Thesis (Ph. D.)--Washington State University, 2005. / Title from PDF title page (viewed on May 22, 2005). Includes bibliographical references.

Thesis (Ph. D.)--Washington State University, May 2008. / Includes bibliographical references.

Title from title page of PDF (University of Missouri--St. Louis, viewed March 2, 2010). Includes bibliographical references (p. 56-60).

Three species of the Portulacaceae each infected by a Physoderma parasite were collected at several locations in Utah. The hosts have been identified as Claytonia lanceolata Pursh., Oreobroma pygmaeum (A. Gray) Howell, and Erocallis triphylla (S. Wats.) Rydb. Since our present knowledge of Physoderma on members of the Portulacaceae is meager, it seemed desirable to learn as much as possible about the parasite, its hosts, and the relationship between parasite and host. Plants of all three hosts activated from perennating organs were grown for extended periods of time under uniform conditions. Cold treatments were most successful in activating host perennating organs and scarifiacation of the seed coat was necessary to induce seed germination. From field and laboratory studies a description was made of the appearance and the effect of the parasite on each host species. Marked hypertrophy of host tissue and frequent distortion of plant organs were characteristic of infections on O. pygmaeum and the stems of E. triphylla. Discoloration and slight or no hypertrophy were characteristic of infections on C. lanceolata and the leaves of E. triphylla. Microscopic study of the endobiotic phase indicated similarities in the vegetative phase of the parasites on the three hosts. Comparative sporangial measurements, however showed differences in the size of resting sporangia from each host. The present report of the occurrence of Physoderma on C. lanceolata and E. triphylla are new records and extend our knowledge of the host range of this parasite. The report of vascular infection on O. pygmaeum and E. triphylla are additions to a limited number of such ingections reported for chytrid parasites. Various attempts to germinate resting sporangia of the parasites and make cross-inoculations on the three host species have been unsuccessful. Such information is important in the classification of the parasites here involved and will undoubtedly contribute to an evaluation of taxonomic characters in the genus Physoderma.

Thesis (M.Sc. (Environmental Science)) - Rhodes University, 2009.

Submitted by Edisangela Bastos (edisangela@ufpa.br) on 2015-02-03T16:51:56Z No. of bitstreams: 2 license_rdf: 22974 bytes, checksum: 99c771d9f0b9c46790009b9874d49253 (MD5) Dissertacao_AvaliacaoAtividadesAntinociceptiva.pdf: 1864065 bytes, checksum: fd0df2d660d2fd9c83c478af56f33a0b (MD5) / Approved for entry into archive by Ana Rosa Silva (arosa@ufpa.br) on 2015-02-04T13:45:40Z (GMT) No. of bitstreams: 2 license_rdf: 22974 bytes, checksum: 99c771d9f0b9c46790009b9874d49253 (MD5) Dissertacao_AvaliacaoAtividadesAntinociceptiva.pdf: 1864065 bytes, checksum: fd0df2d660d2fd9c83c478af56f33a0b (MD5) / Made available in DSpace on 2015-02-04T13:45:40Z (GMT). No. of bitstreams: 2 license_rdf: 22974 bytes, checksum: 99c771d9f0b9c46790009b9874d49253 (MD5) Dissertacao_AvaliacaoAtividadesAntinociceptiva.pdf: 1864065 bytes, checksum: fd0df2d660d2fd9c83c478af56f33a0b (MD5) Previous issue date: 2012 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / FAPESPA - Fundação Amazônia de Amparo a Estudos e Pesquisas / Este estudo investigou a toxicidade aguda oral, o efeito antinociceptivo em modelos de nocicepção química e térmica, bem como a atividade anti-inflamatória em modelos de carragenina e óleo de cróton do extrato hidroetanólico de partes aéreas de Portulaca pilosa (EHEPp). Identificou também alguns possíveis mecanismos envolvidos na antinocicepção do extrato, além dos seus efeitos sobre o sistema nervoso central de ratos. No teste de toxicidade aguda oral, o tratamento com EHEPp (2000 mg/kg) não causou óbitos. No teste de contorções abdominais induzidas por ácido acético, o EHEPp (100, 200, 400 e 600 mg/kg), por via oral (v.o.), reduziu significantemente o número de contorções em 18.18, 33.25, 47.27, 65.81 e 73.94%, respectivamente. No teste da placa quente, o tratamento com EHEPp (200, 400 e 600 mg/kg, v.o.) não alterou a latência ao estímulo térmico de 50 ± 0,5 ºC. No teste da formalina, o tratamento com EHEPp (200,400 e 600mg/kg, v.o.) reduziu de maneira significativa o tempo de lambida nas fases neurogênica (1ª fase) em 38.79, 60.61 e 75.18 %, e inflamatória (2ª fase) em 49.23, 53.03 e 87.53 %, respectivamente. A administração prévia de naloxona reverteu, significativamente, o efeito do EHEPp (600 mg/kg, v.o.) em ambas as fases do teste da formalina. O pré-tratamento com o L-NAME e azul de metileno reverteu o efeito do EHEPp (600 mg/kg, v.o.) de maneira significante em ambas as fases do teste da formalina. O pré-tratamento com o fármaco glibenclamida também reverteu de maneira significativa o efeito do EHEPp (600 mg/kg, v.o.) em ambas as fases do teste da formalina. O EHEPp, na dose 600 mg/kg, v.o., não afetou a atividade locomotora dos ratos submetidos ao teste do campo aberto. No teste de edema de pata induzido por carragenina e edema de orelha induzido pelo óleo cróton, o EHEPp (400 e 600 mg/kg, v.o.) não inibiu a formação de edema de maneira significante em ambos os testes. Os resultados deste estudo mostraram que o HEEPp, oralmente, apresentou baixa toxicidade e sua atuação antinociceptiva observada na fase neurogênica pode envolver interações periféricas com receptores opióides e ativação da via NO/GCs/GMPc/ KATP. Já a atividade antinociceptiva observada na fase inflamatória parece não depender de inibição da via bioquímica fosfolipase A2/ciclo-oxigenases, mas de interações periféricas com receptores opióides e com a via NO/GCs/GMPc/KATP. / This study investigated the acute oral toxicity, the antinociceptive effect in chemical and thermal nociception models as such as the anti-inflammatory activity in carrageenan and croton oil models of the hydroethanolic extract from aerial parts of Portulaca pilosa (HEEPp). Also identified some possible mechanism involved in antinociception of the extract as such as the effects of HEEPp on central nervous system of rats. In the oral acute toxicity test, the treatment with HEEPp ( 2000 mg/kg) caused no deaths. In the acetic acid-induced writhing test, the HEEPp (100, 200, 400 and 600 mg/kg) administered by oral route (p.o.) significantly reduced the number of contortions acetic acid-induced in 18.18, 33.25, 47.27, 65.81 e 73.94%, respectively. In the hot plate test, the treatment with HEEPp (200, 400 e 600 mg/kg, p.o.) did not alter the latency to the thermal stimuli of 50 ± 0,5 ºC. In the formalin test, the treatment with HEEPp (200, 400 e 600 mg/kg, p.o.) significantly reduced the licking-time in neurogenic phase (first phase) in 38.79, 60.61 and 75.18 %, and inflammatory phase (second phase) in 49.23, 53.03 e 87.53 %, respectively. The previous naloxone administration, significantly reversed the effect of HEEPp (600 mg/kg, p.o.) in both phases of the formalin test. The pre-treatment with L-NAME and methylene blue significantly reversed the effect of HEEPp (600 mg/kg, p.o.) in both phases of the formalin test. The pre-treatment with glibenclamide also significantly reversed the effect of HEEPp (600 mg/kg, p.o.) in both phases of the formalin test. HEEPp (600 mg/kg, p.o.) did not affect the locomotor activity of rats in the open field test. In the carrageenan-induced paw edema and croton-induced ear edema, the HEEPp (400 and 600 mg/kg, p.o.) did not inhibit significantly the edema formation in both the tests. The results of this study showed that HEEPp, when administered by oral route, presented low toxicity and its antinociceptive actuation observed in neurogenic phase involves peripherals interaction with opioids receptors and activation of the in the NO/GCs/GMPc/ KATP pathway. Already the antinociceptive activity observed in the inflammatory phase does not seem to depend of the inhibition on via phospholipase A2/cyclooxygenases, but interaction with peripheral opioid receptors and the NO/sGC /cGMP/ KATP pathway.

