Bayreuth, Univ., Diss., 2003. / Computerdatei im Fernzugriff.

Bayreuth, Univ., Diss., 2003. / Computerdatei im Fernzugriff.

Thesis (Ph. D.)--University of Chicago. / Reprinted from the Botanical Gazette, Vol. XLVI, No. 3, pp. 161-178. "Literature cited" p. 176. Also available on the Internet.

Tese (livre docencia) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-07-14T17:00:53Z (GMT). No. of bitstreams: 1 Campello_JayrdePaiva_LD.pdf: 18357182 bytes, checksum: 908d1aa5415eb45c7a9402b4b07048cb (MD5) Previous issue date: 1972 / Tese (livre docencia) - Univer

Orientador : Jayr de Paiva Campello / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-07-17T20:58:59Z (GMT). No. of bitstreams: 1 Vaz_MariaReginaVerzola_M.pdf: 5020832 bytes, checksum: 34113ce3d15a5d006503a1bc4c0697c4 (MD5) Previous issue date: 1975 / Mestrado

The trees belonging to the genus Podocarpus, of which only four species are native to South Africa, are renowned for their superior quality timber. Prior to 1880, Podocarpus henkelii, together with P. falcatus and P. latifolius, played a significant role in the development of the country as they were heavily utilised as timber trees for the building of dwellings, furniture and other necessary items. Due to this over-exploitation in the timber trade, all the Podocarpus species in South Africa have been afforded a ‘Protected’ status on the IUCN red data list of species that are either threatened or in danger of extinction. However, despite the obvious need to conserve the threatened genetic diversity of these species, few attempts (aside from in vitro micropropagation) have been made to explore ex situ Podocarpus germplasm conservation in the long-term. Consequently, the primary aim of this study was to establish a protocol for the long-term conservation of germplasm of Podocarpus henkelii Stapf ex Dallim. Jacks. The seeds of Podocarpus henkelii exhibit recalcitrant behaviour and can therefore not be stored in conventional seed banks. This has necessitated the investigation of alternative methods of germplasm conservation with a focus on cryopreservation which is presently considered the most reliable, efficient and cost-effective means of storing the genetic resources of recalcitrant-seeded species for prolonged periods. The first objective of this study was to investigate the effect of slow (two-step) and ultra-rapid cooling on the post-thaw survival of variously treated P. henkelii embryos. The results of this investigation revealed that the rate of cooling employed had a significant effect on explant viability as none of the precultured, cryoprotected embryos that were slowly cooled survived cryostorage while some of the preconditioned embryos responded to ultra-rapid cooling (i.e. 36% shoot production and 88% callus formation). For ultra-rapid cooling, it was found that flash-drying prior to cooling was a prerequisite for survival as osmotic dehydration alone did not effectively prepare the tissues for the stresses imposed during cryostorage. Furthermore, for those flash drying intervals that yielded positive results, preconditioning explants with 10% glycerol proved the most effective pre-cooling treatment. However, due to the low recovery numbers after ultra-rapid cooling, a third cryopreservation technique i.e. cryogenic vitrification, was investigated. For cooling by vitrification, data obtained from preliminary experiments showed that precultured explants needed to be initially loaded with 18% sucrose (w/v) + 14% glycerol (v/v) for 20 min and subsequently immersed in Plant Vitrification Solution 3 (PVS3) at 0°C for 10 min prior to cooling. However, relatively low success was achieved for P. henkelii embryos cooled by vitrification as the highest post-cooling survival obtained was only 20% germination, 27% shoot formation and 37% callus formation. Due to the low post-thaw survival obtained despite the rigorous manipulations employed in the development of the slow cooling, ultra-rapid cooling and vitrification protocols, it was decided that an alternative explant should be investigated for the conservation of P. henkelii germplasm. The explant of choice was adventitious buds induced to form on, and subsequently excised from, mature P. henkelii embryos. The first objective was to develop a suitable protocol for the induction of adventitious buds on P. henkelii embryos. The medium that induced in the highest percentage of embryos (85%) to form adventitious buds consisted of Douglas-fir cotyledon revised (DCR) basal medium supplemented with 30 g L-1 sucrose, 0.05 mg L-1 NAA, 0.5 mg L-1 BA and 6 g L-1 agar. This medium also resulted in the highest average number of buds formed per embryo (i.e. 35 ± 3 buds per embryo). Once the adventitious bud induction medium was developed, it was necessary to optimise the size of adventitious bud clumps to be used as explants for cryopreservation. Three bud clump sizes were investigated: ca 3, 5 and 10 buds per clump. However, none of the bud clumps survived excision from the mother-tissue despite the investigation of three different types of bud-break media. The resultant tissue mortality is suggested to have occurred because the adventitious bud clumps were excised prior to bud break and shoot development which could have exacerbated excision-related cellular and sub-cellular damage. It was therefore decided that attempts should be made to induce adventitious buds directly on P. henkelii embryos post-cooling, thereby eliminating the possibility of potentially lethal excision-related damage. The protocols that yielded the best results after ultra-rapid cooling and cooling by vitrification were used in this experiment. For ultra-rapid cooling, embryos were first cryoprotected with 5% followed by 10% glycerol for 1 h in each and subsequently flash dried for 30 min prior to immersion in nitrogen slush. For cooling by vitrification, embryos that were first precultured on 0.3 M sucrose for 1 d were loaded with 10% glycerol + 14% sucrose (LS4). The loaded explants were then immersed in ice-cold PVS3 and maintained on ice for 10 min prior to cryostorage. The effect of each pretreatment (either independently or in combination) on adventitious bud production pre-cooling was also investigated. For both protocols the various pretreatments decreased not only the capacity of the embryos to form buds but also the average number of buds formed per embryo (i.e. 7 ± 2 buds per embryo and 14 ± 2 buds per embryo were formed on treated embryos prior to ultra-rapid cooling and cooling by vitrification, respectively). Thus, it was predicted that even if the percentage of cryopreserved embryos forming buds was minimal, the number of possible plantlets that could be regenerated from adventitious buds per cryopreserved explant would compensate for the low recovery of embryos post-cooling. However, none of the embryos that were cryopreserved by either ultra-rapid cooling or by vitrification formed adventitious buds after eight weeks in culture. The very restricted success achieved in this study despite the investigation of three cryopreservation techniques and two different explants only serves to reinforce the difficulties associated with the conservation of recalcitrant germplasm. The large size and structural complexity of P. henkelii embryos, coupled with their high water content post-shedding, are just some of the characteristics to which their intractability to the manipulations involved in the development of a successful cryopreservation protocol could be attributed. For future investigations, development of adventitious buds produced on cryopreserved root segments (as opposed to entire roots), and/or use of seedling meristems as explants which might be amenable to cryopreservation are suggested as possible avenues for the long-term conservation of P. henkelii genetic diversity. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2012.

