Plant invertases are a class of proteins that have enzymatic function in cleaving sucrose to fructose and glucose. Cell wall invertase, located on the exterior of the cell wall of plant cells, plays a key role in the unloading of sucrose from the apoplast to the sink tissues. Cell wall invertase interacts with an inhibitor, cell wall invertase inhibitor, post-transcriptionally to regulate its activity. The inhibitor is constitutively expressed in pollen development, early developing seeds, and senescing leaves: indicative of sucrose allocation being a limiting factor at these stages of development. We introduced algal bicarbonate transporters LCIA/CCP1 to Camelina sativa for the purpose of increasing photosynthetic capacity. The bicarbonate transporters concentrate CO2 at RuBisCO by pumping CO2 in the form of bicarbonate through the membrane, then converting it back to CO2 at RuBisCO, increasing CO2 concentration. Results from these plants have shown an increase in seed number, but not seed mass, along with a faster rate of maturity and senescence. This is indicative of acclimation to high CO2 conditions, resulting from insertion of the bicarbonate transporters. RNA sequencing was performed and a putative invertase inhibitor was recognized as being expressed in the transgenic C. sativa but not in the wild type. Our strategy is to knock out two invertase inhibitors using induced RNA silencing, dramatically altering sucrose allocation into developing seeds and resulting in an increase in seed biomass. It is the aim of this research to increase the biomass of C. sativa seeds in order to increase its effectiveness as an agent to create sustainable biofuels.

No description available.

Energetická náročnost a ekonomická životaschopnost jsou často skloňované pojmy spojené s aquaponickým způsobem produkce potravin. Tato práce si klade za cíl nalézt opatření, která by zvýšila ziskovost podnikání v oblasti aquaponie a zároveň by snížila energetickou náročnost procesu a spotřebu dalších zdrojů. Součástí práce je následné ověření vybraných opatření na zkušební aquaponické farmě. K vyřešení otázky úspory energie a vody byly použity optimalizační metody vycházející z procesního inženýrství. Pro účely automatického monitoringu růstu rostlin, jakožto hlavního zdroje příjmů v aquaponii, byla využita technologie počítačového vidění. Za využití optimalizační metody zvané P-graph, integrace procesů a hledání procesních alternativ bylo nalezeno nejlepší možné uspořádání procesní sítě, které vykazovalo více než devítinásobný čistý roční příjem ve srovnání se současným uspořádáním procesních zařízení v aquaponické farmě. Dalších úspor energie a vody bylo dosaženo instalací reflexních fólií na okraje pěstebních boxů a dalším využitím odpadní vody z aquaponické části farmy v hydroponické sekci určené k pěstování sazenic. Tato opatření mohou napomoci aquaponickým farmám zvýšit konkurenceschopnost a snížit jejich dopad na životní prostředí.

This work was carried out in collaboration with the Department of Adaptive Biotechnologies, Global Change Research Centre AS CR. It deals with the quantitative analysis of photosynthetic cell cultures. It uses images captured by a confocal fluorescent microscope to the automatic determining the number of cells in the sample. The work consists of a theoretical analysis, which briefly describes fluorescence and confocal microscopy. It also concisely introduces a microscope Leica TCS SP8 X, which I used to scan data. One capture is devoted to the theory of digital image processing. The second part deskribes the development of algorithm for processing 3D data and simplified algorithm for processing 2D data and its program implementations in a programming environment MATLAB R2013b. Grafical user interface is explained in detail. Done measurement are presented at the conclusion. It mentions compiled sample preparation protocol. The results of the program are compared with manual counting. Number of cells per 1 ml are determined by created program in samples of cell cultures Chenopodium rubrum (Cr) and Solanum lycopersicum (To).

