Isolation of culturable mycota from Argentinean soils exposed or not-exposed to pesticides and determination of glyphosate tolerance of fungal species in media supplied with the herbicide / Aislamiento de la microbiota cultivable de suelos argentinos expuestos y no expuestos a plaguicidas y determinación de la tolerancia a glifosato de especies fúngicas en medios suplementados con el herbicida

Abstract The current agricultural system has led to the development of glyphosate (GP)-resistant weeds, causing an increase in GP doses and applications. Native mycota of pesticide-contaminated sites are the major source of pesticide-degrading microorganisms. The aims of the present study were to isolate the GP-tolerant culturable mycota in two soils with different pesticide exposure from Córdoba, Argentina, and to evaluate the growth parameters in native fungal isolates in the presence of GP and the effective dose that caused 50% growth reduction. The results showed that the genera Fusarium, Aspergillus, Mucor, Penicil-lium and Sterilia were the prevalent fungi isolated from soils both exposed and not-exposed to pesticides. The highest value (>100 mM) of effective concentration of herbicide that caused 50% growth inhibition (EC50), was found for Trichoderma isolates. Sterilia spp. had EC50 val-ues of 100mM, while Aspergillus spp. and Mucor had EC50 values between 50 and 100mM. The growth rate evaluation varied according to the isolates and GP concentrations. The data showed that all Aspergillus spp., Trichoderma spp., Mucor and three Sterilia spp. had the best growth performance in media supplied with GP after a variable acclimation period. This study provides valuable data for further studies that would allow to know the metabolic capacity of these fungal species that can be potential candidates for GP removal from contaminated environments.

Resumen El sistema agrícola actual condujo ai desarrollo de malezas resistentes a glifos-ato (GP), lo que deriva en el aumento de las dosis y el número de aplicaciones requeridas. La microbiota nativa de sitios contaminados con plaguicidas constituye la fuente principal de microorganismos capaces de degradar este herbicida. Los objetivos del presente estudio fueron aislar la microbiota cultivable tolerante a GP a partir de dos suelos agrícolas con diferente grado de exposición a plaguicidas, ambos de la provincia de Córdoba, Argentina, y evaluar en los hongos nativos aislados los parámetros de crecimiento en presencia de GP y la dosis efectiva que produce un 50% de reducción del crecimiento (EC50). Los géneros Fusarium, Aspergillus, Mucor, Penicillium y Sterilia fueron los de mayor prevalencia, tanto en suelos expuestos como no expuestos a plaguicidas. La mayor EC50 hallada (> 100 mM) correspondió a dos aislamientos de Trichoderma. En dos aislamientos de Sterilia, los valores de EC50 fueron de 100 mM, mientras que en los dos de Aspergillus y en uno de Mucor fueron de entre 50 y 100 mM. La velocidad de crecimiento varió según la concentración de GP empleada y el aislamiento considerado. Todos los aislamientos de Aspergillus, Trichoderma y Mucor, y tres aislamientos de Sterilia mostraron el mejor rendimiento en cuanto al crecimiento en los medios con GP después de un período de aclimatación variable. Este trabajo proporciona datos preliminares valiosos referidos a la capacidad metabólica de estos aislados y su potencial para remover GP en ambientes contaminados.

Efecto del glifosato sobre la microbiota, calidad del suelo y cultivo de frijol biofortificado en el departamento del Cesar, Colombia / Effect of glyphosate on microbiota, soil quality and biofortified bean crop in Codazzi, department of Cesar, Colombia

Resumen Las estrategias en seguridad alimentaria con cultivos de alto contenido nutricionaldeben enmarcarse en prácticas agrícolas sostenibles, orientadas a la conservación del suelo, elalto rendimiento y la inocuidad. Esta última característica implica la producción de alimentos sintrazas detectables de agroquímicos, los que podrían amenazar la salud del consumidor. Se des-arrolló un estudio con el objetivo de evaluar el efecto del herbicida glifosato sobre la fertilidadquímica y microbiológica del suelo, así como su residualidad en la semilla de frijol biofortificadocultivado en el departamento de Cesar, Colombia. La metodología comprendió un análisis corre-lacional de indicadores de calidad de suelo, rendimiento del cultivo y residualidad en los granos.Los tratamientos evaluados incluyeron la aplicación o no de glifosato, el uso de coberturas sin-téticas (mulch) o naturales, frente al control manual de las malezas. Se hallaron diferenciasde rendimiento y de la respuesta de los indicadores químicos y microbiológicos en función deltratamiento y las condiciones iniciales de la rizósfera de frijol. La aplicación del herbicida glifo-sato en suelo sin mulch generó una disminución del 29% en el rendimiento, asociada a la mayorprevalencia de plagas y enfermedades fúngicas. En ninguno de los tratamientos con aplicaciónde glifosato se observó residualidad de este herbicida en semillas, pero sí de otras moléculasderivadas de insecticidas usados en el sistema local de producción. De este estudio se concluyóque en lotes de frijol biofortificado con alta presión de la maleza Cyperus rotundus (coquito), se recomienda el uso del herbicida glifosato acompañado de mulch como alternativa para mantener la productividad en el tiempo. Esto constituye un sistema de protección frente al efectonegativo del herbicida sobre ambos, el sistema radical de la planta y la microbiota del suelo.© 2019 Asociacion Argentina de Microbiologıa. Publicado por Elsevier España, S.L.U. Este es un artıculo Open Access bajo la licencia CC BY-NC-ND (https://creativecommons.org/licenses/by-nc-nd/4.0/).

