A study of nucleic acid changes influenced by gibberellic acid and chilling treatments in peach seed was performed in an attempt to reach a better understanding of the mechanism involved in breaking seed dormancy. Gibberellic acid and the chilling treatment increased the RNA content. These two treatments which break dormancy also increased RNA, suggesting a similar mechanism involving RNA. Chilled seeds contained more RNA than did the gibberellic acid treated seeds. DNA content remained unchanged regardless of treatment. Dry seed had a greater ribonuclease activity than with soaked seeds. Enzyme changes did not correlate well with the RNA content in gibberellic treated seeds. Deoxyribonuclease activity was higher in dry seed than with soaked seeds. Enzyme activity change did not correlate well with the DNA content. The phosphorus content of the seed in regard to the gibberllic acid and chilling treatments was difficult to evaluate. There were no major relationships established. Phosphorus in the methanol fraction from the chilled seed increased some as the storage period increased.

Tez (Yüksek Lisans) - Süleyman Demirel Üniversitesi, Fen Bilimleri Enstitüsü, Biyoloji Anabilim Dalı, 2008. / Kaynakça var.

Fungi and Oomycetes represent the two most important groups of eukaryotic plant pathogens. Besides chemical and physical control of these pathogens, biological control is an approach enjoying increasingly more focus. One of the biological agents increasingly employed in biological control of plant pathogenic fungi is ironically the fungus Trichoderma, more specifically Trichoderma harzianum. Besides control of the fungal plant pathogens, another interesting aspect observed when plants are treated with Trichoderma harzianum are effects such as complete and even stand of plants, faster seed germination, increases in plant height and overall enhanced plant growth. Though there have been various studies on this effect, almost no research has yet been conducted to elucidate the mechanism by which these effects occur. In particular, effects such as faster seed germination suggest that Trichoderma harzianum produces a metabolite that may mimic the plant growth hormone gibberellic acid. Through an evaluation of the various metabolites produced by Trichoderma harzianum; gliotoxin seemed structurally most similar to gibberellic acid. To verify that gliotoxin can indeed serve as an analogue for gibberellic acid and elicit similar physiological responses in plants, a two–pronged approach was followed. Firstly, molecular similarity evaluation through common pharmacophore evaluation was conducted, followed by docking simulations into the recently discovered receptor for gibberellic acid. Common pharmacophore evaluation between gibberellic acid and gliotoxin showed successful alignment of gliotoxin into the gibberellic acid based pharmacophore space. Furthermore, docking simulations further strengthened this by the similarity in docking scores calculated and the similar poses of the ligands (gliotoxin and gibberellic acid) in the receptor space. However, similarity in pharmacophore alignment and docking simulation results only suggest that gliotoxin should be able to occupy the receptor space, but it is not a guarantee that similar physiological responses will be elicited. In the second part of the project, the ability of gliotoxin to elicit similar physiological responses in plants to gibberellic acid was investigated. For this, a–amylase induction; plant emergence and height; and chlorophyll fluorescence were compared for both gliotoxin and gibberellic acid treatments. In terms of a–amylase induction, gliotoxin was able to induce production of the enzyme as visualised by starch–containing native gel electrophoresis (zymograms). Gliotoxin induced the strongest response at a 10–6 M dilution which is typically the range expected for hormones in biological systems in de–embryonated seeds of Phaseolus vulgaris. Gibberellic acid was able to induce the strongest response at a 10–7 M dilution. In essence, similar physiological responses were observed. In terms of plant emergence and plant height, treatment with gliotoxin or gibberellic acid resulted in plant emergence a day earlier than the untreated control. However, even though there were slight differences in plant height favouring the gliotoxin or gibberellic acid treated plants, the differences were not statistically significant. Thus, in this regard similar responses were again observed for both gliotoxin and gibberellic acid treatments. In the final evaluation the effect of gliotoxin and gibberellic acid treatments on the chlorophyll fluorescence of mature plants was investigated. Overall, both gliotoxin and gibberellic acid elicited beneficial effects on plant vitality, expressed through PI(Abs) with the gliotoxin treatment performing better than the equivalent gibberellic acid treatment. Overall, the physiological tests demonstrated that gliotoxin can indeed elicit similar positive physiological responses to gibberellic acid in Phaseolus vulgaris. Furthermore the test used in this project can serve as a standard evaluation bench for screening for gibberellic acid analogues on a laboratory scale before larger scale field trials are considered. / Thesis (Ph.D. (Microbiology))--North-West University, Potchefstroom Campus, 2012.

