Thesis (Ph. D.)--University of Wisconsin--Madison, 1938. / Typescript. Includes abstract and vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 33-35).

Thesis (Ph. D.)--University of Hawaii at Manoa, 1983. / Bibliography: leaves 176-179. / Microfiche. / ix, 179 leaves, bound ill. 29 cm

Dissertation (doctoral)--Universität Münster, 1934. / Cover title. "Botanik." Bibliography: p. 23-[24].

Thesis (MTech (Horticultural Sciences)--Cape Peninsula University of Technology, 2012 / This study evaluated the effects of different combinations of Hoagland’s solution and Azolla filiculoides on Beta vulgaris subsp. cycla ‘FORDHOOK GIANT’ grown in different hydroponic nutrient solutions. These solutions were comprised of a full Hoagland’s solution and a Hoagland’s solution minus nitrogen solution and amalgamations of these with Azolla respectively. The objectives were to assess the effects of different combinations of Hoagland’s solution and A. filiculoides on uptake of nitrogen and other nutrients, photosynthesis, chlorophyll content, growth and development in B. vulgaris grown in hydroponic cultures. The treatments were made up of 1) Hoagland’s minus N solution (as the control), 2) A. filiculoides plus Hoagland’s minus N solution, 3) A. filiculoides plus a full Hoagland’s solution and 4) full Hoagland’s solution. Each treatment was replicated 4 times. Nutrient uptake was measured at 4 and 8 weeks into the experiment. Photosynthesis was measured by analysing the photosynthetic rate, stomatal conductance, intercellular CO2 concentration and the evapotranspiration rate of B. vulgaris on a weekly basis. Chlorophyll content was determined by analysing the samples at 4 and 8 weeks. Growth and development was determined by measuring plant height, leaf number, leaf colour, fresh weight and dry weight. Plant height, leaf number and leaf colour on a biweekly intervals, while fresh and dry weight were analysed at 4 and 8 weeks into the experiment. In this study, the most favourable results were attained by the full Hoagland’s solution. This treatment produced plants with the highest nutrient uptake, photosynthesis, chlorophyll content and best growth and development. Preceding this was the Azolla plus full Hoagland’s solution, followed by the Azolla plus Hoagland’s minus nitrogen solution. The poorest results were noted in the control (Hoagland’s minus nitrogen solution) as all the tested parameters in this treatment were the lowest. In this study, Azolla plus Hoagland's minus N solution treatment produced significant growth in B. vulgaris. Although nitrogen was not applied in this treatment, there was improved nitrogen content in B. vulgaris organs. It is postulated that, probably, Azolla released the fixed nitrogen in its surrounding environment making it available to B. vulgaris hence improving N uptake and growth. This implies that there was a synergistic effect from Azolla–Anabaena symbiosis. More studies to understand the mechanisms involved in improving the plant growth are recommended.

The potential of non-viable Azalia filiculaides for the removal of Cu and Ni from aqueous solutions and the possibility of scaling up existing lab scale Azalia column systems was investigated. The effects of factors such as metal starting concentration, pH and two metals in solution on the removal of Ni and Cu from aqueous solution by dried and crushed Azalia biomass were studied in batch systems. Aqueous solutions of Ni with starting concentrations between 1000 and 2000J.lmolll gave the most efficient Ni removal by Azalla biomass. For Cu the optimum starting concentration for adsorption was 50J.lmol/l. The adsorption capacity of both eu and Ni increased as the starting pH of the sorption media increased. The optimum pH for Ni adsorption was found at pH 7 and for Cu, at pH 5. - Awlla biomass had a higher. maximum binding capacity (qrnax) for Cu than for Ni at pH 5. The removal of both Cu allct Ni showed little or no variation with the presence another metal in solution. Kinetic studies show that both Cu and Ni adsorbed rapidly onto the Azalia biomass. The removal of Cu and Ni from aqueous solutions using non-viable Azalia biomass was investigated in a lab scale fixed-bed column and an upscaled 4L column system. The nonviable Azalla filiculaides biomass when dried and used in a column for adsorption of Cu and Ni showed good physical stability under many different conditions. Preparation of the biomass before it could be used in the columns was very simple and did not involve any significant pretreatment steps. Prolonged exposure to UV light decreases Azalia biomass capacity for Ni and Cu adsorption. Column adsorption of Cu and Ni from aqueous solutions was successfully upscaled approximately 100 times. Relative to the lab scale column, the 4L column performed better for the uptake of Cu and Ni per gram of biomass. The larger column was also able to operate at relatively higher flow rates. The biomass showed good reusability with little change in the amount of Ni adsorbed in 10 consecutive cycles. Electron micrographs showecf little or no change in the physical structure and integrity of the Azolla biomass after exposure to mineral acids, Ni solution and high flow rates over 10 consecutive adsorption and desorption cycles. As much as 80% Ni and 70 % Cu was recovered when desorption profiles were generated using O.lMHCI as a desorption agent. The 4L column system was also tested using a highly concen~rat:~ Ni plating bath solution.(Nicrolyte 1). Only 18 % of the Ni could be removed from the expended Nicrolyte 1 pla~Jng solution after treating only 25L, indicating that Azolla biomass is more suited for removal of metals from more dilute industrial effluents.