Abstract Strategies aimed at achieving food safety in crops of high nutritional value shouldbe carried out through sustainable agricultural practices aimed at soil conservation, high yieldand food safety. This latter characteristic implies food production without detectable tracesof agrochemicals that threaten health. The objective of this study was to assess the effect ofthe herbicide glyphosate on the chemical and biological fertility of the soil and to determineits residual activity on biofortified bean seeds in Codazzi, Department of Cesar, Colombia. Themethod included a correlational analysis of soil quality, crop yield and residuality in bean grains.The treatments included glyphosate application and synthetic and natural mulches, comparedto manual control. The results showed differences in the response of chemical, microbiologicaland yield indicators between treatments and the initial conditions of the bean rhizosphere. Theuse of the herbicide glyphosate in mulch-free soil generates yield losses of 29% associated witha higher incidence of pests and fungal diseases; in all treatments, no glyphosate residualitywas detected in seeds; however, residuality was detected in other molecules derived frominsecticides associated with the local production system. In conclusion, in plots with high weedpressure by Cyperus rotundus, the use of mulch is recommended as an alternative to maintainbean productivity over time; by offering protection against the effect of the herbicide on boththe root system of the plant and the soil microbiota of the biofortified bean crop.© 2019 Asociaci´on Argentina de Microbiolog´ıa. Published by Elsevier España, S.L.U. This is anopen access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/).

Germination constraints of dicarpic cypselae of Bidens pilosa L / Restrições a germinação de cipselas dicárpicas de Bidens pilosa L

Abstract Bidens pilosa L. is a heterocarpic weed species with two cypselae types that present morpho-physiological differences, being the peripheral type smaller and slower to germinate than the central one. We aimed to verify how the germination mechanism varied between types. We focused on two mechanisms: (1) pericarp constraints (physical and chemical) and (2) hormonal stimulation (Abcisic acid [ABA] and Gibberellin [GA]). Both cypselae types are physically constrained by the pericarp, for when it is excised both seed types increase their germination, but behavioral differences still remain. The pericarp of the peripheral type also has chemical inhibitors that effectively inhibited germination of the intact central cypsela. To test the hormonal effects, we focused on the ABA:GA control. Both cypselae responded to an exogenous ABA concentration gradient, however there is no variation between types on the sensitivity to it. Also, both cypselae types were indifferent to Fluridone (ABA inhibitor), which indicates that the dormancy is not maintained by de novo ABA synthesis. Cypselae types had different sensitivity to an exogenous GA3 gradient, the central type being more sensitive to the treatment than the peripheral one. But when the endogenous GA synthesis was blocked by Paclobutrazol, both types responded equally to same GA3 concentrations. This indicates that endogenous GA synthesis may be related to differences observed on germination of cypselae types. To conclude, seed types differ on their growth potential to overcome the pericarp resistance: while the inhibitor in the peripheral pericarp reduces growth potential, GA increases it.

Resumo Bidens pilosa L. é uma espécie de planta daninha heterocarpica com dois tipos de cipselas que possuem diferenças morfofisiológicas, sendo o tipo periférico de menor tamanho e com germinação lenta se comparado com o central. Nosso objetivo foi verificar como o mecanismo de germinação varia entre os tipos. Focamos em dois mecanismos: (1) restrição causada pelo pericarpo (física e química) e (2) estímulo hormonal (Ácido abscísico [ABA] e Giberelina [GA]). Os tipos de cipselas são fisicamente limitados pelo pericarpo, pois quando ambos os tipos de sementes são excisados há um aumento na germinação, contudo as diferenças no processo se mantém. O pericarpo do tipo periférico ainda possui inibidores que efetivamente retardam a germinação das cipselas centrais intactas. Para testar os efeitos hormonais, nós focamos no controle pelo ABA:GA. Ambas cipselas responderam ao gradiente de concentração de ABA exógeno, contudo não houve variação na sensibilidade entre os tipos. Ainda, ambos tipos de cipselas foram indiferentes à Fluoridona (inibidor de ABA), que indica que a dormência não é mantida pela nova síntese de ABA. Tipos de cipselas apresentam diferentes sensibilidades ao gradiente exógeno de GA3, com o tipo central sendo mais sensível ao tratamento que o periférico. Mas quando a síntese endógena de GA foi bloqueada pelo Paclobutrazol, ambos os tipos responderam de forma similar às concentrações de GA 3. Isso indica que a síntese de GA endógena pode estar relacionada com a diferença observada na germinação dos dois tipos de cipselas. Para concluir, os tipos de sementes diferem no potencial para superar a resistência do pericarpo, sendo o inibidor no pericarpo da cipsela periférica o redutor do potencial de crescimento, enquanto a GA aumenta esse potencial.

Effects of ZJ0273 on barley and growth recovery of herbicide-stressed seedlings through application of branched-chain amino acids / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

In this study, we evaluated the effect of the herbicide propyl 4-(2-(4,6-dimethoxypyrimidin-2-yloxy)benzylamino) benzoate (ZJ0273) on barley growth and explored the potential to trigger growth recovery through the application of branched-chain amino acids (BCAAs). Barley plants were foliar-sprayed with various concentrations of ZJ0273 (100, 500, or 1000 mg/L) at the four-leaf stage. Increasing either the herbicide concentration or measurement time after herbicide treatment significantly impaired plant morphological parameters such as plant height and biomass, and affected physiological indexes, i.e. maximal photochemical efficiency (Fv/Fm), quantum yield of photosystem II (ФPSII), net photosynthetic rate (Pn), and chlorophyll meter value (soil and plant analyzer development (SPAD)). Cellular injury of herbicide-treated plants was also evidenced by increased levels of reactive oxygen species (ROS) and antioxidative enzyme activity. Elevated levels of herbicide significantly reduced the activity of acetolactate synthase (ALS)-a key enzyme in the biosynthesis of BCAAs. In a separate experiment, growth recovery in herbicide-stressed barley plants was studied using various concentrations of BCAAs (10, 50, 100, and 200 mg/L). Increasing BCAA concentration in growth media significantly increased the biomass of herbicide-stressed barley seedlings, but had no significant effect on non-stressed plants. Further, BCAAs (100 mg/L) significantly down-regulated ROS and consequently antioxidant enzyme levels in herbicide-stressed plants. Our results showed that exogenous application of BCAAs could reverse the inhibitory effects of ZJ0273 by restoring protein biosynthesis in barley seedlings.