Fungi and Oomycetes represent the two most important groups of eukaryotic plant pathogens. Besides chemical and physical control of these pathogens, biological control is an approach enjoying increasingly more focus. One of the biological agents increasingly employed in biological control of plant pathogenic fungi is ironically the fungus Trichoderma, more specifically Trichoderma harzianum. Besides control of the fungal plant pathogens, another interesting aspect observed when plants are treated with Trichoderma harzianum are effects such as complete and even stand of plants, faster seed germination, increases in plant height and overall enhanced plant growth. Though there have been various studies on this effect, almost no research has yet been conducted to elucidate the mechanism by which these effects occur. In particular, effects such as faster seed germination suggest that Trichoderma harzianum produces a metabolite that may mimic the plant growth hormone gibberellic acid. Through an evaluation of the various metabolites produced by Trichoderma harzianum; gliotoxin seemed structurally most similar to gibberellic acid. To verify that gliotoxin can indeed serve as an analogue for gibberellic acid and elicit similar physiological responses in plants, a two–pronged approach was followed. Firstly, molecular similarity evaluation through common pharmacophore evaluation was conducted, followed by docking simulations into the recently discovered receptor for gibberellic acid. Common pharmacophore evaluation between gibberellic acid and gliotoxin showed successful alignment of gliotoxin into the gibberellic acid based pharmacophore space. Furthermore, docking simulations further strengthened this by the similarity in docking scores calculated and the similar poses of the ligands (gliotoxin and gibberellic acid) in the receptor space. However, similarity in pharmacophore alignment and docking simulation results only suggest that gliotoxin should be able to occupy the receptor space, but it is not a guarantee that similar physiological responses will be elicited. In the second part of the project, the ability of gliotoxin to elicit similar physiological responses in plants to gibberellic acid was investigated. For this, a–amylase induction; plant emergence and height; and chlorophyll fluorescence were compared for both gliotoxin and gibberellic acid treatments. In terms of a–amylase induction, gliotoxin was able to induce production of the enzyme as visualised by starch–containing native gel electrophoresis (zymograms). Gliotoxin induced the strongest response at a 10–6 M dilution which is typically the range expected for hormones in biological systems in de–embryonated seeds of Phaseolus vulgaris. Gibberellic acid was able to induce the strongest response at a 10–7 M dilution. In essence, similar physiological responses were observed. In terms of plant emergence and plant height, treatment with gliotoxin or gibberellic acid resulted in plant emergence a day earlier than the untreated control. However, even though there were slight differences in plant height favouring the gliotoxin or gibberellic acid treated plants, the differences were not statistically significant. Thus, in this regard similar responses were again observed for both gliotoxin and gibberellic acid treatments. In the final evaluation the effect of gliotoxin and gibberellic acid treatments on the chlorophyll fluorescence of mature plants was investigated. Overall, both gliotoxin and gibberellic acid elicited beneficial effects on plant vitality, expressed through PI(Abs) with the gliotoxin treatment performing better than the equivalent gibberellic acid treatment. Overall, the physiological tests demonstrated that gliotoxin can indeed elicit similar positive physiological responses to gibberellic acid in Phaseolus vulgaris. Furthermore the test used in this project can serve as a standard evaluation bench for screening for gibberellic acid analogues on a laboratory scale before larger scale field trials are considered. / Thesis (Ph.D. (Microbiology))--North-West University, Potchefstroom Campus, 2012.

