Importance of sequential herbicide application in the control of Elephantopus mollis / A importância da aplicação sequencial no controle de Elephantopus mollis

RESUMO: Popularmente conhecida como pata de elefante ou sussuaiá, Elephantopus mollis, é uma espécie que recentemente surgiu como uma planta daninha em lavouras de cultivos de grãos. Objetivou-se com este estudo avaliar a sensibilidade diferencial de biótipos de E. mollis oriundos de áreas agrícolas e não agrícolas e determinar as melhores combinações de herbicidas aplicados em diferentes estádios de desenvolvimento para o controle desta espécie. Foram realizados três experimentos. No experimento de sensibilidade diferencial foram utilizados dez herbicidas em dois biótipos em duas fases de desenvolvimento. O experimento de dose resposta foi conduzido com oito doses de sete herbicidas. O experimento a campo foi realizado em uma área que apresenta problemas com a planta daninha para validar os resultados dos experimentos anteriores. O biótipo oriundo de área agrícola apresentou menor sensibilidade aos herbicidas quando comparado ao biótipo oriundo de área não agrícola. Os herbicidas de contato inicialmente apresentam controle superior, mas logo a planta apresenta rebrote em função de gemas presentes no colo da planta. A aplicação isolada de 2,4-D com doses entre 1005 e 1675 g e.a ha-1 possui controle de 25%. Quando o 2,4-D é seguido da aplicação de paraquat (400 g i.a ha-1) o controle passa a ser entre 51 e 68%. O melhor tratamento para o controle de plantas desenvolvidas é a mistura de 2,4-D + glyphosate (1340 + 1080 g e.a ha-1) com aplicação sequencial de paraquat.

ABSTRACT: Elephantopus mollis, popularly known as elephant paw or sussuaiá, is a species that has recently emerged as a weed affecting grain crops. This study aimed to evaluate the differential sensitivity of biotypes of E. mollis obtained from agricultural and nonagricultural areas and to determine the best combinations of herbicides applied at different stages of development for controlling this species. Three experiments were conducted. In the differential sensitivity experiment, 10 herbicides were used in 2 biotypes in 2 stages of development. The dose-response experiment was conducted using 8 doses of 7 herbicides. The field experiment was conducted in an area with weed issues to validate the results of previous experiments. The biotype from the agricultural area showed lower sensitivity to herbicides than the biotype from the nonagricultural area. The contact herbicides initially presented better control; however, the weed shortly showed re-growth due to the presence of buds in the plant crown. Isolated application of 2.4-D amine at doses between 1005 and 1675 g a.e. ha−1 demonstrated 25% control. When 2,4-D amine was followed by paraquat application (400 g a.i. ha−1), the control observed was between 51% and 68%. The best treatment for the control of completely developed weeds is 2,4-D amine + glyphosate mixture (1340 + 1080 g a.e. ha−1), followed by sequential paraquat application.

Remoção do 2,4-D em amostras de águas pela adsorção em leitos fixos de carvão ativado granular em escala reduzida / Removal of 2,4-D in water samples by adsorption in fixed beds of granular activated carbon on reduced scale

RESUMO O objetivo deste trabalho foi avaliar, por meio dos testes rápidos de coluna em escala reduzida, a capacidade de adsorção do carvão ativado granular (CAG) na remoção do ácido 2,4-diclorofenoxiacético (2,4-D) em amostras de água ultrapura e de água filtrada proveniente de estação de tratamento de água. Os valores da capacidade de adsorção obtidos a partir de amostras de água ultrapura foram 67% superiores aos obtidos para água com presença de matéria orgânica natural (MON). A MON influenciou fortemente a remoção de 2,4-D competindo pelos sítios de adsorção do carvão ativado e diminuiu a capacidade de adsorção para 7,43 mg 2,4-D por grama de CAG. Para a concentração de 2,4-D no afluente igual a 7089 ± 104 µg.L-1 e relação volumeágua/volumeCAG estimado em 766, foi possível produzir água com concentração de 2,4-D inferior a 30 µg.L-1, como recomendado pela Portaria Brasileira de Potabilidade de Água, do Ministério da Saúde (Portaria MS nº 2.914/2011).

ABSTRACT The aim of this study was to assess by means of rapid tests of small-scale column the adsorption capacity of granular activated carbon (GAC) for removal of 2,4-dichlorophenoxyacetic acid (2,4-D) from samples of ultrapure water and filtered water from a water treatment plant. The adsorption capacities values obtained from distilled water samples were 67% higher than those obtained for water having natural organic matter (NOM). NOM strongly influenced the removal of 2,4-D, competing for GAC adsorption sites, and decreasing its adsorption capacity to 7 mg 2,4-D g-1 CAG. For 2,4-D concentration of 7089 ± 104 µg L-1 and the water treated volume/GAC volume at 766, it was possible to produce treated water with 2,4-D concentration less than 30 µg L-1 as recommended by Brazilian Drinking Water Legislation of the Ministry of Health (Portaria MS 2914/2011).

