According to our previous results, ethephon-induced sweet potato leaf senescence and senescence-associated gene SPCP1 expression was affected by reduced glutathione, EGTA, and cycloheximide (Chen et al., 2009). These data suggest that calcium influx, reactive oxygen species (ROS) and de novo synthesized proteins can affect ethephon-mediated effects. Therefore, PCR-selective substractive hybridization and RACE-PCR methods were used to clone 5 full-length cDNAs encoded putative calmodulin (SPCAM), catalase (SPCATA), anionic peroxidase (SPPA), ACC oxidase (SPACO), and DSS1-like protein (SPDSS1) from mixed samples of ethephon-treated leaves for 6 and 24 hours. The ORF of SPCAM contains 450 nucleotides and encodes 149 amino acids. There are 4 putative EF-motifs in the deduced protein structure. SPCAM exhibited amino acid sequence identity with isolated Arabidopsis calmodulins from 48% to 100%, and was completely the same as CaM7 calmodulin. The ORF of SPCATA contains 1479 nucleotides and encodes 492 amino acids. SPCAM exhibited high amino acid sequence identity with other plant catalases from 71.2% to 80.9%, and had the highest identity with mangrove catalase. The ORF of SPPA contains 1068 nucleotides and encodes 355 amino acids. SPPA exhibited amino acid sequence identity with other published sweet potato peroxidase isoforms from 28.7% to 97.5%, and had the highest identity with anionic peroxidase SWPA4. The ORF of SPACO contains 930 nucleotides and encodes 309 amino acids. SPACO exhibited high amino acid sequence identity with other plant ACC oxidases from 62.3% to 81.5%, and had the highest identity with tobacco ACC oxidase. The ORF of SPDSS1 contains 228 nucleotides and encodes 75 amino acids. SPDSS1 exhibited amino acid sequence identity with other DSS1 from 25.2% to 62.3%, and had the highest identity with maize DSS1. The chlorophyll contents and Fv/Fm values were significantly reduced, however, the isolated gene expression was remarkably enhanced in natural senescent leaves. DAB staining showed that H2O2 amount was remarkably elevated at S3 senescent leaves compared to leaves of the other developmental stages. Evan blue staining also demonstrated that S3 senescent leaf had more cell death compared to S0 young leaves. In addition ethephon-induced leaf senescence exhibited similar results. The chlorophyll contents and Fv/Fm values were significantly reduced, however, the isolated gene expression was remarkably enhanced in ethephon-treated leaves compared to dark control. DAB staining showed that H2O2 amount was remarkably elevated at 72 hours in ethephon-treated leaves compared to dark control. Evan blue staining also demonstrated that ethephon-treated leaf for 72 hours had more cell death compared to dark control. Based on these data we conclude that SPCAM, SPCATA, SPPA, SPACO and SPDSS1 gene expression were significantly increased in natural and ethephon-induced senescent leaves. The possible functions of these isolated genes in association with events in ethephon-induced leaf senescence, including calcium influx, ROS elevation or scavenge, and following signaling will be discussed.