Thesis (MA)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: The succulent thicket plant community of South Africa, particularly Portulacaria afra (in this study referred to as spekboom), occurring in the Thicket Biome, sequestrates an exceptional amount of carbon dioxide (due to its photosynthetic properties), particularly for a warm, semi-arid region and in this capacity is more akin to forest ecosystems. Spekboom has additional favourable characteristics over forested systems regarding carbon trading (CT), namely: economic water use; potential for combating desertification and poverty in arid environments; and ability to withstand stand-replacing fire (spekboom doesn’t burn) which improves its attraction as a commodity in CT and the payments for ecosystem services (PES) industry. Landowners interested in using the capacity of their land for carbon sequestration (CS) are challenged to calculate their plant communities’ sequestration ability and biodiversity potential and therefore to quantify the carbon credits to be sold. The aim of the study was to quantify the CS ability of a selected property unit by vegetation area and to establish the carbon credits value that can be sold in the carbon market. It commenced by highlighting the problem of global warming and its effect on climate change in South Africa. CS is described as a process and a solution to decrease high and rising atmospheric CO2 levels, and its use in the carbon market to attain a monetary value to promote the growing of vegetation or to protect and conserve biodiversity that will enhance carbon stocks. The study site is Bosch Luys Kloof Private Nature Reserve (BLK PNR) in the semi-arid Karoo. Because CS potential is known to follow a rainfall gradient, one expects the semi-arid Karoo to have a low CS potential. However, this area contains spekboom, an extraordinary thicket type that sequestrates carbon at similar rates to forest ecosystems and should therefore reap the benefits of CT. Yet, accurate mapping of this vegetation is critical for accurate carbon stocks assessment. The CS potential of all vegetation communities in the study area had to be established to estimate the carbon stocks in the whole property unit. ArcGIS was used to map the vegetation communities (sub biomes) and eCognition to refine mapping of the Gamka Thicket (containing spekboom) through an object-orientated approach to automated vegetation mapping. For accuracy assessment a heads-up digitized map was created for comparison. The true surface area was calculated for the vegetation classification to ensure accurate area accounting on the mountainous terrain and this calculated area of the mapped vegetation was used to convert area to carbon sequestration potential. By examining the different markets and trading mechanisms for trading in the carbon market, using CS, a marketing strategy for the land units was advised. Results show that due to BLK PNR's history of overstocking, spekboom remains degraded on the study site. This creates an opportunity to restore the vegetation with funding through CT. The sequestration potential of spekboom on BLK PNR was determined through a regional differentiation comparison. The regional differentiation comparison identified that rainfall amount and carbon accumulation are inversely proportional, therefore more arid conditions (<200mm a year, or a dry season longer than seven and a half months) cause spekboom to switch to Crassulacean acid metabolism (CAM) due to water stress, so increasing the rate of carbon accumulation. In wetter environments, where spekboom is not under water stress, it continues in carbon fixation of 3-phosphoglycerate (C3) having a lower carbon accumulation. This is a remarkable finding as CS is known to follow a rainfall gradient: in this instance spekboom is an exception to the norm. Mapped results showed that eCognition classified spekboom poorly, yielding between 64% and 69% correspondence to the accurate manually classified map. As expected three-dimensional area comparative results show that the true surface area on complex terrains was 10% higher than the original (and surveyed) land area of the estate. Results indicate that there are substantial carbon stocks for CT on BLK PNR. This study recommended the most practised form of CT (restoration) for BLK PNR. Over a period of 30 years of restoration on BLK PNR about 46 000 tons of carbon could be sequestrated. At the current price of carbon credits this could accumulate over R3.7 million over the 30-year restoration period. Combining restoration with conservation strategies into one project type has additional favourable characteristics