Résumé Une meilleure intégration de la fougère aquatique Azolla dans les aliments de O. niloticus en vue de sa production en milieu rural a été recherchée en bassins et en étangs. Six aliments (29,2 % PB; 16,9 kJ g-1 EB, chacun) : A0, A10, A20, A30, A40 et A50 contenant respectivement 0, 10, 20, 30, 40 et 50 % de farine d’Azolla (FA) en remplacement partiel de la farine de poisson ont été testés. En bassins comme en étangs, une réduction de la croissance a été enregistrée lorsque la teneur en FA a dépassé 10 et 20 % respectivement. En étangs, les valeurs de production piscicoles (8220-5120 kg ha-1 an-1) et d’indice de profitabilité (0,42-0,89) sont similaires jusqu’à 20 % et 30 % de FA dans les aliments. L’élevage en étangs pourrait être plus avantageux en nourrissant les poissons avec A20 en étangs dont la surface est couverte à 45 % par un tapis d’Azolla. Dans les deux systèmes d’élevage, la composition des carcasses ne semble pas être affectée, excepté une réduction de la teneur en lipides totaux dans les poissons nourris avec A30, A40 et A50 en bassins et ceux nourris avec A50 en étangs. D’un point de vue environnemental, malgré que la teneur en phosphore des aliments soit passée de 1,13 % à 0,76 % en faisant varier leur teneur en Azolla de 0 % à 50 %, les compositions en phosphore (P) et azote (N) des poissons sont similaires, en bassins comme en étangs. En bassins, les quantités de P et de N rejetées par les poissons ont diminué avec l’augmentation de FA dans les aliments. De même, la quantité de P rejetée en étangs décroît, tandis que celle de l’azote est identique dans tous les traitements. La composition en acides gras des poissons élevés en bassins ressemble à celle des aliments, excepté une augmentation de la teneur en acide arachidonique (ARA) chez les poissons nourris à fort taux d’Azolla. Ceci pourrait être le fait d’une élongation et désaturation de l’acide linoléique. Les valeurs du ratio n-3/n-6 (0,08-0,17) qui en résultent sont faibles chez les poissons nourris avec A40 et A50. Le profil en acides gras des poissons d’étangs est par contre différent de celui des poissons de bassins et de la composition des aliments. Cette dissemblance est particulièrement prononcée chez les poissons nourris avec A30, A40 et A50 qui sont riches en acide éicosapentaénoique (EPA) et acide docosahexaénoique (DHA), principaux acides gras dans le plancton. Cette "signature" du plancton pourrait être due à une consommation supplémentaire de ces nourritures naturelles par ces poissons et expliquerait les valeurs élevées du ratio n-3/n-6 (0,35-0,53) dans les poissons nourris avec les aliments contenant 20 à 50 % de FA. Les paramètres de croissance et le profil en acides gras sont meilleurs en étangs qu’en bassins, et les nutriments rejétés en étangs sont relativement faibles, probablement à cause de la contribution de la nourriture naturelle. En conclusion, Azolla pourrait permettre de réduire le coût des aliments et le coût total de production des poissons, tout en garantissant un bon niveau trophique des étangs et une bonne qualité nutritionnelle des poissons produits. L’étude suggère d’utiliser la fougère jusqu’à 10 % dans les aliments en bassins et 20 à 30 % en étangs. Dans ce dernier