Sixteen native shrub species with various breeding systems and pollination syndromes were investigated in geographically separated populations to determine breeding systems, reproductive success, population structure, and habitat characteristics. Of the sixteen species, seven are hermaphroditic, seven dioecious, and two gynodioecious. Two of the dioecious species are cryptically dioecious, producing what appear to be perfect, hermaphroditic flowers, but that function as either male or female. One of the study species, Raukaua anomalus, was thought to be dioecious, but proved to be hermaphroditic. Teucridium parvifolium, was thought to be hermaphroditic, but some populations are gynodioecious. There was variation in self-compatibility among the four Alseuosmia species; two are self-compatible and two are self-incompatible. Self-incompatibility was consistent amongst individuals only in A. quercifolia at both study sites, whereas individuals in A. macrophylla ranged from highly self-incompatible to self-compatible amongst four study sites. The remainder of the hermaphroditic study species are self-compatible. Five of the species appear to have dual pollination syndromes, e.g., bird-moth, wind-insect, wind-animal. High levels of pollen limitation were identified in three species at four of the 34 study sites. Moderate to high levels of pollen limitation were evident in 50% of the gender dimorphic populations compared with 31% of hermaphroditic populations. Melicope simplex populations were female-biased in 14 study plots and successful fruit set was influenced by combinations of male plant density, male flower numbers and distance to the nearest pollen. Natural fruit set in wind-pollinated species was generally higher than in animal-pollinated taxa. Populations of Coprosma spathulata were mostly malebiased, and male plant density and proximity influenced natural fruit set, with a correlation between low fruit set and low male density. Population recruitment was evident in 32 of the 34 sites. In Pimelea arenaria, recruitment failure was widespread in populations throughout the North Island despite high seed set. Gender ratios showed variation from north to south, with a lower proportion of females with increasing latitude. Many of the sixteen shrubs in this study show remarkable resilience to the effects of fragmentation of natural ecosystems, and many of the species have benefited from the creation of new edge habitat after perturbation - it may be that edges are important refugia for some native taxa, especially shrubs.

To produce plant material for this thesis, Trifolium repens (white clover) (genotype 10F) and Trifolium occidentale (genotype 18Z) were propagated to produce individual stolons trained over a plastic matrix to inhibit nodal root formation. These stolons comprised leaf tissue representative of all developmental stages, from leaf initiation, maturation through to senescence. The developmental pattern for both species in terms of leaf ontogeny was generally reproducible between vegetatively propagated clones. Three distinct 1-aminocyclopropane-1-carboxylatc (ACC) oxidase genes expressed during leaf ontogeny in white clover (Trifolium repens L.) have been identified (Hunter et al., 1999). Of the three ACC oxidase genes identified, one designated TR-ACO2 is expressed in newly initiated and mature green leaves while TR-ACO3 is expressed predominantly in the senescent leaf tissue. In order to further characterize the protein products of these genes, a series of FPLC columns was used to partially purify isoforms of ACC oxidase from leaf tissue of white clover at different developmental stages, followed by 2D gel electrophoresis to obtain further purification. Two distinct isoforms of ACC oxidase were identified and partially purified from newly initiated green (designated the NIGI isoform) and senescent (designated the SEI isoform) leaf tissue. Both purified NIGI and SEI proteins were recognized by western analysis using an anti-(Trifolium repens) TR-ACO2 antibody after SDS-PAGE or 2D gel electrophoresis. To determine