Os metais pesados são elementos químicos com alta densidade (>5 g.cm-3), presentes naturalmente na crosta terrestre, e o aumento das atividades antropogênicas vêm acelerando a liberação destes elementos nos ecossistemas. Tais elementos podem ser extremamente tóxicos (ex. mercúrio, chumbo, cádmio) ou tóxicos quando em concentrações elevadas (zinco e cobre). A fitorremediação é uma técnica de descontaminação que utiliza as plantas para remover poluentes do ambiente ou transformá-los em formas menos perigosas para os seres vivos, sendo que o impacto ambiental e custos de implementação são muito inferiores àqueles alcançados pelos métodos físico-químicos. Uma cultura para ser utilizada com sucesso na recuperação de áreas contaminadas, deve ser eficiente na acumulação de metais, produzir grandes quantidades de biomassa e ser capaz de se adaptar as condições do ambiente contaminado. A cana-de-açúcar apresenta características fisiológicas, que a tornaram uma das culturas mais importantes e difundidas nas regiões tropicais, com alta produtividade de biomassa e rusticidade, possuidora de genes que codificam peptídeos quelantes de metais, já identificados no projeto genoma da cana-de-açúcar (SUCEST). Neste trabalho foi estudada a expressão gênica de metalotioneínas em plântulas de canade- açúcar. As plântulas foram cultivadas em hidroponia contendo níveis elevados de Cu+2 (50, 100, 250 e 500 µM) e Cd+2 (100, 250 e 500µM). A concentração do metal foi determinada nos tecidos de raiz e partes aéreas de plantas coletadas após 11 e 33 dias de tratamento. As maiores doses de Cu (250 e 500 µM) foram letais para as plantas após 11 dias de cultivo, entretanto o efeito das menores dosagens no crescimento foi comparável ao controle aos 33 dias de tratamento. As plantas foram capazes de acumular quantidades significativas de cobre e cádmio, principalmente nas raízes. Todas as dosagens de cádmio limitaram significativamente o crescimento, mas não o impediram. Extratos de RNA total foram analisados para a expressão dos genes de metalotioneína dos tipos I, II e III mediante Northern blot. Os resultados mostraram que houve expressão dos genes para metalotioneínas dos três tipos constitutivamente, sendo mais elevada para MT I e MT II, tanto em folhas como em raízes de cana de açúcar. A expressão de MT I foi maior nas raízes que nas folhas. Já os genes MT II e MT III foram mais expressos em folhas que em raízes. Os genes de metalotioneínas de cana-deaçúcar são pouco afetados ou não são modulados por Cobre. Em relação ao Cd, ocorre um acúmulo de transcritos de MT nas raízes aos 11 dias levemente proporcional à concentração do metal, (exceto para MT III) que é seguido de um decréscimo de transcritos, também paralelo aos teores de Cd na solução, aos 33 dias. Da mesma forma, existe uma indução de MT II e principalmente MT III na parte aérea, com o aumento da concentração de cádmio na solução, mais acentuada aos 11 dias. Estes resultados evidenciam a capacidade da cana-de-açúcar de tolerar e acumular Cu e Cd, sugerindo um potencial fitorremediador para recuperação de áreas contaminadas com esses metais. / Heavy metals are elements with high density (>5 g.cm-3), naturally occurring in soils, and with the increase of anthropogenic activities has accelerated the release of these elements in ecosystems. Heavy metals can be highly toxic (e.g. Mercury; Lead; Cadmium) or toxic at high concentration (Zinc and Copper). Phytoremediation is a clean up technology based on the use of plants to remove pollutants from the environment or to transform them in less toxic forms to living organisms, with less environmental impact at a lower cost than physic-chemical methods. A crop to be successfully used to recover contaminated areas must be efficient in metal accumulation, must yield large amounts of biomass and to be able to adapt to contaminated conditions. Sugarcane (Saccharum spp.) presents physiological characteristics that allowed this crop to become widely adopted in tropical, with high biomass production and with genes associated with chelating peptides already identified by the Sugarcane genome project (SUCEST). In this work, metallothionein gene expression was investigated in sugarcane plantlets. The young plants were growth in ¼ Hoagland solution containing elevated levels of Cu+2 (50, 100, 250 and 500 µM) or Cd+2 (100, 250 and 500µM). Metal concentration were determined in root and shoot tissues harvested at 11 and 33 days of treatment. The highest Cu doses (250 and 500 µM) killed the plants after 11 days of culture, however the effect of the lowest dosages were comparable to the control after 33 days of treatment. The plants were capable of accumulate large amount of Cu and Cd, mainly in roots. All Cd dosages significantly limited growth, but without stopping it. Total RNA was analyzed for metallothionein Type I, II and III gene expression by northern. Results indicated that expression of the three types of metallothionein genes was constitutive, with more expression of MT I and MT II, in leaves and roots. MT I expression was greater in roots than in shoots. But MT II and MT III genes were more expresses in shoots. Metallothionein gene expression was poorly affected or not at all by Cu. But for Cd, there was an accumulation of MT transcripts in roots at 11 days slightly proportional to Cd concentration, except for MT III, which was followed by a decrease in transcripts, also parallel to Cd levels in solution at 33 days. Similarly, there as an induction of MT II and mainly MT III in shots with the increase of Cd concentration in solution, more pronounced at 11 days of treatment. These results demonstrated the ability of sugarcane to tolerate and accumulate Cu and Cd, suggesting a potential application in phytoremediation of areas contaminated with heavy metals.

