Thesis (Ph.D.) - University of Queensland, 2005. / Includes bibliography.

Thesis (MSc)--Stellenbosch University, 2002. / ENGLISH ABSTRACT: The aim of this thesis was to define the interactions of the androgen receptor (AR) with an analog of a non-steroidal plant compound, Compound A (CpdA), as well as two synthetic progestins, medroxyprogesterone acetate (MPA) and norethindrone acetate (NET-A). The data presented indicates that CpdA has antiandrogenic properties, as it represses androgen-induced activation of both specific and non-specific androgen-responsive reporter constructs. It was found that CpdA exerts these effects by a mechanism other than competition with androgen for binding to the ligand-binding domain (LBD) of the receptor. On the other hand, it is demonstrated that both MPA and NET-A compete with androgen for binding to the AR and induce partial agonist activity via the receptor. Using mammalian two-hybrid assays it was revealed that CpdA, similar to anti-androgenic compounds that are able to compete with androgens for binding to the receptor, represses the androgen-induced interaction between the NH2- and COOH-terminals of the AR (N/C-interaction) without competing for binding to the LBD. Furthermore, it was shown that CpdA slightly represses the androgen-dependent recruitment of steroid receptor co-activator 1 (SRC1) to the activation function (AF2) domain of the AR. When the effects of MPA and NET-A on the N/C-interaction were studied, intriguing results were obtained. NET-A, as expected, induced this AR agonist-induced interaction. MPA, however, repressed this AR agonist-induced interaction, an effect previously associated with anti-androgenic activity, despite displaying partial agonist activity in transctivation experiments. On the other hand, both MPA and NET-A induced the interaction between SRC1 and the AF2 domain. In additional experiments with CpdA, it was found that CpdA did not affect the recruitment of SRC1 to the AF1 domain of the receptor; neither did it influence the constitutive activity of the NH2-terminal domain. The anti-androgenic activities of CpdA were confirmed by the toxic effect that this compound had on the androgen-dependent lymph node carcinoma of the prostate (LNCaP) cell-line as well as its ability to repress the androgen-induced expression of the prostate specific antigen (PSA) protein. Taken together, the results presented in this thesis, in combination with the knowledge available on AR function, contribute to an improved understanding of AR function. Furthermore, the importance of defining the precise mechanism by which individual compounds exert their effects is highlighted. In this regard it is demonstrated that two compounds (MPA and NET-A) that display partial agonist activity, can exert their effects via different mechanisms at the molecular level. Detecting such differences in the molecular mechanisms of action could facilitate the improved design of progestins as well as aid clinicians and their patients in selecting the best method of contraception. Lastly, the insights gained into the mechanisms of the anti-androgenic action of CpdA could be useful in therapeutic drug design for diseases, such as prostate cancer, that have an androgen-dependent etiology. / AFRIKAANSE OPSOMMING: Die doel van hierdie tesis was om die interaksies van die androgeen reseptor (AR) met ‘n analoog van ‘n nie-steroiediese plant verbinding, Verbinding A (VbgA), sowel as met twee sintetiese progestogene, medroksiprogesteroon asetaat (MPA) en noretiendroon asetaat (NET-A), te definieer. Die data verskaf dui daarop dat VbgA anti-androgeniese eienskappe besit deurdat dit androgeen-gei'nduseerde aktivering van beide spesifieke- en nie-spesifieke androgeen-responsiewe rapporteerderkonstrukte onderdruk. VbgA veroorsaak hierdie effekte deur ‘n meganisme wat nie kompetisie met androgeen vir binding aan die ligand-bindingsdomein (LBD) van die reseptor behels nie. In teenstelling hiermee word getoon dat beide MPA en NET-A kompeteer met androgeen vir binding aan die AR en gedeeltelike agonistiese aktiwiteit induseer via hierdie reseptor. Deur gebruik to maak van ‘n soogdier twee-hibried essai word getoon dat VbgA, soos ander anti-androgeniese verbindings wat kompeteer met androgeen vir binding aan die reseptor, die androgeen-gei'nduseerde interaksies tussen die NH2- en COOH-terminale van die AR (N/C-interaksie) onderdruk, sonder om te kompeteer vir binding aan die LBD. Daarby is dit bewys dat VbgA die androgeenafhanklike werwing van steroied reseptor ko-aktiveerde 1 (SRC1) na die aktiverings funksie (AF2) domein van die AR gedeeltelik onderdruk. Die studie van die effekte van MPA en NET-A op die N/C-interaksie het interessante resultate opgelewer. NETA, soos verwag, het hierdie AR agonis-gei'nduseerde interaksie geinduseer. MPA, aan die ander kant, het hierdie AR agonis-gei'nduseerde interaksie onderdruk, ‘n effek wat tevore met anti-androgeniese aktiwiteit geassosieer is, al het die transaktiveringseksperimente daarop gedui dat MPA ‘n AR agonis is. Aan die ander kant, het beide MPA en NET-A die interaksie tussen SRC1 en die AF2 domein geinduseer. In addisionele eksperimente met VbgA is gevind dat VbgA geen effek het op die werwing van SRC1 na die AF1 domein van die reseptor nie en ook geen invloed het op die konstitutiewe aktiwiteit van die NHh-terminaal domein nie. VbgA se antiandrogeniese eienskappe is bevestig deur die toksiese effekte op die androgeenafhanklike limfknoop karsinoom van die prostaat (LNCaP) sellyn sowel as deur sy vermoe om die androgen-gei'nduseerde uitdrukking van die prostaat spesifieke antigeen (PSA) protei'en te onderdruk. Die resultate aangebied in hierdie tesis, in kombinasie met die beskikbare kennis oor AR funksie, dra by tot ‘n verbeterde kennis van AR funksionering. Verder word die belang van die definiering van die meganisme waardeur individuele verbindings hulle effekte veroorsaak, getoon. In hierdie verband is getoon dat twee verbindings (MPA en NET-A), wat gedeeltelike agonistiese aktiwiteit besit, hulle effekte via verskillende meganismes op die molekulere vlak veroorsaak. Deur hierdie verskille in die molekulere meganismes van aksie uit te wys, kan beter progestogene ontwikkel word, en verder sal dit vir dokters en hul pasiente help om die beste voorbehoedmiddel te kies. Laastens, die insig wat verkry is ten opsigte van die meganismes van anti-androgeniese aktiwiteit van VbgA mag nuttig wees in die ontwerp van terapeutiese middels vir die behandeling van siektetoestande met androgeen-afhanklikke etiologie (bv. prostaatkanker).

Asexual species which never incorporate novel genetic material from other lineages will go extinct faster than sexually reproducing species, because adaptive variability may be lower and a larger number of harmful mutations may accumulate. One form of asexuality, androgenesis, results in offspring that are clones of the father. Both androgenetic and sexual species are found in the clam genus Corbicula. I used genetic data to explore why there are multiple species of androgenetic Corbicula, and whether genetic exchange occurs between species. I found that in North American locations where two invasive, androgenetic species co-occur, restriction digest mapping of rDNA failed to detect recent nuclear exchange. However, in these same locations, mitochondrial markers were shared between species. In places where only one species was found, mitochondrial markers were unique to that species. This suggests androgenetic clams are able to parasitize eggs of closely related species. Whereas maternal mitochondria are retained in the fertilized egg, maternal nuclear chromosomes are expelled, and the mother incubates male clones of another species. To look at possible gene exchange over the long term, I compared phylogenetic tree topologies of one mitochondrial and two nuclear markers from multiple sexual and androgenetic species. Since several androgenetic species share similar or identical alleles, androgenesis seems to have evolved relatively recently in Corbicula. However, since different androgenetic species also have divergent alleles not shared between species, genetic capture of maternal nuclear DNA from other species may rarely occur. This rare capture of genetic material from other species may permit the long-term persistence of androgenesis in Corbicula. / text