A dendrocronologia constitui-se no estudo dos anéis de crescimento e sua sequencia cronológica, que pode trazer importantes informações a respeito do crescimento dos vegetais lenhosos e seu ambiente. No presente trabalho foram analisados os anéis de crescimento de Podocarpus lambertii em uma população situada em sua zona limite de distribuição, no município de Morro do Chapéu, estado da Bahia. O local apresenta condições diferenciadas, sendo uma elevação em meio a caatinga com afloramentos rochosos que formam estreitos corredores onde os exemplares da espécie se distribuem. Através da dendrocronologia foi construída uma cronologia de 73 anos com 19 indivíduos e 43 raios da população, comprovando a anualidade dos anéis da espécie e sua capacidade de intercorrelação e boa sensitividade, embora a presença de anéis confluentes e falsos tenha ocasionado dificuldades na datação. Essa cronologia é a primeira realizada com P. lambertii. Os resultados mostraram um lento desenvolvimento da espécie no local, como no exemplo de um indivíduo de apenas 12 cm de diâmetro de tronco e 104 anos de idade. Com relação ao clima, os anéis apresentaram grande influência deste fator, com o crescimento sendo negativamente influenciado pela temperatura e precipitação na estação de crescimento (novembro a abril) e positivamente pela insolação. Na avaliação das reservas presentes no xilema de P. lambertii, os resultados mostraram uma distribuição aparentemente homogênea por todo o lenho, não permitindo relacioná-las diretamente com a formação dos anéis de crescimento, sugerindo grande capacidade de acúmulo de reservas pela árvore. A análise da condução de seiva pelo xilema ativo permitiu identificar que os anéis de crescimento mais jovens (próximos ao câmbio) são os maiores responsáveis pela condução, em um possível alburno, já que esta diferenciação não é obtida visualmente. / The Dendrochronology is the science that studies of annual growth rings present in the xylem. It allows to access information stored during the life tree. One of its basic requirements is the annual nature of growth ring formation, a feature usually present in conifers. In Brazil there are two genus of conifers, Araucaria and Podocarpus, but just the first was studied dendrochronology. Podocarpus lambertii, target species of this study was analyzed in a growing population living at Morro do Chapeu, Bahia State, Brazil, located at the Northern limit of species distribution. A total of 19 individuals were sampled, they were polished and this growth rings were measured. Missing and confluent rings difficulted to determine precise ages but after dendrochronological analysis it was possible to built good chronology, with significative intercorrelation and sensivity. A series of 73 years (1935-2008), confirmed the annual nature of growth rings of this species by dendrochronology. The history of local weather informations was compared with the chronology and allowed a good understanding the species growth, which respond negatively to higher temperatures (December and January) and also negatively to higher solar radiation (January), that suggests that heatstroke is an important point of activation and formation of the ring\'s growth.