Made available in DSpace on 2016-08-10T10:44:45Z (GMT). No. of bitstreams: 1 MAX VINICIUS DE PAULA ABREU.pdf: 1697992 bytes, checksum: ce7b9a79a60a8a03cf9c71827e0052c9 (MD5) Previous issue date: 2015-02-27 / The objective of this study was to investigate and evaluate the influence of different nickel concentrations on germination and initial growth of Leucaena leucocephala (Lam.) thee Wit., aiming its use in restoration projects of contaminated areas. Initially defined five treatments for nickel concentrations, A-0 mg.L-1(control), B-40 mg.L-1, C-80 mg.L-1, D-120 mg.L-1e E-200 mg.L-1. Each treatment had ten repetitions, where each experimental unit was considered as a plastic container (350 ML) containing, two filter paper discs and twenty scarified seeds of the species. Each recipient received 10 ML of nickel nitrate solution (Ni(NO3)2) according to its concentration and then were placed in a bench of plant Biology Laboratory at PUC-Goiás, until the collection of data on germination and early growth. The nickel containing different concentrations were obtained by diluting a standard stock solution (100.0 mg L-1) using (Ni(NO3)2). To verify the effect of nickel on the growth of L. leucocephala seedlings was mounted a second experiment using plants with 120 days after germination. For this, was performed the production of 80 seedlings in 40 plastic bags (20x15 cm) containing a mixture of sand and organic substrate (1.1), 2 seedlings being allocated in each plastic bag. The seedlings remain in the nursery of the Plant Biology Laboratory at PUC-Goiás for a period of 180 days and periodically received water and nutrient solution complete of Hoagland Fortnightly. Four treatments were set for nickel concentrations, A-0 mg.L-1 (control), B-100 mg.L-1 C-200 mg.L-1,D-400 mg.L-1, with 10 replicates for each treatment. The data were analyzed using ANOVA and Tukey at 5% significance level. The results showed that the germination and initial growth of L. leucocephala plants was not significantly affected by different concentrations of nickel, revealing that the species under study has considerable tolerance to this Heavy Metal without damage to their physiology and development, making promising its use in the recovery of areas contaminated by this element and creating sustainable alternative for remediation of these areas though Phytoremediation. / O objetivo deste estudo foi investigar e avaliar a influência de diferentes concentrações de níquel sobre a germinação e crescimento inicial de Leucaena leucocephala (Lam.) de Wit., visando sua utilização em projetos de recuperação de áreas contaminadas. Foram definidos cinco tratamentos em relação às concentrações de níquel: A-0 mg.L-1 (controle); B-40 mg.L-1, C-80 mg.L-1, D-120 mg.L-1 e E-200 mg.L-1. Cada tratamento teve dez repetições, onde cada unidade experimental foi considerada como sendo um recipiente plástico (350 mL) contendo dois discos de papel de filtro e vinte sementes escarificadas da espécie. Cada recipiente recebeu 10 mL de solução de nitrato de níquel (Ni(NO3)2) de acordo com a respectiva concentração e foram colocados em bancada do laboratório de Biologia Vegetal da PUC-Goiás até a coleta dos dados referentes à germinação e crescimento inicial. As diferentes concentrações contendo níquel foram obtidas pela diluição de uma solução estoque padronizada (100,0 mg.L-1 utilizando (Ni(NO3)2). Para verificar o efeito do níquel sobre o crescimento das mudas de L. leucocephala foi conduzido um segundo experimento utilizando plantas com 120 dias após a germinação. Para isso, foi realizada a produção de 80 mudas em 40 sacos plásticos (20x15 cm) contendo uma mistura de areia e substrato orgânico (1:1), com duas mudas em cada saco plástico. As mudas permaneceram no viveiro do Laboratório de Biologia Vegetal da PUC-Goiás por um período de 180 dias e receberam água periodicamente e solução nutritiva completa de Hoagland quinzenalmente. Foram definidos quatro tratamentos em relação às concentrações de níquel: A- 0 mg.L-1 (controle); B-100 mg.L-1, C-200 mg.L-1 e E-400 mg.L-1, sendo 10 repetições para cada tratamento. Os dados foram analisados através do teste de ANOVA e de Tukey ao nível de 5% de significância. Os resultados demonstraram que a germinação e crescimento inicial das plantas de L. leucocephala não foram afetadas significativamente pelas diferentes concentrações de níquel, revelando que a espécie em estudo possui considerável resistência a este metal pesado sem que haja danos à sua fisiologia e desenvolvimento, tornando promissor o seu emprego na recuperação de áreas contaminadas por este elemento e criando alternativa sustentável para remediação dessas áreas através da fitorremediação.