Résumé : Le syndrome des ovaires polykystiques (SOPK) affecte 6-10% des femmes en âge de procréer et est la principale cause d’infertilité anovulatoire. Cette condition est principalement caractérisée par une hyperandrogénie provenant des ovaires et des glandes surrénales. De plus en plus d’études, à la fois in vivo et in vitro, indiquent qu’une surexposition ovarienne en gras, de même que les mécanismes lipotoxiques subséquents pourraient causer l’hyperandrogénie chez ces femmes. Ainsi, cette étude vise à 1) évaluer l’implication des gras et de l’inflammation folliculaire dans la production des androgènes ovariens par une étude de corrélation; et 2) comparer les niveaux folliculaires de gras, métabolites lipidiques et marqueurs inflammatoires entre les femmes SOPK et non-SOPK. Cette étude transversale a recruté 80 femmes en cours de fécondation in vitro. Treize étaient SOPK, 58 étaient non-SOPK et 9 avaient un diagnostic incertain. Les participantes au projet avaient un âge moyen de 33 ± 4 ans. Tout groupe confondus, les niveaux folliculaires de testostérone corrélaient avec les gras (r=0,381; P=0,001; indépendamment de l’IL-6), les acylcarnitines (r≥0,255; tout P=0,008; non indépendamment des gras) et l’IL-6 (r=0,300; P=0,009; indépendamment des gras). De plus, les niveaux folliculaires de gras corrélaient avec les acylcarnitines (r≥0,594; tout P<0,001). Lorsque comparées aux femmes non-SOPK, les femmes SOPK étaient plus obèses (BMI: 31,2 vs. 25,1 kg/m2; P=0,009) et avaient des niveaux folliculaires plus élevés de testostérone (12,9 vs. 0,29 nM; P=0,001), de gras (P=0,001), d’acylcarnitines (tout P=0,001) et du marqueur inflammatoire IL-6 (13,0 vs. 8.6 pg/mL; P=0,018), le tout indépendamment de l’IMC. Les résultats suggèrent qu’une exposition intra-ovarienne en gras pourrait contribuer à une augmentation de la production des androgènes. Les mécanismes pourraient inclure une β-oxydation insuffisante, illustré par des acylcarnitines élevés, menant à l’accumulation de métabolites lipidiques toxiques, et une inflammation ovarienne, possiblement suite à une infiltration de macrophages. Ces deux mécanismes semblent être indépendants. De plus, l’environnement ovarien des femmes SOPK est caractérisé par une élévation des gras, de métabolites lipidiques et de marqueurs inflammatoires. Il peut donc être proposer que l’hyperandrogénie caractéristique du SOPK soit causée en partie par la lipotoxicité. // Abstract : Polycystic ovary syndrome (PCOS) affects 6-10% of the women of childbearing age and is the main cause of anovulatory infertility. It is mainly characterised by hyperandrogenism that can originate from the adrenal gland and the ovaries. A growing number of evidences, either in vivo or in vitro, points toward an overexposition to fat and lipotoxic mechanisms (lipid induced cellular toxicity) as the cause of PCOS hyperandrogenesis. Therefore, we aimed to: 1) evaluate the implication of follicular fluid (FF) levels of fat and inflammation markers in the ovarian production of androgens through a correlation analysis; and 2) compare FF levels of lipids, lipid metabolite levels and inflammation markers between PCOS and non-PCOS women. This cross-sectional controlled study was performed with 80 women undergoing an IVF procedure. Among them, 13 were PCOS, 58 were non-PCOS and 9 had an uncertain diagnosis. Participants were aged 33 ± 4 years old and had an average body mass index (BMI) of 25.7 ± 6.2. When analysing all women, follicular levels of testosterone correlated significantly with fat (NEFA + triglycerides) (r=0.381; P=0.001; independently of l’IL-6), acylcarnitines (r≥0.255; all P=0.008; not independently of fat) and l’IL-6 (r=0.300; P=0.009; independently of fat). Moreover, follicular levels of fat significantly correlated with acylcarnitines (r≥0.594; all P<0.001). When compared to non-PCOS women, PCOS women were significantly more obese (BMI: 31.2 vs. 25.1 kg/m2, P=0.009) and had significantly higher follicular levels of testosterone (12.9 vs. 0.29 nM, P=0.001), fat (P=0.001), acylcarnitines (all P=0.001) and inflammatory marker IL-6 (13.0 vs. 8.6 pg/mL, P=0.018), everything independently of BMI. Our results suggest that intra-ovarian exposure to fat may be responsible for the increased production of androgens. Mechanisms are likely to include an insufficient β-oxidation, leading to the accumulation of toxic lipid metabolites, and ovarian inflammation, possibly through macrophage infiltration. Both these mechanisms seem independent of one another. Also, intra-ovarian environment of PCOS women are characterized by increased levels of fat, acylcarnitines and inflammatory marker. It can thus be proposed that lipotoxic mechanisms are responsible for the increased production of androgen that is characteristic of PCOS women.