Conifers are important both ecologically and socioeconomically, however, same parts of their biology are not that well researched. This includes genetics and breeding and partly even physiology. Because quantitative genetic analyzes applied in breeding necessitate an analysis of a large number of samples, and conventional methods of analysis are quite time-consuming, certain parameters describing e.g. the activity of photosynthetic electron-transport chain (ETC) are considered for such use. Several methods of the measurement of the activity of photosynthetic ETC exist, but there are some problems with their usage in conifers. I studied this issue from different points of view in three parts of this thesis. 1) I compared the photosynthetic ETC activity in 8 species of conifers using chlorophyll (Chl) fluorescence measurements on intact needles and polarographic measurements in isolated chloroplasts. Each method brought different information. 2) I measured Chl fluorescence parameters, reflectance spectra and pigment content in 536 genetically defined trees of Pinus sylvestris L. Many parameters showed relatively high genetic variability and heritability. I have also determined the suitability of various reflectance indices to estimate pigment and water content of needles. 3) I have optimized the...

Cyanobakterien sind die einzig bekannten Prokaryoten, die in der Lage sind oxygene Photosynthese zu betreiben. Sie besitzen ein großes Potenzial als nachhaltige Ressourcen für die Herstellung zahlreicher industriell und medizinisch relevanter Wirkstoffe. Trotz ihrer essentiellen Bedeutung ist jedoch das Wachstum von Cyanobakterien bis jetzt nur unzureichend verstanden. Im Rahmen dieser Arbeit habe ich daher ein mathematisches Modell entwickelt, das das Wachstum von Cyanobakterien auf der Grundlage von intrazellulärer Proteinverteilung beschreibt. Dabei wurde das Proteom in wenige relevante Protein-Klassen unterteilt, die an fundamentalen zellulären Prozessen beteiligt sind, darunter Kohlenstoffaufnahme, -fixierung und -stoffwechsel, sowie Photosynthese und Proteintranslation. Besonders interessant sind die aus dem Modell resultierenden sogenannten mikrobiellen Wachstumsgesetze, sprich die Korrelationen zwischen der Wachstumsrate und der Proteinverteilung, die im stationären Zustand des Wachstums beobachtet werden. Das Modell prognostiziert eine charakteristische Krümmung für die Wachstumsgesetze jener Proteine, welche mit Lichtabsorption und Proteintranslation assoziiert werden. Verursacht wird diese Krümmung durch hohe Lichtintensitäten, die eine Abnahme der Wachstumsrate zur Folge haben. Die prognostizierten Wachstumsgesetze werden durch Proteindaten, die mittels Massenspektrometrie erhoben wurden, vom Cyanobakterium Synechocystis sp. PCC 6803 gestützt. Des Weiteren bietet das Modell einen geeigneten Ausgangspunkt für die Erweiterung von der Charakterisierung von Einzelzellen zu einer Population von Zellen in einem lichtlimitierten Chemostat. Das erweiterte Modell stellt einen Zusammenhang her zwischen intrazellulärer Proteinverteilung, Wachstum der Population und Kultivierungseigenschaften, und bietet somit einen neuartigen Ansatz zur Untersuchung und Verbesserung der Kultivierung von phototrophen Organismen und die Optimierung der photosynthetischen Produktivität. / Cyanobacteria are the only known prokaryotes that perform oxygenic photosynthesis, and therefore, hold significant potential as sustainable resources for the production of numerous industrially and medically relevant compounds. Despite their importance, however, the (molecular) limits and cellular economy of photoautotrophic growth are still insufficiently understood. In this thesis, I present a mathematical model based on a coarse-grained description of cellular protein allocation to describe cyanobacterial growth. The model describes cellular trade-offs considering only proteins that are involved in key cellular processes (carbon uptake, fixation, and metabolism, as well as photosynthesis and protein translation). Of particular interest are the resulting microbial growth laws, i.e., correlations between the growth rate and the protein distribution observed during balanced growth. The model predicts a characteristic kink for the growth laws of the light harvesting components and the translational machinery induced by photoinhibition, a decrease in growth rate due to high light intensities. The resulting growth laws are supported by quantitative mass spectrometry-based proteomics data of the cyanobacterium Synechocystis sp. PCC 6803. The proteomics data shows that the mathematical model has intrinsic predictive power, and thus, provides a suitable starting point for extending it from describing single cells to describe a growing population in a light-limited chemostat. The extended modeling framework goes beyond current models using phenomenological growth equations and establishes a mechanistic link between intracellular protein allocation, population growth and cultivation properties. The extended model provides a novel approach to study and guide phototrophic cultivation improvements that maximize photosynthetic productivity.