as it takes into account the CS potential of all vegetation communities on the land unit and the ecosystem services it promotes. Conservation of BLK PNR would yield 758 000 tons of carbon. Calculated through emission abandonment, this could be valued at R8-10 million. The economic importance of the vegetation community’s biodiversity on BLK PNR and significant differences between biomes were recorded and implies a total intrinsic value in excess of R830 000 per annum. To date, pilot projects elsewhere have successfully acquired carbon credits for avoided deforestation through the climate, community and biodiversity alliance (CCBA). However, owing to the pilot stage status there is little literature that substantiates the calculation of the monetary value of conservation. This is a fertile area for further research. / AFRIKAANSE OPSOMMING: Die sukkulent-struikplantgemeenskap van Suid-Afrika, in besonder Portulacaria afra (waarna in hierdie studie as Spekboom verwys word), wat in die Struikgewasbioom voorkom, neem ‘n uitsonderlike hoeveelheid koolstofdioksied op (weens die fotosintetiese eienskappe daarvan), veral vir ‘n warm, semi-ariede streek en is in hierdie kapasiteit meer verwant aan woud-ekosisteme. Spekboom het, met betrekking tot koolstofuitruiling (KU) of koolstofhandel, addisionele gunstige eienskappe bo dié van woudsisteme, naamlik lae waterbenutting; potensiaal vir die bestryding van woestynvorming en armoede in ariede omgewings; en die vermoë om brand te weerstaan (Spekboom brand nie), wat sy aantreklikheid as ‘n kommoditeit in KU verhoog, en die betaling vir dienste in die ekosisteem-industrie (BED) verbeter. Grondeienaars wat geïnteresseerd is in die benutting van hul grond vir koolstofopname (KO), word uitgedaag om hul plantgemeenskappe se opnamevermoë en potensiaal vir biodiversiteit te bereken, en gevolglik die hoeveelheid koolstofkrediete wat verkoop kan word, te kwantifiseer. Die doel van die studie was om die KO-vermoë van ‘n geselekteerde eiendomseenheid volgens die oppervlakte onder plantegroei te kwantifiseer en om die waarde van koolstofkrediete wat in die koolstofmark verkoop kan word, vas te stel. Ten aanvang is die probleem van aardverwarming en die uitwerking daarvan op klimaatsverandering in Suid-Afrika uitgelig. KO word beskryf as ‘n proses en oplossing om die hoë en stygende atmosferiese CO2-vlakke te verminder, en die gebruik daarvan in die koolstofmark, om ‘n monetêre waarde te verkry om plantbedekking te bevorder of om biodiversiteit, wat koolstofvoorraad sal vermeerder, te beskerm en te bewaar. Die studieperseel is Bosch Luys Kloof Privaat Natuurreservaat (BLK PNR) in die semi-ariede Karoo. Omrede KO-potensiaal bekend is daarvoor om ‘n reënvalgradiënt te volg, verwag mens dat die semi-ariede Karoo ‘n lae KO-potensiaal sal hê. Hierdie gebied bevat egter Spekboom, ‘n buitengewone struiksoort wat koolstof teen soortgelyke tempo’s as woud-ekosisteme opneem, en behoort daarom voordeel uit KU te trek. Akkurate kartering van hierdie plantegroei is kritiek vir akkurate assessering van koolstofvoorraad. Die KO-potensiaal van alle plantgemeenskappe in die studiegebied is derhalwe vasgestel om die koolstofvoorrade in die totale eiendomseenheid te skat. ArcGIS is gebruik om die plantgemeenskappe (sub-biome) te karteer en eCognition is gebruik om die kartering van die Gamkaruigte (wat Spekboom bevat) deur ‘n objek-georiënteerde benadering tot geoutomatiseerde plantegroeikartering te verfyn. Vir akkuraatheidsassessering is ‘n vergelykbare plantegroeikaart per hand versyfer. Die werklike oppervlakte van die gebied is vir die plantegroeiklassifikasie bereken om akkurate oppervlakberekening van die bergagtige terrein te verseker, en hierdie berekende oppervlakte van die gekarteerde plantegroei is gebruik om oppervlakte na koolstofopname-potensiaal te herlei. Advies oor ‘n bemarkingstrategie vir die grondeenhede is gegee, deur die verskillende markte en uitruilings- of handelsmeganismes vir handel in die koolstofmark te ondersoek. Resultate toon dat weens die BLK PNR se geskiedenis van oorbeweiding, Spekboom op die studieperseel gedegradeer het. Dit skep ‘n geleentheid om die plantegroei met befondsing deur KU te herstel. Die opname-potensiaal van Spekboom op BLK PNR is deur ‘n streeksdifferensiasie-vergelyking bepaal. Die streeksdifferensiasie-vergelyking toon dat hoeveelheid reënval en koolstofakkumulasie omgekeerd eweredig of proporsioneel is, en gevolglik veroorsaak meer ariede omstandighede (<200 mm/jaar, of ‘n droë seisoen van langer as sewe en ‘n half maande) dat Spekboom weens waterstres na Crassulacea-suurmetabolisme (CSM) oorskakel, en sodoende die tempo van