Magister Scientiae - MSc / Doubled Haploid (DH) Technology is an important tool for plant breeding and biotechnological applications as it accelerates the breeding cycle of plants by shortening the time required to attain homozygosity. Anther culture has become one of the most frequent and well-established methods for the induction of haploid embryogenesis and regeneration in barley. Anther culture is easily reproduced and workable for a wide range of genotypes. The aim of this study was to determine the optimal pre-treatment for barley anther culture. Three pre-treatments, 0.3 M Mannitol, 0.7 M Mannitol and a cold treatment with a moist cloth (CMC), were studied. The results suggest that CMC is the optimal pre-treatment to use for green plant regeneration. Anthers treated with CMC showed a higher response percentage than that of 0.7 M Mannitol and 0.3 M Mannitol. CMC also induced a significantly higher callus formation and green plant regeneration frequencies than 0.7 M Mannitol and 0.3 M Mannitol. Further research has to be conducted to further optimize green plant yields per treatment as well as reduce the number of albinos regenerated through barley anther culture.

Cette thèse vise à améliorer notre connaissance des processus évolutifs et écologiques liés aux invasions biologiques au travers de l'étude de populations envahissantes et non envahissantes de la petite fourmi de feu, Wasmannia auropunctata. Cette espèce présente un polymorphisme du système de reproduction original. Dans les populations ancestrales, les reines et les mâles se reproduisent selon le mode de reproduction sexué classique des hyménoptères (haplo-diploïde). Dans d'autres populations, les reines sont parthénogénétiques et les mâles sont produits de manière clonale via les œufs pondus par la reine. Ces reines et ces mâles produisent néanmoins des ouvrières stériles sexuellement. Ce mode de reproduction clonal semble associé indirectement au succès d'invasion des populations. Dans un premier temps nous avons identifié les mécanismes sous-jacents au système de reproduction des populations clonales. Nos résultats montrent que les reines utilisent la parthénogenèse automictique associée à une réduction du taux de recombinaison pour la production de reines, l'androgenèse pour la production des mâles et la reproduction sexuée pour la production d'ouvrières stériles. La fixation des génomes parentaux dans les descendances successives permet la reproduction entre individus d'une même cohorte en évitant la dépression de consanguinité dans la descendance ouvrière. Nous avons ensuite montré que le changement de système de reproduction de la sexualité vers la clonalité est associé à un changement adaptatif permettant aux ouvrières des populations clonales de mieux tolérer les températures stressantes caractéristiques des localités envahies, comparativement aux ouvrières des populations sexuées ancestrales. Enfin, l'utilisation d'une approche multidisciplinaire couplant des modèles de distribution d'espèces, des analyses de génétique des populations et des expériences en laboratoire, nous a permis de montrer que les changements évolutifs clefs associés au succès d'invasion des populations, ont lieu dans des habitats marginaux de l'aire native, avant la dispersion vers des localités distantes caractérisées par des conditions environnementales similaires. / The main goal of this thesis is to provide new insights on the evolutionary processes associated to biological invasions through the study of invasive and non-invasive populations of the little fire ant, W. auropunctata. This species is characterised by an eccentric breeding system polymorphism. In ancestral populations, queens and males reproduce following the classical sexual reproduction system of hymenopteran species (haplo-diploid). In some other populations, queens reproduce by parthenogenesis and the males are reproduced clonally through queens' eggs. These clonal queens and males nevertheless produce sterile workers sexually. Interestingly this clonal reproduction seems indirectly associated with the invasive success of populations. In this study, we first identified the mechanisms underlying the breeding system of clonal populations. Our results indicate that queens use automictic parthenogenesis associated with a drastic reduction of meiotic recombination rate, androgenesis and sexual reproduction for the production of queens, males, and sterile workers respectively. The fixation of parental genomes in the successive generations allows individuals from the same cohort to reproduce together avoiding inbreeding depression in their worker offspring. We also found that the change of breeding system from sexuality to clonality is associated with an adaptive change that allow workers from clonal populations to better tolerate the stressing temperatures of invaded areas better than workers from ancestral sexual populations. Finally, we used a developed mutlidisciplinary approach combining niche modelling, genetic analyses and laboratory experiments, and found that the above evolutionary changes occur within the native range in marginal habitats prior to long-distance dispersal events into localities that display similar environmental conditions.

