Research objective. The study was aimed to identify the dynamics of accumulation of phenolic compounds and glucosinolates in oilseed rape and the effect of different morphological parts of oilseed rape on agricultural plants and weeds. The goals of the studies. The following goals were set in order to reach the aim of the studies: 1. To identify the dynamics of accumulation of phenolic compounds in oilseed rapeduring vegetation. 2. To analyse composition of allelochemical compounds of different morphological parts of rape residues after harvesting and ascertain quantitative and qualitative changes of these compounds in rape residues that decomposed in the soil for a different period. 3. To ascertain the effect of different morphological parts of oilseed rape that remain immediately after harvesting on the germination, shoot height and root length of agricultural plants and weeds. 4. To ascertain the effect of different morphological parts of oilseed rape that decomposed in the soil for a different period on the germination, growth of shoots and roots of agricultural plants and weeds. / Tyrimų tikslas. Nustatyti fenolinių junginių ir gliukozinolatų kaupimosi rapsuose dinamiką bei rapsų skirtingų morfologinių dalių liekanų poveikį žemės ūkio augalams ir piktžolėms. Tyrimų uždaviniai: 1. Nustatyti fenolinių junginių kaupimosi dinamiką rapsuose vegetacijos metu. 2. Ištirti alelocheminių junginių sudėtį rapsų skirtingų morfologinių dalių liekanose po derliaus nuėmimo ir nustatyti jų kiekybinius ir kokybinius pokyčius skirtingą laiką dirvoje irusiose rapsų liekanose. 3. Nustatyti rapsų atskirų morfologinių dalių, liekančių iškart po derliaus nuėmimo, poveikį žemes ūkio augalų ir piktžolių sėklų dygimui, daigų aukščiui ir šaknų ilgiui. 4. Nustatyti skirtingą laiką dirvoje irusių rapsų morfologinių dalių poveikį žemės ūkio augalų ir piktžolių sėklų dygimui, daigų bei šaknų augimui.

Submitted by Daniele Amaral (daniee_ni@hotmail.com) on 2016-10-05T20:11:42Z No. of bitstreams: 1 TeseLJJ.pdf: 3082295 bytes, checksum: 1f3b55b503c9c9ccf53f773842702e2c (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-10-20T16:22:19Z (GMT) No. of bitstreams: 1 TeseLJJ.pdf: 3082295 bytes, checksum: 1f3b55b503c9c9ccf53f773842702e2c (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-10-20T16:22:27Z (GMT) No. of bitstreams: 1 TeseLJJ.pdf: 3082295 bytes, checksum: 1f3b55b503c9c9ccf53f773842702e2c (MD5) / Made available in DSpace on 2016-10-20T16:22:36Z (GMT). No. of bitstreams: 1 TeseLJJ.pdf: 3082295 bytes, checksum: 1f3b55b503c9c9ccf53f773842702e2c (MD5) Previous issue date: 2016-03-18 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Pteridium plants are ferns (monilopytes) distributed all around the globe. These plants are considered problem species as they invade recently abandoned or burned areas, and areas under anthropogenic impacts. In Brazil, Pteridium arachnoideum (Kaulf.) Maxon. has become an important problem species at the Cerrado (Tropical Savanna) and Atlantic Forest biomes. To understand the mechanisms underlying invasive plants success are one of the greatest challenges of the last decades. Among the interaction that can influence this success, we find allelopathy. However, untill now we have few evidences for this phenomenon on these plants, especially from the isolation and indentification of secondary metabolites with activities related to allelopathy. Therefore, the present work aimed to evaluate the allelopathy role by direct phytotoxicity and abiotic changes in Pteridium arachnoideum (Kaulf.) Maxon. dominance in the areas it invades. To do so, the bioguided phytochemical study of this plant tissues and litter was performed, as well as the evaluation of the phytotoxic activity of phenolic compounds present in its litter and of its isolated and identified secondary metabolite against the early development of sesame, verifying the presence of this compound in the soil, its quantification, and evaluation of its interactions with physical and chemical soil characteristics. The phytochemical study led to the isolation and identification of a majoritarian compound in the plants green fronds and litter, the proanthocianidin selligueian A. This