A dendrocronologia constitui-se no estudo dos anéis de crescimento e sua sequencia cronológica, que pode trazer importantes informações a respeito do crescimento dos vegetais lenhosos e seu ambiente. No presente trabalho foram analisados os anéis de crescimento de Podocarpus lambertii em uma população situada em sua zona limite de distribuição, no município de Morro do Chapéu, estado da Bahia. O local apresenta condições diferenciadas, sendo uma elevação em meio a caatinga com afloramentos rochosos que formam estreitos corredores onde os exemplares da espécie se distribuem. Através da dendrocronologia foi construída uma cronologia de 73 anos com 19 indivíduos e 43 raios da população, comprovando a anualidade dos anéis da espécie e sua capacidade de intercorrelação e boa sensitividade, embora a presença de anéis confluentes e falsos tenha ocasionado dificuldades na datação. Essa cronologia é a primeira realizada com P. lambertii. Os resultados mostraram um lento desenvolvimento da espécie no local, como no exemplo de um indivíduo de apenas 12 cm de diâmetro de tronco e 104 anos de idade. Com relação ao clima, os anéis apresentaram grande influência deste fator, com o crescimento sendo negativamente influenciado pela temperatura e precipitação na estação de crescimento (novembro a abril) e positivamente pela insolação. Na avaliação das reservas presentes no xilema de P. lambertii, os resultados mostraram uma distribuição aparentemente homogênea por todo o lenho, não permitindo relacioná-las diretamente com a formação dos anéis de crescimento, sugerindo grande capacidade de acúmulo de reservas pela árvore. A análise da condução de seiva pelo xilema ativo permitiu identificar que os anéis de crescimento mais jovens (próximos ao câmbio) são os maiores responsáveis pela condução, em um possível alburno, já que esta diferenciação não é obtida visualmente. / The Dendrochronology is the science that studies of annual growth rings present in the xylem. It allows to access information stored during the life tree. One of its basic requirements is the annual nature of growth ring formation, a feature usually present in conifers. In Brazil there are two genus of conifers, Araucaria and Podocarpus, but just the first was studied dendrochronology. Podocarpus lambertii, target species of this study was analyzed in a growing population living at Morro do Chapeu, Bahia State, Brazil, located at the Northern limit of species distribution. A total of 19 individuals were sampled, they were polished and this growth rings were measured. Missing and confluent rings difficulted to determine precise ages but after dendrochronological analysis it was possible to built good chronology, with significative intercorrelation and sensivity. A series of 73 years (1935-2008), confirmed the annual nature of growth rings of this species by dendrochronology. The history of local weather informations was compared with the chronology and allowed a good understanding the species growth, which respond negatively to higher temperatures (December and January) and also negatively to higher solar radiation (January), that suggests that heatstroke is an important point of activation and formation of the ring\'s growth.