Biennial bearing, low precocity, and vigorous vegetative growth are major production constraints of ‘Northern Spy’ apple trees. Experiments were conducted in bearing and non-bearing ‘Northern Spy’/M.9 orchards to determine whether plant bioregulator applications of ethephon (ETH), napthaleneacetic acid (NAA), prohexadione-calcium (P-Ca), and/or benzyladenine (BA) could be used to overcome these production constraints of ‘Northern Spy’. Ethephon application at 150, 300, or 450 mg∙L-1 in the ‘on’ year increased return bloom, fruit yield, and alleviated biennial bearing in the ‘off’ year in a positive linear relationship to concentration when trees were moderately biennial in cropping. Applications applied 22 June were more effective than 27 July or 31 Aug. applications. However, single or multiple (2, 3, or 4) application(s) of 150 mg∙L-1 ETH or 5 mg∙L-1 NAA were ineffective when trees were not biennial. Two ETH applications at 1500 mg∙L-1 to non-bearing trees significantly increased flowering and fruit yield the year following treatment. The combination of P-Ca with ETH had an additive effect on shoot growth and improved growth control compared to P-Ca alone. Two BA applications at 500 mg∙L-1 had no effect on lateral branching of young trees. / Chudleigh's Limited, MITACS Accelerate

Memoria para optar al título profesional de: Ingeniero Agrónomo Mención: Fruticultura / La prolongada floración del granado tiene como consecuencia una marcada heterogeneidad en el estado de desarrollo de los frutos al momento de la cosecha, lo cual implica que un alto porcentaje de ellos no llega a madurez. Este hecho evidencia la necesidad de raleo de frutos en los huertos de granado, práctica que, en la actualidad, se realiza de forma manual. El objetivo de este estudio fue evaluar diferentes reguladores de crecimiento como posibles raleadores químicos de flores y/o frutos de granado. Con este fin se realizaron cinco ensayos en un huerto comercial de granados de la variedad Wonderful ubicado en la Región Metropolitana, que consistió en la evaluación de cinco productos químicos, en cinco concentraciones diferentes cada uno: ácido naftalenacético (ANA), en un rango de concentraciones entre 0 y 40 mg L-1; ethephon (ET), en un rango de concentraciones entre 0 y 400 mg L-1; benciladenina (BA), en concentraciones entre 0 y 400 mg L-1; ácido giberélico (AG), en concentraciones entre 0 y 100 mg L-1; y aminoetoxivinilglicina (AVG), en un rango de concentraciones entre 0 y 200 mg L-1. Se realizaron dos aplicaciones del producto químico con un lapso de dos semanas entre ellas, comenzando la tercera semana de enero. Se evaluó la dinámica de caída de flores y frutos durante las seis semanas siguientes a la primera aplicación. En la cosecha se recolectó toda la fruta presente en el árbol, clasificando cada fruto según cobertura externa de color, cohorte de floración a partir de la cual se desarrolló y peso fresco. Los ensayos se analizaron mediante correlaciones y regresiones. El ET fue el único producto evaluado que presentó efecto raleador, disminuyendo la proporción de frutos de la segunda y tercera cohorte de floración. Adicionalmente, el ET incrementó el color de los frutos y redujo el peso fresco de los frutos de la primera cohorte de floración.

Orientador: Fernando Mendes Pereira / Banca: João Alexio Scarpare Filho / Banca: Sérgio Ruffo Roberto / Banca: Antonio Baldo Geraldo Martins / Banca: Aparecida Conceição Boliani / Resumo: Para a produção de uva na entressafra (setembro-outubro), é necessário que a poda seja realizada em período de provável ocorrência de baixas temperaturas, o que prejudica a emissão e desenvolvimento de brotos. Embasado em trabalho anterior, objetivou-se desenvolver uma técnica para viabilizar a emissão e desenvolvimento das brotações do cv. Niagara Rosada, mesmo em condições desfavoráveis com temperaturas abaixo de 10 ºC. Os experimentos foram conduzidos em vinhedos comerciais, na região de Jales-SP. Foram testadas quatro concentrações de ethephon (0; 720; 1.440 e 2.160 mg.L-1), aplicado de maio a junho, via foliar antes da poda de produção, em seis distintos experimentos, sendo três em 2001 e três em 2002. Verificou-se que a aplicação de ethephon promoveu o desfolhamento das videiras, principalmente nas concentrações de 1.440 e 2.160 mg.L-1. A aplicação em plantas pouco enfolhadas e/ou em período sem ocorrência de baixas temperaturas,não produziu resultados estatisticamente significativos na produção. Porém, observou-se um aumento na emissão e no desenvolvimento dos brotos nas concentrações mais elevadas. A aplicação de ethephon na concentração de 2.160 mg.L-1 em videiras com enfolhamento superior a 70% e temperaturas abaixo de 10 ºC, propiciou resultados excelentes no que se refere ao maior número de gemas brotadas, ao maior desenvolvimento dos ramos (comprimento e diâmetro) e a maior produção. O uso de ethephon não alterou o período da poda à floração, os teores de sólidos solúveis totais e a acidez total titulável mas, proporcionou aumento no comprimento e peso dos cachos e das bagas, na largura dos cachos e no diâmetro das bagas, melhorando a qualidade