The abundance of invasive alien plants, with their numerous associated negative effects, has resulted in challenging and costly management requirements in South Africa. Management of invasives is further complicated when species have rapid inherent growth rates, atmospheric nitrogen fixing capabilities and large, persistent seed banks. Management strategies other than the usual mechanical, chemical, and biological (and combinations thereof) methods may be more effective. An alternative strategy is ’habitat management’, whereby management may be aimed at favouring native species. If the native species could compete favourably with, and possibly exclude, the invasive species, which is more likely when the species are ecologically similar, management may be more effective. This study investigated the competitive performance of two invasive species, Acacia mearnsii De Wild. and Acacia melanoxylon R.Br., and an indigenous ecological analogue, Virgilia divaricata Adamson, on the southern Cape Coast of South Africa. Both acacias are included among the five worst invasive species in the native forest and fynbos shrubland ecosystems. Performance was compared among the three species in terms of germination success (responses to five stimuli, namely chipping, hot water exposure, dry heat pulse, smoke, and control, incubated at 12 or 20°C), soil-stored seed bank densities and viability at different soil depths, and individual growth performance in seedling and sapling stages (and the effect of inter-specific competition on the latter). Virgilia divaricata performed comparably to the acacias in most aspects. Responses to germination stimuli at both temperature regimes were comparable among species, with chipping and hot water exposure resulting in the highest germination success. Acacia melanoxylon displayed poorer germination response under the cool temperature regime than the warm regime. Of the three species, A. mearnsii (7 596 seeds m-2) had the highest seed bank density, followed by V. divaricata (938 seeds m-2) and A. melanoxylon (274 seeds m-2). Seed viability was high (87-91%) in all three species. Neither seed density nor seed viability differed significantly between soil depths, and there were no clear differences in this aspect between species. In terms of growth during the seedling stage, V. divaricata outperformed A. mearnsii. In the sapling stage, growth was comparable between the three species and was not affected by the extent of competition from neighbouring saplings. Overall, the findings of this study suggest that the success of A. mearnsii as an invader is primarily attributable to its large seed banks. However, the good performance of V. divaricata seedlings and no apparent negative effect of competition on sapling growth from A. mearnsii and A. melanoxylon suggest that it may be used in the management of the acacias along with other management strategies. Due to the similarity observed between the three species, any management operation (such as fire) that would benefit V. divaricata recruitment would benefit the acacias equally (except for potentially reduced germination of A. melanoxylon in cooler seasons). Management should thus attempt to prevent the germination of Acacia seeds. Alternatively, dense localised Acacia seed banks may be reduced by repeat burning. On a small scale, areas where V. divaricata would occur naturally (or which are completely compromised ecologically) can be seeded with pre-treated (chipped or hot water exposure) V. divaricata seeds. If V. divaricata is given enough time to establish dense stands, subsequent germination and growth of the acacias should be suppressed and simultaneously promote forest re-establishment. To further decrease Acacia success, biocontrol (seed-boring weevils, flower-galling midges, and rust fungus) should be widely disseminated.

Orientador: Angelo Luiz Cortelazzo / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-07T07:38:47Z (GMT). No. of bitstreams: 1 Ribeiro_ViktoriaKovesdy_M.pdf: 7983680 bytes, checksum: 5d4ac508a6df0a6cc6853aab29ae2d9a (MD5) Previous issue date: 2006 / Resumo: As restingas da região nordeste são pouco estudadas em todos os seus aspectos. Assim, o presente trabalho teve como objetivo analisar sementes de espécies de grande ocorrência na restinga da Reserva Particular do Patrimônio Nacional (RPPN) de Nossa Senhora do Outeiro de Maracaípe em Ipojuca, no litoral pernambucano, dentro de uma perspectiva mais ampla de análise para contribuir com o conhecimento de sua estrutura e das potencialidades de utilização econômica junto à população local. Foram coletadas sementes de 22 espécies, que foram fixadas em solução de FAA 70 ou fixador de Karnovsky para processamento e análise microscópica. Destas, oito espécies foram incluídas em historesina Leica ou em parafina, seguindo-se corte em micrótomo com 5 a 8 cm de espessura, conforme o meio de inclusão: Coccoloba laevis Casar. (Polygonaceae), Licania rigida (Chrysobalanaceae), Myrcia guianensis (Aulb.) DC. (Myrtaceae), Simaba cuneata A.St.