A buva (Conyza spp.) é uma planta daninha anual, comum em lavouras de soja da região Sul do Brasil, onde os herbicidas chlorimuron-ethyl e glyphosate são os mais utilizados para o seu controle. No entanto, nas últimas safras de soja observou-se controle insatisfatório desta planta daninha com esses herbicidas. Esse fato gerou a suspeita de seleção de biótipos resistentes. Assim, o objetivo da pesquisa foi avaliar a ocorrência de resistência múltipla aos herbicidas chlorimuron-ethyl e glyphosate em biótipos de buva. Na primeira etapa do trabalho, foram feitas coletas de sementes de buva em áreas com controle insatisfatório, totalizando 25 biótipos. Esses biótipos foram avaliados com relação à suscetibilidade e resistência ao chlorimuron e glyphosate, aplicando-se a máxima dose de registro desses herbicidas. Para segunda etapa do trabalho, foram selecionados 5 biótipos de buva com grau de suscetibilidade contrastante. Esses biótipos foram avaliados com curvas de dose-resposta e com 5 doses do herbicida chlorimuron-ethyl, aplicadas no estádio fenológico de 3 a 4 folhas. Na terceira etapa do trabalho, foi avaliada a resposta de 4 biótipos de buva aos herbicidas chlorimuron-ethyl, glyphosate e associação de chlorimuron-ethyl e glyphosate. Os herbicidas foram empregados em oito doses: 0,0; 6,25; 12,5; 25; 50; 100; 200 e 400, representadas em porcentagem da dose de 20 g ha-1 chlorimuron-ethyl, e de 720 g e.a. ha-1 glyphosate, aplicadas em três estádios de desenvolvimento (altura 0,5 a 1 cm e/ou 3 a 4 folhas; altura 1 a 2 cm e/ou 6 a 7 folhas e; altura 10 a 12 cm e/ou 12 a 14 folhas) dos biótipos de buva. Na última etapa do trabalho, avaliaram-se 15 herbicidas para controle alternativo da buva no estádio de desenvolvimento de 5 a 7 cm de altura e/ou 7 a 8 folhas. O trabalho foi conduzido na casa de vegetação, da Estação Experimental da Embrapa Trigo, em Passo Fundo/RS. Os resultados evidenciam que todos os biótipos são controlados com a dose de 20 g ha-1 de chlorimuronethyl, no estádio de desenvolvimento de 3 a 4 folhas. Contudo, observou-se susceptibilidade diferencial entre os biótipos em doses menores que 20 g ha-1 indicando resistência de nível baixo. Também, ficou evidente que os estádios de desenvolvimento dos biótipos de buva afetam significativamente a resposta destes aos herbicidas, sendo que quanto mais avançado o estádio menor a sensibilidade. A exceção foi o biótipo 5 que demonstrou resistência ao glyphosate, independentemente do estádio de desenvolvimento. Por fim, os tratamentos alternativos 2,4-D (1.042 g ha-1); amonium glufosinate (400 g ha-1); glyphosate (900 g e.a. ha- 1) + 2,4-D (1.042 g ha-1); glyphosate (900 g e.a ha-1) + amonium glufosinate (400 g ha-1); paraquat (600 g ha-1) + diuron (300 g ha-1); tembotrione (84 g ha-1) e tembotrione (84 g ha-1) + atrazine (1.000 g ha-1) controlaram, eficientemente, os biótipos de buva avaliados. Como conclusão, indica-se a aplicação do herbicida chlorimuron-ethyl nas doses máximas registradas, em estádios de desenvolvimentos da buva inferiores a cinco folhas, e que a prática de rotação de mecanismos de ação seja usada no manejo químico dessas áreas. / The horseweed (Conyza spp.) is an annual weed, common in soybean crops in southern Brazil, where the herbicide chlorimuron-ethyl and glyphosate are the most commonly used for its control. However, in recent soybean harvests it was observed unsatisfactory control of this weed with these herbicides. This fact originated suspicion of selection of resistant biotypes. The objective of the research was to evaluate the occurrence of multiple resistances to herbicides chlorimuron-ethyl and glyphosate in horseweed biotypes. In the first stage of the research, were collected horseweed seeds in areas with unsatisfactory control, totaling 25 biotypes. These biotypes were assessed for susceptibility and resistance to chlorimuron and glyphosate, applying the maximum dose of herbicide registration. In the second stage, were selected 5 horseweed biotypes