whether NIGI is coded for by TR-ACO2 and SEI is coded for by gene TR-ACO3, protein spots (after 2D gel electrophoresis) were digested with trypsin and the masses of the peptide determined by matrix-assisted laser desorption ionization-timc of flight (MALDI-TOF) mass spectrometric analysis. For NIGI, the coverage of the putative protein sequence (TR-ACO2) by tryptic digestion ranged from 24.5% to 37.6%, while the observed pI (5.1) and molecular mass (37 kDa) were close to the theoretical pI (5.3) and computed mass (35.7 kDa). For SEI, the percentage coverage of the putative protein sequence (TR-ACO3) from the peptides identified ranged from 13.4% to 18.0%, while the observed pI (5.2) and molecular masses (35.0-35.5 kDa) were also close to the theoretical pI (5.5) and computed mass (35.2 kDa). These data suggest that the NIGI isoform is encoded by TR-ACO2, while the SEI isoform is encoded by TR-ACO3. ACC oxidase activity in vitro and ACC oxidase protein accumulation over 24 h in mature green leaf tissue extracts during both short and long days has been shown to be under circadian control. There are two ACC oxidase activity peaks observed, in which the pattern of fluctuation in ACC oxidase activity resulted in a high level of enzyme activity at 12:00 am (0.18-0.27 nmol ethylene/h/mg), and maximum activity at 12:00 pm (0.24-031 nmol ethylene/h/mg). Lowest activity was observed in both long and short days at 9:00 pm (0.09-0.10 nmol ethylene/h/mg). In addition, northern analysis indicated that the TR-ACO2 mRNA level also displayed a circadian pattern of expression. Investigation of the effect of protein phosphorylation and dephosphorylation on ACC oxidase activity indicated that ACC oxidase activity in vitro during the periods of maximum activity increased 36% (at 12:00 am) and 56% (at 12:00 pm) after dephosphorylation, respectively. However, there was only 21% increase in enzyme activity at the time point with lowest activity (9:00 pm) in the dephosphorylated extracts. SDS-PAGE using a mini-protein gel system or a gradient gel system showed that the molecular mass of ACC oxidase decreased after dephosphorylation when compared with phosphorylation of the enzyme. These results suggest that the phosphorylation and dephosphorylation of the ACC oxidase proteins occurs in vitro and the state does affect enzyme activity. In the second part of this thesis, the coding regions of putative ACC oxidase gene transcripts were generated from leaf tissue of genotype 18Z of T. occidentale using RT-PCR. Sequence alignments indicated that the sequences could be grouped into two distinct classes, and these coding regions were designated TO-ACO2 (Trifolium occidentale ACC oxidase 2) and TO-ACO3 (Trifolium occidentale ACC oxidase 3). TO-ACO2 and TO-ACO3 share 82% similarity in nucleotide sequence and 84% similarity in amino acid sequence. The TO-ACO2 and TO-ACO3 sequences were validated as encoding ACC oxidases by comparison with other ACC oxidases in the GenBank database and both TO-ACO2 and TO-ACO3 deduced amino acid sequences contain all the residues hitherto shown to be important for maximal activity of the enzyme. Further, TO-ACO2 had 97% identity with TR-ACO2 at the nucleotide level, and 98% identity at the amino acid level. TO-ACO3 had 97% identity with TR-ACO3 at the nucleotide level, and 96% identity at the amino acid level. Genomic Southern analysis, using 3'-UTRs of TR-ACO2 and TR-ACO3 as probes, could not confirm that TO-ACO2 and TO-ACO3 arc encoded for by distinct genes. Expression studies of TO-ACO2 and TO-ACO3 genes during leaf maturation and senescence of T. occidentale were examined using northern analysis. TO-ACO2 is expressed predominantly in newly initiated and at the onset of the mature-green leaf stage, while TO-ACO3 shows maximal expression in senescent leaf tissue. The changes of ACC oxidase activity during leaf ontogeny of T. occidentale coincided with the pattern observed for ACC oxidase protein accumulation using western analysis and image analysis.

Diss. (sammanfattning) Alnarp : Sveriges lantbruksuniv. / Härtill 5 uppsatser.