koolstofakkumulasie verhoog. In natter omgewings, waar Spekboom nie aan waterstres onderwerp word nie, gaan dit voort met koolstofbinding van 3-fosfogliseraat (C3) en het ‘n laer koolstofakkumulasie. Dit is ‘n merkwaardige bevinding aangesien KO daarvoor bekend is dat dit ‘n reënvalgradiënt volg: in hierdie geval is Spekboom ‘n uitsondering op die reël. eCognition het Spekboom swak onderskei, en slegs ‘n ooreenstemming van tussen 64% en 69% met die akkurate hand-geklassifiseerde gehad. Soos verwag, toon vergelykende resultate van driedimensionele oppervlakte dat die werklike oppervlakte byna 10% hoër is as die oorspronklike (en gemete) grondoppervlak van die eiendom. Resultate dui aan dat daar aansienlike koolstofvoorrade vir KU op BLK PNR is. Hierdie studie beveel die mees gebruikte praktyke van KU (herstelproses) vir BLK PNR aan. Oor ‘n hersteltydperk van 30 jaar op BLK PNR kan ongeveer 46 000 ton koolstof opgeneem word. Teen die huidige prys van koolstofkrediete kan dit meer as R3.7 miljoen oor die hersteltydperk van 30 jaar akkumuleer. Die kombinasie van herstelprosesse en bewaringstrategieë in een tipe projek, hou addisionele voordeel in, omdat dit die KO-potensiaal van alle plantgemeenskappe op die grondeenheid en die ekosisteem-dienste in berekening bring. Bewaring van BLK PNR sal 757 913 ton koolstof lewer. As dit in terme van die staking van uitlatings bereken word, kan dit teen R8-10 miljoen gewaardeer word. Die ekonomiese belangrikheid van die ekosisteem en plantgemeenskap-biodiversiteit op BLK PNR impliseer ‘n totale intrinsieke waarde van meer as R800 000 per jaar. Loodsprojekte elders was suksesvol in die verkryging van koolstofkrediete vir die vermyding van ontbossing deur die klimaat-, gemeenskap- en biodiversiteitsalliansie (KGBA). Vanweë die loodsprojekstatus, is daar egter min literatuur beskikbaar wat die berekening van die monetêre waarde van bewaring staaf. Dit laat ruimte vir verdere navorsing.

The semi-arid forms of subtropical thicket in the Eastern and Western Cape have been heavily degraded through unsustainable pastoralism over the last century or more. The degraded areas exhibit a significant loss of above-ground and belowground carbon stocks, and consequently provide an opportunity for restoration through the formal and informal carbon markets. A prerequisite for the attainment of carbon credits is to ensure sound carbon stock baselines prior to effecting restoration. I report on the carbon stocks (including sub-pools) for a number of intact subtropical thicket types, as well as the differentials between the intact and degraded states (including the sub-pools). Total carbon stocks (TCS in t C ha⁻¹) for intact vegetation (to a soil depth 0–25 cm), ranged from 87.73±6.51 to 70.64±17.24. For degraded vegetation (including old lands), TCS (t C ha⁻¹) ranged from 34.05±3.61 to 21.03±2.70. For all vegetation types, the differentials in TCS along the degradation gradient (0–25 cm) are highly significant and strengthen the possibility for carbon credit financing to catalyse the restoration of the degraded semi-arid subtropical thickets. This study has shown a mean loss of 57.23 t C ha⁻¹ in Baviaanskloof spekboom thickets, when measured to a soil depth of 25 cm. Portulacaria afra is a key species within the semi-arid subtropical thickets, being a canopy dominant and a driver of soil nutrient status, but has been largely lost from the degraded landscapes. Degraded semi-arid subtropical thicket vegetation lacks regeneration via seedling recruitment; restoration therefore requires the manual replanting of P. afra using cut truncheons. Survivorship trials were undertaken infield in 2005 to establish restoration protocols for P. afra, with survivorship being recorded in 2006 and 2008. Overall survivorship for all treatments was found to be 43.2±2.8% in 2006, dropping to 35.8±2.7% in 2008. Planting posture (flat or upright) showed the most significant results of all the factors tested in 2006 and 2008. Micro-damming also influenced survivorship in that micro-damming was associated with marginally higher survivorship (47.4 ±2.0% with damming vs. 39.1±1.5% without damming in 2006, and 39.3±1.9% vs. 32.3±1.5% in 2008). Higher planting density only showed a significant positive impact on survivorship in 2008. Neither stem diameter nor clumping significantly affected degree of survival. A key finding in the study has been the non-static nature of P. afra truncheon survivorship, even after being well established (three years since planting). The results from the study will guide the restoration protocols for the restoration of degraded subtropical thickets, where P. afra requires replanting.