Células de Nicotiana tabacum cv BY-2 foram tratadas por cinco dias com 0,075 e 0,750 mM de NiCl2. A relação entre a toxidade do níquel (Ni) e as reações oxidativas foram estudadas nas células durante a acumulação do metal. A atividade da superóxido dismutase não se alterou na presença do Ni. Entretanto, as atividades da catalase e da guaiacol peroxidase aumentaram às 36 e 72h depois do tratamento com o metal. As atividades da glutationa redutase, da glutationa-Stransferase e da ascorbato peroxidase aumentaram nas primeiras horas do tratamento. A peroxidação lipídica da membrana aumentou somente às 24h do tratamento com o metal. Os resultados sugerem que a desordem oxidativa é resultante dos efeitos da toxidade do Ni nas células de Nicotiana tabacum cv BY-2. / Células de Nicotiana tabacum cv BY-2 foram tratadas por cinco dias com 0,075 e 0,750 mM de NiCl2. A relação entre a toxidade do níquel (Ni) e as reações oxidativas foram estudadas nas células durante a acumulação do metal. A atividade da superóxido dismutase não se alterou na presença do Ni. Entretanto, as atividades da catalase e da guaiacol peroxidase aumentaram às 36 e 72h depois do tratamento com o metal. As atividades da glutationa redutase, da glutationa-Stransferase e da ascorbato peroxidase aumentaram nas primeiras horas do tratamento. A peroxidação lipídica da membrana aumentou somente às 24h do tratamento com o metal. Os resultados sugerem que a desordem oxidativa é resultante dos efeitos da toxidade do Ni nas células de Nicotiana tabacum cv BY-2.

<p>U radu je analiziran&nbsp; uticaj limunske kiseline na morfolo&scaron;ke, fiziolo&scaron;ke i&nbsp; biohemijske<br />karakteristike&nbsp; odabranih&nbsp; klonova&nbsp; vrba&nbsp; (Salix&nbsp; spp.)&nbsp; gajenih&nbsp; u&nbsp; zemlji&scaron;tu&nbsp; umereno zagađenom&nbsp; kadmijumom&nbsp; (Cd).&nbsp; Definisanjem&nbsp; parametara&nbsp; akumulacije,&nbsp; otpornosti&nbsp; i tolerantnosti različitih klonova vrba na prisustvo kadmijuma u podlozi, kao i uspe&scaron;nosti primene&nbsp; limunske&nbsp; kiseline&nbsp; kao&nbsp; helatora&nbsp; u&nbsp; procesu&nbsp; asistirane&nbsp; fitoremedijacije,&nbsp; mogao&nbsp; bi se&nbsp; identifikovati&nbsp; klon&nbsp; (ili&nbsp; klonovi)&nbsp; pogodan&nbsp; za&nbsp; dekontaminaciju&nbsp; zemlji&scaron;ta&nbsp; zagađenog kadmijumom. Da&nbsp; bi&nbsp; se&nbsp; postigao&nbsp; cilj&nbsp; istraživanja biljke su gajene u polu-kontrolisanim uslovima tokom 3 meseca. Eksperiment je podeljen u dve faze (dve godine istraživanja),zasnovane&nbsp; na&nbsp; razlikama&nbsp; u&nbsp; metodolo&scaron;kom&nbsp; pristupu.&nbsp; Tokom&nbsp; prve&nbsp; godine&nbsp; limunska kiselina je dodata jednom, dok je tokom druge druge godine aplikacija ovog helatora vr&scaron;ena&nbsp; u&nbsp; tri&nbsp; ponavljanja.&nbsp; U&nbsp; radu&nbsp; je&nbsp; analizaran&nbsp; sadržaj&nbsp; i&nbsp; distribucija&nbsp; Cd&nbsp; u&nbsp; zemlji&scaron;tu&nbsp; i<br />različitim&nbsp; biljnim&nbsp; organima&nbsp; (koren,&nbsp; izdanak,&nbsp; mladi&nbsp; i&nbsp; stari&nbsp; listovi);&nbsp; uticaj&nbsp; Cd i&nbsp; limunske kiseline na morfometrijske parametre: visina i prečnik izdanka, masa i povr&scaron;ina listova, broj&nbsp; listova,&nbsp; masa&nbsp; i&nbsp; zapremina&nbsp; korena;&nbsp; na&nbsp; fotosintetičke&nbsp; karakteristike:&nbsp; intenzitet fotosinteze,&nbsp; intenzitet&nbsp; transpiracije,&nbsp; stomatalnu&nbsp; provodljivost,&nbsp; intercelularnu koncentraciju&nbsp; CO2,&nbsp; efikasnost&nbsp; kori&scaron;ćenja&nbsp; vode,&nbsp; koncentraciju&nbsp; fotosintetičkih&nbsp; pigmenata; na mineralnu ishranu i distribuciju makronutrijenata u biljkama (sadržaj azota, fosfora i kalijuma);&nbsp; na&nbsp; sadržaj&nbsp; aminokiseline&nbsp; prolina&nbsp; i&nbsp; cisteina;&nbsp; na&nbsp; aktivnost&nbsp; antioksidativnih enzima&nbsp; (katalaza,&nbsp; askorbat-peroksidaza,&nbsp; gvajakol-peroksidaza),&nbsp; kao&nbsp; neezmiskih antioksidanata poput sadržaja redukovanog glutationa i tiola. Dobijeni&nbsp; rezultati&nbsp; su&nbsp; ukazali&nbsp; na&nbsp; genotipsku&nbsp; specifičnost&nbsp; analiziranih&nbsp; klonova&nbsp; vrba&nbsp; u procesu&nbsp; fitoremedijacije&nbsp; u&nbsp; zavisnosti&nbsp; od&nbsp; primenjenog&nbsp; tretmana,&nbsp; doze&nbsp; Cd&nbsp; i&nbsp; prisustva limunske kiseline. Toksično dejstvo nije bilo jasno uočljivo na morfolo&scaron;kom nivou, dok su&nbsp; primenjeni&nbsp; tretmani&nbsp; signifikantno&nbsp; uticali&nbsp; na&nbsp; fiziolo&scaron;ko-biohemijske&nbsp; procese&nbsp; u biljkama.&nbsp; Sa&nbsp; povećanjem&nbsp; sadržaja&nbsp; Cd&nbsp; u&nbsp; biljkama&nbsp; je&nbsp; utvrđena&nbsp; tendencija&nbsp; smanjenja intenziteta fotosinteze, transpiracije, kao i efikasnosti&nbsp; kor&scaron;ćenja vode, dok je primena limunske&nbsp; kiseline&nbsp; ublažila&nbsp; &scaron;tetan&nbsp; efekat&nbsp; ovog&nbsp; te&scaron;kog&nbsp; metala,&nbsp; &scaron;to&nbsp; je&nbsp; registrovano&nbsp; na<br />kombinovanim tretmanima.