da uva. / Abstract: For off-season grape production (September-October), pruning it is necessary in period of probable occurrence of low temperatures, what damages the emission and development of sprouts. Based in previous work, it was developed a technique to make possible the emission and development the sprout of the grape 'Niagara Rosada', even though unfavorable conditions of climate. These studies were carried out at commercial vineyards, in region of Jales, SP, Brazil. Four levels of ethephon (0; 720; 1,440 and 2,160 mg.L-1), applied from May to June, on leaves before the frutification pruning, in six experiments, on 2001 and three on 2002. It was observed that application of ethephon promoted defoliation of the grapevines, mainly in levels of 1,440 and 2,160 mg.L-1. The application in plants with less leaves and/or period without occurrence of low temperatures, did not produce significant results in the production. However, a trend of increase in emission and development of sprouts when higher levels of ethephon was observed. The application of ethephon (2,160 mg.L-1) on grapevines with more that 70% of leaves, in period of occurrence of lower temperatures (smaller 10 ºC), propitiated excellent results regarding the number of sprouted buds, shoot growth (length and diameter) and production. The use of ethephon did not modify the duration of the period from pruning to flowering, the total soluble solids and titrabre concentration acidity, but increased the length, diameter, the width and mass of the clusters and berries, improving the grape quality. / Doutor

Made available in DSpace on 2014-06-11T19:33:38Z (GMT). No. of bitstreams: 0 Previous issue date: 2004-12-02Bitstream added on 2014-06-13T19:44:34Z : No. of bitstreams: 1 fracaro_aa_dr_jabo.pdf: 924092 bytes, checksum: 53fa7d51e3e6f4744e2563f9c1463ec6 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Para a produção de uva na entressafra (setembro-outubro), é necessário que a poda seja realizada em período de provável ocorrência de baixas temperaturas, o que prejudica a emissão e desenvolvimento de brotos. Embasado em trabalho anterior, objetivou-se desenvolver uma técnica para viabilizar a emissão e desenvolvimento das brotações do cv. Niagara Rosada, mesmo em condições desfavoráveis com temperaturas abaixo de 10 ºC. Os experimentos foram conduzidos em vinhedos comerciais, na região de Jales-SP. Foram testadas quatro concentrações de ethephon (0; 720; 1.440 e 2.160 mg.L-1), aplicado de maio a junho, via foliar antes da poda de produção, em seis distintos experimentos, sendo três em 2001 e três em 2002. Verificou-se que a aplicação de ethephon promoveu o desfolhamento das videiras, principalmente nas concentrações de 1.440 e 2.160 mg.L-1. A aplicação em plantas pouco enfolhadas e/ou em período sem ocorrência de baixas temperaturas,não produziu resultados estatisticamente significativos na produção. Porém, observou-se um aumento na emissão e no desenvolvimento dos brotos nas concentrações mais elevadas. A aplicação de ethephon na concentração de 2.160 mg.L-1 em videiras com enfolhamento superior a 70% e temperaturas abaixo de 10 ºC, propiciou resultados excelentes no que se refere ao maior número de gemas brotadas, ao maior desenvolvimento dos ramos (comprimento e diâmetro) e a maior produção. O uso de ethephon não alterou o período da poda à floração, os teores de sólidos solúveis totais e a acidez total titulável mas, proporcionou aumento no comprimento e peso dos cachos e das bagas, na largura dos cachos e no diâmetro das bagas, melhorando a qualidade da uva. / For off-season grape production (September-October), pruning it is necessary in period of probable occurrence of low temperatures, what damages the emission and development of sprouts. Based in previous work, it was developed a technique to make possible the emission and development the sprout of the grape 'Niagara Rosada', even though unfavorable conditions of climate. These studies were carried out at commercial vineyards, in region of Jales, SP, Brazil. Four levels of ethephon (0; 720; 1,440 and 2,160 mg.L-1), applied from May to June, on leaves before the frutification pruning, in six experiments, on 2001 and three on 2002. It was observed that application of ethephon promoted defoliation of the grapevines, mainly in levels of 1,440 and 2,160 mg.L-1. The application in plants with less leaves and/or period without occurrence of low temperatures, did not produce significant results in the production. However, a trend of increase in emission and development of sprouts when higher levels of ethephon was observed. The application of ethephon (2,160 mg.L-1) on grapevines with more that 70% of leaves, in period of occurrence of lower temperatures (smaller 10 ºC), propitiated excellent results regarding the number of sprouted buds, shoot growth (length and diameter) and production. The use of ethephon did not modify the duration of the period from pruning to flowering, the total soluble solids and titrabre concentration acidity, but increased the length, diameter, the width and mass of the clusters and berries, improving the grape quality.

