No description available.

No description available.

The aim of this research was to study the effects of Salinity & Heavy Metals on the Sporophyte & Gametophyte generations of Arabidopsis thaliana. After developing a pollen germinating protocol, some basic experiments were conducted to determine the effects on chemical & physical parameters on pollen germination & pollen tube growth. Additions of heavy metals & high concentrations of buffer (Tris-HCI) in pollen germinating medium (PGM), inhibited pollen germination (PG) & pollen tube length (PTL), while pH range (7.0-9.0) had little effect. The idea of 2-fold effect (nutritional & osmotic) of sucrose was supported in results. In vivo pollen growth was much greater than in vitro & genotypic differences occurred among the mutants for PG & PTL. Comparing the pollen nutritional requirements for PG & PTL between Cicer arietinum & A. thaliana, it was noted that the pollen of the former had a greater requirement for H(_3)BO(_3) & Ca(N0(_3))(_2) than latter. The range of temperatures (0 C-35 C) studied, indicated that the most favourable temperature for PG was 20 C & for PTL 25 C , while extreme temperatures (0 C, 35 C) were harmful to A. thaliana pollen. 20 C was found to be optimum temperature for PG & PTL of C. arietinum. Correlation between pollen tube growth rates (PTGRs) and sporophytic traits of Fls showed a generally strong positive correlation with most of sporophytic traits, but a very loose to negative correlation for earliness parameters. Recording the impacts of salinity, parallel effects were found for the sporophytic & gametophytic generations of the plant, as reported by earlier workers. The results also indicated that it is possible to develop a pollen plant salinity index (PPSI) for plant species under specific plant growing conditions. It was also observed that salinity stress during pollen gametogenesis preconditioned pollen to high salinity levels, resulting in higher PG & PTL than in pollen raised under non-saline conditions. Similarly, the fruit-setting, seed-setting & seed-filling were relatively less affected by saline-stress, in progeny when pollen and pistilate plants were grown under similar saline regimes. Anatomical studies showed that salinity induced changes in the epidermis, cortex, pericycle, xylem, pith & cross sectional diameter of vascular bundle (CSDVB) in stem, leaf & root tissues. Lower reductions for the fruit-setting, seed-setting & seed-filling were recorded in response to the high heavy metal concentrations in progeny when pollen and pistilate plants were raised under similar heavy metal regimes. It was apparent that pollen become conditioned to a stress environment during its development in the anthers of stressed plants, & this preconditioning allowed its pollen tubes to grow more successfully in the styles of the female parents growing in a similarly stressed environment, where the pistil may have accumulated higher levels of heavy metals. Heavy metals induced changes in stem shape, epidermis, cortex, vascular bundles & chloroplasts in stems. The metals induced changes in the leaf thickness, epidermis, palisade cell size, spongy mesophyll area, size of intercellular spaces & chloroplasts in the leaf, causing disruption of cortical layers, lignification of pericycle & phloem, damage to the endodermis and increase in xylem cell size & stele diameter in roots.

No description available.

Climate change is one of the biggest challenges facing agriculture today. Transient or prolonged heat stress can be detrimental to plant reproductive development. The male gametophyte, pollen, is particularly sensitive to heat stress, resulting in sterile pollen (pre-anthesis) or deformed/stunted pollen tubes (post-anthesis). Quinoa (Chenopodium quinoa Willd.) has recently seen a rise in global interest due to its nutritional qualities, but global expansion of quinoa is partially hindered by its susceptibility to heat. It has been hypothesized that introgression of heat tolerance traits from wild relatives that occupy warmer environments can increase thermotolerance in quinoa. The goal of this research was to investigate the effect of heat stress on mature pollen grains from quinoa and its wild relatives, C. berlandieri and C. hircinum. To answer this question, several experiments were performed: 1. The nuclear number of the pollen of wild relatives was assessed to determine whether mature pollen grains were released at the trinucleate stage. All pollen was found to be trinucleate. 2. Pollen germination medium was optimized for four accessions: C. quinoa (QQ74; PI 614886), C. berlandieri var. zschackei (CB; BYU14118), and C. hircinum (CHA; Hircinum-069 and CHC; BYU17105). Optimal sucrose and PEG concentrations were determined to be: 5% sucrose/20% PEG for QQ74 and CB; 20% sucrose/0% PEG for CHA; and 10% sucrose/20% PEG for CHC. 3. Temperature optima for pollen germination for QQ74 was 32°C-36°C; CB was 30°C-34°C; CHA was 36°C; and CHC was 32°C -34°C. Overall, pollen from wild relatives was not found to be more heat-tolerant than pollen from domesticated quinoa. 4. Pollen tube elongation over time was observed for all four accessions at 34°C and 38°C, with CHA and QQ74 having the lowest decrease in rate at 38°C (35 and 45%, respectively). This study provides a new method for pollen collection for quinoa and its wild relatives, further optimizes the pollen germination media for QQ74, introduces pollen germination media for three wild accessions, and investigates the effect of heat stress on mature pollen grains. These observations can be employed in future studies investigating heat stress response of pollen in quinoa and its wild relatives.