Thesis (MSc)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Almost all processes during the life of a plant are affected by the environment. Changes in phytohormone, metabolite and protein levels follow in response to changes in the environment. Plant growth promoting substances can stimulate changes at these levels to facilitate increased plant growth and yields above what the plant would normally establish. In this study, the effects of two growth promoting substances, smoke water (SW) derived from bubbling smoke from the burning of plant material through water, and a synthetic strigolactone analogue, GR24, on plant growth and architecture, as well as the proteome and metabalome of salt stressed Nicotiana benthamiana seedlings were investigated. Physiological studies were conducted to identify the effects of the growth substances on salt stressed seedlings in a tissue culture system. Under non-stress conditions, SW treatment increased seedling fresh mass, root length and leaf area. Under salt stress conditions (100 mM and 150 mM NaCl), SW increased fresh mass, root length, leaf number and lateral root number significantly. Under non-stress conditions, GR24-treated seedlings showed increased fresh mass, leaf number and area and root length. When GR24-treated seedlings were placed under salt stress, the seedlings showed significant increases in fresh mass, leaf number and lateral root number, but only marginal increases in root length and leaf area. Despite these similarities, slight differences were observed in the metabolomes and proteomes of smoke water and GR24-treated seedlings, both with and without the addition of salt stress. Relatively few of the differentially expressed proteins could be identified with the instruments available. Changes in the metabolome indicated that photoassimilation and photosynthesis could be affected in response to smoke water and GR24 treatment. Our results suggest that smoke water and GR24 both promote growth under salt stress conditions in seedlings and we furthermore conclude that, although there are distinct overlaps between treatments, this is accomplished via slightly different mechanisms. / AFRIKAANSE OPSOMMING: Gedurende ‘n plant se lewe word omtrent alle prosesse deur die omgewing geaffekteer. Veranderinge in die omgewing word gevolg deur veranderinge in hormoon, metaboliet en protein vlakke. Plant groei stimulante affekteer hierdie vlakke om plant groei en -opbrengs na bo normalle vlakke te verhoog. In hierdie studie word die effek van twee groei stimulante, rook water verkry deur rook van plant materiaal deur water te borrel en ‘n sintetiese strigolaktoon, GR24, ondersoek op ‘n morfologiese, metaboliese en ‘n proteomiese vlak in Nicotiana benthamiana saailinge. ’n Studie is onderneem om die veranderinge as gevolg van die onderskeie groei stimulante te ondersoek in ‘n weefsel kultuur sisteem. Rook water het onder normale groei omstandighede vars en droeë massa, blaar aantal asook wortel en blaar lengte verhoog. Rook water het na sout behandeling (100 en 150 mM NaCl) steeds vars massa, wortel lengte, blaai aantal en laterale wortel aantal beduidend verhoog in vergelyking met die sout stres kontrole. Behandeling met GR24 het ook vars massa, wortel lengte, blaar aantal en grootte verhoog en onder sout stres met GR24 is ‘n beduidende vergroting opgemerk in vars massa, blaar grootte en laterale wortel aantal. Ongeag van die veranderinge in groei is klein verskille opgemerk in die metaboliet en protein studies. Net ‘n paar proteine kon positief geidentifiseer word met die apparaat beskikbaar. Verandering in die metaboloom wys na veranderinge in fotoassimilasie en fotosintese in reaksie tot rook water en GR24. Hierdie resultate lei tot die gevolgtrekking dat rook water en GR24 beide groei verbeter in saailing behandel met sout en ook dat alhoewel daar sekere ooreenkomste is tussen die reaksies as gevolg van die plant groei stimulante, dit wel geskiet deur geringe verskillende meganismes.