Morphological effects on helminth parasites caused by herbicide under experimental conditions / Efeitos morfológicos em helminto parasito causado por herbicida em condições experimentais

Abstract Helminth parasites have been studied as potential accumulators for different pollutants. Echinostoma paraensei is a foodborne trematode whose vertebrate host, the rodent Nectomys squamipes, is naturally exposed to environmental pesticides. However, little information exists regarding the pesticide's effects on helminths. This study investigated the morphological effects on the trematode, E. paraensei, after experimental Roundup® herbicide exposure, in concentrations below those recommended for agricultural use. After two hours of exposure, scanning electron microscopy (SEM) showed changes to the tegument, such as furrowing, shrinkage, peeling, spines loss on the peristomic collar, and histopathological evidence of altered cells in the cecum and acinus vitelline glands with vacuoles and structural changes to the muscular layers. Glycidic content was decreased, primarily in the connective tissue. As E. paraensei is an intestinal parasite of the semi-aquatic wild rodent, N. squamipes, it is predisposed to pesticide exposure resulting from agricultural practices. Therefore, we emphasize the need to evaluate its impact on helminth parasites, due to their pivotal role in regulating host populations.

Resumo Helmintos parasitos tem sido estudados como acumuladores potenciais para diferentes poluentes. O trematódeo E. paraensei tem como hospedeiro vertebrado o roedor Nectomys squamipes naturalmente exposto a pesticidas no meio ambiente. No entanto, pouca informação está disponível sobre os efeitos dos pesticidas em helmintos parasitos. O presente estudo investigou, em condições experimentais, os efeitos morfológicos no trematódeo E. paraensei após a exposição ao herbicida Roundup®, em concentrações abaixo das recomendadas para a utilização agrícola. A microscopia eletrônica de varredura (MEV) mostrou após duas horas de exposição, alterações no tegumento, como enrugamento, contração e descamação com perda de espinhos no colar peristômico e análise histopatológica evidenciou células do ceco alteradas, as glândulas vitelínicas com vacúolos e mudanças estruturais nas camadas musculares. Diminuição do conteúdo glicídico, principalmente no tecido conjuntivo, também foi observado. Considerando a predisposição à exposição a pesticidas agrícolas de N. squamipes infectado por E. paraensei, são necessários estudos para avaliar o impacto de tais resíduos frente aos helmintos e seus hospedeiros.

Potential effects of fungicide and algaecide extracts of Annona glabra L. (Annonaceae) on the microalgae Raphidocelis subcapitata and on the oomycete Pythium

ABSTRACT Annona glabra L. is a semi-deciduous tree that contains several active substances, including secondary metabolites, with antifungal activity. Phytopathogenic strains of the genus Pythium cause billion dollar losses all over the world on natural and crop species. Searching for eco-friendly algaecides and fungicides, we analyzed the effects of acetone extracts of A. glabra leaves on the algae Rhaphidocelis subcapitata (Korshikov) and on the oomycete Pythium aphanidermatum (Edson). We evaluated ten extract concentrations for each organism - 0 to 400 mg L-1 for algae and 0-1000 µg disc1 for oomycete. The results showed no effect on algae up to 75 mg L-1, but a significant inhibitory effect at 125 mg L-1 and above, which reduced the growth rate and the final biomass of the algae. Extract concentrations above 200 mg L-1 were completely inhibitory. The half maximal inhibitory concentration for 72 and 96 h of exposure to our crude extracts are comparable to those obtained with commercial fungicides and herbicides used in aquatic ecosystems. The P. aphanidermatum inhibition concentrations have effects comparable to fungicides as Cycloheximide and Bifonazole. Some substances isolated from the extracts are described as antifungals, which could explain part of anti-oomycete activity. Our results highlight the importance of searching bioactive compounds from plants.

Phytotoxic potential of young leaves from Blepharocalyx salicifolius (Kunth) O. Berg (Myrtaceae) / Potencial fitotóxico de folhas jovens de Blepharocalyx salicifolius (Kunth) O. Berg

Abstract The loss of leaves by plant species found in the Cerrado (Brazilian savanna) is an energetically expensive process due to adverse environmental conditions and predation by herbivory. The mature leaves have adaptations which minimize these events. However, the young individuals lack these structures and produce high leaf concentrations of secondary metabolites as a form of protection. These compounds can be used in bioprospection of natural herbicides. Thus, this study aimed to evaluate the phytotoxicity of hexane, ethyl acetate and aqueous extracts of young leaves from Blepharocalyx salicifolius (Kunth) O. Berg on the elongation of wheat coleoptiles (Triticum aestivum L.) and evaluate the potential phytotoxic of ethyl acetate extract on germination, growth and cell size of metaxylem of sesame (Sesamum indicum L.) seedlings. The hexane and ethyl acetate extracts inhibited the elongation of wheat coleoptiles at all concentrations; however, the most promising results were observed in coleoptile fragments treated with the ethyl acetate extract. This treatment changed the mean germination time and the synchrony of sesame seeds, inhibited the growth of shoots and roots, reduced the dry weight of seedlings, led to abnormalities in the seedlings and reduced the length of the metaxylem cells in the sesame seedlings. These results demonstrated the phytotoxic potential of young leaf extracts of B. salicifolius and the high phytotoxicity of the ethyl acetate extract in the initial development of S. indicum.