-Hil. & Tul. (Simaroubaceae), Manilkara salzmannii (A.DC.) Lam (Sapotaceae), Maytenus impressa Reiss. (Celastraceae), Ocotea gardneri (Meisn.) Meiz (Lauraceae) e Serjania sp (Sapindaceae). Os materiais foram corados por diversos métodos gerais e citoquímicos, visando a determinação de proteínas, polissacarídeos, lipídios, radicais aniônicos totais e compostos fenólicos. Para as quatro primeiras espécies citadas, foram dosadas as principais reservas presentes nas sementes. Os resultados citoquímicos foram confirmados pelas dosagens bioquímicas revelando que C. laevis é uma espécie onde predomina o amido, L. rígida tem maiores teores de proteínas e S. cuneata é oleaginosa. M guianensis mostrou-se moderadamente rica em carboidratos e proteínas. Chamou a tenção a incomum quantidade de açúcares livres presentes nas sementes, que variou de 10% em C. laevis até 25% em L. rígida, podendo representar fator adaptativo interessante à falta de água. Cristais de oxalato, presença de taninos e tegumento lignificado também foram características encontradas na maioria das espécies e também podem estar relacionadas à defesa e estratégias de dispersão das sementes. Os testes citoquímicos revelaram ainda que O. gardneri e Serjania sp são ricas em amido e proteínas, enquanto que M. salzmannii apresenta lipídios em quantidades apreciáveis. Finalmente, pôde ser notado que M. impressa apresenta endosperma bem desenvolvido, possivelmente com hemiceluloses como sua principal reserva; seus cotilédones apresentaram quantidades apreciáveis de proteínas. As demais espécies coletadas encontram-se processadas para inclusão e corte para futura análise e caracterização citoquímica / Abstract: ¿ Restinga of the northeast have been barely studied in all their aspects. Thus, this work was as objective analyzes seeds of arboreal species of great occurrence in the ¿Reserva Particular do Patrimônio Nacional (RPPN) de Nossa Senhora do Outeiro de Maracaípe¿ in Ipojuca, located at the sea coast of Pernambuco to contribute with the knowledge of structure and these economic potentialities. Twenty-two species of fruits were harvested and the seeds were fixed in FAA70 or Karnovsky solutions and processed for microscopic analysis. Of these, eight species were embedded in Leica Historesin or paraffin and sectioned (5-7cm thick): Coccoloba laevis Casar. (Polygonaceae), Licania rigida (Chrysobalanaceae), Myrcia guianensis (Aulb.) DC. (Myrtaceae), Simaba cuneata A.St.-Hil. & Tul. (Simaroubaceae), Manilkara salzmannii (A.DC.) Lam (Sapotaceae), Maytenus impressa Reiss. (Celastraceae), Ocotea gardneri (Meisn.) Meiz (Lauraceae) and Serjania sp (Sapindaceae). After removing the paraffin and hydration, the materials were stained using several cytochemical methods to detect anionic residues, proteins, polysaccharides, starch, lipids and lignin. The stained sections were examined by light microscopy, using polarized light in some cases. The first four mentioned species of seeds were submitted to extraction to detect their principal reserves. The cytochemical results were confirmed by biochemical dosage revealing that C. laevis is a species where the starch is predominant; L. rigida has got higher contents of proteins and S. cuneata is oleaginous. M guianensis showed moderately rich in carbohydrates and proteins. Free and soluble sugars presented an unusual quantity in the seeds, with variation from 10% in C. laevis up to 25% in L. rigida , showing an possible and interesting adaptative factor to lack of water. Oxalate crystals, presence of tannins and lignified teguments were also characteristics found in most of the species and can be related to the defense and strategies of dispersion of the seeds. The cytochemical analysis revealed that although O. gardneri and Serjania sp are rich in starch and proteins, M. salzmannii presents lipids in appreciable amounts. Finally, it could be found that M. impressa presents endosperm well developed, possibly with hemiceluloses as the principal reserve while their cotyledons presented appreciable amounts of proteins. The other harvested fruits and seeds were processed for embebition and cut for future analysis and cytochemical characterization / Mestrado / Biologia Celular / Mestre em Biologia Celular e Estrutural

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Pendant la maturation des graines, la germination, tolérance à la dessication et longévité sont acquises de manière séquentielle. La maturation s’achève par la dessication qui amène l’embryon à l’état de quiescence. La maturité des graines à la récolte est le premier facteur qui in¿ uence la longévité et l’établissement de la culture lors du semis. On ne comprend pas comment la longévité est installée pendant la maturation et comment un séchage prématuré in¿ uence la longévité et la reprise des activités cellulaires pendant l’imbibition. L’objectif de la thèse était de répondre à ces questions en comparant les transcriptomes de graines immatures et matures de soja et Medicago truncatula pendant la dessication et l’imbibition. Les graines