Thesis (MScAgric (Horticulture))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: Creasing, also known as albedo breakdown, is a preharvest disorder that affects the albedo of citrus fruit causing creases on the surface of the fruit. It is a recurrent problem in Navel and Valencia oranges and can cause individual orchard losses which often exceed 50%. Although the contributing factors are known, the physiological basis of creasing development is unresolved and the current control measures do not prevent creasing satisfactory. Hence, better control measures and further understanding of the physiology of creasing development is required. The objective of this two-year study was to determine if the position of fruit in a tree, light and carbohydrate manipulation techniques, and albedo mineral nutrients influence creasing development. Furthermore, the most effective application timing of gibberellic acid (GA3) with the least negative effect on fruit rind colour development and the effectiveness of cytokinins, other products and different root biostimulants to reduce creasing incidence were evaluated. The position of fruit in the tree and light influenced the development of creasing and the distribution of mineral nutrients in the albedo. Creasing incidence was higher on the south side than on the north side of the tree and fruit from the inside sub-sectors had a greater creasing incidence compared to fruit from the outside sub-sectors. The shady part of outside fruit was more creased compared to the sunny part of the fruit and covering fruit with brown paper bags increased creasing severity. The light manipulation techniques used on the leaves and fruit increased the nitrogen (N), phosphorus (P), potassium (K) and manganese (Mn) concentrations in the albedo and differences in the albedo mineral nutrients amongst the sub-sectors evaluated were observed, but creasing severity or creasing incidence was not significantly correlated with the albedo mineral concentrations at harvest. Albedo mineral concentrations earlier in the season may play a role in creasing development, as creasing severity was significantly correlated with copper (Cu), K, and Mn concentrations in the albedo during stage II of fruit development. Creasing incidence and albedo mineral concentrations were not affected by any of the carbohydrate manipulation techniques used in this study. The incidence and severity of creasing was significantly reduced, with a minor negative effect on fruit rind colour development, by the application of GA3, from mid November to mid January. Localised fruit application of CPPU [N-(2-chloro-4-pyridyl)-N-phenylurea], MaxCel (6- Benzyladenine) and CPPU in combination with calcium after physiological fruit drop reduced the incidence and severity of creasing, although creasing incidence was not significantly different from the control. The application of Messenger®, AVG (aminoethoxyvinylglycine) and different root biostimulants did not reduce creasing incidence. The results showed that cytokinins could reduce creasing incidence and justify further studies on application and uptake efficiency. The use of different root biostimulants are not recommended, but it is suggested that treatment effects may be more pronounced over a longer period. / AFRIKAANSE OPSOMMING: Kraakskil is ‘n vooroes abnormalitiet wat die albedo van sitrusvrugte affekteer, deur krake op die oppervlak van vrugte te veroorsaak. Dit is ‘n algemene probleem in Navel en Valencia lemoene en kan boordverliese van tot 50% of soms hoër veroorsaak. Alhoewel die bydraende faktore bekend is, is die fisiologiese basis van kraakskil ontwikkeling onopgelos en die beskikbare beheermaatreëls is nie bevredigend nie. Dus, beter beheermaatreëls en ‘n beter begrip van die fisiologie van kraakskil ontwikkeling is nodig. Die doel van die twee-jaar studie was om te bepaal of die posisie van vrugte in ‘n boom, lig en koolhidraat manipulasie tegnieke en minerale elemente in die albedo, kraakskil ontwikkeling beïnvloed. Die mees effektiewe toedieningstyd van gibberelliensuur (GA3) sonder ‘n negatiewe effek op vrugkleur is bepaal en die effektiwiteit van sitokiniene, ander produkte en verskillende wortel biostimulante om kraakskil voorkoms te verminder, is geëvalueer. Die posisie van vrugte in ‘n boom en lig het kraakskil ontwikkeling en die verspreiding van minerale element in die albedo beïnvloed. Kraakskil voorkoms was hoër aan die suidekant van die boom as aan die noordekant en vrugte in die binnekant van die boom het ‘n groter kraakskil voorkoms as vrugte in die buitekant van die boom gehad. Die skadukant van buitevrugte het meer kraakskil gehad as die sonkant en die toemaak van vrugte met ‘n bruin papiersak het die graad van kraaksil verhoog. Die lig manipulasie tegnieke wat op die blare en vrugte gebruik is, het die stikstof (N), fosfaat (P), kalium (K) en mangaan (Mn) konsentasies in die albedo verhoog en verskille in die albedo minerale elemente tussen sub-sektore is waargeneem, maar betekenisvolle korrelasies is nie tussen die graad en voorkoms van kraakskil en die albedo minerale element konsentrasies by oestyd waargeneem nie. Albedo minerale element konsentrasies vroeër in die seisoen mag ‘n rol speel by kraakskil ontwikkeling, omdat die graad van kraakskil betekenisvol gekorreleer was met albedo koper (Cu), K, en Mn konsentrasies tydens fase II van vrugontwikkeling. Kraakskil voorkoms en albedo minerale element konsentrasies is nie deur enige van die koolhidraat manipulasie tegnieke geaffekteer nie. Die voorkoms en graad van kraakskil is betekenisvol verlaag, met ‘n geringe negatiewe effek op vrugkleur, deur die toediening van GA3 vanaf mid November tot mid Januarie. Gelokaliseerde vrugtoedienings van CPPU [N-(2-chloro-4-piridiel)-N-phenielureum], MaxCel (6- Bensieladenien) en CPPU saam met kalsium na fisiologiese vrugval het die voorkoms en graad van kraakskil verlaag, alhoewel kraakskil voorkoms nie betekenisvol van die kontrole verskil het nie. Die toediening van Messenger®, AVG (amino etoksievinielglisien) en veskillende wortel biostimulante het nie kraakskil voorkoms verlaag nie. Die resultate het getoon dat sitokiniene kraakskil voorkoms kan verlaag en verdere studies op die toediening en opname effektiwiteit word aanbeveel. Die gebruik van verskillende wortel biostimulante word nie aanbeveel nie, maar die effek behoort meer sigbaar te wees na ‘n langer periode van behandeling.