système, une couverture des étangs de maximum 45 % de leur surface pourrait permettre de produire des poissons, en même temps qu’elle fournirait de l’Azolla à incorporer dans les aliments ou pour d’autres utilisations bénéfiques. Abstract An improved integration of the aquatic fern Azolla in diets for production of Nile tilapia O. niloticus in rural area was investigated in tanks and in ponds. Six diets (29.2% CP; 16.9 kJ g-1 GE, each) were tested, containing 0% (diet A0), 10% (diet A10), 20% (diet A20), 30% (diet A30), 40% (diet A40) and 50% (diet A50) of Azolla meal (AM) as fishmeal (FM) substitutes. The diet A0 served as a control. Growth parameters decreased, significantly when Azolla level exceeds 10% and 20% in diets, respectively in tanks and ponds. In ponds, the variation of annual fish production follows the trend in growth parameters, with values decreasing from 8220 to 5120 kg ha-1 year-1. Identical profitability index (range: 0.42-0.89) was obtained up to 30% Azolla. Feeding with A20 could be more advantageous by rearing fish in ponds covered with Azolla mat at a maximum of 45% of the water surface. In tanks and in ponds, fish carcass was not significantly affected, except for the total lipid content of fish fed 30, 40 and 50% Azolla in tanks, and those fed 50% Azolla in ponds. From an environmental point of view, phosphorus and nitrogen contents in experimental fish show similar values, both in tanks and ponds, although phosphorus content in diets varied from 1.13% to 0.76% when Azolla level increased from 0% to 50%. In tanks, phosphorus (P) and nitrogen (N) discharged as wastes by fish decreased with increasing Azolla level in diets. Also, P decreased significantly in ponds whereas identical values were found for nitrogen in all treatments. In tanks, fish fatty acids mirror the profile in diets, except for the high arachidonic acid content (ARA) in high AM-fed fish, probably as a result of elongation and desaturation of linoleic acid. This leads to a lower n-3/n-6 ratio (range: 0.08-0.17) in fish fed A40 and A50. Fatty acid composition of fish fed in ponds was different from that in fish fed in tanks, and from diets. The lower resemblance of fish composition was more pronounced in fish fed A30 to A50 in which large amounts of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were found, reflecting closely the composition in plankton. The reason could be a supplemental consumption of plankton by those fish as a response to the deficiency in diets A30-A50. Then, the n-3/n-6 ratios (range: 0.35-0.53) were higher in fish fed A20 to A50. Growth and fatty acid composition were better in ponds, and nutrients loading into pond water were lower, probably due to the contribution of natural foods. In conclusion, Azolla use leads to reduced feed and total fish production costs, while ensuring a suitable pond trophic level and a good nutritional quality of the fish produced. The study suggests using Azolla in tanks up to 10% in diets, while up to 20-30% can be recommended in ponds. In the latter case, covering the ponds surface with Azolla mat at a maximum of 45% of its surface could lead to produce fish, while ensuring Azolla mass production for diets and other beneficial utilization.