In order to study the growth and the relationship with environmental variables of Podocarpus lambertii Klotzsch ex Endl. in two phyto-geographical regions of Rio Grande do Sul state, over hill fields (São Francisco de Paula) and Central depression (São Sepé), four subjects were sampled in each place and went through an complete stern analysis. The results allowed to conclude that the annual increment in diameter presented a positive and significant correlation about the precipitation and relative humidity, indicating that the increase of these variants favors the growth of the diameter. The average temperatures of maximum, absolute maximum, absolute minimal and solar radiation presented significant negative correlations where the increase of these variants represents a tendency of restriction to the growth in diameter. The climate variants explained 25% of the adjust of the annual increment of this species. Some chemical elements of the soil present a positive correlation when related to the periodic annual increment in diameter, urth phosphorum (P), calcium(Ca), magnesium(Mg) and alluminum (Al), explaining 58% of the increment of this species. In São Francisco de Paula, the Podocarpus lambertii presented a maximum diameter of 38.8 cm, in the age of asymptotic of 140 years and, in São Sepé, the maximum diameter was 24.4 cm, in the age of asymptotic of 96 years. The growth in diameter, when compared in the two regions, showed different tendency from 34 years and on, moment when the trees presented the same diameter of 12 cm. From this age, the trees grown in São Francisco de Paula tend to have a higher speed in growth than the ones from São Sepé. Through Backmann s growth of model, using variable dummy 1 (São Francisco de Paula) and dummy 2 (São Sepé), the equations for growing in diameter were obtained, with adjusted coefficient of determination of 0.567 and coefficient of variation of 22.1%; height growing, with coefficient of determination of 0.612 and coefficient of variation of 23.2% and growth in volume, with coefficient of determination of 0.745 and coefficient of variation of 33,2.%. / Com objetivo de estudar o crescimento e a relação com as variáveis ambientais de Podocarpus lambertii Klotzsch ex Endl. em duas regiões fitogeográficas do Rio Grande do Sul Campos de Cima da Serra (São Francisco de Paula) e Depressão Central (São Sepé) foram amostrados quatro indivíduos em cada local, nas quais realizou-se análise de tronco completa. Os resultados obtidos permitiram concluir que o incremento corrente anual em diâmetro apresentou correlação positiva e significativa em relação à precipitação e umidade relativa, indicando que o aumento dessas variáveis favorece o crescimento em diâmetro. As temperaturas médias das máximas, mínimas, máxima absoluta, mínima absoluta e radiação solar apresentaram correlações negativas significativas, em que o aumento destas variáveis representa uma tendência de restrição ao crescimento em diâmetro. As variáveis climáticas explicaram 25% do ajuste do incremento corrente anual desta espécie. Alguns elementos químicos do solo apresentaram correlação positiva quando relacionados com o incremento periódico anual em diâmetro, como fósforo (P), potássio (K), cálcio (Ca), magnésio (Mg) e alumínio (Al), explicando 58% do incremento desta espécie. Em São Francisco de Paula, o Podocarpus lambertii apresentou um diâmetro máximo de 38,8 cm, na idade de assíntota de 140 anos e, em São Sepé, o diâmetro máximo foi de 24,4 cm na idade de assíntota de 96 anos. O crescimento em diâmetro, quando comparado nas duas regiões, apresentou tendência diferente a partir dos 34 anos, momento em que as árvores apresentaram mesmo diâmetro de 12 cm. A partir dessa idade, as árvores que crescem em São Francisco de Paula tendem a um ritmo mais acelerado do que as árvores de São Sepé. Por meio do modelo de crescimento de Backmann, utilizando as variáveis dummy 1 (São Francisco de Paula) e dummy 2 (São Sepé), obtiveram-se as equações para crescimento em diâmetro, com coeficiente de determinação ajustado de 0,567 e coeficiente de variação de 22,1%; crescimento em altura, com coeficiente de determinação de 0,612 e coeficiente de variação de 23,2% e crescimento em volume, com coeficiente de determinação de 0,745 e coeficiente de variação de 33,2%.