Orientador: Orivaldo Arf / Resumo: A utilização de reguladores de crescimento como técnica que permite redução na estatura da planta e consequente fortalecimento dos colmos pode ser uma opção para minimizar o acamamento em plantas, evitando assim, perdas na cultura. Assim propôs o estudo com o objetivo de avaliar o efeito de doses de etil-trinexapac (zero; 37,5; 75,0; 112,5 e 150,0 g ha-1 do i.a) e épocas de aplicação (6ª, 7ª e 8ª folha completamente formada no colmo principal) durante o desenvolvimento da cultura do arroz de terras altas irrigado por aspersão. O delineamento experimental foi o de blocos ao acaso, disposto em esquema fatorial 5x3, com quatro repetições. A pesquisa foi desenvolvida na área experimental da Faculdade de Engenharia – UNESP, Campus de Ilha Solteira - SP, localizada no município de Selvíria – MS, durante o ano agrícola de 2016/17, utilizando o cultivar BRS Esmeralda. Foram avaliados os componentes de produção, altura de plantas, acamamento, produtividade dos grãos, rendimento industrial e viabilidade econômica. Devido a fatores climáticos como chuvas e ventos fortes as vésperas da colheita, parcelas em que não receberam a aplicação do regulador acamaram totalmente. Aplicações por ocasião da oitava folha além de promover maior número de grãos chochos, as doses de 75,0; 112,5 e 150,0 g ha-1 propiciam menores valores para altura de plantas, massa de cem grãos, massa hectolítrica, rendimento de benefício e grãos inteiros, reduzindo a produtividade de grãos, e influenciando negativamente... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The use of growth regulators as a technique that allows reduction in plant height and consequent strengthening of the stalks might be an option for elimination of lodging in plants, thus avoiding losses of the crop. However, the information on the subject is still scarce. Therefore, the study aimed to evaluate the effect of doses (zero; 37,5; 75,0; 112,5 e 150,0 g ha-1 of active ingredient) and times of application of ethyl-trinexapac (6th leaf, 7th leaf and 8th leaf completely formed in the main stem) during the development of the upland rice crop irrigated by sprinkler. The experimental design was randomized complete blocks, arranged in a 5x3 factorial scheme, with four repetitions. It was developed in the experimental area of Engineering University- UNESP at the Ilha Solteira, São Paulo State, Brazil – Campus, located in Selvíria, Mato Grosso do Sul State, Brazil, during the season of 2016/17, using the cultivar BRS Esmeralda. The components of production, plant height, lodging, grain yield, industrial yield and economic viability were evaluated. Due to climatic factors like rains and strong winds on the eve of the harvest, plots in which they did not receive the application of the regulator completely lodging. Applications for the eighth leaf in addition to promoting higher number of dry grains, the doses of 75.0, 112.5 and 150.0 g ha-1 of active ingredient provide lower values for plant height, weight of 100 grains, hectoliter weight, yield of benefit and whole grains, r... (Complete abstract click electronic access below) / Mestre

A alelopatia pode desempenhar um papel relevante na dinâmica de campos e também no manejo de plantas daninhas em pastagens. Na região dos campos do sul do Brasil, monoculturas de Eucalyptus têm sido plantadas. A vegetação é escassa sob os plantios, o que pode estar associado à alelopatia. Em uma perspectiva aplicada, aleloquímicos de Eucalyptus poderiam ser potencialmente empregados como herbicidas naturais. Esta tese tem como objetivo avaliar se a alelopatia pode ser um fator determinante na estruturação da vegetação campestre, e se pode consistir em uma potencial ferramenta no controle de plantas daninhas. No capítulo I, uma revisão sistemática foi feita, visando evidenciar tendências gerais, antigas e atuais na pesquisa sobre alelopatia em ecossistemas campestres, com foco nos métodos utilizados. O capítulo II objetivou avaliar a fitotoxidez do extrato aquoso e do óleo essencial das folhas da serapilheira de Eucalyptus saligna Sm. sobre espécies campestres em laboratório. No capítulo III, os efeitos das folhas da serapilheira