immatures furent récoltées après le remplissage avant la dessiccation, lorsque la longévité n’est pas encore acquise.Chez le soja, la comparaison des transcriptomes des graines immatures et matures montre que le séchage forcé n’est pas identique à la dessication in planta qui se caractérise par la synthèse de protéines chaperones. Plus de 89% des gènes différentiellement exprimés après 18 h d’imbibition présentent des pro¿ ls d’expression identiques dans les graines immatures et matures, en accord avec la germination comparable de celles-ci. L’analyse des transcrits dont la teneur augmente uniquement pendant l’imbibition des graines mature suggère la mise en place de mécanismes de réparation. La comparaison de ces données avec Medicago montre que l’imbibition des graines matures se caractérise par une sur-représentation des gènes liés au / During seed maturation, germination, desiccation tolerance and longevity are acquired sequentially. Seed maturation is terminated by a desiccation phase that brings the embryo to a quiescent state. Seed maturity at harvest in¿ uences seed longevity and crop establishment. After harvest, seeds are usually dried to water content compatible with long term storage and post-harvest treatments. However, there is a lack of understanding of how seed longevity is acquired during seed maturation and how premature drying impacts longevity and resumption of cellular activities during imbibition. This was addressed here by comparing transcriptome changes associated with maturation drying and imbibition of seeds of soybean and Medicago truncatula, harvested at an immature stage and mature dry stage.The immature stage corresponded to end of seed ¿ lling when longevity was not acquired while other vigor traits were acquired. Transcriptome characterization in soybean revealed that enforced drying was not similar to maturation drying in planta, which stimulated degradation of chlorophyll and synthesis of protective chaperones. Eighty-nine % of the differentially expressed genes during a 18h-imbibition period showed a similar pattern between immature and mature seeds, consistent with a comparable germination between stages. An analysis of the 147 transcripts that increased during imbibition of mature seeds but not in immature seeds suggested an activation of processes associated with shoot meristem development and DNA repair. These data were compared with imbibing immature and mature seeds

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Importance of research on the provenance problem, which is basically one of seed transfer from collection site to outplanting area, is discussed with special emphasis on coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii). The "Co-operative Douglas-fir provenance test," begun in 1957 and involving sixteen coastal seed sources from British Columbia, Washington and Oregon, is described in detail. Height measurements collected at the University of British Columbia Research Forest, when the trees were eleven years old, are analysed and the results are discussed. Due to site heterogeneity and young age of the Co-operative test, no significant height growth differences between provenances can be shown, although the local seed source, from the University of British Columbia Research Forest, seems to be the fastest growing and the southernmost origin, Butte Falls, the slowest of all provenances investigated. The Co-operative test is critically evaluated and specifications for further studies are recommended. / Forestry, Faculty of / Graduate

Planícies amazônicas alagáveis apresentam espécies arbóreas que estão sujeitas a um pulso de inundação proveniente das chuvas anuais. Muitas destas espécies apresentam estratégias de adaptação ao alagamento, germinando suas sementes e estabelecendo as plântulas antes do próximo período de cheia. Este é o caso de Macrolobium acaciifolium (Benth) Leguminosae (Caesalpinoideae), que ocorre nas cotas altitudinais mais altas das várzeas e igapós amazônicos. Neste trabalho, pela primeira vez foi caracterizado o sistema de mobilização de reservas ao longo do período de germinação e estabelecimento das plântulas de M. acaciifolium, com o objetivo de compreender os mecanismos fisiológicos e bioquímicos relacionados à sua estratégia em face à inundação. O experimento teve duração de 56 dias, nos quais foram realizadas coletas destrutivas e análises não-destrutivas de sementes e de diferentes partes das plântulas para análises de crescimento, fotossíntese, carboidratos não estruturais (frutose, glucose, sacarose e amido), xiloglucano de reserva e análises citoquímicas correspondentes à detecção de proteínas, amido e xiloglucano de reserva. Após análises citoquímicas e de açúcares, é reportado pela primeira vez na literatura científica, a existência de uma semente que acumula simultaneamente amido e xiloglucano de reserva na parede celular. Não foi observada a presença de corpos protéicos, que é uma característica comum de armazenamento de nitrogênio em sementes de Leguminosae, o que indica