Resumo A perda das folhas pelas plantas do Cerrado é um processo energeticamente custoso devido às condições ambientais adversas e intensa predação por herbivoria. As folhas maduras possuem adaptações que minimizam esses eventos. Entretanto, os indivíduos jovens carecem dessas estruturas e produzem elevadas concentrações foliares de metabólitos secundários como forma de proteção. Esses compostos podem ser utilizados na bioprospecção de herbicidas naturais. Dessa forma, objetivamos com este estudo avaliar a fitotoxicidade dos extratos hexânico, acetato etílico e aquoso de folhas jovens de Blepharocalyx salicifolius (Kunth) O. Berg sobre o alongamento de coleóptilos estiolados de Triticum aestivum L. (trigo) e avaliar o potencial fitotóxico do extrato acetato etílico sobre a germinação, crescimento e comprimento das células do metaxilema de Sesamum indicum (gergelim). Os extratos hexânico e acetato etílico inibiram o alongamento dos coleóptilos em todas as concentrações testadas, entretanto os resultados mais promissores foram observados nos fragmentos submetidos ao extrato acetato etílico. Este extrato alterou o tempo médio de germinação e a sincronia das sementes de gergelim, inibiu o crescimento da parte aérea e subterrânea com redução da massa seca das plântulas, levou ao surgimento acentuado de anomalias e causou redução no comprimento médio das células do metaxilema de plântulas de gergelim. Assim, ficou comprovado o potencial fitotóxico dos extratos de folhas jovens de B. salicifolius e a acentuada fitotoxicidade do extrato acetato etílico sobre o desenvolvimento inicial de S. indicum.

Efeito protetor da melatonina sobre intoxicações por herbicidas / Protective effect of melatonin on poisoning by herbicides

O uso inadequado de herbicidas pode resultar em intoxicações agudas e, às vezes, crônicas por exposição em longo prazo a baixos níveis desses agentes tóxicos, podendo o herbicida atuar também como agentes teratogênicos, mutagênicos, cancerígenos e desreguladores endócrinos, com o aparecimento de doenças neurodegenerativas e distúrbios reprodutivos. Estudos têm revelado que a melatonina tem propriedades antioxidantes, anti-inflamatórias e imunomoduladoras e atua na reprodução. Essa indolamina está entre os agentes que têm se mostrado benéfico em intoxicações por herbicidas, porém não há relatos do uso de melatonina contra intoxicações por Glifosato-Roundup®, muito menos em associação com o Paraquat. Dessa forma, o maior interesse no tratamento das intoxicações por herbicidas, tem-se concentrado em medidas que impeçam ou minimizem as lesões celulares provocadas nos diversos sistemas biológicos. Assim, a melatonina, como antioxidante conhecido, pode ser mais uma alternativa contra as intoxicações por herbicidas associados e/ou individuais.

The inadequate use of herbicides may cause serious and sometimes chronic poisoning due to long exposure to low levels of toxic agents. Herbicides may also be teratogenic, mutagenic, cancerigenous agents and endocrine disruptors, with the occurrence of neurodegenerative diseases and reproduction disorders. Several studies have shown that melatonin has antioxidant, anti-inflammatory and immune-modulating qualities, besides affecting the reproduction system. It is among the agents which are beneficent in poisoning by herbicides even though no reports are extant on the use of melatonin against poisoning by Glyphosate-Roundup® alone or associated with Paraquat. Solutions that prevent or minimize cell lesions caused by several biological systems have been focused upon in the treatment for poisoning with herbicides. Thus, melatonin, a known antioxidant, may be an alternative against the poisoning by single or associated herbicides.

Avaliação de extratos das espécies Helianthus annuus, Brachiariabrizanthae Sorghum bicolor com potencial alelopático para uso como herbicida natural / Evaluation of extracts from Helianthus annuus, brizantha and Sorghum bicolor with allelopathic potential for use as a natural herbicide

RESUMO Objetivou-se avaliar o potencial alelopático de extratos aquosos de braquiária, girassol e sorgo na germinabilidade e crescimento inicial de alface (Lactuca sativa L.) visando o uso destes extratos como herbicida natural. O estudo foi realizado no Laboratório de Fisiologia Vegetal da Universidade Federal do Recôncavo da Bahia. Foi instalado um experimento no delineamento inteiramente casualizado, com 4 tratamentos e 6 repetições. Os tratamentos foram extratos de braquiária, girassol, sorgo e como controle, água destilada. Os extratos foram obtidos, utilizando 200 g de material vegetal para 1000 mL de água destilada. Os aquênios de alface foram distribuídos em caixa gerbox contendo duas folhas de papel germitest umedecidas com os tratamentos e levadas para câmara de germinação. A germinação foi acompanhada diariamente. Foram avaliados o tempo médio de germinação e, após dez dias, o crescimento inicial, medindo-se o comprimento da parte aérea (CPA) e o comprimento do sistema radicular (CSR). Os dados gerados foram submetidos à análise de variância e as médias comparadas pelo teste de Tukey. Com base nos resultados, os extratos de braquiária, girassol e sorgo não afetaram a germinação da alface, mas os de braquiária e sorgo aumentaram o tempo médio de germinação. Os extratos causaram aumento na parte aérea, diminuíram o crescimento do sistema radicular e a formação de plântulas normais. Por causarem inibição no crescimento do sistema radicular da alface, apresentam potencial para serem utilizados como herbicidas naturais.

ABSTRACT This study aimed to evaluate the allelopathic potential of aqueous extracts of Brachiaria, sunflower, sorghum germination and early growth of lettuce (Lactuca sativa L.), in the attempt of employing these extracts as a natural herbicide. The study was conducted at the Laboratory of Plant Physiology of the Universidade Federal do Recôncavo da Bahia. A trial was arranged in a completely randomized design with 4 treatments and 6 replications. The treatments were extracts of Brachiaria, sunflower, sorghum, and, as a control, distilled water. The extracts were obtained by using 200 g of plant material in 1000 mL of distilled water. First, the lettuce seeds were distributed in a seedling box containing two sheets of germitest moistened paper with treatments, and then were taken to a germination chamber. The germination was daily monitored. The average germination time and the initial growth were evaluated after ten days, through the measuring of the aerial part length (APL) and the root system length (RSL). The data generated were subjected to analysis of variance and the means were compared by the Tukey test. Based on the results, the extracts of Brachiaria, sunflower and sorghum did not affect the germination of lettuce, but, on the other hand, the Brachiaria and sorghum increased the germination time. The extracts caused an increase in the aerial part and reduced the root system growth and the formation of normal seedlings. Since they caused inhibition on the growth of the lettuce root system, have also potential to be used as natural herbicides.