de E. saligna sobre espécies campestres foram investigados em plantios, bem como se esses efeitos estavam relacionados à alelopatia. O capítulo IV visou avaliar o potencial bioherbicida do óleo essencial das folhas da serapilheira de E. saligna e determinar quais componentes estavam associados a sua fitotoxidez. No capítulo I, evidenciou-se a potencial relevância da alelopatia na dinâmica de campos e no manejo de plantas daninhas em sistemas cultivados. Além disso, observou-se que os trabalhos recentes sobre alelopatia melhoraram em alguns aspectos de desenho experimental, mas não em outros, e que há inconsistência na terminologia utilizada. No capítulo II, observou-se que as folhas da serapilheira de E. saligna apresentaram substâncias fitotóxicas que geraram estresse oxidativo e levaram a danos nas membranas, afetando a germinação e o crescimento de plântulas. No capítulo III, evidenciou-se que as folhas da serapilheira inibiram a vegetação campestre em plantios de E. saligna, mas os efeitos foram principalmente físicos, e efeitos alelopáticos não foram detectados. No capítulo IV, foi demonstrado o potencial do óleo essencial de E. saligna como herbicida natural. O óleo foi mais fitotóxico que seus componentes majoritários, mas isso variou com o método e com as espécies receptoras. Esta tese evidenciou que generalizações sobre fitotoxidez e alelopatia devem ser evitadas. Conclui-se que a alelopatia possui um potencial maior como alternativa no manejo de plantas daninhas do que como um fator atuante sobre o estabelecimento e desenvolvimento de espécies vegetais campestres. Um maior conhecimento sobre alelopatia e seus mecanismos pode levar a avanços na ciência e em áreas aplicadas. / Allelopathy may play a relevant role in dynamics of grasslands, and also in weed management in pastures. In Southern Brazilian grasslands region, Eucalyptus monocultures have been planted. Vegetation is scarce under plantations, which may be associated with allelopathy. In an applied perspective, Eucalyptus allelochemicals may be potentially employed as natural herbicides. This thesis aimed to evaluate if allelopathy may be a key factor shaping grassland vegetation, and if it consists in a potential tool for weed control. In chapter I, a systematic review was conducted, in order to evidence general, old and current trends in allelopathy research in grassland ecosystems, focusing in used methods. Chapter II aimed to assess the phytotoxicity of Eucalyptus saligna Sm. leaf litter aqueous extract and essential oil on grassland species, in laboratory conditions. In chapter III, effects of E. saligna leaf litter on grassland species were investigated in plantations, as well as if these effects were related to allelopathy. Chapter IV aimed to evaluate the bioherbicide potential of E. saligna leaf litter essential oil, and to determine which compounds were related to the oil phytotoxicity. In chapter I, the potential relevance of allelopathy was evidenced in dynamics of grasslands and in weed management in cultivated systems. Moreover, the review demonstrated that allelopathy research has improved in some experimental design issues, but not in others, and inconsistency in terminology was observed. In chapter II, Eucalyptus saligna leaf litter showed phytotoxic compounds that generated oxidative stress and led to membrane damage, affecting seeds and seedling growth. In chapter III, leaf litter was evidenced to inhibit grassland species in E. saligna plantations, but effects were mainly physical, and allelopathic effects were not detected. In chapter IV, the essential oil showed potential as a natural herbicide. In general, E. saligna essential oil was more phytotoxic than its major compounds, but this varied according to the method and the recipient species. This thesis evidenced that generalizations should not be made, neither about phytotoxicity, nor about allelopathy. In conclusion, allelopathy showed greater potential as a tool for weed management than as a relevant factor influencing establishment and development of grassland vegetation. A better knowledge about allelopathy and its mechanisms may lead to advances in science and in applied fields.