&nbsp; Kao odgovor na akumulaciju Cd u biljnom tkivu utvrđena<br />je&nbsp; promena&nbsp; aktivnosti&nbsp; antioksidativnih&nbsp; enzima,&nbsp; kao&nbsp; i&nbsp; neezimskih&nbsp; komponenti<br />odbrambenog&nbsp; sistema&nbsp; za&scaron;tite.&nbsp; Pored&nbsp; toga,&nbsp; u&nbsp; radu&nbsp; je&nbsp; utvrđeno&nbsp; da&nbsp; primena&nbsp; limunske kiseline&nbsp; utiče&nbsp; na&nbsp; usvajanje,&nbsp; akumulaciju&nbsp; i&nbsp; toleranciju vrba na prisustvo Cd,&nbsp; te&nbsp; rezultati ove&nbsp; studije&nbsp; imaju&nbsp; praktičan&nbsp; značaj&nbsp; u&nbsp; usavr&scaron;avanju&nbsp; tehnika&nbsp; fitoremedijacije&nbsp; i dekontaminacije zagađenih područja.</p> / <p>The role of citric acid on morphological, physiological and biochemical characteristics of selected willow clones (Salix spp.) grown in soil with moderately polluted cadmium (Cd)&nbsp; was&nbsp; presented.&nbsp; The&nbsp; aim&nbsp; of&nbsp; this&nbsp; study&nbsp; was&nbsp; to&nbsp; determine&nbsp; the&nbsp; Cd&nbsp; accumulation, translocation&nbsp; and tolerance of different willow clones, as well as the influence of citric acid as a chelator in the assisted phytoremediation process.&nbsp; In order to achieve this goal, plants&nbsp; were&nbsp; grown&nbsp; in&nbsp; semi-controlled&nbsp; conditions&nbsp; for&nbsp; 3&nbsp; months.&nbsp; The&nbsp; experiment&nbsp; was divided&nbsp; into&nbsp; two&nbsp; phases&nbsp; (two&nbsp; years&nbsp; of&nbsp; research),&nbsp; based&nbsp; on&nbsp; differences&nbsp; in&nbsp; the methodological approach, regarding the application of citric acid. During the first-year experiment, citric acid was added once, while in the second year the application of this chelator was performed in three repetitions.&nbsp; The analyses included:&nbsp; the accumulation and distribution of Cd in soil and various plant organs (root, stem, young and old leaves); influence of Cd and citric&nbsp; acid on morphometric parameters: stem hight and diameter, number&nbsp; of&nbsp; leaves,&nbsp; biomass&nbsp; and&nbsp; area&nbsp; of&nbsp; leaves,&nbsp; biomass&nbsp; and&nbsp; volume&nbsp; of&nbsp; the&nbsp; root;&nbsp; on&nbsp; photosynthetic&nbsp; characteristics:&nbsp; net&nbsp; photosynthetic&nbsp; and&nbsp; transpiration&nbsp; rate,&nbsp; water&nbsp; use efficiency, stomatal conductance, intercellular concentration of CO2, concentration of photosynthetic&nbsp; pigments;&nbsp; on&nbsp; mineral&nbsp; nutrition&nbsp; and&nbsp; distribution&nbsp; of&nbsp; macronutrients&nbsp; in plants (nitrogen, phosphorus and potassium content); on the content of the amino acid proline&nbsp; and&nbsp; cysteine;&nbsp; on&nbsp; the&nbsp; activity&nbsp; of&nbsp; antioxidant&nbsp; enzymes&nbsp; (catalase,&nbsp; ascorbate peroxidase,&nbsp; guaiacol&nbsp; peroxidase),&nbsp; as&nbsp; non- enzymatic&nbsp; components&nbsp; such&nbsp; as&nbsp; reduced glutathione and thiol content.<br />The obtained results indicated the genotypic specificity of the analyzed willow clones in the phytoremediation process, depending on the treatment applied, the Cd dose, and the presence of&nbsp; citric acid.&nbsp; The toxic effect was not evident on the morphological&nbsp; level, while&nbsp; the&nbsp; applied&nbsp; treatments&nbsp; showed&nbsp; a&nbsp; significant&nbsp; influence&nbsp; on&nbsp; the&nbsp; physiologicalbiochemical processes in the willows. The net photosynthetic rate, transpiration rate, as well as,&nbsp; water use eficiency&nbsp; showed decreasing with increasing Cd concentration in plant tissue,&nbsp; while&nbsp; the&nbsp; application&nbsp; of&nbsp; citric&nbsp; acid&nbsp; mitigated&nbsp; the&nbsp; harmful&nbsp; effect&nbsp; of&nbsp; this&nbsp; heavy metal, which was registered on combined treatments. In response to the accumulation of Cd in plant tissue, a&nbsp; change in the&nbsp; activity&nbsp; of&nbsp; anti-oxidant enzymes,&nbsp; as&nbsp; well as nonenzymatic&nbsp; components&nbsp; of&nbsp; the&nbsp; defense&nbsp; system&nbsp; has&nbsp; been&nbsp; established.&nbsp; In&nbsp; addition,&nbsp; the<br />application of citric acid showed the promotion role on the&nbsp; absorption, accumulation and tolerance of willows grown in moderately polluted soil cadmium, which has a practical significance in the improvement of phytoremediation techniques and decontamination of polluted soil.</p>