We are now witnessing changing environmental conditions and these changes will likely continue into the coming decades due to projected increases in temperatures on the earth surface. Recent model projections suggest that the global mean surface air temperatures will increase by 1.4 to 5.8 °C by 2100. The consequences of these high temperatures include reductions in crop yields. Soybean is one of the major crops grown in the US, where high temperatures (>35 °C) during reproductive growth decreased yield. Two experiments were conducted to determine the effects of temperature on soybean pollen germination properties and identify responses to temperature among genotypes. Pollen collected from 44 genotypes grown outdoors in large pots was subjected to in vitro temperature treatments that varied from 15 to 50 °C at 5 °C increments in Experiment I. The mean cardinal temperatures (Tbase, Topt, and Tmax), averaged over 44 genotypes, were 13.2, 30.2 and 47.2 °C for pollen germination and 12.1, 36.1 and 47.0 °C for pollen tube growth. The relationship between Tbase and Topt for pollen germination was high indicating that genotypes with high Tbase also had higher Topt. The relationship was weak between Tbase and Tmax. The Topt for pollen tube growth was 5.8 ¢XC higher than the Topt for pollen germination. The study also showed significant genotypic variability for physiological parameters studied, but no significant correlations between the observed physiological parameters with any of the pollen germination or pollen tube growth parameters were studied. This indicated that physiological parameters, measured under ambient conditions may not be useful to identify reproductive tolerance to high temperatures in soybean. Total response index (TSRI), the sum of individual responses of all pollen parameters differentiated genotypes and their tolerance to high temperature. A heat-tolerant genotype (DG 5630RR) identified using TSRI technique, when grown at optimum and high temperature conditions in experiment II, were actually less sensitive to high temperatures compared to heat-sensitive and heat-intermediate sensitive genotypes indicating that pollen can be used as screening tool for heat tolerance. The identified high-temperature tolerant genotypes, based on pollen germination parameters, might be useful in current and future soybean breeding programs.

Made available in DSpace on 2014-08-20T14:22:09Z (GMT). No. of bitstreams: 1 Dissertacao_Thais_Cappellaro.pdf: 4211704 bytes, checksum: d61c0d95003eba8753dc50509ea70b01 (MD5) Previous issue date: 2010-03-26 / The olive tree (Olea europaea L.) is a member of the Oleaceae family which includes about 35 species of the genera Olea. All native and cultivated olive trees belong to the Olea europaea species. Researches with olive trees have recently been restarted in Brazil, and that is why there are little informations about this crop in this country. For this reason, it is important to develop studies about bloom period and pollen viability on olive cultivars such as Arbequina and Koroneiki. The objectives for this study were: to define the blooming period; to compare methods for pollen viability evaluation; to evaluate the effects of boric acid added to the medium on pollen germination; and to evaluate the viability of 12 months cold stored pollen, for these two cultivars. The data of bloom period for the two cultivars were obtained from 5 year-old trees grown in an orchard located in Bagé-RS, through observations made during the blooming period in the years of 2008 and 2009. Pollen viability of these two cultivars, were evaluated through three experiments in a laboratory. The first experiment were compared three methods of pollen viability evaluation: colorimetric method; in vitro germination; and in vivo germination. The variable was the pollen viability expressed as percentage (colorimetric, identified only