Response of ligninolytic macrofungi to the herbicide atrazine: dose-response bioassays / Respuesta de macrohongos ligninolíticos al herbicida atrazina: bioensayos dosis-respuesta

The effect of atrazine concentrations on mycelial growth and ligninolytic enzyme activities of eight native ligninolytic macrofungi isolated in Veracruz, México, were evaluated in a semi-solid culture medium. Inhibition of mycelial growth and growth rates were significantly affected (p = 0.05) by atrazine concentrations (468, 937, 1875, and 3750 mg/l). In accordance with the median effective concentration (EC50), Pleurotus sp. strain 1 proved to be the most tolerant isolate to atrazine (EC50 = 2281.0 mg/l), although its enzyme activity was not the highest. Pycnoporus sanguineus strain 2, Daedalea elegans and Trametes maxima showed high laccase activity (62.7, 31.9, 29.3 U mg/protein, respectively) without atrazine (control); however, this activity significantly increased (p < 0.05) (to 191.1, 83.5 and 120.6 U mg/protein, respectively) owing to the effect of atrazine (937 mg/l) in the culture medium. Pleurotus sp. strain 2 and Cymatoderma elegans significantly increased (p < 0.05) their manganese peroxidase (MnP) activities under atrazine stress at 468 mg/l. The isolates with high EC50 (Pleurotus sp. strain 1) and high enzymatic activity (P. sanguineus strain 2 and T. maxima) could be considered for future studies on atrazine mycodegradation. Furthermore, this study confirms that atrazine can increase laccase and MnP activities in ligninolytic macrofungi.

Se evaluó el efecto de diferentes concentraciones de atrazina sobre el crecimiento micelial y la actividad enzimática de ocho macrohongos ligninolíticos aislados en Veracruz, México. La inhibición del crecimiento micelial y la tasa de crecimiento diaria fueron significativamente (p < 0,05) afectadas por todas las dosis de atrazina (468, 937, 1875 y 3750 mg/l) adicionadas al medio de cultivo. De acuerdo con la concentración efectiva media (CE50), Pleurotus sp. cepa 1 fue el aislamiento más tolerante a la atrazina (CE50 = 2281 mg/l), aunque sus actividades enzimáticas no fueron altas. Pycnoporus sanguineus cepa 2, Daedalea elegans y Trametes maxima mostraron actividades altas de lacasa (62,7, 31,9 y 29,3 U mg/proteína, respectivamente) en ausencia de atrazina (control); estas actividades se incrementaron (p < 0,05) significativamente (191,1, 83,5 y 120,6 U mg/proteína, respectivamente) en presencia de atrazina (937 mg/l) en el medio de cultivo. Pleurotus sp. cepa 2 y Cymatoderma elegans incrementaron significativamente (p < 0,05) sus actividades de manganeso peroxidasa (MnP) bajo la concentración de 468 mg/l de atrazina. Los aislamientos con alta CE50 (Pleurotus sp. cepa 1) y alta actividad enzimática (P. sanguineus cepa 2 y T. maxima) podrían ser considerados para futuros estudios en la micodegradación de atrazina. Además, el presente estudio confirma que la atrazina puede incrementar las actividades lacasa y MnP en macrohongos ligninolíticos.

Intellectual property rights related to the genetically modified glyphosate tolerant soybeans in Brazil

The present work analyzes the different modalities of protection of the intellectual creations in the biotechnology agricultural field. Regarding the Brazilian legislations related to the theme (the Industrial Property Law - no. 9. 279/96 and the Plant Variety Protection Law - no. 9. 456/97), and based in the international treaties signed by Brazil, the present work points to the inclusions of each of them, as well as to their interfaces using as reference the case study of glyphosate tolerant genetically modified soybean. For this case study, Monsanto's pipelines patents were searched and used to analyze the limits of patent protection in respect to others related to the Intellectual Property (IP) laws. Thus, it was possible to elucidate the complex scenario of the Intellectual Property of the glyphosate tolerant soybeans, since for the farmer it is hard to correlate the royalties payment with the IP enterprise's rights.

O presente trabalho analisa as diferentes modalidades de proteção das criações intelectuais no campo da biotecnologia agrícola. A partir das leis Brasileiras relacionadas ao tema (Lei da Propriedade Industrial - nº 9.279/96 e Lei da Proteção de Cultivares - nº 9.456/97), e com base nos tratados internacionais assinados pelo Brasil, o presente trabalho aponta as inclusões de cada uma, assim como, suas interfaces usando como referência o estudo de caso da soja geneticamente modificada para tolerância ao glifosato. Para este caso, patentes pipelines da Monsanto foram buscadas e usadas para analisar os limites de proteção das patentes frente às outras leis de Propriedade Intelectual (PI) relacionadas. Assim, foi possível elucidar o cenário complexo da Propriedade Intelectual das sojas tolerantes ao glifosato, já que para o agricultor não é fácil correlacionar o pagamento dos royalties com os direitos de PI da empresa.