Thesis (MScAgric (Viticulture and Oenology)--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: ‘Crimson Seedless’ is currently one of the most important and popular table grape cultivars produced in South Africa, and as such it is of great economic value for table grape producers. Major concerns with ‘Crimson Seedless’ is that it is prone to inadequate colouring, and with increased yields the berry size decreases. An additional difficulty is that methods used to increase berry size, further impede berry colouring. A plant growth regulator (PGR) commonly used in table grape production, to enhance colour formation, is ethephon (2-chloro-ethyl-phosphonic acid, 2-CEPA). In recent years significant research has been done on the effect of sunlight on anthocyanin production in grapes, although this has primarily been on wine grape cultivars. Currently, there is limited knowledge on the effect of sunlight on table grapes, and how this might influence their anthocyanin composition and content. The effect of ethephon on colour of grapes and other fruit have been extensively researched and well documented. However, the effect of ethephon on the anthocyanin composition of ‘Crimson Seedless’ is not well known. The current study aimed to explore the effect of sunlight (by matter of exclusion) and management practices, namely defoliation and ethephon application, on the anthocyanin profile and content of ‘Crimson Seedless’. Four different treatments were applied to two ‘Crimson Seedless’ vineyards, the first site located in Paarl, and the second in De Doorns. The treatments were: 1. Naturally exposed bunches, 2. Exposed bunches treated with ethephon, 3. Bunches kept in shade boxes, 4. Shaded bunches treated with ethephon. At the De Doorns site an additional defoliation treatment was superimposed over the above treatments. An HPLC technique was modified for the separation and detailed profiling of ‘Crimson Seedless’ anthocyanins and was used to analyse the effect of the reported treatments on the anthocyanin profile of berry skins. The predominant anthocyanin in ‘Crimson Seedless’ is peonidin-3-glucoside (Pn-gluc), and this was found to be significantly increased only by ethephon application, and was not altered by sunlight or leaf removal. The responses of the other anthocyanin types varied according to the respective treatments applied. However, a general observation was that ethephon application more consistently increased the concentration of anthocyanins in berry skins than did sunlight. Leaf removal had the least significant effect on anthocyanin concentration. / AFRIKAANSE OPSOMMIMG: ‘Crimson Seedless’ is tans een van die belangrikste en gewildste tafeldruif cultivars wat in Suid-Afrika verbou word en daarom is dit van groot ekonomiese waarde vir tafeldruifprodusente. ‘Crimson Seedless’ is egter daarvoor bekend dat dit te swak kleur (volgens uitvoer spesifikasies) en tweedens is die cultivar geneig om kleiner korrels te ontwikkel wanneer die oeslading vermeerder word. ‘n Addisionele probleem is dat die praktyke wat in die industrie gebruik word om korrels te vergroot ‘n verdere negatiewe impak op ‘Crimson Seedless’ se kleur ontwikkeling kan veroorsaak. Die plant-groei-reguleerder wat algemeen in tafeldruif verbouing gebruik word, ten einde beter gekleurde druiwe te produseer, is ethephon (2-chloro-ethyl-phosphonic acid, 2-CEPA). In die laaste paar jaar was daar baie navorsing gedoen oor die effek wat sonlig het op die antosianien produksie van druiwe, maar navorsing was gefokus op wyndruif cultivars. Huidiglik is daar beperkte tegniese kennis oor die effek wat sonlig op tafeldruiwe het, en hoe dit moontlik die antosianien samestelling en inhoud kan beïnvloed. Daar is ook reeds verskeie studies gedoen en data gepubliseer oor die invloed wat ethephon op die kleur het van druiwe en ander vrugte, maar die invloed wat ethephon op die antosianien samestelling van ‘Crimson Seedless’ het, is nie wel bekend nie. Die doel van hierdie studie was om die effek van sonlig (deur uitsluiting) en bestuurspraktyke (blaarverwydering en ethephon toediening) te bestudeer en hoe dit die antosianien samestelling van ‘Crimson Seedless’ beïnvloed. Vier verskillende behandelings is toegedien in twee ‘Crimson Seedless’ wingerde, die eerste proefperseel in die Paarl en die tweede proefperseel in De Doorns. Die behandelings was: 1. Natuurlik blootgestelde trosse, 2. blootgestelde trosse met ethephon, 3. Trosse met skadubokse omhul, 4. Skaduboks trosse met ethephon. By De Doorns is ‘n addisionele blaarverwydering proef bygebring. ‘n HPLC tegniek was aangepas om die antosianien samestelling en inhoud van ‘Crimson Seedless’ te bepaal, en om die effek van die behandelings te ondersoek. Die HPLC data het getoon dat peonodien-3-glukosied (Pn-gluc) die primêre antosianien in ‘Crimson Seedless’ is met die hoogste inhoud van al die antosianiene. Pn-gluc was betekenisvol beïnvloed deur ethephon toediening, terwyl die ander behandelings geen betekenisvolle effekte daarop gehad het nie. Die effekte wat die ander antosianiene gehad het, het gevarieer volgens die behandelings wat toegedien was. ‘n Algemene observasie was dat ethephon toediening die antosianien konsentrasie in ‘Crimson Seedless’ druiwe skille meer konsekwent vermeerder het as die sonlig blootstelling. Die blaarverwydering het die minste betekenisvolle effek op die antosianien inhoud van ‘Crimson Seedless’ gehad.