by staining of pollen in vitro and in vivo, the percentage of pollen germinated). The second experiment were compared the effects on pollen germination of boric acid concentrations (0; 25; 50; 75; 100; or 125 mg.L-1) added to the germination medium containing agar 1% plus sucrose 15%. In a third experiment, pollens of both cultivars placed inside desiccators containing silica-gel and kept at -16°C for 12 months, were evaluated on their germination viability. It was observed that: In 2008, both cultivars started bloom on October 16th, and end of blooming on November 11th, while in 2009 the starting of bloom was on October 20th and the end of blooming on November 3rd for both cultivars. Therefore the blooming period was shorter in 2009 (21 days) as compared to that of 2008 (27 days); the colorimetric method make possible to identify highest percentages of viable pollen grains, however this method may overestimate pollen viability; the addition of boric acid to the media do not affect pollen germination; and pollen of both cultivars decreased their viability when stored in desiccators at -16°C during 12 months. / A oliveira (Olea europaea L.) pertence à família Oleaceae, a qual é composta por cerca de 35 espécies do gênero Olea. Todas as oliveiras cultivadas e as silvestres são da espécie europaea. No Brasil, há pouca pesquisa em realização, a qual foi praticamente interrompida nos últimos 30 anos. Somente nesta última década, a pesquisa com oliveiras foi reiniciada. Portanto, as informações técnicas obtidas em condições nacionais são quase inexistentes. Assim, é importante a realização de pesquisas para obtenção de conhecimentos quanto aos principais aspectos técnicos que abrangem sistemas de produção. O presente trabalho teve como objetivos determinar o período de floração e a viabilidade do pólen das cultivares de oliveira Arbequina e Koroneiki , em Bagé/RS, nos anos de 2008 e 2009. As avaliações do período de floração foram realizadas entre os meses de setembro a novembro. O delineamento foi inteiramente casualizado, sendo utilizado quatro repetições (planta). Em cada planta foram selecionados cerca de 200 rácimos florais por quadrante imaginário (Leste, Oeste, Norte e Sul), totalizando aproximadamente 800 rácimos/planta. Nos ramos e rácimos florais, identificou-se o estádio fenológico de cada estrutura vegetativa ou reprodutiva, utilizando a metodologia adaptada por Fernández- Escobar e Rallo (1981), na qual são definidos, resumidamente: a) repouso invernal (dormente); b) começo da brotação; c) formação dos rácimos florais; d) inchamento dos botões florais; e) diferenciação das corolas; f) início da floração; f1) plena floração; g) queda das pétalas; h) formação dos frutos. Para avaliar a viabilidade do pólen conduziram-se três experimentos em Laboratório, nos anos de 2008 e 2009. O primeiro experimento constou de diferentes testes de viabilidade do pólen (colorimétrico, germinação in vitro e germinação in vivo). A variável avaliada foi à viabilidade do pólen expressa em porcentagem (teste colorimétrico, identificada somente pela coloração do pólen; testes in vitro e in vivo, pela percentagem de pólen germinado). O segundo experimento foi composto de diferentes concentrações de ácido bórico (0, 25, 50, 75,100 e 125 mg.L-1) adicionadas a meios de culturas compostos por 1% de ágar e 15% de sacarose. A variável avaliada foi viabilidade do pólen caracterizada pela porcentagem de pólen germinado. O terceiro experimento comparou a viabilidade de polens armazenados durante 12 meses em dessecadores com sílica-gel com polens frescos (coletado e colocado para germinar após a deiscência das anteras). A variável avaliada foi viabilidade do pólen caracterizada pela ii porcentagem de pólen germinado. Segundo a metodologia utilizada, a floração das oliveiras Arbequina e Koroneiki , em 2008 e 2009, teve início nos dias 16 e 20 de outubro e término nos