Diss. (sammanfattning) Umeå : Sveriges lantbruksuniv., 2007. / Härtill 4 uppsatser.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2006. / Härtill 3 uppsatser.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The aim of this study was to evaluate the effect of growth regulator products in seed treatment, on the physiological potential and biochemical activity at normal conditions and drought; the physiological potential in salt stress; the growth models; and the field performance and productivity of maize hybrids. Thus, different experiments were conducted in the laboratory and an experimental field area using maize hybrids (30F53H and CD393) and the products: gibberellic acid, Stimulate® and thiamethoxam. In general, the effect of the products on the function of plant growth regulator in the seed treatment varies according to the hybrid and the environmental conditions. Gibberellic acid and Stimulate promote an increase on germination rate in both normal and stressed conditions. All products acted beneficially on the seeding establishment of maize in the field. Treatment with thiamethoxam and Stimulate allow faster growth rates. However, the observed differences in vigor and growth are not reflected in higher productivity. Moreover, superoxide dismutase and guaiacol peroxidase do not result the improved performance of plants under water deficit, when treated with growth regulator products. / O objetivo do presente trabalho foi avaliar a interferência de produtos reguladores de crescimento, no tratamento de sementes, sobre: o potencial fisiológico e a atividade bioquímica em condições normais e de déficit hídrico; o potencial fisiológico em condições de estresse salino; os modelos de crescimento; e, o desempenho em campo e produtividade de híbridos de milho. Para isso, diferentes experimentos foram conduzidos em laboratório e, em área experimental de campo, utilizando híbridos de milho e os produtos: ácido giberélico, Stimulate® e tiametoxam. De maneira geral, o efeito dos produtos com função de regulador do crescimento vegetal, no tratamento de sementes varia com o híbrido utilizado e com o ambiente. Ácido giberélico e stimulate® promovem aumento na velocidade de germinação tanto em condições normais quanto, quando submetidas a estresses. Todos os produtos atuam de forma benéfica sobre o estabelecimento das plântulas de milho em campo. O tratamento de sementes com tiametoxam e Stimulate®, possibilita maior taxa de crescimento. No entanto, as diferenças de vigor e crescimento observadas não se refletem em maior produtividade. Além disso, superóxido dismutase e guaiacol peroxidase não apresentam relação com o melhor desempenho de plantas sob deficiência hídrica, quando tratadas com produtos reguladores de crescimento.

Orientador: João Domingos Rodrigues / Resumo: O presente trabalho foi conduzido na área experimental do Departamento de Engenharia Rural da Faculdade de Ciências Agronômicas - FCA, UNESP, campus de Botucatu/SP, com o objetivo de estudar a indução floral de Zantedeschia sp, com a aplicação de ácido giberélico (GA3), fornecido via água de irrigação, aplicação foliar e tratamento por imersão, nas condições de Botucatu/SP, a fim de se determinar a dosagem, a época e o modo de aplicação, visando-se otimizar o sistema instalado, facilitando o manejo da cultura. Não foi possível avaliar estatisticamente os dados referentes à produtividade de flores, pois estes não apresentaram distribuição normal de probabilidade, alguns tratamentos não emitiram flores. Considerando o número total de flores produzidas ao longo de 86 dias, o tratamento convencional por imersão pré-plantio (100 mg.L-1) emitiu 4 flores, num total de 10 vasos; enquanto que os tratamentos T12 (15 dias pós plantio-200 mg.L-1 de GA3) e T35 (15+30 dias pós plantio-500 mg.L-1 de GA3) produziram 7 e 6 flores, respectivamente, por 10 vasos. Os demais tratamentos produziram quantidades inferiores em relação à testemunha. A ausência de produção para alguns tratamentos e a baixa produtividade dos tratamentos em geral, pode ter ocorrido devido ao longo período de armazenamento dos bulbos, acima de oito meses, compromentendo a integridade física do material botânico, pelo ressecamento ou suberização dos tecidos externos do bulbo dificultando