with contrasting degree of susceptibility and evaluated dose-response curves, with 5 doses of the herbicide chlorimuron-ethyl applied at growth stage 3 - 4 leaves. In the third stage, we evaluated the response of four biotypes of horseweed to the herbicide chlorimuron-ethyl, glyphosate and association of chlorimuronethyl and glyphosate. Herbicides were applied in eight doses: 0.0, 6.25, 12.5, 25, 50, 100, 200 and 400, represented as a percentage of the dose of 20 g ha-1 chlorimuron-ethyl, and 720 g a.e. ha-1 glyphosate applied at three stages of development (height 0.5 - 1 cm and / or 3 - 4 leaves, height 1 - 2 cm, and / or 6 - 7 and leaves, height 10 - 12 cm and / or 12 - 14 leaves) biotypes of horseweed. In the last stage of the study, evaluated 15 alternative herbicides to control horseweed at stage 5 - 7 cm high and / or 7 - 8 leaves. The study was conducted in a greenhouse, at the Experimental Station of Embrapa Trigo, Passo Fundo / RS. The results show that all biotypes can be controlled with the dose of 20 g ha-1 chlorimuron-ethyl, at stage 3 - 4 leaves. However, it was observed differential susceptibility among biotypes at doses under than 20 g ha-1 indicating low resistance. It was also evident that the developmental stages of the biotypes of horseweed, significantly affect the response to these herbicides, whereas the more advanced the stage the lower sensitivity. The exception was the biotype 5 that show resistance to glyphosate, regardless of the stage of development. Finally, alternative treatments 2,4-D (1.042 g ha-1); ammonium glufosinate (400 g ha-1), glyphosate (900 g a.e. ha- 1) + 2,4-D (1.042 g ha-1), glyphosate (900 g a.e. ha-1) + ammonium glufosinate (400 g ha-1), paraquat (600 g ha-1) + diuron (300 g ha-1); tembotrione (84 g ha-1) and tembotrione (84 g ha- 1) + atrazine (1,000 g ha-1), effectively controlled the biotypes of horseweed evaluated. Conclusion indicates the application of herbicide chlorimuron-ethyl in maximum doses recorded in stadiums horseweed developments less than five leaves, and that the practice of rotating mechanisms of action are used in the chemical management of these areas.

Cadmium (Cd) concentration in the environment has increased in most recent decades, which represents a serious socio-environmental problem, since Cd is toxic to most living beings. Thus, it is important to reduce the concentration of this metal in contaminated environments, and the use of plants properly supplied with sulfur (S) can contribute to this (phytoextraction), since S is a component of metabolites involved in defense responses against stress caused by Cd. Therefore, our aim with this study was to evaluate the effect of S on i) Cd uptake kinetics, ii) root development and nutrient uptake, iii) metabolic profiling and thiol peptides synthesis, and iv) activity of antioxidant and photosynthetic system of Massai grass (Panicum maximum Jacq. cv. Massai) used for Cd phytoextraction. The studies were carried out in a greenhouse conditions using pots of 0.5 and 2.0 L for development of the study about Cd uptake kinetics (treatments represented by combinations of S: 0.1 and 1.9 mmol L-1 and Cd concentrations: 0.1 and 0.5 mmol L-1) and Cd detoxification mechanisms (treatments represented by combinations of S: 0.1, 1.9 and 3.7 mmol L-1 and Cd concentrations: 0.0, 0.1 and 0.5 mmol L-1), respectively. Pots were distributed in randomized blocks, with four replications. Plants used in Cd kinetics study were exposed to treatments for 14 days after they remained in solutions containing only S for 42 days, while plants used in Cd detoxification study were exposed to treatments for 9 days after growing in solutions containing only S for 44 days. At the end of studies, plants used were harvested and sent for analysis. Maximum uptake rate (Vmax) and Cd apoplastic influx of Massai grass exposed to highest Cd concentration was highest when the plants were supplied with highest S concentration. The root development of Massai