Submitted by (lucia.rodrigues@ufrpe.br) on 2017-02-17T13:39:56Z No. of bitstreams: 1 Camila Cristina Lage de Andrade.pdf: 845467 bytes, checksum: ef8d7e269cd9b79e14fc8dbcd17e8edd (MD5) / Made available in DSpace on 2017-02-17T13:39:56Z (GMT). No. of bitstreams: 1 Camila Cristina Lage de Andrade.pdf: 845467 bytes, checksum: ef8d7e269cd9b79e14fc8dbcd17e8edd (MD5) Previous issue date: 2012-02-16 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The bacterial speck caused by Pseudomonas syringae pv. tomato (Pst) (Okabe) Young, Dye & Wilkie has economic relevance to the tomato for industry in Brazil. The use of products that potentiate and/or induce plant defenses is an alternative that meets the requirements of integrated disease management. This study aimed to evaluate the effect of silicon (Si) and chemical inducers in some components of tomato resistance to bacterial speck and activity of enzymes involved in plant defense. In the first study, tomato plants were grown in: soil without calcium silicate (control) (T1), soil without calcium silicate and plants sprayed with Supa Silica® (SS) (2 mL/L SS) (T2) and soil with calcium silicate (0.38 g) (T3), being inoculated by spraying with a suspension of the pathogen. Our research evaluated the incubation period (IP), number of lesions (NL) per plant, severity estimated by the software QUANT 1.0 (SEQ) and leaf concentration of Si, as well as the activity of enzymes peroxidases (POX), polyphenoloxidases (PPO) β-1,3-glucanases (GLU), phenylalanine ammonia lyases (PAL), lipoxygenases (LOX) and concentration of malondialdehyde (MDA). It was assessed the effect of SS in the Pst growth in vitro. There was no significant difference between treatments for the IP and the foliar concentration of Si. No significant differences were found for the NL per plant and SEQ between T3 and control. T2 significantly reduced NL in 46.8 and 45.1% and SEQ in 61.5 and 56.2% when compared with control and T3, respectively. There was negative linear response of SS doses on the Pst growth in vitro. The activity of POX, PPO and GLU was significantly higher in T2 and T3. The activity of FAL and LOX was significantly higher in T3. The MDA concentration was significantly higher in T2 compared to control, in non-inoculated plants and at 7 days after inoculation (d.a.i.), being significantly lower at 10 d.a.i. In the second study, three experiments were conducted to evaluate the effect of jasmonic acid (JA; 0.1 mM), ethephon (ET, 0.5 mM) and acibenzolar-S-methyl (Bion®, ASM; 300 mg/L) sprayed 48 h before inoculation with Pst, evaluating the IP and NL per plant, and the activity of enzymes POX, PPO, GLU and LOX. It was also assessed the effect of JA and ET in the growth of Pst in vitro. Only in experiment 3 incubation period increased significantly by one day in the plants sprayed with ASM compared with control. In all experiments, NL per plant was significantly reduced by JA, ET e ASM in relation to the control reaching values of 38.9, 45.3 and 68.1%, respectively, in experiment 2. The growth of Pst in vitro was not significantly influenced. In some evaluation times JA has significantly raised the activity of POX, PPO and GLU; ASM has elevated the activity of PPO, GLU and LOX, while ET only significantly raised the activity of GLU and LOX compared to the control. The results of these studies suggest that spraying tomato plants with SS and the inducers JA, ET and ASM affected some components of tomato