Plant growth inhibitory activity of N, N´-di-(4-R-phenyl)-alkanediamides / Actividad inhibitoria de crecimiento de plantas de N, N’-di-(4-R-phenyl)-alcanodiamidas

Diamides are a class of metabolites that occurring in some Meliaceae plants, in Aglaia spp for example, with an ample body of biological activities, being insecticidal and herbicidal two of the most important. In our program of search for botanical pesticides, a series of N,N´-di-(4-R-phenyl)-alkanediamides was evaluated for its herbicidal activity. Many of the analogues tested exhibited moderate to good herbicidal activity both pre-emergence and post-emergence and have been found to inhibit energetic metabolism of pre-emergence weeds. The structure-activity relationships were probed by substitution on the benzene ring. Among the variations investigated, it was found that maximal herbicidal activity was obtained by substitution of –F, -CN and -Br at the aromatic portion and by n=2 of the aliphatic long chain. This last number of carbons (n=2) substitution was the key for the inhibitory activity.

Diamidas son una clase de metabolitos que estan presentes en plantas perteneciente a la familia de la Meliaceas, en Aglaia por ejemplo, poseen un amplio cuerpo de actividades biologicas, siendo la insecticida y la herbicida dos de las mas importantes. En nuestro programa para la busqueda de pesticidas botanicos, una serie de N,N’-di-(4-R-phenyl)-alkanodiamidas se evaluo para su actividad herbicida. Muchos de los analogos exhibieron desde buenas a moderadas actividades, tanto como pre-emergentes como post-emergentes y ademas se encontro que inhiben el metabolismo pre-emergente energetico de malezas. La relacion estructura-actividad fue probada por sustitución sobre al anillo aromatico. Entre las variaciones investigadas, se encontro que la maxima actividad herbicida se obtuvo por sustitución de F, CN y Br en la porcion aromatica y por n=2 del largo de la cadena alifatica. Este ultimo numero de carbonos de sustitución (n=2) fue clave para la actividad inhibitoria.

Effects of 2,4-D on the germination of megaspores and initial development of Regnellidium diphyllum Lindman (Monilophyta, Marsileaceae) / Efeitos do 2,4-D sobre a germinação de megásporos e o desenvolvimento inicial de Regnellidium diphyllum Lindman (Monilophyta, Marsileaceae)

Regnellidium diphyllum is considered as endangered, occurring in the State of Rio Grande do Sul, Brazil, and a few adjoining localities in Uruguay, Argentina and the State of Santa Catarina. It grows in wetlands frequently altered for agricultural activities. Herbicides based on 2,4-dichlorophenoxyacetic acid (2,4-D) are widely used in these fields. The effects of 2,4-D on the germination of megaspores and initial sporophytic development of R. diphyllum were investigated. Six concentrations of 2,4-D (0.32; 0.64; 1.92; 4.80; 9.60 and 19.20 mg.L-1), and the control (0.00 mg.L-1), were tested in vitro, using Meyer's medium. Cultures were maintained in a growth chamber at 24 ± 1 °C, under artificial light with nominal irradiance of 110 µmol.m-2/s and 16 hours photoperiod. Megaspore germination was lower at 9.60 and 19.20 mg.L-1 of 2,4-D (56 and 48 percent, respectively), compared with the control (68 percent). Herbicide concentrations of up to 1.92 mg.L-1 did not significantly decrease the number of sporophytes formed. At 19.20 mg.L-1, no sporophytes were formed. The lengths of the primary root, primary and secondary leaves were greater at concentrations of 0.32 and 0.64 mg.L-1 of 2,4-D. Low concentrations of 2,4-D do not affect germination rates and initial development of R. diphyllum in a significant way. However, higher concentrations (9.60 and 19.20 mg.L-1) affect substantially the germination of the megaspores and interfere with the establishment of the species.

Regnellidium diphyllum é considerada ameaçada, ocorrendo no Estado do Rio Grande do Sul, Brasil, e em algumas localidades vizinhas no Uruguai, na Argentina e no Estado de Santa Catarina. Cresce em áreas alagáveis, frequentemente alteradas para atividades agrícolas. Herbicidas baseados em ácido 2,4-diclorofenoxiacético (2,4-D) são largamente utilizados nestas plantações. Os efeitos do 2,4-D sobre a germinação de megásporos e o desenvolvimento esporofítico inicial de R. diphyllum foram investigados. Seis concentrações de 2,4-D (0,32; 0,64; 1,92; 4,80; 9,60 e 19,20 mg.L-1), além do controle (0,00 mg.L-1) foram testadas in vitro, utilizando meio de Meyer. As culturas foram mantidas em câmara de germinação a 24 ± 1 °C, sob luz artificial, com irradiância nominal de 110 mmol.m-2/s e fotoperíodo de 16 horas. A germinação de megásporos foi menor em 9,60 e 19,20 mg.L-1 de 2,4-D (56 e 48 por cento, respectivamente), comparada ao controle (68 por cento). Concentrações até 1,92 mg.L-1 não diminuíram significativamente o número de esporófitos formados. Em 19,20 mg.L-1, não houve formação de esporófitos. Os comprimentos da raiz primária e das folhas primária e secundária foram maiores em concentrações de 0,32 e 0,64 mg.L-1 de 2,4-D. Baixas concentrações de 2,4-D não afetam significantemente as taxas de germinação e o desenvolvimento inicial de R. diphyllum. Entretanto, maiores concentrações (9,60 e 19,20 mg.L-1) afetam substancialmente a germinação de megásporos e interferem no estabelecimento da espécie.

Germination behaviour of seeds from herbicide treated plants of Chenopodium album L

The carry-over effect of sub-lethal herbicides was investigated on the germination of seeds collected from surviving Chenopodium album plants, which had received 1/8, 1/8 twice, 1/8 three times, 1/4, 1/2, 1/1 doses of either pre-emergence ioxynil or post-emergence bentazone in a previous onion (Allium cepa) crop. Seeds were also collected from surviving C. album plants, which had received 1/4, 1/2, 1/1 of either pre-emergence pendimethalin, propachlor and linuron, or 1/8, 1/8 twice, 1/8 three times, 1/4, 1/2, 1/1 of post-emergence ioxynil or linuron in a previous leek (Allium porrum) crop. Seeds of surviving plants were collected and tested for germination at temperature of 5, 10, 15, 20 and 25°C. The effect of different temperatures on the total number of germinated seeds was significant. Germination was minimum at low temperatures (5°C or 10°C). Herbicides did not show any effect on germination of C. album and resulted in the same final germination percentage as seeds collected from the unsprayed control plots.