grass was strongly inhibited when plants were exposed to 0.5 mmol L-1 Cd, but proper (1.9 mmol L-1) S supply allowed highest Cd uptake, while excessive S supply (3.7 mmol L-1) decreased iron plaques formation in the roots of plants. Lysine, cysteine, ornithine, arginine, tryptophan and histidine were accumulated in more than one tissue in plants exposed to Cd, as well as galactinol. Glutathione (GSH), phytochelatins (PCs) and their homologues were strongly induced by Cd, whereas plants supplied with 1.9 and/or 3.7 mmol L-1 S showed the highest concentrations of these peptides. Plants supplied with highest S concentration showed lowest lipid peroxidation and highest photosynthetic rate, which evidences that antioxidant system of these plants was more efficient in mitigating the damages caused by Cd. In view of these results, it is clear that Massai grass properly supplied with S shows greatest Cd tolerance, as well as phytoextraction potential / A concentração de cádmio (Cd) no ambiente aumentou em décadas recentes, o que representa sério problema sócio-ambiental, visto que o Cd é tóxico para a maioria dos seres vivos. Por isso, é importante reduzir a concentração desse metal em ambientes contaminados e o uso de plantas adequadamente supridas com enxofre (S) pode contribuir para isso (fitoextração), uma vez que o S é componente de metabólitos envolvidos no combate ao estresse causado pelo Cd. Assim, o nosso objetivo com esse estudo foi avaliar o efeito do S na i) cinética de absorção do Cd, no ii) desenvolvimento radicular e na absorção de nutrientes, no iii) perfil metabólico e síntese de compostos tiol, e iv) na atividade do sistema antioxidante e fotossintético do capim-massai (Panicum maximum Jacq. cv. Massai), utilizado para fitoextração de Cd. Os estudos foram conduzidos em casa de vegetação utilizando-se vasos de 0,5 e 2,0 L para a condução do estudo de cinética de absorção de Cd (tratamentos representados pelas combinações das doses de S de 0,1 e 1,9 mmol L-1 e Cd de 0,1 e 0,5 mmol L-1) e para o estudo dos mecanismos de detoxificação de Cd (tratamentos representados pelas combinações das doses de S de 0,1; 1,9 e 3,7 mmol L-1 e Cd de 0,0; 0,1 e 0,5 mmol L-1), respectivamente. Os vasos foram distribuídos em blocos ao acaso, com quatro repetições. As plantas utilizadas no estudo de cinética foram expostas aos tratamentos durante 14 dias após as mesmas terem permanecido em soluções contendo apenas S durante 42 dias, enquanto as plantas utilizadas no estudo de detoxificação de Cd foram expostas aos tratamentos pelo período de 9 dias após terem crescido em soluções contendo apenas S por 44 dias. Ao final dos estudos, as plantas utilizadas foram colhidas e encaminhadas para análises. A velocidade máxima de absorção (Vmax) e o influxo apoplástico de Cd do capim-massai exposto à maior dose de Cd foram maiores quando as plantas foram supridas com a maior dose de S. O desenvolvimento radicular do capim-massai foi fortemente inibido quando as plantas foram expostas à dose de Cd de 0,5 mmol L-1, mas o adequado (1,9 mmol L-1) suprimento de S permitiu maior absorção de Cd, enquanto o suprimento excessivo (3,7 mmol L-1) de S diminuiu a formação de placas de ferro nas raízes das plantas. A lisina, cisteína, ornitina, arginina, triptofano e histidina foram acumulados em mais de um tecido nas plantas expostas ao Cd, assim como o galactinol. A glutationa (GSH), as fitoquelatinas (PCs) e seus homólogos foram fortemente induzidos pelo Cd, sendo que as plantas supridas com as doses de S de 1,9 e/ou 3,7 mmol L-1 apresentaram as maiores concentrações desses peptídeos. As plantas supridas com as maiores doses de S apresentaram menor peroxidação lipídica e maior taxa fotossintética, o que demonstra que o sistema antioxidante dessas plantas foi mais eficiente na atenuação dos danos causados pelo Cd. Diante desses resultados, fica claro que o capim-massai suprido adequadamente com S apresenta maior tolerância ao Cd, assim como maior potencial de fitoextração