O cádmio (Cd) é importante poluente ambiental, que prejudica a produtividade das plantas e traz consequências graves à saúde humana. Uma das possíveis estratégias para mitigar os danos provocados pelo Cd na planta é o suprimento adequado de potássio (K), uma vez que esse nutriente atua na modulação de processos fisiológicos e mecanismos antioxidantes dos vegetais. Objetivou-se avaliar a importância do K nos mecanismos envolvidos na tolerância do capim tanzânia (Panicum maximum cv. Tanzânia) ao estresse oxidativo induzido pelo Cd. As plantas foram cultivadas em casa de vegetação com delineamento de blocos completos ao acaso, em esquema fatorial 3x4, com três doses de K (0,4; 6,0 e 11,6 mmol L-1) combinadas com quatro doses de Cd (0,0; 0,5; 1,0 e 1,5 mmol L-1) fornecidas em solução nutritiva, com seis repetições, sendo três destinadas à avaliação dos parâmetros produtivos e nutricionais e outras três aos parâmetros fisiológicos e metabólicos. Foram avaliados dois períodos de crescimento das plantas, sendo o primeiro corte aos 35 dias após o transplantio das mudas e o segundo aos 27 dias após o primeiro. No segundo crescimento não foi adicionado Cd na solução nutritiva. O aumento do fornecimento de K resultou em incremento na produção de massa seca da parte aérea do capim tanzânia exposto às doses de Cd até 1,0 mmol L-1, no segundo corte. O acúmulo de Cd na parte aérea do capim foi mais elevado em condições de alta disponibilidade de Cd (1,5 mmol L-1) e de K (11,6 mmol L-1). O aumento das doses de Cd resultou em mais baixas concentrações de cálcio, magnésio, enxofre e manganês e mais elevadas concentrações de K, cobre, ferro e zinco na parte aérea do capim, no segundo corte. O maior fornecimento de K proporcionou mais elevadas taxas de assimilação de CO2 e de transpiração, condutância estomática, eficiência quântica do fotossistema II e taxa de transporte de elétrons em plantas expostas a doses intermediárias de Cd (0,5 a 1,0 mmol L-1). As concentrações de malondialdeído (MDA), peróxido de hidrogênio (H2O2) e prolina na parte aérea das plantas foram mais altas em condições de altas disponibilidades de Cd. As mais altas doses de K para plantas submetidas ao estresse por Cd resultaram em mais baixas concentrações de MDA devido ao incremento proporcionado por esse nutriente na atividade das enzimas antioxidantes superóxido dismutase (SOD), catalase (CAT), guaiacol peroxidase (GPX), ascorbato peroxidase (APX) e glutationa redutase (GR), avaliadas no segundo corte. O K promoveu aumento das concentrações de espermidina e espermina em plantas sob toxidez por Cd. Portanto, o K ameniza os efeitos tóxicos induzidos pelo Cd no capim tanzânia, reduzindo o estresse oxidativo por meio do aumento da atividade das enzimas antioxidantes e da concentração de poliaminas, o que resulta em maior produção de massa seca da parte aérea e maior acúmulo de Cd, aumentando a capacidade de fitoextração de Cd pelo capim tanzânia. / Cadmium (Cd) is an important environmental pollutant, which damages plant productivity and has serious consequences for human health. One of the possible strategies to mitigate the damage caused by Cd in the plant is the supply of potassium (K), since this nutrient acts in the modulation of the physiological processes and antioxidant mechanisms of the plants. The aim of this study was to evaluate the importance of K in the mechanisms involved in the tolerance of tanzania guinea grass (Panicum maximum cv. Tanzania) to the oxidative stress induced by Cd. Plants were grown in a greenhouse, in randomized complete block design, using a 3x4 factorial, with three rates of K (0.4, 6.0 and 11.6 mmol L-1) combined with four rates of Cd (0.0, 0.5, 1.0 and 1.5 mmol L-1) provided in nutrient solution, with six replications, three for the evaluation of productive and nutritional parameters and three for physiological and metabolic parameters. Two plant growth periods were evaluated, with the first harvest done at 35 days after seedlings transplanting and the second at 27 days after the first. In the second growth, Cd was not added to the nutrient solution. High K supply increased dry matter yield of tanzania guinea grass receiving Cd rates up to 1.0 mmol L-1, at the second harvest. The accumulation of Cd in the shoots of the grass was high in the conditions of high availability of Cd (1.5 mmol L-1) and K (11.6 mmol L-1). The increase in Cd rates resulted in low concentrations of calcium, magnesium, sulfur and manganese and high concentrations of K, copper, iron and zinc in the shoots of the grass at the second harvest. High K supply provided high rates of CO2 assimilation, transpiration, stomatal conductance, quantum efficiency of photosystem II and rate of electron transport in plants grown in intermediate rates of Cd (0.5 to 1.0 mmol L-1). The concentrations of malondialdehyde (MDA), hydrogen peroxide (H2O2) and proline in the shoots were high in conditions of high availability of Cd. High rates of K in plants submitted to Cd stress resulted in low concentrations of MDA due to the activities superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (GPX), ascorbate peroxidase (APX) and glutathione reductase (GR) determined in the second harvest. K resulted in high concentrations of spermidine and spermine in plants under the toxic effect of Cd. Therefore, K alleviates the toxic effects induced by Cd in tanzania guinea grass, reducing oxidative stress by increasing the activity of antioxidant enzymes and the concentration of polyamines, which results in high shoot dry mass production and high Cd accumulation, increasing the capacity of Cd phytoextraction by tanzania guinea grass.