Orientador: Rafael Silva Oliveira / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-27T10:25:03Z (GMT). No. of bitstreams: 1 Muller_CarolineSignori_M.pdf: 1389363 bytes, checksum: 90f312d9e875f306ba1ded4eb5ff7c45 (MD5) Previous issue date: 2015 / Resumo: Diversos modelos climáticos predizem mudanças no regime hídrico e secas extremas nos mais variados ecossistemas, dentre esses, as florestas tropicais nebulares (FTNs), que são apontadas como ambientes sensíveis às mudanças no clima. Nas FTNs a frequência e intensidade de neblina são determinantes na composição da vegetação. As predições são de que o aquecimento terrestre causará um deslocamento da área atual de ocorrência de neblina para altitudes maiores, acima da maioria das FTNs do mundo. Com diminuição da neblina nesses ambientes é provável que ocorra um aumento da evapotranspiração e estresse hídrico da vegetação, podendo haver mortalidade das plantas. Em nosso estudo investigamos as relações hídricas de duas coníferas que ocorrem em FTNs A. angustifolia e P. lambertii, além disso avaliamos se o ponto de perda de turgor (?tlp) é um bom preditor de mortalidade para essas espécies. Para compreendermos os efeitos da neblina no status hídrico de A. angustifolia avaliamos duas populações em altitudes diferentes, sendo elas, montanha (1950 m) e vale (1500 m). Os indivíduos localizados na montanha mantiveram potenciais hídricos menos negativos do que os localizados no vale, durante todo o período de monitoramento. Conduzimos um experimento em casa de vegetação para avaliar a resistência a seca de A. angustifolia e P. lambertii. Também avaliamos a importância da absorção de água da neblina pelas folhas (AAF) e do aporte hídrico diretamente no solo na recuperação do status hídrico dessas espécies depois de submetidas à secas em que seu potencial hídrico foliar (?Folha) chegou ao ponto de perda de turgor (?tlp). As duas espécies apresentaram diferentes estratégias de manutenção do status hídrico, A. angustifolia foi mais resistente à seca, sobrevivendo por até 17 semanas de seca P. lambertii sobreviveu a 12 semanas de seca, no entanto, esta espécie apresentou maior capacidade de manutenção do ?Folha quando a única fonte de água foi à neblina. O ?tlp foi um bom preditor de mortalidade para essas duas espécies / Abstract: Several climate models predict changes in the water regime and extreme droughts in a wide variety of ecosystems. Among these ecosystems, there are the tropical montane cloud forests (TMCFs), pointed as sensitive environments to climate changes. Frequency and intensity of fog are crucial to the composition of vegetation in TMCFs. Predictions are that global warming will cause a shift in fog occurrence from the current area to higher altitudes, above most TMCFs in the world. With the fog decrease in these areas it is likely to occur an increase in the evapotranspiration and water stress of the vegetation, which may result in plant mortality. In this research we look into water relations of two conifers that occur in TMCFs, A. angustifolia and P. lambertii. Furthermore, it is evaluated if the turgor loss point (?tlp) is a good mortality predictor for these two species. To comprehend the fog effects in A. angustifolia's water status we evaluate two populations in different altitudes: mountain (1950m) and valley (1500m). Individuals located in the mountain kept water potentials less negative than the ones located in the valley throughout the monitoring period. An experiment was conducted in greenhouse to evaluate the resistance to drought of A. angustifolia and P. lambertii. Were also evaluated the importance of fog water uptake by leaves (LWU) and of water input directly into the ground in the water status recovery of the species after being subjected to drought in which their leaf water potential (?Leaf) reached the turgor loss point (?tlp). Both species presented different strategies of water status maintenance. A. angustifolia was more resistant to drought, surviving for up to 17 weeks of it, while P. lambertii survived for 12. However, P. lambertii showed higher capacity of ?Leaf maintenance when the only source of water was fog. Turgor loss point was a good mortality predictor for these two species / Mestrado / Biologia Vegetal / Mestra em Biologia Vegetal