Fusarium wilt has been damaging the chrysanthemum crop in the central region of Rio Grande do Sul, especially in those cultivated in greenhouse. Four experiments were done with the objective of studying the effect of doses, environment, and forms of infection of Fusarium solani f. sp. chrysanthemi in chrysanthemum and its control by Trichoderma virens. In the first experiment, the objective was to select the inoculum quantity of F. solani f. sp. chrysanthemi needed to infect chrysanthemum plants cv. Calabria and 6g/600 g of soil was found to be the most damaging to the plants. In the second experiment, the inoculation of the pathogen by soil infestation or root immersion, with and without physical damage of the roots, was tested. There was no difference between the inoculation forms and the plants with damaged roots showed less growth. In the third and fourth experiments six isolates and five doses of biological powders of Trichoderma virens were tested in the control of the Fusarium wilt and the growth of plants. Since the plants did not show symptoms of Fusarium, it was not possible to determine the best doses of Trichoderma to control the disease and the utilization of the biological powders interfered negatively in the growth of chrysanthemum plants cv. Calabria. / A murcha de Fusarium tem causado danos à cultura do crisântemo na região central do Rio Grande do Sul, especialmente nos cultivos em ambiente protegido. Quatro experimentos foram desenvolvidos com o objetivo de estudar o efeito de doses, ambiente e formas de inoculação de Fusarium solani f. sp. chrysanthemi em crisântemo, e seu controle por Trichoderma virens. No primeiro experimento, objetivou-se selecionar a quantidade de inóculo de F. solani f. sp. chrysanthemi necessária à infecção de plantas de crisântemo cv. Calabria, sendo que 6g/600g de solo foi considerada a mais prejudicial às plantas. No segundo experimento, foi testada a inoculação do patógeno por infestação do solo ou imersão de raízes, em presença ou não de dano nas raízes. Não houve diferença entre as formas de inoculação e as plantas com dano nas raízes apresentaram menor desenvolvimento. No terceiro e quarto experimentos, foram testados seis isolados e cinco doses de pós contendo inóculo de Trichoderma virens no controle da murcha de Fusarium e no desenvolvimento das plantas. Em decorrência da ausência de sintomas de Fusarium, não foi possível determinar a melhor dose de Trichoderma para o controle da murcha e a utilização dos pós de Trichoderma interferiu negativamente no crescimento das plantas de crisântemo cv. Calabria.

Made available in DSpace on 2014-06-11T19:26:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-12-20Bitstream added on 2014-06-13T20:54:59Z : No. of bitstreams: 1 junglaus_rw_me_botfca.pdf: 402477 bytes, checksum: 77f2aa9e503173f8168c0007cf5967ac (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Avaliou-se o efeito de reguladores vegetais em pepineiro, em um hibrido tipo japonês ‘Tsuyataro’, a campo e em ambiente de cultivo protegido, avaliando-se as aplicações de reguladores vegetais em plantas enxertadas e não enxertadas, sobre o número de frutos e peso de frutos comerciais e totais. Aplicou-se o Stimulate® em diferentes concentrações via foliar, aos 30 dias pós transplante. Observou-se aumentos significativos com a concentração de 375 mL de Stimulate® ha -1, para número de frutos, massa de frutos totais e comercias por metro quadrado em plantas não enxertadas. / Evaluate the effect of plant regulators in cucumber, in a hybrid type japanese 'Tsuyataro', the field and on environment of cultivation protected, evaluating the applications of regulators vegetable on plants grafted and non-grafted, above the number of fruit, and fruit weight and total trade. Applies is the Stimulate ®, in different concentrations merry way, at 30 days post transplant, is observed significant increases with the concentration of 375 mL of Stimulate ® ha -1, for number of fruit, total weight of fruits and total trade by square meter for non-grafted plants.