Made available in DSpace on 2015-03-26T13:36:46Z (GMT). No. of bitstreams: 1 texto completo.pdf: 279034 bytes, checksum: 141cff7d975ad2a0d439e0f2d5e92fd3 (MD5) Previous issue date: 2006-09-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The influence of different concentrations of As over some aspects of growth and antioxidant system were studied in three water species: Azolla caroliniana, Lemna gibba and Salvinia minima, in nutrient solution. After the three species being exposed to five concentrations of As (0.0, 0.25, 0.5, 1.0 and 1.5 mg.L-1) in nutrient solution, the As content into the plants, relative growth rate (TCR), superoxide dismutase (SOD), catalase (CAT), peroxidase (POX), ascorbate peroxidase (APX) and glutatione reductase (GR) enzymatic activity, total thiol, non protein thiol and protein thiol content and anthocyanin content were determined. L. gibba showed the highest tolerance to As, requiring 967,6 μg g-1MD to reduce growth in 50%. A. caroliniana required 429,2 μg g-1MD to show this level of growth reduction and S. minima required 255,08 μg g-1MD for the same response. Antioxidant mechanisms to the increase in As concentration in the medium characterized each species. A. caroliniana went through increases in CAT and GR activities, keeping unaltered SOD and POX activities, and showing reduction in APX activity, although it presented the highest activity of this enzyme. S. minima exhibited increase in SOD, CAT, APX and GR activities, keeping POX activity unaltered, with the increase of As concentration in the growth medium. L. gibba higher tolerance to As effects seem to be related to the enzymatic antioxidant mechanisms and also to the non-enzymatic ones. This species, besides presenting higher SOD, CAT, POX and GR activities, also showed higher thiol and anthocyanin content than the other two species studied. Although A. caroliniana and S. minima also presented increase in the activity of several enzymes, L. gibba s higher tolerance seems to be due not only to the increase in these antioxidant processes, but also to superior basal activity of these enzymes, and to higher thiol and anthocyanin basal content. Besides the increase in enzymatic activities, L. gibba exhibited total-thiol and non-protein thiol content increase, diminishing protein thiol content. A. caroliniana and S. minima practically did not suffer alterations in thiol content. As L. gibba, A. caroliniana and S. minima revealed an increment in anthocyanin content after exposure to increasing concentrations of As in the solution. In this context, L. gibba showed the highest potential to be employed in phytoremediation. / A influência do As sobre alguns aspectos do crescimento e do sistema antioxidante foi estudada em três espécies aquáticas: Azolla caroliniana, Lemna gibba e Salvinia minima, expostas cinco concentrações de As (0,0, 0,25, 0,5, 1,0 e 1,5 mg L-1) em solução nutritiva. Foram determinados o teor de As nas plantas, a taxa de crescimento relativo (TCR), as atividades enzimáticas da dismutase do superóxido (SOD), da catalase (CAT), de peroxidases (POX), da peroxidase do ascorbato (APX) e da redutase da glutationa (GR), o teor de tióis totais, de tióis não protéicos e de tióis protéicos e, ainda, o teor de antocianinas. Lemna gibba foi a macrófita que apresentou maior tolerância ao As, requerendo 967,6 μg g-1MS para reduzir em 50 % a TCR. Azolla caroliniana demandou 429,2 μg g-1MS para a ocorrência dessa redução e, por último, demonstrando ser a mais sensível, S. minima requereu 255,08 μg g-1MS. Em relação aos mecanismos antioxidantes, as três espécies responderam de forma diferente ao aumento da concentração de As no meio. Azolla caroliniana sofreu aumentos nas atividades da CAT e da GR, manteve inalteradas as atividades da SOD e da POX, sofrendo diminuição na atividade da APX, embora tenha sido a espécie que apresentou maior atividade desta enzima. Salvinia minima exibiu aumentos nas atividades de SOD, CAT, APX e GR, mantendo inalterada a atividade de POX, com o aumento da concentração de As no meio de cultivo. A maior tolerância de L. gibba aos efeitos do As parece estar relacionada tanto aos mecanismos antioxidantes enzimáticos e não enzimáticos. Esta espécie, além de apresentar maiores atividades de SOD, CAT, POX e GR, também apresentou maiores teores de tióis e antocianinas que as outras duas espécies analisadas. Embora A. caroliniana e S. minima também tenham apresentado incrementos nas atividades de várias enzimas, a maior tolerância de L. gibba parece ser devida não somente ao aumento nestes processos antioxidantes, mas à superior atividade basal dessas enzimas e ao maior conteúdo basal de tióis e antocianinas. Além do aumento nas atividades enzimáticas, L. gibba exibiu aumentos nos teores de tióis totais e tióis não protéicos, diminuindo os teores de tióis protéicos. A. caroliniana e S. minima praticamente não sofreram alterações no conteúdo de tióis. Assim como L. gibba, A. caroliniana e S. minima revelaram acréscimos nos teores de antocianinas após exposição às concentrações crescentes de As na solução. Neste contexto, dentre as três macrófitas estudadas, L. gibba foi a que apresentou maior potencial para ser empregada em programas de fitorremediação.