dias 11 e 09 de novembro. O período de floração para as duas cultivares, nos anos de 2008 e 2009 foi idêntico, sendo 27 e 15 dias, respectivamente. O método colorimétrico superestima o percentual de polens viáveis em oliveiras Arbequina e Koroneiki . O uso de ácido bórico no meio de cultura não influencia na germinação in vitro de pólen de cultivares de oliveira Arbequina e Koroneiki. Polens de oliveiras Arbequina e Koroneiki , armazenados a -16°C em dessecador com sílica-gel, durante doze meses, diminuem a porcentagem de viabilidade em ambas as cultivares. A oliveira (Olea europaea L.) pertence à família Oleaceae, a qual é composta por cerca de 35 espécies do gênero Olea. Todas as oliveiras cultivadas e as silvestres são da espécie europaea. No Brasil, há pouca pesquisa em realização, a qual foi praticamente interrompida nos últimos 30 anos. Somente nesta última década, a pesquisa com oliveiras foi reiniciada. Portanto, as informações técnicas obtidas em condições nacionais são quase inexistentes. Assim, é importante a realização de pesquisas para obtenção de conhecimentos quanto aos principais aspectos técnicos que abrangem sistemas de produção. O presente trabalho teve como objetivos determinar o período de floração e a viabilidade do pólen das cultivares de oliveira Arbequina e Koroneiki , em Bagé/RS, nos anos de 2008 e 2009. As avaliações do período de floração foram realizadas entre os meses de setembro a novembro. O delineamento foi inteiramente casualizado, sendo utilizado quatro repetições (planta). Em cada planta foram selecionados cerca de 200 rácimos florais por quadrante imaginário (Leste, Oeste, Norte e Sul), totalizando aproximadamente 800 rácimos/planta. Nos ramos e rácimos florais, identificou-se o estádio fenológico de cada estrutura vegetativa ou reprodutiva, utilizando a metodologia adaptada por Fernández- Escobar e Rallo (1981), na qual são definidos, resumidamente: a) repouso invernal (dormente); b) começo da brotação; c) formação dos rácimos florais; d) inchamento dos botões florais; e) diferenciação das corolas; f) início da floração; f1) plena floração; g) queda das pétalas; h) formação dos frutos. Para avaliar a viabilidade do pólen conduziram-se três experimentos em Laboratório, nos anos de 2008 e 2009. O primeiro experimento constou de diferentes testes de viabilidade do pólen (colorimétrico, germinação in vitro e germinação in vivo). A variável avaliada foi à viabilidade do pólen expressa em porcentagem (teste colorimétrico, identificada somente pela coloração do pólen; testes in vitro e in vivo, pela percentagem de pólen germinado). O segundo experimento foi composto de diferentes concentrações de ácido bórico (0, 25, 50, 75,100 e 125 mg.L-1) adicionadas a meios de culturas compostos por 1% de ágar e 15% de sacarose. A variável avaliada foi viabilidade do pólen caracterizada pela porcentagem de pólen germinado. O terceiro experimento comparou a viabilidade de polens armazenados durante 12 meses em dessecadores com sílica-gel com polens frescos (coletado e colocado para germinar após a deiscência das anteras). A variável avaliada foi viabilidade do pólen caracterizada pela ii porcentagem de pólen germinado. Segundo a metodologia utilizada, a floração das oliveiras Arbequina e Koroneiki , em 2008 e 2009, teve início nos dias 16 e 20 de outubro e término nos dias 11 e 09 de novembro. O período de floração para as duas cultivares, nos anos de 2008 e 2009 foi idêntico, sendo 27 e 15 dias, respectivamente. O método colorimétrico superestima o percentual de polens viáveis em oliveiras Arbequina e Koroneiki . O uso de ácido bórico no meio de cultura não influencia na germinação in vitro de pólen de cultivares de oliveira Arbequina e Koroneiki. Polens de oliveiras Arbequina e Koroneiki , armazenados a -16°C em dessecador com sílica-gel, durante doze meses, diminuem a porcentagem de viabilidade em ambas as cultivares.

