,5 e 14,5 dias de gestação. A capacidade de síntese e de divisão celular das CBH foi mantida em todos os períodos de gestação. Os radicais livres lipoperoxidados mostraram quantidades insignificantes em CBH nos diferentes dias de gestação. / Stem cells are able to differentiate into virtually all cell types and can be used in replacement therapies in various diseases. Cells of embryonic and fetal liver lines can be an important source for cell therapy in patients with liver disease because they have a high rate of differentiation into hepatocytes and biliary duct cells. The aim of this study was to evaluate the potential and control of the proliferative response of liver bud cells during the maturation of hepatocytes in culture. The acquirement of liver bud cells was performed for 12.5, 14.5 and 16.5 days of gestation and the fragments were cultured in DMEM-F12. Morphological characterization was performed on inverted light microscopy and scanning electron microscopy. The characterization of mesenchymal cell markers, cytoskeleton, and progression stages of the cell cycle, cell death and mitochondrial electric potential were performed by flow cytometry. The biochemical function was performed by analysis of liver transaminases and the production of free radicals lipoperoxidados. The results found in rats\' mating isogenic Fischer 344 followed the protocol of 12 hours of light reaching the reproductive rate satisfactory. The isolation and separation of the liver bud of this strain of mice allowed the isolation, expansion and characterization of a primary culture at different days of gestation, 12.5, 14.5 and 16.5 days. The morphological features were found of spindle cell type to fibroblast-like cells of the liver bud in culture. Analyses of hepatic transaminases GOT and GPT showed lower concentrations in the period 12.5 days of gestation. The expression of stem cell markers of mesenchymal origin (CD90, Nanog, Oct STRO1 and ¾), cytoskeletal markers (CK8, CK18 and desmin) markers involved in checking and cell cycle progression (P53, P21, P27 and Cyclin D1) and markers involved in apoptosis (Annexin V / PI, caspase 3, Bax, Bad and Bcl2) showed differentially expressed in different gestational periods. In the analysis of mitochondrial electrical potential in the gestation periods of 14.5 and 16.5 days, it was observed the higher proportion of quiescent cells with lower metabolic of functional capacity when compared to the periodo of 12.5 days or even compared to a normal hepatocyte adult rat. In the analysis of cell cycle phases it was observed the concentration of cell in the G0/G1 phase, resulting in modulation of proliferation capacity and the increase in the proportion of cells with fragmented DNA, CBH in the period 16.5 days compared to other periods and the normal hepatocyte. The increase of DNA fragmentation on average 3.5 and 2.3 times respectively in the periods of 12.5 and 14.5 days of gestation. The synthesis and cellular division of CBH was maintained in all stages of pregnancy. The free radicals lipoperoxidados showed insignificant amounts of CBH in the days of gestation.

No description available.

Experimental objective - the study was aimed to establish the developmental regularities of winter rape and its hybrids under the conditions of autumn-winter period becoming warmer and variable in length, to estimate the peculiarities of their biopotential formation and to optimize the measures of adaptation to changeable climate conditions. Statements to be defended: 1. Winter rape development until the end of autumn vegetation depends on sowing date and plant genotype. 2. The changes in nutrients in the rosette of winter rape ant its hybrids plants occurring after resumption of vegetation during the wintering period differ and depend not only on the genotype and sowing date but also on the year’s weather conditions. 3. Different sowing time influences over winter survival of winter rape and its hybrids plants. Rape hybrids respond less sensitively to the delay in sowing date. 4. Sowing time exerts a greater effect on the seed yield of winter rape compared with winter rape hybrids. / Tyrimų tikslas - nustatyti žieminių rapsų ir jų hibridų vystymosi dėsningumus skirtingos trukmės šiltėjančiu rudens – žiemos periodu, įvertinti jų biopotencialo formavimosi ypatumus bei optimizuoti prisitaikymo prie besikeičiančių klimato sąlygų adaptacines priemones (sėjos laiką). Disertacijos ginamieji teiginiai: 1. Žieminių rapsų vystymasis iki rudens vegetacijos pabaigos priklauso nuo sėjos laiko ir augalo genotipo. 2. Atsinaujinus vegetacijai žiemojimo metu, rapsų ir jų hibridų skrotelėje vykstantys maisto medžiagų pokyčiai skiriasi ir priklauso ne tik nuo genotipo ir sėjos laiko, bet ir nuo metų meteorologinių sąlygų. 3. Skirtingas sėjos laikas įtakojo žieminių rapsų ir jų hibridų peržiemojimą. Rapsų hibridai yra mažiau jautrūs sėjos laiko vėlinimui. 4. Sėjos laikas daro didesnę įtaką rapsų nei jų hibridų sėklų produktyvumui.