Cadmium (Cd) concentration in the environment has increased in most recent decades, which represents a serious socio-environmental problem, since Cd is toxic to most living beings. Thus, it is important to reduce the concentration of this metal in contaminated environments, and the use of plants properly supplied with sulfur (S) can contribute to this (phytoextraction), since S is a component of metabolites involved in defense responses against stress caused by Cd. Therefore, our aim with this study was to evaluate the effect of S on i) Cd uptake kinetics, ii) root development and nutrient uptake, iii) metabolic profiling and thiol peptides synthesis, and iv) activity of antioxidant and photosynthetic system of Massai grass (Panicum maximum Jacq. cv. Massai) used for Cd phytoextraction. The studies were carried out in a greenhouse conditions using pots of 0.5 and 2.0 L for development of the study about Cd uptake kinetics (treatments represented by combinations of S: 0.1 and 1.9 mmol L-1 and Cd concentrations: 0.1 and 0.5 mmol L-1) and Cd detoxification mechanisms (treatments represented by combinations of S: 0.1, 1.9 and 3.7 mmol L-1 and Cd concentrations: 0.0, 0.1 and 0.5 mmol L-1), respectively. Pots were distributed in randomized blocks, with four replications. Plants used in Cd kinetics study were exposed to treatments for 14 days after they remained in solutions containing only S for 42 days, while plants used in Cd detoxification study were exposed to treatments for 9 days after growing in solutions containing only S for 44 days. At the end of studies, plants used were harvested and sent for analysis. Maximum uptake rate (Vmax) and Cd apoplastic influx of Massai grass exposed to highest Cd concentration was highest when the plants were supplied with highest S concentration. The root development of Massai grass was strongly inhibited when plants were exposed to 0.5 mmol L-1 Cd, but proper (1.9 mmol L-1) S supply allowed highest Cd uptake, while excessive S supply (3.7 mmol L-1) decreased iron plaques formation in the roots of plants. Lysine, cysteine, ornithine, arginine, tryptophan and histidine were accumulated in more than one tissue in plants exposed to Cd, as well as galactinol. Glutathione (GSH), phytochelatins (PCs) and their homologues were strongly induced by Cd, whereas plants supplied with 1.9 and/or 3.7 mmol L-1 S showed the highest concentrations of these peptides. Plants supplied with highest S concentration showed lowest lipid peroxidation and highest photosynthetic rate, which evidences that antioxidant system of these plants was more efficient in mitigating the damages caused by Cd. In view of these results, it is clear that Massai grass properly supplied with S shows greatest Cd tolerance, as well as phytoextraction potential / A concentração de cádmio (Cd) no ambiente aumentou em décadas recentes, o que representa sério problema sócio-ambiental, visto que o Cd é tóxico para a maioria dos seres vivos. Por isso, é importante reduzir a concentração desse metal em ambientes contaminados e o uso de plantas adequadamente supridas com enxofre (S) pode contribuir para isso (fitoextração), uma vez que o S é componente de metabólitos envolvidos no combate ao estresse causado pelo Cd. Assim, o nosso objetivo com esse estudo foi avaliar o efeito do S na i) cinética de absorção do Cd, no ii) desenvolvimento radicular e na absorção de nutrientes, no iii) perfil metabólico e síntese de compostos tiol, e iv) na atividade do sistema antioxidante e fotossintético do capim-massai (Panicum maximum Jacq. cv. Massai), utilizado para fitoextração de Cd. Os estudos foram conduzidos em casa de vegetação utilizando-se vasos de 0,5 e 2,0 L para a condução do estudo de cinética de absorção de Cd (tratamentos representados pelas combinações das doses de S de 0,1 e 1,9 mmol L-1 e Cd de 0,1 e 0,5 mmol L-1) e para o estudo dos mecanismos de detoxificação de Cd (tratamentos representados pelas combinações das doses de S de 0,1; 1,9 e 3,7 