Waste water from the mining industry is generally extremely complex and contains numerous species which influence the adsorption of the metals to any biomass. A variety of factors need to be addressed before treatment is considered viable. It is also beneficial to establish the binding characteristics of the metal of interest to maximise its interaction with the biomass to be utilised. Azalia filiculaides was investigated in the adsorption of gold(III), lead(II), iron(ID), copper(II) and platinum (IV). In batch studies, the optimum biomass and initial gold(III) concentrations were found to be 5 gIL and 8 mgIL respectively. The adsorption of gold(ID) is principally pH-dependent with optimal removal at pH 2. Lead(II), iron(III) and copper(II) did not compete with gold(III) adsorption under equimolar and simulated effluent conditions. Halides, with increasing affinity for gold (chloride < bromide < iodide), can affect gold uptake with the soft base, iodide, exhibiting the most inhibition (25%) and the hard base, chloride, O%. Mercaptoethanol (soft base) showed no interference in gold(III) adsorption while the presence of sulphate (hard base) and sulphite (borderline base) showed that concentrations in excess of 1 0 mM may adversely affect gold(ill) uptake, most likely due to competition for cationic sites on the biomass. Column studies, better suited to high volume treatment, indicated that a flow-rate of 5 mL/min and an initial gold(ill) concentration of 5 mgIL was optimal. Competitive effects between lead, iron, copper and gold again showed little or no interference. The halides, chloride, bromide and iodide, affect gold(ill) uptake similarly to the batch studies, while the bases mercaptoethanol and sulphate minimally affect gold(III) binding with sulphite severely hampering adsorption (70% inhibition). To optimise gold desorption, preliminary batch studies indicated that a ratio of 1:1 of adsorbentdesorbent was optimal, whilst gas purging of thiourea with oxygen, air and nitrogen decreased gold elution in proportion to decreased amounts of oxygen. A series of desorbents were utilised, in column studies, to optimise and determine the speciation of bound gold. The presence of an oxidant with thiourea enhanced desorption greater than 3 fold when compared with thiourea alone. Thiourea desorption studies, aided by the oxidant, suggest that gold is present in the + I and 0 oxidation states. Ultimately thiourea, perchloric acid and hydrochloric acid was found to be the most optimal elutant for gold (J 00% recovery). For selective metal recovery oflead and copper, pre-washing the plant material with water, utilising an acid (0.3 M nitric acid), pumping in an up-flow mode, and recycling the desorbent six times was found to be optimal elutant for gold (J 00% recovery). Cost analysis of utilising elutant versus incinerating the biomass for gold recovery indicated the latter as the most economical. Over a 5 cycle adsorption and desorption series, acid desorption before each adsorption cycle was found to result in greater than 92% desorption for lead and 96% for copper. Gold recovery was 97% with incineration. A preliminary study with gold effluent (Mine C) indicated that nickel and sulphate was removed in batch and column studies. Gold removal was found to be 100% and 4% in batch and column studies respectively. Adsorption of gold in the effluent study was accompanied by the release ofHt. Modifying the plant material with various reagents failed to identify the primary binding sites and the role of polysaccharides, proteins and lipids in gold(ill) uptake. The mode of gold binding is suggested as being initially ionic, this is very rapid, with the interaction of the anionic complex, [AuCI₄]". with the cationic biomass (PH 2). This eventually leads to the displacement of the chloride ligand(s) initiating covalent binding. Spectral studies of the chemical interaction between gold and the representative tannins indicated the protonated hydroxy groups to be responsible. All evidence suggests that the binding mechanisms of gold are not simple. Preliminary adsorption studies of platinum by Azalia filiculaides were conducted. Batch studies indicated that J gIL biomass concentration, initial platinum concentration of 20 mgIL and pH 2 are optimal, while the column studies indicated a flow-rate of! 0 rnL/min and initial platinum concentration of 20 mgIL as optimal. In the platinum effluent study, platinum showed a removal of 23 % and 2 J % for the batch and column studies respectively. Again adsorption was accompanied by //' release. Azalia filiculaides demonstrated its feasibility in the removal of gold and platinum from simulated as well as waste water solutions. Its potential viability as a biosorbent was demonstrated by the high recovery from synthetic solutions of greater than 99% for gold (2-10 mgIL), and greater than 89% for platinum (20 mgIL).