is the first time this compound is described for P. arachnoideum, as well as for the Dennstaediaceae family. Selligueain A showed phytotoxic activity against wheat coleoptiles elongation, with inhibitory activity over 71%, and IC50 of 0.69 mM. The poliphenols enriched fraction extracted from P. arachnoideum litter exert inhibitory activity against the early development of bioindicators species, native and invasive species of the Cerrado biome, specially over the development of these seedlings roots, besides activity against the metaxylem cells of sesame, and against chlorophyll content of sesame and the native weed Setaria parviflora. The allelopathic potential of the main poliphenolic compound of P. arachnoideum, selligueain A, was also evaluated against the early growth of sesame seedlings, promoting root and shoot growth in all the concentrations tested. Sesame seedlings grown in the presence of selligueain A showed smaller metaxylem cells when compared to the control, in the concentrations of 0.3 mM e 1 mM, with 50.82% inhibition in the greatest concentration and IC50 value of 0.98 mM. There was no activity of selligueain A against chlorophyll content of these seedlings. Analyses of extracts of soil collect under a P. arachnoideum patches pointed to the presence of selligueain A as major compound in soil solution, and, therefore, as a putative allelochemical produced by this plant. The concentration observed for this compound in the soil raged between 0.02 and 0.65 mM. According to allelopathic potential results, this concentration rage is sufficient to act over cooccurring plant species, promoting P. arachnoideum dominance. The presence of P. arachnoideum in Cerrado areas alters the chemical conditions of the soil, especially regarding N and Al, when compared to the presence of U. decumbens. Additionally, Al concentration is correlated to litter mass and to selligueain A concentration at the sites sampled. These results corroborates the hypothesis of allelopathy as a dominance mechanism of this plant in the areas where it occurs, with the first report of an allelochemical for a Pteridium species, by direct phytotoxic activity as well as by controlling Al concentration at those areas. / Plantas do gênero Pteridium são samambaias (monilófitas) e estão distribuídas em todo mundo. São consideradas espécies problemas pois invadem áreas recentemente queimadas, abandonadas ou sob impacto antrópico. No Brasil, Pteridium arachnoideum (Kaulf.) Maxon. apresenta-se como uma importante espécie problema do Cerrado e da Mata Atlântica. Compreender os mecanismos que governam o sucesso de plantas com comportamento invasor tem se mostrado um dos maiores desafios das últimas décadas. Dentre as interações que podem influenciar este sucesso está a alelopatia. No entanto, poucas são as evidências apresentadas até então para este fenômeno, especialmente a partir do isolamento e identificação de substâncias do metabolismo secundário destas plantas. Assim, o objetivo deste trabalho foi avaliar o papel da alelopatia por fitotoxicidade direta e alterações abióticas na dominância de P. arachnoideum nas áreas em que ocorre. Para isso, foi realizado estudo fitoquímico biodirigido de diferentes órgãos e serrapilheira desta planta, avaliação da atividade fitotóxica dos polifenóis e do metabólito secundário isolado e identificado sobre o desenvolvimento inicial da espécie bioindicadora gergelim, identificação da presença deste composto no solo, sua quantificação e avaliação de sua interação com características físicoquímicas do solo. O estudo fitoquímico levou ao isolamento de um composto majoritário presente em suas frondes verdes e serrapilheira desta planta, a proantocianidina selligueina A. Esta é a primeira vez que este composto é descrito para P. arachnoideum, assim como para a família Dennstaediaceae. A selligueina A apresentou atividade fitotóxica sobre o alongamento de coleóptilos de trigo, com atividade inibitória acima de 71%, e IC50 de 0,69 mM. A fração enriquecida em polifenóis extraídos da serrapilheira de P. arachnoideum exerceu atividade inibitória sobre o desenvolvimento inicial de espécies bioindicadoras, nativa e invasora do Cerrado, especialmente