resistance to bacterial speck, and activated the enzymes POX, PPO, GLU, PAL and LOX, involved in defense responses of tomato plants to Pst. / A pinta bacteriana causada por Pseudomonas syringae pv. tomato (Pst) (Okabe) Young, Dye & Wilkie tem importância econômica para a cultura do tomateiro industrial no Brasil. O uso de agentes potencializadores e/ou indutores das defesas das plantas é uma alternativa que atende aos requisitos do manejo integrado de doenças. Este estudo avaliou o efeito do silício (Si) e de indutores químicos em alguns componentes de resistência do tomateiro à pinta bacteriana e na atividade de enzimas envolvidas na defesa das plantas. No primeiro estudo plantas de tomateiro foram cultivadas em: solo sem silicato de cálcio (controle) (T1), solo sem silicato de cálcio e plantas pulverizadas com Supa Sílica® (SS) (2 mL/L de SS) (T2) e solo com silicato de cálcio (0,38 g) (T3), sendo inoculadas por pulverização com suspensão do patógeno. Foram avaliados o período de incubação (PI), número de lesões (NL) por planta, severidade estimada pelo software QUANT 1.0 (SEQ) e concentração foliar de Si, bem como a atividade das enzimas peroxidases (POX), polifenoloxidases (PFO), β-1,3-glucanases (GLU), fenilalanina amônia-liases (FAL), lipoxigenases (LOX) e concentração de aldeído malônico (MDA). Também foi avaliado o efeito do SS no crescimento de Pst in vitro. Não houve diferença significativa entre os tratamentos para o PI e para a concentração foliar de Si. Não houve diferença significativa para o NL por planta e a SEQ entre o tratamento T3 e o controle. O tratamento T2 reduziu significativamente o NL 46,8 e 45,1% e a SEQ 61,5 e 56,2%, em relação ao controle e ao tratamento T3, respectivamente. Houve resposta linear negativa das doses de SS no crescimento da Pst in vitro. A atividade das POX, PFO e GLU foi significativamente maior nos tratamentos T2 e T3. A atividade das FAL e das LOX foi significativamente maior no T3. A concentração de MDA foi significativamente maior no tratamento T2 em relação ao controle, nas plantas não inoculadas com Pst e aos 7 dias após inoculação (d.a.i.); sendo significativamente menor aos 10 d.a.i. No segundo estudo, três experimentos foram realizados para avaliar o efeito dos indutores ácido jasmônico (AJ; 0,1 mM), ethephon (ET; 0,5 mM) e acibenzolar-S-metil (Bion®, ASM; 300 mg/L) pulverizados 48 h antes da inoculação da Pst, avaliando-se o PI e o NL por planta, além da atividade das enzimas POX, PFO, GLU e LOX. Também foi avaliado o efeito do AJ e do ET no crescimento da Pst in vitro. Apenas no experimento 3 o PI aumentou significativamente em 1 dia nas plantas pulverizadas com ASM em relação ao controle. O NL por planta foi significativamente reduzido pelos tratamentos AJ, ET e ASM em relação ao controle para todos os experimentos, atingindo valores de 38,9, 45,3 e 68,1%, respectivamente, no experimento 2. O crescimento da Pst in vitro não foi influenciado significativamente pelo AJ ou ET. Em determinadas épocas de avaliação, o AJ elevou significativamente a atividade das POX, PFO e GLU; ASM elevou a atividade das PFO, GLU e LOX e o ET elevou a atividade das GLU e LOX em relação ao controle. Os resultados desses estudos evidenciam que a pulverização com SS e com indutores AJ, ET e ASM afetaram alguns dos componentes de resistência do tomateiro à pinta bacteriana, além de potencializar as enzimas POX, PFO, GLU, FAL e LOX, relacionadas com a defesa das plantas em resposta à Pst.