Avaliou-se o efeito residual de doses sub-letais de herbicidas sobre a germinação de sementes de plantas de Chenopodium album sobreviventes em uma cultura prévia de cebola (Allium cepa), que recebeu 2x, 3x, 1/4, 1/2 ou a dose recomendada de ioxynil em pré-emergência ou bentazone em pós-emergência. As sementes foram também coletadas de plantas de C. album sobreviventes de um campo de alho-porró (Allium porrum) que havia sido tratado com 1/4, 1/2 ou a dose recomendada de pendimethalin, propachlor e linuron em pré-emergência, ou ainda 2x, 3x, 1/4, 1/2 ou a dose recomendada de ioxynil ou linuron em pós-emergência. As sementes destas plantas sobreviventes foram coletadas e testadas quanto à germinação a temperaturas de 5°C, 10°C, 15°C, 20°C e 25°C. Verificou-se que o efeito das temperaturas na germinação destas sementes foi significativa. A germinação foi mínima a baixas temperaturas (5°C e 10°C). Os herbicidas não causaram nenhum efeito na germinação das sementes de C. album tendo resultado no mesmo nível daquelas das plantas controles de culturas não pulverizadas.

Biomarcadores histológicos: toxicidade crônica pelo Roundup em piauçu (Leporinus macrocephalus) / Histological biomarkers: chronic toxicity for roundup in piauçu (Leporinus macrocephalus)

Avaliou-se o uso de brânquias, fígado e rins como biomarcadores histológicos em ensaio de toxicidade crônica com o herbicida Roundup® em piauçu (Leporinus. macrocephalus). Para tanto, os animais foram expostos a 1,58mg/L, dose equivalente a 1/10 da CL50 para a espécie por 14 e 28 dias, sendo utilizados cinco animais por tratamento correspondentes aos dias 0, 14 e 28. Hemorragia e necrose hepática e congestão renal foram as alterações que apresentaram diferenças entre os animais expostos e os não expostos. Dentre os órgãos usados como biomarcadores histopatológicos, o fígado foi o que apresentou os melhores resultados, seguido pelo rim.

The use of gills, liver, and kidneys as histological biomarkers was evaluated in a chronic toxicity analysis with herbicide Roundup® in piauçu (Leporinus macrocephalus). The animals were exposed to 1/10 of LC50 (1.58mg/L), during a period of 14 and 28 days. Five animals were used for treatment (days 0, 14, and 28). Hepatic hemorrhage and necrosis and renal congestion were the alterations that presented differences between exposed and non-exposed animals. Among the organs used as histological biomarkers, the liver presented the best results, followed by the kidneys.

The effect of the glyphosate, 2,4-D, atrazine e nicosulfuron herbicides upon the Edaphic collembola (Arthropoda: Ellipura) in a no tillage system

The use of herbicides is a common and intensive practice in no tillage systems. The herbicides can influence, directly or indirectly, the population of edaphic arthropods. Collembola is a group that functions as a bio-indicator of soil conditions. The degree of abundance and diversity of Collembola provides the level of soil disturbance provoked by agricultural practices. This experiment was designed to compare the influence of herbicides on the population fluctuation of Collembola in a no-till soil preparation system. The work was conducted in a non irrigated no-till area at the Núcleo Experimental de Ciências Agrárias of the Universidade Federal de Mato Grosso do Sul (UFMS), Campus de Dourados, in soil planted with corn as a surface covering, during the period of December, 2002 to December, 2003. The data were analyzed according to a completely randomized model, in a split plot design. The plots received four types of herbicides: glyphosate, atrazine, 2,4-D and nicosulfuron. A fifth plot did not receive any herbicide (control), for a total of five treatment types. The sub plots were represented by their collection times (10, 20, 30 and 40 days after the herbicide applications). Both the type of herbicide and the time of data sampling influenced the Collembola population fluctuaction. The treatments with atrazine and 2,4-D caused the most reduction of the population of Collembola, depending on the time of application.

No plantio direto o uso de herbicidas é uma prática comum e intensiva, que influencia direta ou indiretamente a população de artrópodes da mesofauna edáfica. O grau de abundância e diversidade de Collembola comumente é indicado para comprovar a extensão de distúrbios de várias práticas agrícolas, pois esse grupo serve como bioindicador das condições do solo. Esta pesquisa teve como objetivo comparar a influência de alguns herbicidas na flutuação populacional de Collembola, em solo sob o sistema de plantio direto. O trabalho foi realizado em uma área de plantio direto de sequeiro, do Núcleo Experimental de Ciências Agrárias da Universidade Federal de Mato Grosso do Sul (UFMS), Campus de Dourados, em latossolo roxo distroférrico com cobertura de milho, durante os meses de outubro de 2002 a janeiro de 2003. Os dados obtidos foram analisados segundo o modelo inteiramente casualizado constituído de tratamentos dispostos no esquema de parcelas subdivididas, onde as parcelas são representadas por uma testemunha mais quatro herbicidas: glifosate, atrazina, 2,4-D e nicosulfuron (totalizando cinco tratamentos) e as subparcelas pelas épocas de cada coleta (10, 20, 30 e 40 dias após aplicação dos herbicidas). Tanto os herbicidas testados quanto as épocas de coleta influenciaram a população de Collembola. Dependente do período de degradação dos herbicidas no solo, os tratamentos com 2,4-D, Atrazina, foram os que mais influenciaram a abundância de Collembola reduzindo sua população.