O avanço industrial e urbano associado ao aumento da produção dos bens de consumo resultou na geração de resíduos que, por muito tempo, foram descartados indiscriminadamente no ambiente, provocando danos quase sempre irreversíveis e de difícil recuperação. Dois experimentos foram conduzidos em solos contaminados por metais pesados, o primeiro devido ao descarte de produtos inorgânicos contendo grande carga de poluentes no solo; no segundo estudo a contaminação deve-se ao uso sucessivo de fungicidas contendo cobre em pomares cítricos do sul da Flórida. O primeiro estudo objetivou avaliar o uso de amenizantes orgânicos como mitigadores da toxicidade de bário, boro, cádmio, chumbo, cobre, níquel e zinco presentes no solo contaminado decorrente da adição de resíduo de sucata automobilística e avaliar o potencial fitoextrator do pinhão-manso (Jatropha curcas L.). Observou-se que o fornecimento da matéria orgânica na forma de turfas não amenizou a contaminação por metais pesados (Ba, Cd, Cu, Ni, Pb,Zn) e B; tal efeito pode ter ocorrido devido ao elevado pH deste solo mantido pelas práticas constantes de calagem. Os elementos apresentaram maior disponibilidade no solo ao longo das avaliações, exceto o boro que não apresentou significância. As plantas apresentaram sintomas de fitotoxicidade causados pelo elevado teor de boro e metais pesados no solo. A maior parte dos elementos metálicos se acumulou nos colmos e o boro nas folhas do pinhão manso, ou seja, a planta foi eficiente em translocar tais elementos para a parte aérea, situação desejável em uma fitoextratora. Ao final do experimento, os teores de Ba, Cd, Cu, Ni, Pb e Zn estavam mais disponíveis às plantas. O que indica que a matéria orgânica presente nas turfas mineralizou e tornou mais disponível estes metais pesados às plantas ao longo das avaliações. Pelos índices de transferência, de translocação e de remoção o pinhão manso foi viável somente para fitoextração de boro da área contaminada; estes índices também apontaram que o pinhão manso apresentou potencial para acumular B, Ba e Cd. O segundo experimento foi desenvolvido em casa de vegetacão com um argissolo coletado em uma área que tem recebido sucessivas aplicações de fungicidas a base de cobre, o que tem promovido o acúmulo significativo deste elemento nos solos sob produção de citros. O objetivo foi avaliar o potencial de fitoextração de cobre pelas plantas chinesas Splendens elsholtzia e Argyi elsholtzia para remover o excesso de cobre em solos contaminados devido a aplicação sucessiva de fungicidas cúpricos em pomares cítricos do sul da Flórida. A produção de massa seca de folhas, colmos e raízes e a concentração de cobre nos tecidos da Splendens elsholtzia foram superiores ao da espécie Argyi elsholtzia, o que indica que a Splendens elsholtzia é mais tolerante aos elevados níveis de cobre no solo. Assim, esta espécie pode ser indicada para programas de fitoextração em solos contaminados com cobre; entretanto, o índice de translocação do cobre indicou que as duas espécies não foram eficientes em translocar o cobre da raíz para parte aérea. / The industrial and urban progress associated with increased production of consumer goods has resulted in the generation of waste, which, for a long time, was indiscriminately discarded in the environment, causing damage usually irreversible to recover. Two experiments were conducted in soils contaminated with heavy metals: the first aimed at the disposal of products containing high loads of inorganic pollutants in the soil and the second focused on contamination due to the successive uses of fungicides containing copper in citrus groves of South Florida. The first study aimed to evaluate the use of organic soothers as mitigators of toxicity caused by barium, boron, cadmium, lead, copper, nickel and zinc in soil contaminated with waste resulting from the disposal of automobile scrap and to evaluate the phytoextraction potential of Jatropha (Jatropha curcas L.). It was observed that the supply of organic matter in the form of peat did not alleviate the contamination with heavy metals (Ba, Cd, Cu, Ni, Pb, Zn) and B, which may be attributed to the high pH of the soil due to constant practices of liming. The items showed higher availability in the soil during the evaluations, except for boron which showed no significance. The plants showed symptoms of phytotoxicity caused by high levels of boron and heavy metals in the soil. Most metallic elements are accumulated in the stems and boron in the leaves of Jatropha curcas, thus, the plant was efficient in the translocation of these elements to the shoot, a situation is desirable in phytoextraction. At the end of the experiment, the concentrations of Ba, Cd, Cu, Ni, Pb and Zn were more available to plants. This indicates that the organic matter present in the peat mineralized and made these heavy metals more available to plants. Considering the transfer rates of translocation and removal, the Jatropha was feasible only for phytoextraction of boron in the contaminated area, which shows that Jatropha has the potential to accumulate B, Ba and Cd. The second experiment was conducted in a greenhouse in an alfisol collected in an area that received repeated applications of copper-based fungicides, which promoted significant accumulation of this element in soils under citrus production. The objective was to evaluate the potential for phytoextraction of copper by the Chinese plants Splendens elsholtzia and Argyi elsholtzia to remove excess of copper in contaminated soils due to repeated application of copper-based fungicides in citrus groves of South Florida. The dry weight of leaves, stems and roots and the concentration of copper in the tissues of Splendens elsholtzia were higher than in Argyi elsholtzia, which indicates that the Splendens elsholtzia is more tolerant to high copper levels in the soil. Thus, this species may be indicated for phytoextraction of soils contaminated with copper; however, the rate of copper translocation indicated that the two species were not efficient to translocate copper from root to shoot.