que a plântula provavelmente estabelece a assimilação de nitrogênio pelas raízes ao invés de armazenar e mobilizar reservas para isto. Nas sementes de M.acaciifolium xiloglucano e amido juntos perfazem 21,6% da massa da semente quiescente. No início da germinação, parte do amido é degradado e há um aumento concomitante de xiloglucano que leva a um equilíbrio entre as duas reservas. Dos 10 aos 14 dias após a embebição (DAE), o amido dos cotilédones é exaurido com concomitante desenvolvimento das raízes e do caule das plântulas. A partir de 20 DAE, o xiloglucano passa a ser degradado e a mobilização ocorre sem alterações na estrutura do polissacarídeo na parede celular e simultâneo acúmulo transitório de galactose, glucose, xilose e amido. Os produtos de degradação do xiloglucano levam à produção de folhas e ao estabelecimento da fotossíntese. As observações feitas neste trabalho sugerem que M. acaciifolium apresenta mecanismos de adaptação aos pulsos de inundação da Amazônia durante o processo de germinação e estabelecimento das plântulas / The Amazonian floodplains display tree species that are subjected to yearly inundation pulses. Several of these species colonize these regions are well adapted to the flood pulses, germinating their seeds and establishing seedlings before the next pulse comes. This is the case of Macrolobium acaciifolium (Benth) Leguminosae (Caesalpinoideae) that occur in the upper part of the riverbanks of the amazonian várzeas and igapós. In the present work, we characterized for the first time the system of storage mobilization along the period of seed germination and seedling establishment with the objective of understanding the physiological and biochemical mechanisms related to the strategy of M. Acaciifolim to face the next flooding season. The experiment was performed for 56 days in which destructive and non-destructive analyses of the seed and different parts of seedlings were performed for analyses of growth, photosynthesis, non-structural carbohydrates (fructose, glucose, sucrose, raffinose and starch), storage xyloglucan and corresponding cytochemical analyses to detect proteins, starch and storage xyloglucan in cotyledon tissues. After cytochemical and sugar analyses, it is reported for the first time in scientific literature the existence of a seed that accumulates starch and storage xyloglucan on the cell wall simultaneously. The presence of protein bodies, a common feature of seeds of the Leguminosae, was not observed, indicating that seedlings probably establish nitrogen assimilation very quickly through the newly formed roots instead of using a storage mobilization system for this reserve type. In seeds of M. Acaciifolium starch and xyloglucan correspond to 21,6% of the quiescent seed mass. At the beginning of germination, some starch is degraded with a concomitant increase in storage xyloglucan so that the yields of the two polymers become equal. From 10 to 14 days after imbibition (DAI), all starch is mobilized to support root and stem growth. From 20 DAI, xyloglucan is completely degraded without changes in its structure and with transient accumulation of galactose, glucose, xylose and starch. The products of degradation of storage xyloglucan lead to the production of leaves and photosynthesis establishment. The observations made in this work suggest that M. Acaciifolium show unique mechanisms of adaptation to the inundation pulses in the Amazon during the germination and seedlings establishment

Two populations derived by crossing LDN x LDN Dic-3A (Population I) and LDN x LDN Dic-3B (Population II) were genetically characterized for the seed dormancy present on chromosome 3A and 3B of durum wheat. The genes for seed dormancy in these two populations were contributed by the wild parent T. dicoccoides. Although the populations showed transgressive segregants for both dormant as well as nondormant parent, the populations were similar to the dormant parent at Langdon and Prosper 2006 field locations for Population I and at Langdon 2007 and Autumn greenhouse season for Population II. Genotypic and phenotypic analysis over the combined populations showed an environmental effect on expression of the trait. Different QTL were identified for both field and greenhouse season for the population derived from the cross between LDN x LDN Dic-3A. Five QTL for seed dormancy were identified on chromosome 3A for the QTL analysis performed over combined field locations. One QTL ranging between marker interval Xcfa2193 and Xcfd2a was consistently present for the 30 day period of seed germination and was also found to be linked to red grain color trait. The QTL analysis performed on the population derived from the cross between LDN x LDN Dic-3B identified only one major QTL on the long arm of chromosome 3B between the marker interval Xbarc84 and Xwmc291. This QTL was consistently present for all the field and spring greenhouse season for the seed germination period of 30 days. The QTL x E effect was also observed for this QTL, however it was very small.