Seed germination and seedling growth of the Mexican sunflower Tithonia diversifolia (Compositae) in Nigeria, Africa

We studied seed germination and seedling growth of the Mexican sunflower Tithonia diversifolia in Nigeria. This involved the usage of some dormancy-releasing methods and the effect of some concentrations of three herbicide formulations on the young seedlings. Initial germination tests on fresh and stored seeds revealed a low percentage germination of less than 30%. The seeds of the weed exhibit dormancy. Subjecting the seeds to wet heat at 80 and 100 degrees C and light treatment terminated dormancy both in the fresh and stored seeds. Light greatly enhanced the germination percentage of seeds by about 70%. There was gradual increase in germination percentage with increase in storage period in dormancy-released seeds. The mean LAR (Leaf Area Ratio), NAR (Net Assimilation Rate) and RGR (Relative Growth Rate) are comparatively high in young seedlings. Concentrations of 0.5-2.0% of Gramoxone, Primextra and Galex are toxic to 1 month old seedlings. For eradication, the seedlings should be attacked at one month stage.

Se estudió la germinación y crecimiento de las plántulas del girasol mexicano Tithonia diversifolia. Se usaron métodos de periodo de latencia y germinación, y el efecto de varias concentraciones de tres herbicidas sobre las plántulas jóvenes. Las pruebas iniciales de germinación con semillas frescas y almacenadas revelaron un bajo porcentaje de germinación (30%). Las semillas de malezas permanecieron latentes. Al someter las semillas a tratamientos de calor húmedo de 80 y 100oC y luz se terminó con el periodo de latencia en las semillas frescas y en las almacenadas. La luz aumentó el porcentaje de germinación a cerca del 70%. Hubo un incremento gradual en el porcentaje de germinación en el periodo de almacenamiento en las semillas salidas de la latencia. Los promedios de cociente de área foliar, tasa neta de asimilación y tasa de crecimiento relativo son comparativamente altos en las plántulas jóvenes. Las concentraciones de 0.5-2.0% de Gramoxone, Primextra y Galex son tóxicas para las plántulas de un mes de edad.

Effect of pesticides on nitrification in aquatic sediment

O objetivo desta pesquisa foi avaliar o efeito dos herbicidas "Glyphosate", Ácido Nonânico e "Dichlorprop-P" e dos insecticidas "Potassium oil", "Malation" e "Pyretrin" e da combinação destes compostos sobre o processo de nitrificação. As taxas de nitrificação foram mensuradas em uma mistura de água e sedimento do lago Brabrand, um lago raso e eutrófico (Aarhus, Dinamarca), por meio da inibição da oxidação do nitrito a nitrato por cloreto. Foi observada uma influência negativa de todos os herbicidas e inseticidas sobre o processo de nitrificação. A Concentração Sem Efeito Observado (CSEO) foi de 30 µg.L-1 para Glyphosate e Ácido Nonânico e 1 µg.L-1 para Dichlorprop-P. A CSEO para Malation e Pyretrin foi 3 µg.L-1. Não foi observado um efeito conjunto dos inseticidas Malation e Pyrethin e de todos os três herbicidas estudados, indicando que o impacto ambiental é baixo quando reduzidas concentrações destas substâncias estão presentes ao mesmo tempo no ambiente. O procedimento utilizado nesta pesquisa pode ser uma ferramenta útil para obtenção de limites nas concentrações de pesticidas ou outros produtos químicos em um curto período de tempo.

Herbicide effects on cuticle ultrastructure in Eleusine indica and Portulaca oleracea

Eleusine indica and Portulaca oleracea are two common weeds in peanut crops in southern Córdoba. Two chemicals are frequently used to control them, quizalofop for grasses and lactofen for dicots. The objective is to study the effects of quizalofop and lactofen on cuticle ultrastructure in E. indica and P. oleracea, respectively. In the lab, quizalofop was applied on E. indica and lactofen on P. oleracea. Three plant categories were analyzed in each species: 3, 1-2, and no tiller in E. indica, and 8, 6, and 2 nomophylls in P. oleracea. Leaf samples from both species were collected at 7 and 16 days post-application and were treated for scanning electron microscopy. E. indica cuticle treated with lethal dose shows areas where epicuticular waxes disappear, specially in the youngest individua1s. These areas are located predominantly on periclinal walls of typical epidermic cells and subsidiary cells. On the other hand, P. oleracea shows cuticle discontinuities that may be caused by lactofen entry. They are smaller and less frequent in plants having 8 or more nomophylls. The remaining waxes act as a herbicide accumulation compartment and, therefore, would partially prevent the active ingredient entry to epidermic cells.

Effect of 2,4-D, hydric stress and light on indica rice (Oryza sativa) somatic embryogenesis

With the purpose of increasing the embryogenesis regeneration process in vitroplants obtained from somatic embryos of the indica rice variety CR-5272 (Oryza sativa L.), two independent experiments were performed. The first experiment consisted in the effect of combination of three concentrations of the gelling agent PhytagelTM (1.8, 2.4, and 3 gL-1) and four 2,4-D concentrations (2.26, 4.52, 6.78, and 9.05 m M) on the induction and subsequent regeneration of embryogenic calli. On the second experiment, the pre-regeneration phase was modified; calli were subjected to darkness or diffuse light conditions for one, two, and three weeks. In embryogenesis induction, 35% calligenesis was obtained using the MS culture medium supplemented with 6.78 m M of 2,4-D and 2.4 gL-1 PhytagelTM , whereas on the control treatment (MS medium supplemented with 9.05 m M of 2,4-D and 3 gL-1 PhytagelTM ) 24% calligenesis was obtained. In addition, regeneration percentages were improved (22% and 16% for calli induced with the above treatments, respectively). Furthermore, in light exposure experiments, the best result was obtained by exposing the embryogenic calli to darkness for one week in pre-regeneration, followed by direct light exposure during the regeneration phase