La regeneración de plantas a partir de explantes es la base de partida para poder aplicar tecnologías tales como la obtención de plantas haploides o la transformación genética. Este carácter presenta una amplia variabilidad inter e intraespecífica. Así, incluso dentro de la misma especie, podemos encontrarnos genotipos recalcitrantes cuya falta o escasa regeneración limita la aplicación de estas técnicas. Además del componente genético, otros factores que condicionan el éxito de la regeneración son: las condiciones fisiológicas del material de partida, los componentes del medio de cultivo, los reguladores de crecimiento, la temperatura, la luz, etc¿ La falta de información acerca de qué factores determinan que este proceso se produzca por una u otra vía morfogenética (la vía organogénica o la embriogénica) y la incertidumbre de cuantos genes están implicados, indica la necesidad de investigación básica de este proceso. El objetivo principal de este trabajo se centra en incrementar el conocimiento de la base genética así como la localización de QTLs implicados en la regeneración por la vía organogénica que es la predominante en tomate. Para ello, se han utilizado dos poblaciones de mapeo (F2, BC1) obtenidas por la Dra. Gisbert. La población F2 se obtuvo a partir de la autofecundación de una planta F1, resultante del cruce de una planta de tomate (S. lycopersicum L.) seleccionada por su escasa capacidad regenerativa (Anl27) y la accesión PE-47 de S. pennellii Correll. con alta capacidad de regeneración. Por su parte, la población BC1 se obtuvo a partir del cruce (Anl27 x F1). Con estos materiales se ha realizado una caracterización fenotípica y genotípica en clones de cada genotipo, que se han mantenido en cultivo in vitro. Utilizando el programa informático MapQTL¿ se han identificado seis QTL implicados en la regeneración localizados en los cromosomas 1, 3, 4, 7 y 8. Cinco de los QTLs (SpRg-1, Rg-3, SpRg-4a, SpRg- 4b, SpRg-7) proceden del tomate silvestre S. pennellii y uno (SlRg-8) procede de S. lycopersicum. El porcentaje de varianza explicada por cada QTL va desde el 7,4% al 27%, dentro del rango común (6-26%) registrado en el mapeo genético de QTLs relacionados con la regeneración in vitro en otros cultivos. SpRg-1 es el mayor responsable de la respuesta morfogenética mientras que SpRg-7 promueve el desarrollo del brote hacia una planta completa. Por otra parte los QTLs detectados en los cromosomas 8 (SlRg-8) y 4 (SpRg-4a, SpRg-4b) podrían contener genes que influyen en la formación de yemas y su desarrollo, respectivamente. Finalmente Rg-3, situado en la mitad del cromosoma 3 y ligado al gen de la invertasa ácida, se presenta como un alelo putativo del gen Rg detectado en S. peruvianum (Rg-1) y S. chilense (Dunal) Reiche. (Rg-2). Además del genotipo, el tipo y combinación de reguladores de crecimiento son importantes para el éxito de los protocolos de regeneración. En tomate, los reguladores de crecimiento más utilizados son las citoquininas, o la combinación de estas con auxinas. Otros reguladores como el etileno se han estudiado poco y los trabajos publicados muestran conclusiones dispares. Con el fin de estudiar la influencia del etileno en la regeneración se han realizado ensayos con dos compuestos liberadores de etileno (Ácido 1-aminociclopropano-1- carboxílico ¿ACC¿ y ácido 2-Cloroetil fosfónico ¿Ethephon¿) y dos inhibidores de etileno: AgNO3, que inhibe la acción del etileno; y CoCl2, que inhibe la producción de etileno. Los resultados obtenidos muestran que la concentración y el momento de la aplicación son dos factores fundamentales a tener en cuenta para el éxito de la respuesta organogénica. En concreto, la aplicación de inhibidores de etileno y su consecuente disminución tiene un efecto negativo sobre la regeneración en tomate ya que se disminuye y se retrasa la respuesta. Así mismo, las plantas regenerantes obtenidas presentan tamaño reducido, pudiendo aparecer vitrificación y malformaciones. Por otra parte, la suplementación de etileno puede mejorar la regeneración. Así, el número de plantas regeneradas a partir de explantes de S. pennellii se duplicó en los medios con ACC respecto al medio control. Si la aplicación de ACC se realiza tras la inducción de las yemas, pasados 10 días, el rendimiento total será mayor. Este resultado indica que éste compuesto podría ser utilizado para mejorar la regeneración en aquellos genotipos donde una vez formadas las yemas, el desarrollo de estas hacia plantas es el paso limitante. Por otra parte, las plantas regenerantes obtenidas muestran buen desarrollo, por lo que la suplementación de etileno no afecta al posterior crecimiento de las plantas regeneradas. Finalmente se ha estudiado la capacidad organogénica de las