mmol L-1 e Cd de 0,0; 0,1 e 0,5 mmol L-1), respectivamente. Os vasos foram distribuídos em blocos ao acaso, com quatro repetições. As plantas utilizadas no estudo de cinética foram expostas aos tratamentos durante 14 dias após as mesmas terem permanecido em soluções contendo apenas S durante 42 dias, enquanto as plantas utilizadas no estudo de detoxificação de Cd foram expostas aos tratamentos pelo período de 9 dias após terem crescido em soluções contendo apenas S por 44 dias. Ao final dos estudos, as plantas utilizadas foram colhidas e encaminhadas para análises. A velocidade máxima de absorção (Vmax) e o influxo apoplástico de Cd do capim-massai exposto à maior dose de Cd foram maiores quando as plantas foram supridas com a maior dose de S. O desenvolvimento radicular do capim-massai foi fortemente inibido quando as plantas foram expostas à dose de Cd de 0,5 mmol L-1, mas o adequado (1,9 mmol L-1) suprimento de S permitiu maior absorção de Cd, enquanto o suprimento excessivo (3,7 mmol L-1) de S diminuiu a formação de placas de ferro nas raízes das plantas. A lisina, cisteína, ornitina, arginina, triptofano e histidina foram acumulados em mais de um tecido nas plantas expostas ao Cd, assim como o galactinol. A glutationa (GSH), as fitoquelatinas (PCs) e seus homólogos foram fortemente induzidos pelo Cd, sendo que as plantas supridas com as doses de S de 1,9 e/ou 3,7 mmol L-1 apresentaram as maiores concentrações desses peptídeos. As plantas supridas com as maiores doses de S apresentaram menor peroxidação lipídica e maior taxa fotossintética, o que demonstra que o sistema antioxidante dessas plantas foi mais eficiente na atenuação dos danos causados pelo Cd. Diante desses resultados, fica claro que o capim-massai suprido adequadamente com S apresenta maior tolerância ao Cd, assim como maior potencial de fitoextração

A buva (Conyza spp.) é uma planta daninha anual, comum em lavouras de soja da região Sul do Brasil, onde os herbicidas chlorimuron-ethyl e glyphosate são os mais utilizados para o seu controle. No entanto, nas últimas safras de soja observou-se controle insatisfatório desta planta daninha com esses herbicidas. Esse fato gerou a suspeita de seleção de biótipos resistentes. Assim, o objetivo da pesquisa foi avaliar a ocorrência de resistência múltipla aos herbicidas chlorimuron-ethyl e glyphosate em biótipos de buva. Na primeira etapa do trabalho, foram feitas coletas de sementes de buva em áreas com controle insatisfatório, totalizando 25 biótipos. Esses biótipos foram avaliados com relação à suscetibilidade e resistência ao chlorimuron e glyphosate, aplicando-se a máxima dose de registro desses herbicidas. Para segunda etapa do trabalho, foram selecionados 5 biótipos de buva com grau de suscetibilidade contrastante. Esses biótipos foram avaliados com curvas de dose-resposta e com 5 doses do herbicida chlorimuron-ethyl, aplicadas no estádio fenológico de 3 a 4 folhas. Na terceira etapa do trabalho, foi avaliada a resposta de 4 biótipos de buva aos herbicidas chlorimuron-ethyl, glyphosate e associação de chlorimuron-ethyl e glyphosate. Os herbicidas foram empregados em oito doses: 0,0; 6,25; 12,5; 25; 50; 100; 200 e 400, representadas em porcentagem da dose de 20 g ha-1 chlorimuron-ethyl, e de 720 g e.a. ha-1 glyphosate, aplicadas em três estádios de desenvolvimento (altura 0,5 a 1 cm e/ou 3 a 4 folhas; altura 1 a 2 cm e/ou 6 a 7 folhas e; altura 10 a 12 cm e/ou 12 a 14 folhas) dos biótipos de buva. Na última etapa do trabalho, avaliaram-se 15 herbicidas para controle alternativo da buva no estádio de desenvolvimento de 5 a 7 cm de altura e/ou 7 a 8 folhas. O trabalho foi conduzido na casa de vegetação, da Estação Experimental da Embrapa Trigo, em Passo Fundo/RS. Os resultados evidenciam que todos os biótipos são controlados com a dose de 20 g ha-1 de chlorimuronethyl, no estádio de desenvolvimento de 3 a 4 folhas. Contudo, observou-se susceptibilidade diferencial entre os biótipos em doses menores que 20 g ha-1 indicando