Les champignons endomycorhiziens arbusculaires (MA) forment des relations symbiotiques avec la majorité des espèces végétales terrestres. Leur rôle écologique dans la productivité et la stabilité des agrosystèmes sont connus depuis de nombreuses années. Plusieurs études ont montré que ces symbiotes augmentent la croissance végétale et la résistance des plantes aux stress biotiques et abiotiques. Malgré le potentiel avéré de la symbiose MA pour augmenter durablement la productivité des agrosystèmes dans le cadre d’une agriculture à faibles apports d’intrants, cette biotechnologie est encore sous exploitée. Ce constat résulte essentiellement de difficultés techniques pour produire en quantité un inoculum fongique de qualité et un manque de connaissance concernant les facteurs biologiques régulant la réceptivité des sols à l’inoculation des champignons MA. Les principaux objectifs de ces travaux sont d’optimiser les performances d’un inoculum MA. (1), en associant le champignon MA avec des bactéries PGPR ou MHB. Cette stratégie vise à promouvoir l’établissement et le fonctionnement de la symbiose MA. En effet, ces bactéries bénéfiques aux plantes peuvent augmenter la croissance végétale, directement en fournissant à la plante des composés bénéfique (phytohormone, etc), et indirectement en réduisant ou prévenant les effets délétères de phytopathogènes ou en augmentant l’établissement de la symbiose MA. (2), par la gestion des cultures, notamment par l’association céréales/légumineuses en culture intercalaire. Les légumineuses sont souvent dépendantes des associations symbiotiques avec les champignons MA, et ceux-ci peuvent participer dans la nutrition azotée et phosphatée de la plante. (3), par l’amendement en composé ou organique. Ces amendements peuvent être solubilisés et dégradés par des bactéries et ainsi promouvoir la nutrition végétale sans augmenter la disponibilité de P et N dans le sol. (4), en développant des inocula complexes associant bactéries bénéfiques, champignons MA et amendement, l’ensemble contenu dans un gel d’alginate. / Arbuscular Mycorrhizal fungi (AM) are ubiquitous microorganisms forming symbiotic relationships with the majority of terrestrial plant species. Their ecological functions in the productivity and stability of agroecosystems have been recognized for many years. Many studies have shown that these symbionts improved plant growth and plant resistance to biotic and abiotic stresses. Despite the proven potential of mycorrhizal symbiosis to sustainably improve the productivity of agroecosystems under low input agriculture, this biotechnology is still under exploited. This failure mainly results from technical difficulties to mass-produced fungal inoculum of high quality and a lack of knowledge about the biological factors regulating the soil receptivity of AM inoculation. The main objectives of our studies are to optimize the performance of an AM fungal inoculum. (1), by combining the AM fungus with Plant Growth Promoting Rhizobacteria, or Mycorrhizal Helper Bacteria. This strategy aims to promote the establishment and the functioning of the mycorrhizal symbiosis. Indeed, this plant beneficial bacteria may affect plant growth through two different pathways, directly by providing to the plant some beneficial compounds (i.e. phytohormones, etc), indirectly, by reducing or preventing the deleterious effects of phytopathogens or by improving the establishment of the mycorrhizal symbiosis. (2), by plant management with the association of cereal/leguminous in intercropping. Leguminous are often dependent of AM association and AM fungi may participate to promote N and P plant uptake. (3), by amendment of mineral or organic compounds. These amendments can be degraded slowly by bacteria and promote plant nutrition without increase P and N soil availability. (4), by development of complex inocula associating beneficial bacteria, AM fungi and amendment, based on the entrapment of these inocula in alginate gels