especies silvestres de tomate derivadas del complejo S. peruvianum L. sensu lato (s.l.): Solanum arcanum Peralta., Solanum huaylasense Peralta., Solanum corneliomulleri J. F. Macbr. y Solanum peruvianum L. sensu stricto (s.s.). Estas especies pueden tener un papel fundamental en la mejora, sobre todo de resistencias a factores bióticos. Sin embargo, debido a las barreras de hibridación que existen entre éstas y el tomate cultivado, no se han explotado en su totalidad en la mejora del cultivo. Para realizar cruces se ha recurrido a la fusión de protoplastos y el rescate de embriones. Sin embargo, no se ha estudiado la capacidad organogénica de las especies derivadas del complejo Peruvianum, lo que limita la aplicación de estas técnicas. En este trabajo se ha encontrado variabilidad intra e interespecífica en la capacidad organogénica de las especies silvestres derivadas de este complejo. En general, todas las accesiones ensayadas de S. corneliomulleri y S. huaylasense mostraron una elevada capacidad regenerativa y se han identificado accesiones recalcitrantes en S. arcanum (LA-2185) y S. peruvianum s.s (ECU-106 y CH-20). En este trabajo, también se ha realizado un análisis morfológico de las hojas que ha determinado que el número de foliolos y el nivel de dentición de los mismo pueden ser utilizados en la identificación in vitro de las especies del complejo. Sin embargo, el área de foliolo solo permite distinguir a S. arcanum del resto de especies del complejo. Finalmente se ha observado que las accesiones cuyas hojas tienen mayor número de foliolos y mayor nivel de dentición tienen una mayor regeneración. / Trujillo Moya, C. (2013). Estudio de la Capacidad Organogénica en tomate y especies relacionadas: Localización de QTLS implicados y estudio de la influencia del Etileno [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/31665 / TESIS

Lodging poses a serious limitation to successful economic production of small grain cereals and can lead to extensive yield and quality losses. Plant growth regulators (PGR's) that reduce plant height and lodging have been employed in management systems in Europe and the United States, however, these compounds have not been evaluated on commercial cultivars of wheat, barley and oats in South Africa. Current recommendations to reduce lodging include limiting N inputs, seeding rates and critical irrigations, all of which may also limit yield potential and grain quality. The objectives of this study were to assess the effects of two common stem-elongation-inhibiting PGR's (chlormequat chloride and ethephon) on the growth, development, and agronomic characteristics of wheat, barley and oats. The aim of the study was to introduce an additional component of intensive cereal management in the form of PGR's, and to allow producers to implement intensive production practices without incurring losses due to lodging. Field trials were conducted with each of the three cereal crops in the 2003 and 2004 seasons at Vaalharts and Bethlehem. The PGR's were applied separately and in combination with each other to lodging-tolerant and -susceptible cultivars (wheat and oats) at different stages of development (tillering, elongation, flag leaf stage). The PGR's were also tested in combination with different levels of N (barley) applied at the haulm elongation stage, the flag leaf stage, or both. The PGR chlormequat produced negligible effects on plant height, lodging, yield, or quality components in all of the tested cultivars . Ethephon and the PGR combination successfully reduced plant height (by 120 to 150mm) and lodging (by 25 to 94%) when applied to the lodging susceptible cultivars of wheat and oats at the flag leaf stage or as a split application to the barley cultivar "Puma" (plant height and lodging reduced by 180 to 230mm and 83 to 92% respectively). Effects on grain yield were variable, ranging from occasional reductions (by 3 t ha(-1) and improvements (by 1 t ha(-1) with the barley, and no effects with the wheat and oats. Wheat quality parameters such as protein content and hectolitre mass were improved by 2 and 4% respectively. However, the nature of the responses was highly dependent on the times of application with later applications producing the greatest positive effects on quality, yield and lodging reductions. Additionally, ethephon and the PGR combination allowed higher levels of N to be employed without increases in lodging of barley. Generally, ethephon and the PGR combination applied at the flag leaf stage of growth are suitable anti-lodging tools for small grain cereal production and should be employed as an insurance measure against lodging in intensive management systems. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2006.