Les lignées clonales sont un outil puissant pour une meilleure caractérisation génétique des organismes utilisés en recherche. En utilisant les techniques de reproduction uniparentale, de telles lignées peuvent être développées chez les poissons en seulement deux générations. L'androgenèse avait déjà été réalisée chez plusieurs espèces d'eau douce et a été tentée chez le loup, une espèce d'intérêt économique et scientifique. Le faible nombre d'individus contenant effectivement uniquement le patrimoine génétique du père, après irradiation des œufs aux UV, a soulevé des questions quant à la présence de composés photoprotecteurs dans les œufs pélagiques. Les acides aminés de type mycosporines et le gadusol ont été recensés dans de nombreux organismes marins et d'eau douce, mais leur présence n'a pu être reliée au comportement flottant ou coulant des œufs. Tandis que le gadusol apparaissait en plus grande quantité dans les œufs marins flottants, ce résultat était beaucoup moins clair en eau douce et le type de composés photoprotecteurs semble lié à la phylogénie. D'autres études sur les mécanismes de photoréparation de l'ADN pourraient éclairer les résultats obtenus dans les expériences d'androgenèse. La gynogenèse avait déjà été reportée chez le loup mais le grand nombre d'individus méiotiques contaminant les descendances homozygotes produites a conduit à valider des marqueurs microsatellites efficaces à distinguer les individus mitotiques. De plus, un retard de développement des gonades a été observé, augmentant les difficultés à obtenir les lignées clonales. La grande variabilité observée entre les individus quant au succès des reproductions uniparentales a montré que la caractérisation et la qualité des gamètes sont un préalable indispensable. / Clonal lines are a powerful scientific tool for improved genetic characterization of organisms used in research. Inbred fish lines can be produced in only two generations using uniparental reproduction techniques. Androgenesis, achieved with variable success in several freshwater species, has been attempted in the European sea bass (Dicentrarchus labrax L), a marine fish of commercial and scientific interest. The low yields of progenies inheriting only the paternal genome after UV-irradiation of eggs led to considerations on the occurrence of UV screening compounds in pelagic eggs. Mycosporine-like amino acids and gadusol were found in many marine and freshwater organisms, but their occurrence in fish eggs was not clearly related to a behavioral pattern and while gadusol appeared in higher proportions in pelagic marine eggs compared to benthic species, this statement did not apply in freshwater, and moreover the kind of compounds was related to phylogeny. Further studies on DNA photorepair could enlighten hypotheses to understand the mechanisms underlying the disparate results obtained in inducing androgenesis in different fish species. Gynogenesis was reported successful to produce clonal founders in the sea bass, but high numbers of meiotic individuals contaminating fully homozygous progenies highlighted the need for efficient DNA markers to distinguish mitotic gynogenetic individuals. Furthermore, gonad development was highly delayed in gynogenetic progenies enhancing the difficulties to produce clonal lines. A high variability between individuals in the success of uniparental reproduction brought out gamete characterization and quality as a prerequisite.