resistência de nível baixo. Também, ficou evidente que os estádios de desenvolvimento dos biótipos de buva afetam significativamente a resposta destes aos herbicidas, sendo que quanto mais avançado o estádio menor a sensibilidade. A exceção foi o biótipo 5 que demonstrou resistência ao glyphosate, independentemente do estádio de desenvolvimento. Por fim, os tratamentos alternativos 2,4-D (1.042 g ha-1); amonium glufosinate (400 g ha-1); glyphosate (900 g e.a. ha- 1) + 2,4-D (1.042 g ha-1); glyphosate (900 g e.a ha-1) + amonium glufosinate (400 g ha-1); paraquat (600 g ha-1) + diuron (300 g ha-1); tembotrione (84 g ha-1) e tembotrione (84 g ha-1) + atrazine (1.000 g ha-1) controlaram, eficientemente, os biótipos de buva avaliados. Como conclusão, indica-se a aplicação do herbicida chlorimuron-ethyl nas doses máximas registradas, em estádios de desenvolvimentos da buva inferiores a cinco folhas, e que a prática de rotação de mecanismos de ação seja usada no manejo químico dessas áreas. / The horseweed (Conyza spp.) is an annual weed, common in soybean crops in southern Brazil, where the herbicide chlorimuron-ethyl and glyphosate are the most commonly used for its control. However, in recent soybean harvests it was observed unsatisfactory control of this weed with these herbicides. This fact originated suspicion of selection of resistant biotypes. The objective of the research was to evaluate the occurrence of multiple resistances to herbicides chlorimuron-ethyl and glyphosate in horseweed biotypes. In the first stage of the research, were collected horseweed seeds in areas with unsatisfactory control, totaling 25 biotypes. These biotypes were assessed for susceptibility and resistance to chlorimuron and glyphosate, applying the maximum dose of herbicide registration. In the second stage, were selected 5 horseweed biotypes with contrasting degree of susceptibility and evaluated dose-response curves, with 5 doses of the herbicide chlorimuron-ethyl applied at growth stage 3 - 4 leaves. In the third stage, we evaluated the response of four biotypes of horseweed to the herbicide chlorimuron-ethyl, glyphosate and association of chlorimuronethyl and glyphosate. Herbicides were applied in eight doses: 0.0, 6.25, 12.5, 25, 50, 100, 200 and 400, represented as a percentage of the dose of 20 g ha-1 chlorimuron-ethyl, and 720 g a.e. ha-1 glyphosate applied at three stages of development (height 0.5 - 1 cm and / or 3 - 4 leaves, height 1 - 2 cm, and / or 6 - 7 and leaves, height 10 - 12 cm and / or 12 - 14 leaves) biotypes of horseweed. In the last stage of the study, evaluated 15 alternative herbicides to control horseweed at stage 5 - 7 cm high and / or 7 - 8 leaves. The study was conducted in a greenhouse, at the Experimental Station of Embrapa Trigo, Passo Fundo / RS. The results show that all biotypes can be controlled with the dose of 20 g ha-1 chlorimuron-ethyl, at stage 3 - 4 leaves. However, it was observed differential susceptibility among biotypes at doses under than 20 g ha-1 indicating low resistance. It was also evident that the developmental stages of the biotypes of horseweed, significantly affect the response to these herbicides, whereas the more advanced the stage the lower sensitivity. The exception was the biotype 5 that show resistance to glyphosate, regardless of the stage of development. Finally, alternative treatments 2,4-D (1.042 g ha-1); ammonium glufosinate (400 g ha-1), glyphosate (900 g a.e. ha- 1) + 2,4-D (1.042 g ha-1), glyphosate (900 g a.e. ha-1) + ammonium glufosinate (400 g ha-1), paraquat (600 g ha-1) + diuron (300 g ha-1); tembotrione (84 g ha-1) and tembotrione (84 g ha- 1) + atrazine (1,000 g ha-1), effectively controlled the biotypes of horseweed evaluated. Conclusion indicates the application of herbicide chlorimuron-ethyl in maximum doses recorded in stadiums horseweed developments less than five leaves, and that the practice of rotating mechanisms of action are used in the chemical management of these areas.