a penetração da solução do regulador vegetal. / Abstract: This study was conducted in the experimental site of the Rural Engineering Departament of the Agronomical Sciencies College - FCA, UNESP, campus of Botucatu, with the objective of study the Zantedeschia sp flower induction by gibberellic acid (GA3) application, supplied by irrigation system, foliar application and preplant immersion, in the Botucatu/SP conditions, to determined the application concentration, epoch and mode. With the purpose of optimize the system installed, faciliting the culture management. It not possible evaluation statisticment datas of flowers production, because datas no presented normal probability distribution. Some treatments did not producted flowers. Considering the total flowers production during 86 days, results were: the mean production of standard treatment, preplant immersion (100 mg.L-1), was compatible with de São Paulo state farmers (4 flowers/10 pots); while treatments T12 (15 days after plant -200 mg.L-1 of GA3) e T35 (15+30 days after plant - 500 mg.L-1 of GA3) producted 7 and 6 flowers, respectivement, in 10 pots. Others treatments producted fewer when compared with standard treatment. No production and the fewer productived of some treatments can occurred owing storage duration. Increasing duration of tuber storage reduce flowering, because reduces the plants sensitivity and ability to absorb the gibberellins. / Doutor

Made available in DSpace on 2014-06-11T19:26:08Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-07-29Bitstream added on 2014-06-13T20:54:09Z : No. of bitstreams: 1 vedovato_npf_me_jabo.pdf: 472091 bytes, checksum: 2541548e6ff5199c3f8bd4fe048ab8f9 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O pinhão-manso (Jatropha curcas L.) é uma oleaginosa da família Euphorbiaceae, que se destaca pelo seu grande potencial sócio econômico e como uma excelente alternativa para a produção de biodiesel. O presente trabalho teve como objetivo principal a padronização e otimização de protocolos de cultivo in vitro para embriões e sementes com adição dos suplementos complexo vitamínico e ácido giberélico em meio MS, visando a obtenção de plântulas assépticas para a extração de explantes que serão utilizados em outros processos de cultura de tecidos e transformação genética para a produção futura de mudas comerciais padronizadas. No primeiro experimento com embriões, em meio MS com sacarose e ágar foram acrescidas várias dosagens de um complexo vitamínico (0,0; 0,5; 1,0; 2,0; 3,0 e 4,0 ml.L-1) e após duas semanas do estabelecimento, dez variáveis foram analisadas. Foi utilizado o delineamento inteiramente casualizado com quatro repetições. Os dados foram submetidos à análise de variância, e as variáveis significativas tiveram suas médias comparadas pelo teste Tukey (5%) e algumas pela regressão polinomial. Os resultados indicaram que a adição de vitaminas ao meio de cultura não é essencial para a germinação e crescimento inicial. No entanto, para a formação de raízes, a presença do complexo vitamínico forneceu incrementos nos resultados. A presença de folhas também respondeu positivamente com o aumento da dosagem de vitaminas. No segundo experimento com as sementes, várias dosagens de ácido giberélico GA3 (0,0; 1,0; 2,0; 4,0; 6,0 e 8,0 mg.L-1) foram acrescentadas em meio MS com sacarose e ágar e após duas semanas dez variáveis foram analisadas. Foi utilizado o delineamento inteiramente casualizado com quatro repetições. Os dados foram submetidos à análise de variância... / The phisic nut (Jatropha curcas L.) is an oil family Euphorbiaceae, which is distinguished by its great potential economic partner and as an excellent alternative to produce biodiesel. The present work had as main objective the standardization and optimization of protocols for in vitro embryos and seeds with the addition of multivitamin supplements and gibberellic acid on MS medium, in order to obtain seedlings for the extraction of aseptic explants to be used in other processes of tissue culture and genetic transformation for the future production of standard commercial seedlings. In the first experiment with embryos in MS medium with sucrose and agar were added various doses of a vitamin complex (0.0, 0.5, 1.0, 2.0, 3.0 and 4.0 ml.l-1) and