O trigo é um alimento básico da humanidade cuja demanda cresce proporcionalmente ao aumento populacional. Existe carência de pesquisas sobre o efeito da nutrição da planta doadora na resposta androgenética. Este trabalho teve por objetivo avaliar a influência de cinco concentrações de nitrogênio e de boro (25%, 50%, 100%, 150% e 200%) a partir da solução de Sarruge modificada, no cultivo de plantas de trigo doadoras de anteras visando à obtenção de estruturas embriogênicas androgenéticas. Para tanto, foram avaliados os componentes do rendimento (número de colmos, diâmetro e comprimento do colmo principal; comprimento, largura e área da folha bandeira; teor de clorofila da folha bandeira, distância entre a folha bandeira e o último nó e comprimento da espiga); o acúmulo de graus dias e duração do ciclo da semeadura até a coleta das espigas para a cultura de anteras; a formação de estruturas embriogênicas androgenéticas e o desenvolvimento dos micrósporos (tétrade, mononucleado central, mononucleado periférico, binucleado e pólen P). Constatou-se que as concentrações de nitrogênio afetaram significativamente os componentes do rendimento, a formação de estruturas embriogênicas androgenéticas e o desenvolvimento dos micrósporos. A duração do ciclo das plantas cultivadas na concentração de 25% de nitrogênio foi menor que nas demais doses, apresentando diferença de até 3,3 dias quando comparada às plantas submetidas a doses mais elevadas. Houve aumento linear na produção de estruturas embriogênicas androgenéticas em função das doses crescentes de nitrogênio utilizadas no cultivo das plantas doadoras das anteras. As doses de nitrogênio interferiram também no estádio de desenvolvimento dos micrósporos, para todas as variáveis estudadas. Essa influência no desenvolvimento dos micrósporos foi efetiva enquanto a folha bandeira menos um encontrava-se no primeiro terço de deslocamento em relação à distância total entre a folha bandeira e o último nó do colmo. As concentrações de boro utilizadas nas soluções de cultivo das plantas de trigo doadoras de anteras não influenciaram nos componentes do rendimento, na formação de estruturas embriogênicas, na duração do ciclo da planta e na maioria das variáveis estudadas com relação ao desenvolvimento dos micrósporos. O desenvolvimento dos micrósporos na espiga seguiu o padrão normal descrito para a espécie, independentemente dos nutrientes estudados. Concluiuse que as concentrações de nitrogênio influenciaram positivamente nos componentes do rendimento (exceto no comprimento da espiga), na formação de estruturas embriogênicas e na distância entre a folha bandeira e o último nó do colmo (marcador morfológico da coleta das espigas para cultura de anteras), enquanto que as concentrações de boro utilizadas no cultivo das plantas doadoras de anteras não apresentaram esse efeito. / Wheat is the staple food of humanity whose demand grows in proportion to the population growth. There is lack of research about the effect of the nutrition of the donor plant in the androgenetic response. This work aim for evaluate the influence of five concentrations of nitrogen and boron (25%, 50%, 100%, 150% and 200%) from the solution of Sarruge modified, in the cultivation of wheat plants donors of anthers aiming the obtainment of androgenetics embryogenic structures. Both for, were evaluated the yield components (number stalks, diameter and length of the main stem; length, width and area of flag leaf; chlorophyll content of flag leaf, distance between flag leaf and the last node and ear length); the accumulation of degree-days and cycle duration of sowing until collection of ears to the anther´s culture; the formation of androgenetics embryogenic structures and the development of microporous (determination of the number of cells in stages: tetrad, central mononucleate, peripheral mononucleate and binucleated and occurrence of pollen P). It was found that the concentrations of nitrogen significantly affected the yield components, the formation of androgenetics embryogenic structures and the development of microspores. The duration of the cycle of the cultivated plants in the concentration of 25% of nitrogen was lower than in other doses, presenting difference of up to 3.3 days when compared to plants subjected to higher doses. There was a linear increase in the production of androgenetics embryogenic structures in function of increasing doses of nitrogen used in cultivation of donor plants of the anthers. The doses of nitrogen interfered also at the stage of development of microspores, for all variables studied. This influence on the development of microspores was effective while the flag leaf less one was in the first third of displacement in relation to the total distance between the flag leaf and the last node of the culm. The concentrations of boron used in solutions of cultivation of wheat donors plants of anthers did not affect the income components, in the formation of embryogenic structures, on the duration of the cycle of the plant and in the majority of the variables studied in relation to the development of the microspores. The development of microspores in spike followed the normal pattern described for the species, regardless of the nutrients studied. It was concluded that the concentrations of nitrogen positively influenced in yield components (except the length of the ear), the formation of embryogenic structures on and the distance between the flag leaf and the last node of the culm (morphological marker of collection of ears to anther culture), while the concentrations of boron used for the cultivation of plants donated anthers did not have this effect.