Submitted by Luis Ricardo Andrade da Silva (lrasilva@uefs.br) on 2016-02-22T22:50:07Z No. of bitstreams: 1 Disserta??o_Alex_RGV_Final2.pdf: 2862200 bytes, checksum: e222cf5496c76484ec34f8fdd9012d23 (MD5) / Made available in DSpace on 2016-02-22T22:50:07Z (GMT). No. of bitstreams: 1 Disserta??o_Alex_RGV_Final2.pdf: 2862200 bytes, checksum: e222cf5496c76484ec34f8fdd9012d23 (MD5) Previous issue date: 2015-11-16 / Conselho Nacional de Pesquisa e Desenvolvimento Cient?fico e Tecnol?gico - CNPq / In Brazil, research on Arecaceae pollen grains are related to melissopalynology, the palynotaxonomy, being scarce the physiology of pollen. Reproductive biology studies pollination are of great importance in different cultures, from their results can obtain parameters to be used to obtain a considerable increase in the production of croops, as well as the size and quality of fruits, helping for good economic income of the producers. In vitro pollen germination also allows you to check its viability and reproductive strength, and are important tools in breeding programs of plants, assisting in the selection of the most effective genotypes and training hybrids. The chapter one of this work consists of evaluation of the type of culture medium and implications on the choice of micronutrients which form part of its composition, as well as the pretreatment of specimens. It was observed that oil palm pollen (Elaeis guineensis Jacq.) Showed an increase in germination rates after being dissected for a period of four hours and the culture medium with only boric acid and calcium nitrate, in addition to the power source (sucrose) are efficient to display their germination potential. Chapter two contained in the evaluation glycoconjugate (lectins) on the pollen germination of oil palm, which was discussed metabolic interactions of these processes. Lectins are important regulators and operate in recognition and acknowledgment of pollen on the pistil and can act as genetic incompatibility factors. Germination was evaluated in BCa means (boron and calcium) with the addition of lectins: Crotalaria pallida lectin (CPL), Concanavalin A (ConA) and Jacalin (JAC) in two concentrations. An increase of the germination rate in the presence of ConA and CPL lectins and inhibition in the presence of JAC. The results of this study were valuable, since aggregate informative values and extend discussions on the processes involving the germination of pollen grains and formation of pollen tubes of oil palm. / No Brasil, pesquisas com gr?os de p?len da fam?lia Arecaceae est?o relacionados ? melissopalinologia e palinotaxonomia, sendo escassos aqueles voltados ? fisiologia do p?len. Estudos de biologia reprodutiva relacionados ? poliniza??o s?o de grande import?ncia nas diversas culturas, visto que a partir dos seus resultados pode se obter par?metros a serem utilizados visando o aumento consider?vel da produ??o de plantas cultivadas, bem como no tamanho e na qualidade dos frutos, contribuindo para bons rendimentos econ?micos dos produtores. A germina??o de gr?os de p?len in vitro tamb?m permite verificar seu vigor reprodutivo, sendo importante ferramentas em programas de melhoramento gen?tico de plantas, auxiliando na sele??o de gen?tipos mais eficazes para cruzamentos e forma??o de h?bridos. O cap?tulo um deste trabalho teve como prop?sito avaliar o tipo de meio de cultura e as implica??es da escolha dos micronutrientes que fazem parte da sua composi??o, bem como do tratamento pr?vio das amostras. Foi observado que o p?len de dendezeiro (Elaeis guineensis Jacq.) apresentou aumento nas taxas de germina??o depois de ser desidratado por um per?odo de quatro horas e que o meio de cultura com apenas ?cido b?rico e nitrato de c?lcio, al?m da sacarose como fonte de energia, s?o eficientes para exibir o potencial germinativo. O cap?tulo dois consta da avalia??o de prote?nas glicoconjugadas (lectinas) sobre a germinabilidade pol?nica do dendezeiro. Foram discutidas as intera??es metab?licas desses processos, bem como o papel das lectinas que s?o importantes reguladores sobre a recogni??o e reconhecimento do p?len no pistilo, podendo atuar como fatores de incompatibilidade gen?tica. Foi avaliada a germina??o em meio BCa (boro e c?lcio) com adi??o das lectinas: Lectina de Crotalaria pallida Aiton (CPL), Concanavalina A (ConA) e Jacalina (JAC), em duas concentra??es. Verificou-se aumento das taxas de germina??o na presen?a das lectinas CPL e ConA e inibi??o da germina??o na presen?a da JAC. Os resultados deste trabalho agregam valores informativos sobre a compreens?o da biologia reprodutiva de dendezeiro (Arecaceae) ocorrente na ?Costa do Dend??/Bahia e ampliam as discuss?es sobre os processos que envolvem a germina??o de gr?os de p?len e forma??o dos tubos pol?nicos.