after two weeks of the establishment, ten variables were analyzed. We used a completely randomized design with four replications. Data were subjected to analysis of variance, and the significant variables had their means compared by Tukey test (5%) and some by polynomial regression. The results indicated that the addition of vitamins to the culture medium is not essential for germination and early growth. However, for root formation, the presence of vitamin complex increments provided in the results. The presence of leaves also responded positively by increasing the dosage of vitamins. In the second experiment with the seeds, various doses of gibberellic acid GA3 (0.0, 1.0, 2.0, 4.0, 6.0 and 8.0 mg.L-1) were added in MS medium with sucrose and agar, and after two weeks ten variables were analyzed. We used a completely randomized design with four replications. Data were subjected to analysis of variance, and the significant variables had their means compared by Tukey test (5%) and some by polynomial regression, as in the first experiment. The results indicated that the... (Complete abstract click electronic access below)

Made available in DSpace on 2014-06-11T19:32:44Z (GMT). No. of bitstreams: 0 Previous issue date: 2002-12Bitstream added on 2014-06-13T20:43:49Z : No. of bitstreams: 1 mucoucah_fj_dr_botfca.pdf: 642144 bytes, checksum: 6f887b11b2bb55259a83ec18f6ee2714 (MD5) / O presente trabalho foi conduzido na área experimental do Departamento de Engenharia Rural da Faculdade de Ciências Agronômicas - FCA, UNESP, campus de Botucatu/SP, com o objetivo de estudar a indução floral de Zantedeschia sp, com a aplicação de ácido giberélico (GA3), fornecido via água de irrigação, aplicação foliar e tratamento por imersão, nas condições de Botucatu/SP, a fim de se determinar a dosagem, a época e o modo de aplicação, visando-se otimizar o sistema instalado, facilitando o manejo da cultura. Não foi possível avaliar estatisticamente os dados referentes à produtividade de flores, pois estes não apresentaram distribuição normal de probabilidade, alguns tratamentos não emitiram flores. Considerando o número total de flores produzidas ao longo de 86 dias, o tratamento convencional por imersão pré-plantio (100 mg.L-1) emitiu 4 flores, num total de 10 vasos; enquanto que os tratamentos T12 (15 dias pós plantio-200 mg.L-1 de GA3) e T35 (15+30 dias pós plantio-500 mg.L-1 de GA3) produziram 7 e 6 flores, respectivamente, por 10 vasos. Os demais tratamentos produziram quantidades inferiores em relação à testemunha. A ausência de produção para alguns tratamentos e a baixa produtividade dos tratamentos em geral, pode ter ocorrido devido ao longo período de armazenamento dos bulbos, acima de oito meses, compromentendo a integridade física do material botânico, pelo ressecamento ou suberização dos tecidos externos do bulbo dificultando a penetração da solução do regulador vegetal. / This study was conducted in the experimental site of the Rural Engineering Departament of the Agronomical Sciencies College - FCA, UNESP, campus of Botucatu, with the objective of study the Zantedeschia sp flower induction by gibberellic acid (GA3) application, supplied by irrigation system, foliar application and preplant immersion, in the Botucatu/SP conditions, to determined the application concentration, epoch and mode. With the purpose of optimize the system installed, faciliting the culture management. It not possible evaluation statisticment datas of flowers production, because datas no presented normal probability distribution. Some treatments did not producted flowers. Considering the total flowers production during 86 days, results were: the mean production of standard treatment, preplant immersion (100 mg.L-1), was compatible with de São Paulo state farmers (4 flowers/10 pots); while treatments T12 (15 days after plant -200 mg.L-1 of GA3) e T35 (15+30 days after plant - 500 mg.L-1 of GA3) producted 7 and 6 flowers, respectivement, in 10 pots. Others treatments producted fewer when compared with standard treatment. No production and the fewer productived of some treatments can occurred owing storage duration. Increasing duration of tuber storage reduce flowering, because reduces the plants sensitivity and ability to absorb the gibberellins.