O trigo é um alimento básico da humanidade cuja demanda cresce proporcionalmente ao aumento populacional. Existe carência de pesquisas sobre o efeito da nutrição da planta doadora na resposta androgenética. Este trabalho teve por objetivo avaliar a influência de cinco concentrações de nitrogênio e de boro (25%, 50%, 100%, 150% e 200%) a partir da solução de Sarruge modificada, no cultivo de plantas de trigo doadoras de anteras visando à obtenção de estruturas embriogênicas androgenéticas. Para tanto, foram avaliados os componentes do rendimento (número de colmos, diâmetro e comprimento do colmo principal; comprimento, largura e área da folha bandeira; teor de clorofila da folha bandeira, distância entre a folha bandeira e o último nó e comprimento da espiga); o acúmulo de graus dias e duração do ciclo da semeadura até a coleta das espigas para a cultura de anteras; a formação de estruturas embriogênicas androgenéticas e o desenvolvimento dos micrósporos (tétrade, mononucleado central, mononucleado periférico, binucleado e pólen P). Constatou-se que as concentrações de nitrogênio afetaram significativamente os componentes do rendimento, a formação de estruturas embriogênicas androgenéticas e o desenvolvimento dos micrósporos. A duração do ciclo das plantas cultivadas na concentração de 25% de nitrogênio foi menor que nas demais doses, apresentando diferença de até 3,3 dias quando comparada às plantas submetidas a doses mais elevadas. Houve aumento linear na produção de estruturas embriogênicas androgenéticas em função das doses crescentes de nitrogênio utilizadas no cultivo das plantas doadoras das anteras. As doses de nitrogênio interferiram também no estádio de desenvolvimento dos micrósporos, para todas as variáveis estudadas. Essa influência no desenvolvimento dos micrósporos foi efetiva enquanto a folha bandeira menos um encontrava-se no primeiro terço de deslocamento em relação à distância total entre a folha bandeira e o último nó do colmo. As concentrações de boro utilizadas nas soluções de cultivo das plantas de trigo doadoras de anteras não influenciaram nos componentes do rendimento, na formação de estruturas embriogênicas, na duração do ciclo da planta e na maioria das variáveis estudadas com relação ao desenvolvimento dos micrósporos. O desenvolvimento dos micrósporos na espiga seguiu o padrão normal descrito para a espécie, independentemente dos nutrientes estudados. Concluiuse que as concentrações de nitrogênio influenciaram positivamente nos componentes do rendimento (exceto no comprimento da espiga), na formação de estruturas embriogênicas e na distância entre a folha bandeira e o último nó do colmo (marcador morfológico da coleta das espigas para cultura de anteras), enquanto que as concentrações de boro utilizadas no cultivo das plantas doadoras de anteras não apresentaram esse efeito. / Wheat is the staple food of humanity whose demand grows in proportion to the population growth. There is lack of research about the effect of the nutrition of the donor plant in the androgenetic response. This work aim for evaluate the influence of five concentrations of nitrogen and boron (25%, 50%, 100%, 150% and 200%) from the solution of Sarruge modified, in the cultivation of wheat plants donors of anthers aiming the obtainment of androgenetics embryogenic structures. Both for, were evaluated the yield components (number stalks, diameter and length of the main stem; length, width and area of flag leaf; chlorophyll content of flag leaf, distance between flag leaf and the last node and ear length); the accumulation of degree-days and cycle duration of sowing until collection of ears to the anther´s culture; the formation of androgenetics embryogenic structures and the development of microporous (determination of the number of cells in stages: tetrad, central mononucleate, peripheral mononucleate and binucleated and occurrence of pollen P). It was found that the concentrations of nitrogen significantly affected the yield components, the formation of androgenetics embryogenic structures and the development of microspores. The duration of the cycle of the cultivated plants in the concentration of 25% of nitrogen was lower than in other doses, presenting difference of up to 3.3 days when compared to plants subjected to higher doses. There was a linear increase in the production of androgenetics embryogenic structures in function of increasing doses of nitrogen used in cultivation of donor plants of the anthers. The doses of nitrogen interfered also at the stage of development of microspores, for all variables studied. This influence on the development of microspores was effective while the flag leaf less one was in the first third of displacement in relation to the total distance between the flag leaf and the last node of the culm. The concentrations of boron used in solutions of cultivation of wheat donors plants of anthers did not affect the income components, in the formation of embryogenic structures, on the duration of the cycle of the plant and in the majority of the variables studied in relation to the development of the microspores. The development of microspores in spike followed the normal pattern described for the species, regardless of the nutrients studied. It was concluded that the concentrations of nitrogen positively influenced in yield components (except the length of the ear), the formation of embryogenic structures on and the distance between the flag leaf and the last node of the culm (morphological marker of collection of ears to anther culture), while the concentrations of boron used for the cultivation of plants donated anthers did not have this effect.

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