The field of nanoecotoxicology has been pioneered in recent years as concern grows in response to the potential environmental hazards of engineered nanoparticle release. Silver nanoparticle (AgNP) release through induction into commercial products as an antimicrobiont is of particular interest. Plausible routes of AgNPs to reach aquatic systems and their biological impacts have been investigated, but none have addressed the potential remediation of these waters using the heavy metal accumulating fern Azolla caroliniana. This study employed biological staining techniques and fluorescence microscopy to identify oxidative stress, wounding responses of cell wall and membrane, and cell death of A. caroliniana roots to assess the capability of this plant to withstand AgNP exposure. Two concentrations series were applied, 0-1.0ppm and 0-10.0ppm for 1, 3, 5 days after transfer (DAT), 0ppm being a control. Oxidative stress, measured in production of non-specific ROS, increased in a dose-dependent manner with increasing AgNP concentration. Callose (1,3-β-glucan) was deposited in response to potential cell wall damage and was also observed to be elevated in a dose-dependent manner. Cell vitality appeared from a general decline in fluorescence of nucleic content to visual nuclei lysis. Statistically significant and severe responses to AgNPs was observed at 1 DAT but recovery could be seen at 3~5 DAT. In sum, these data suggest a toxicity threshold of 1.0ppm at which A. caroliniana roots can mediate exposure.

The removal of lead from aqueous solution and lead-acid battery manufacturing waste-water by the non-viable biomass of the water fern Azolla filiculoides was investigated in both batch and column reactors. The maximum lead uptake by the Azolla biomass at a pH value of approximately 5, was found to be 100 mg lead/g biomass from aqueous solution. Lead removal varied from 30% of the initial lead concentration at pH 1.5 to approximately 95% at pH values of 3.5 and 5.6. Lead removal from aqueous solution decreased to 30% of the initial lead concentration if the lead concentration was initially over 400 mg/l. At initial lead concentrations of less than 400 mg/l, percentage lead removal was found to be over 90% of the initial lead concentration. Lead removal remained at approximately 90% between 10°C and 50°C. Biomass concentration (4-8 mg/l) had little effect on lead removal. The presence of iron (Fe) and lead, copper (Cu) and lead or all three metal ions in solution at varying ratios to each other did not appear to have any significant effect on lead removal. Percentage lead, copper and iron removal from aqueous solution was 80-95, 45-50 and 65-75% respectively for the different multiple-metal solutions studied. No break-through points were observed for lead removal from aqueous solutions in column reactors, with initial lead concentrations of less than 100 mg/l at varying flow rates of 2, 5 and 10 ml/min. This suggested that flow rate, and therefore retention time, had little effect on percentage lead removal from aqueous solution, which was more that 95%, at low initial lead concentrations (less than 100 mg/l). At initial lead concentrations of 200 mg/l or more, an increase in flow rate, which equates to a decrease in column retention time, resulted in break-through points occurring earlier in the column run. Percentage lead removal values, from lead-acid battery efiluent in column systems, of over 95% were achieved. Desorption of approximately 30% and 40% of bound lead was achieved, with 0.5 M HNO₃ in a volume of 50 ml, from two lead-acid battery. Repeated adsorption and desorption of lead by the Azalia biomass over 10 cycles did not result in any decrease in the percentage lead removal from effluent, which strongly suggested that the Azalla biomass could be re-used a number of times without deterioration in its physical integrity, or lead removal capacity. No evidence of deterioration in the Azolla biomass's physical integrity after 10 successive adsorption and desorption procedures was observed using scanning electron microscopy. The Azolla filiculoides biomass was, therefore, found to be able to effectively remove lead from aqueous solution and lead-acid battery effluent repeatedly, with no observed reduction in it's uptake capacity or physical integrity.