Les zones humides naturelles méditerranéennes sont des écosystèmes rares et vulnérables souvent altérés par les pollutions des milieux adjacents. Le développement de zones humides artificielles (ZHA) servant au traitement secondaire des pollutions permettrait de limiter l’impact des activités industrielles sur les milieux naturels. Pour végétaliser ces ZHA et tolérer les contraintes du climat méditerranéen, l’utilisation d’espèces végétales locales éco-adaptées est recommandée. Toutefois ce type de ZHA, utilisant des plantes locales méditerranéennes, a fait l’objet d’un nombre restreint de travaux. Les objectifs de cette thèse sont donc : - de suivre la biocénose implantée et spontanée d’une ZHA pour évaluer la mise en place de ce nouvel écosystème (suivis floristique, faunistique et phytoplanctonique),- d’évaluer ses fonctionnalités et son efficacité épuratoire (suivis physico-chimique et biologique),- de questionner la pérennité de tels systèmes dans une contexte de changements globaux, notamment climatique. Les résultats montrent qu’un nombre restreint d’espèces végétales locales sélectionnées peut permettre la création d’un nouvel écosystème fonctionnel et durable qui soutient l’enjeu de biodiversité, tout en améliorant le traitement des effluents rejetés par le bassin industrialisé. Ces travaux valident l’intérêt des ZHA à hélophytes locales en méditerranée pour traiter les pollutions de bassins versants industrialisés mais un effort de recherche reste à faire pour adapter la conception aux spécificités des sites dans une véritable démarche d’ingénierie écologique. / Natural wetlands in Mediterranean areas are rare and vulnerable ecosystems, frequently impacted by various pollutants from nearby environments. In order to decrease industrial activities lethal effects on natural areas, constructed wetlands (CWs) are an interesting opportunity to remediate their pre-treated wastewaters. Such CWs would take advantage with using local plant species, well adapted to Mediterranean climate’s rigors. Nevertheless, CWs planted with Mediterranean plant species are still scarce and poorly studied. Aims of this thesis are thus:• to follow up on planted and adventive biocœnosis of a CW (flora, fauna and phytoplankton), in order to assess a novel ecosystem settlement,• to get better knowledge on its functions and remediation efficiency (physico-chemical and biological parameters),• to question durability of such techno-ecosystems in a context of global changes (with focus on climate).Main result let us know that it only takes a few local plant species, wisely chosen, to allow the settlement of a sustainable and fully functional ecosystem, supporting biodiversity stakes while increasing the remediation of pre-treated wastewaters collected from industrialized catchment. This work assess CWs planted with local helophytes as a powerful tool to treat industrialized catchment wastewaters in Mediterranean area, but researches are still needed to fit each design with each site characteristics, following a sustainable ecological engineering approach.