sobre o desenvolvimento das raízes dessas plântulas, e atividade sobre as células do metaxilema de gergelim, e sobre o conteúdo de clorofila de gergelim e de capim rabo-de-raposa. O potencial alelopático do principal composto polifenólico desta planta, selligueina A, também foi testado sobre o crescimento inicial de gergelim, promovendo inibição do comprimento final do caule e da raiz de plântulas de gergelim em todas as concentrações testadas. Plântulas de gergelim crescidas na presença de selligueina A apresentaram células do metaxilema menores do que o as do controle nas concentrações de 0,3 mM e 1 mM, com inibição de 50,82% na maior concentração e IC50 de 0,98 mM. Não houve atividade de selligueina A sobre o conteúdo de clorofila dessas plântulas. Análises dos extratos de solo coletado sob manchas de P. arachnoideum apontaram a presença de selligueina A como composto majoritário na solução do solo, e, portanto, como aleloquímico produzido por esta planta. As concentrações do composto no solo variaram entre 0,02 e 0,65 mM. De acordo com resultados de potencial alelopático essa faixa de concentração seria suficiente para potencialmente atuar sobre espécies co-ocorrentes, favorecendo a dominância de P. arachnoideum. A presença de P. arachnoideum em áreas de Cerrado altera condições químicas do solo, especialmente com relação à concentração do nutriente N e de Al, quando comparada à presença de braquiária (U. decumbens). Além disso, a concentração de Al se encontra correlacionada à massa de serrapilheira e à concentração de selligueina A nas áreas amostradas. Estes resultados corroboram a hipótese de alelopatia como mecanismo de dominância dessa planta nas áreas em que ocorre, com a primeira descrição de um aleloquímico para uma espécie do gênero Pteridium, que apresenta atividade não apenas por fitotoxicidade direta, mas também por ação indireta, ao controlar a concentração de Al nessas áreas.

Phytoplankton blooms compromise the quality of freshwater ecosystems and the efficient processing of water by treatment works worldwide. This research aims to determine whether in-situ filamentous biofiltration processes mediated by living roots and synthetic filters as media can reduce or remove the phytoplankton loading (micro-algae and cyanobacteria) prior to a potable water treatment works intake. The underlying biofiltration mechanisms were investigated using field and laboratory studies. A novel macroscale biofilter with three plant species, named the "Living-Filter", installed in Farmoor II reservoir, UK, was surveyed weekly for physicochemical and biological variables under continuous flow conditions during 17 weeks. The efficiency of a mesoscale biofilter using the aquatic plant Phalaris arundinacea and synthetic filters, was tested with Microcystis aeruginosa under continuous flow conditions and in batch experiments. The 'simultaneous allelochemical method' was developed for quantifying allelochemicals from Phalaris in aqueous samples. Microscale studies were used to investigate biofilter allelochemical release in response to environmental stressors and Microcystis growth inhibition in filtered and unfiltered aqueous root exudate. Results demonstrate that the removal of phytoplankton biomass by physical mechanisms has a removal efficiency of ≤45% in the "Living-Filter" (filamentous biofilter plus synthetic fabric) and that the removal of Microcystis biomass using only biofilters was 25%. Chemical mechanisms that reduce Microcystis cell numbers are mediated by allelochemicals released from biofilter roots. Root exudate treatments on Microcystis revealed that Microcystis growth is inhibited by allelochemicals, not by nutrient competition, and that protists and invertebrates play a role in removing Microcystis. Filamentous biofilters can remove phytoplankton biomass by physical, chemical and biological mechanisms. Biofilters and synthetic filters in combination improve removal efficiency. Application of macroscale biofilters prior to potable water treatment works benefits the ecosystem. Plant properties, biofilter size to surface water ratio, and retention time must be considered to maximise the benefits of biofiltration processes.