Content removed due to copyright restrictions: Anderson, C., Moreno, F., & Meech, J. (2005). A field demonstration of gold phytoextraction technology. Minerals Engineering, 18(4), 385-392. / Mercury (Hg) is a toxic heavy metal that is concentrated in organisms. Injudicious use of Hg and its compounds have resulted in widespread soil contamination. This study investigates the potential use of plants for the remediation of Hg-contaminated mine wastes. Plants can remove soil Hg via phytoextraction and phytovolatilisation. I investigated both of these strategies by focusing on a methodology for Hg analyses in plants and soils with a view to the determination of volatile Hg emitted from plants. Secondly, I determined the feasibility of Hg phytoextraction and phytovolatilisation from contaminated mine wastes. An accurate method for the analysis of Hg in air, plant and various soil fractions was a key component of this study. I developed a hydride-generation atomic absorption spectroscopy method for total Hg analyses in digest and liquid matrices of the aforementioned samples. Quality assurance was ensured by comparing results with those of an external certified laboratory. The maximum discrepancy was 15 %. To measure plant Hg-volatilisation, a method that captures Hg-vapour in solution for subsequent analyses was developed. Initially this system was used to trap Hg vapours released from the root system of Brassica juncea plants grown in hydroponic solutions. A subsequent study improved the Hg trapping system, allowing the capture of volatile Hg from both roots and shoots. Mercury recoveries from the whole plant system (traps + plant + solutions) averaged 90 % using this experimental apparatus. In most contaminated substrates, plant Hg uptake is insignificant, possibly due to the low bioavailability of Hg. This represents an obstacle for effective remediation using phytoextraction. Geochemical studies were carried out in Hg-contaminated substrates to examine the potential of chemical agents to induce Hg solubility and subsequent plant uptake. These studies utilised Hg-contaminated mine tailings collected from three locations: the Tui base-metal mine, in the North Island of New Zealand, the Gold Mountain mine, in North-Central China and, the Serra Pelada artisanal mine site, in Northern Brazil. The results demonstrated that Hg solubility in all tested substrates is increased in the presence of sulphur-containing chemical ligands. The effectiveness of these ligands was influenced by site-specific geochemistry. Plants species were able to accumulate up to 60 mg/kg of Hg in shoot tissues upon addition of sulphur-containing ligands to Tui and Gold Mountain substrates. The degree of plant-Hg accumulation was shown to be dependant on plant species and on the thioligand-induced soluble Hg fraction. Shoot Hg transport was inhibited for Gold Mountain substrate amended with 1.25g/kg of humic acid. The maximum Hg extraction yield for B. juncea plants growing in Tui field sites averaged 25 g per hectare following application of sodium thiosulphate. Volatilisation of Hg vapour from barren substrates occurred as a result of biotic (microorganisms) and abiotic (chemical and photochemical reduction) processes. The presence of B. juncea plants in substrates enhanced the volatilisation process up to 23 fold. Phytovolatilisation was the dominant pathway responsible for between 75 to 99.5 % of the total Hg removed from substrates. It was concluded that Hg removal from contaminated mine wastes can be accomplished by both thioligand-induced phytoextraction and phytovolatilisation. There are risks of groundwater contamination by Hg species mobilised after application of thioligands to substrates. Estimated Hg (0) emissions from plant-based operations at contaminated sites ranged between 1.5 to 3.6 kg of Hg/ha per year. Due to extensive atmospheric dilution, Hg emissions from small-scale phytoremediation operations would not cause serious harm to the local population or the regional environment. Phytoremediation combined with gold-phytoextraction can help to mitigate Hg-pollution in artisanal mine sites in the developing world.

Since the undertaking of urban planning as a prescriptive discipline, landscape projects have demonstrated their ability to integrate valuable cultural spaces with the construction of complex infrastructural systems, including systems that manage urban waste outflows. By the twenty-first century, urban planners have been tasked with the reclamation of derelict post-industrial sites and their abandoned infrastructural networks. The reclamation of these sites typically deploys complex operations in order to salvage and recycle valuable materials. These operations are also tasked with the disposal, stabilization or treatment of hazardous waste, contaminated soils and waterborne pollutants. Urban practitioners and theorists increasingly recognize the suitability of landscape as an interdisciplinary medium to expedite the reurbanization of these sites, assembling expertise from multiple engineering disciplines, horticultural and zoological science, and architectural design. The thesis proposition is a masterplan for the post-industrial Lachine Canal in Montréal, Québec. The masterplan integrates government plans to rehabilitate aging highway infrastructure through the adjacent, now defunct Turcot Rail Yard. Using the analytical mappings defined by Alan Berger in Drosscsape and Pierre Belanger’s “infrastructural landscapes” as a point of departure, the masterplan outlines a strategy to coordinate emergent waste diversion industries along the canal. Proposed interventions include a hybridized infrastructural landscape upon the abandoned rail yard to manage municipal organic waste, the effluents of brownfield reclamation, and construction debris. The application of phytoremediation landfarming and constructed wetlands comprise new landscapes that facilitate decontamination of existing brownfields along the Canal, promoting their reintegration with the surrounding urban environment. The thesis illustrates a speculative evolution of the site as an adaptively managed landscape, valued for its diverse biological wildlife habitat and for its recreational use by the citizens of Montréal.

Since the undertaking of urban planning as a prescriptive discipline, landscape projects have demonstrated their ability to integrate valuable cultural spaces with the construction of complex infrastructural systems, including systems that manage urban waste outflows. By the twenty-first century, urban planners have been tasked with the reclamation of derelict post-industrial sites and their abandoned infrastructural networks. The reclamation of these sites typically deploys complex operations in order to salvage and recycle valuable materials. These operations are also tasked with the disposal, stabilization or treatment of hazardous waste, contaminated soils and waterborne pollutants. Urban practitioners and theorists increasingly recognize the suitability of landscape as an interdisciplinary medium to expedite the reurbanization of these sites, assembling expertise from multiple engineering disciplines, horticultural and zoological science, and architectural design. The thesis proposition is a masterplan for the post-industrial Lachine Canal in Montréal, Québec. The masterplan integrates government plans to rehabilitate aging highway infrastructure through the adjacent, now defunct Turcot Rail Yard. Using the analytical mappings defined by Alan Berger in Drosscsape and Pierre Belanger’s “infrastructural landscapes” as a point of departure, the masterplan outlines a strategy to coordinate emergent waste diversion industries along the canal. Proposed interventions include a hybridized infrastructural landscape upon the abandoned rail yard to manage municipal organic waste, the effluents of brownfield reclamation, and construction debris. The application of phytoremediation landfarming and constructed wetlands comprise new landscapes that facilitate decontamination of existing brownfields along the Canal, promoting their reintegration with the surrounding urban environment. The thesis illustrates a speculative evolution of the site as an adaptively managed landscape, valued for its diverse biological wildlife habitat and for its recreational use by the citizens of Montréal.