Evaluación de déficit hídrico en variantes somaclonales de maracuyá (Passiflora edulis var. flavicarpa, Deneger), usando mediciones morfométricas / Water deficit evaluation in somaclonal variants of passion fruit (Passiflora edulis var. flavicarpa, Deneger), using morphometric measurements

El aumento de las temperaturas y el cambio en los regímenes pluviales tienen efectos directos sobre el rendimiento de los cultivos, el maracuyá no tolera épocas secas marcadas, lo que puede resultar en poca inducción floral y en caída de frutos, hasta la defoliación de la planta. El mejoramiento genético vegetal aparece como estrategia para favorecer la adaptación de los cultivos al estrés ambiental. Una de las herramientas del fitomejoramiento es el cultivo de tejidos vegetales, con éste se ha obtenido variedades mejoradas usando variación somaclonal. Por tal motivo, se planteó un proyecto de selección in vitro de variantes somaclonales (VS) de maracuyá, buscando tolerancia al déficit hídrico. La investigación cuenta con cuatro etapas, 1. Inducción de callogénesis (2,4-D), 2. Organogénesis directa e indirecta; 3. Inducción de estrés hídrico (PEG 6000); 4. Selección in vitro de VS tolerantes a déficit hídrico. Se encontraron diferencias estadísticamente significativas en plántulas sembradas en medios con 20g PEG/l, para longitud, grosor y número de raíces, en cuanto a tallo no se encontraron diferencias estadísticas. El número de hojas presentó diferencias significativas respecto a los demás medios que inducían estrés hídrico [25 y 30g PEG/L]. Finalmente, las variables morfométricas permitieron diferenciar los mejores tratamientos y las plántulas, que mostraron tolerancia al déficit hídrico, esto expresado en términos de crecimiento longitudinal, grosor, ancho y número, pese a las concentraciones del agente estresante PEG 6000. Lo obtenido se convierte en insumo importante para continuar con el proceso de fitomejoramiento del maracuyá en la Universidad del Tolima.

The increase in temperatures and the change in rainfall regimes have direct effects on crop yields, passion fruit does not tolerate marked dry seasons, which can result in little floral induction and fruit fall, until the defoliation of the plant. Plant genetic improvement appears as a strategy to favor the adaptation of crops to environmental stress. One of the tools of plant breeding is the cultivation of plant tissues, with this one has obtained improved varieties using somaclonal variation. For this reason, a project was proposed for in vitro selection of somaclonal variants (VS) of passion fruit, seeking tolerance to the water deficit. The research has four stages, 1. Induction of calllogenesis (2,4-D), 2. Direct and indirect organogenesis; 3. Water stress induction (PEG 6000); 4. In vitro selection of VS tolerant to water deficit. Statistically significant differences were found in seedlings planted in media with 20g PEG / l, for length, thickness and number of roots, in terms of stem no statistical differences were found. The number of leaves showed significant differences with respect to the other means that induced water stress [25 and 30g PEG / L]. Finally, the morphometric variables allowed differentiating the best treatments and seedlings, which showed tolerance to the water deficit, this expressed in terms of longitudinal growth, thickness, width and number, despite the concentrations of the stressful agent PEG 6000. The obtained becomes important input to continue the process of plant breeding of passion fruit at the University of Tolima.

EFFECT OF GENOTYPE ON THE in vitro REGENERATION OF Stevia rebaudiana VIA SOMATIC EMBRYOGENESIS / Efecto del genotipo sobre la regeneración in vitro de Stevia rebaudiana a través de embriogénesis somática

Stevia rebaudiana (Asteraceae) is a plant of economic importance because of its medicinal properties and the presence of sweetener compounds on its leaves. These compounds can be a substitute for sucrose in a wide variety of products used by persons with diabetes and obesity problems. To standardize an efficient and effective propagation method for the different Stevia genotypes grown in Colombia, this study evaluated the effect of different combinations of the plant growth regulators 2,4-dichlorophenoxyacetic acid (2,4-D), indole-3-acetic acid (IAA), indole-3-butyric acid (IBA), 6-(gamma, gamma-dimethylallylamino) purine (2iP) and Zeatin on the induction and development of somatic embryos. Adenine and coconut water were also evaluated as supplements in the basal culture medium Murashige and Skoog Basal Salt Mixture (MS) with glutamine. The combination of 2,4-D (18.09 µM) and 2iP (7.38 µM) produced the highest number of somatic embryos per explant, which had well-defined characteristics. The genotype showed a significant effect on the embryogenic response. In the "SRQ-93" genotype, the formation and development of somatic embryos was achieved, whereas the genotypes "Bertoni" and "Morita II" only yielded embryogenic and non-embryogenic calli, respectively. The conversion to seedlings was achieved on the regeneration medium containing gibberellic acid (GA3) (0.29 µM) and activated charcoal.

Stevia rebaudiana (Asteraceae), es una planta de gran importancia económica debido a sus propiedades medicinales y a la presencia de compuestos endulzantes en sus hojas, los cuales pueden sustituir la sacarosa en gran variedad de productos utilizados por personas con problemas de diabetes y obesidad. Con el propósito de estandarizar un método de propagación eficiente y efectivo para diferentes genotipos de Stevia cultivados en Colombia, en la presente investigación se evaluó el efecto sobre la inducción y desarrollo de embriones somáticos de diferentes combinaciones de los reguladores de crecimiento vegetal 2,4-D, IAA, IBA, 2iP y Zeatina, además de los suplementos adenina y agua de coco en el medio de cultivo basal Murashige y Skoog (1962), adicionado con glutamina. Con la combinación 2,4-D (18.09 µM) y 2iP (7.38 µM) se obtuvo el mayor número embriones somáticos por explante con características bien definidas. El genotipo tuvo un efecto significativo en la repuesta embriogénica, en el genotipo "SRQ-93" se logró la formación y el desarrollo de embriones somáticos, mientras que en los genotipos "Bertoni" y "Morita II", solo se obtuvo callo embriogénico y no embriogénico respectivamente. La conversión a plántulas se alcanzó en el medio de regeneración conteniendo GA3 (0.29 µM) y carbón activado.

Isolation and 2,4-D-degrading characteristics of Cupriavidus campinensis BJ71

An indigenous bacterial strain capable of utilizing 2,4-dichlorophenoxyacetic acid as the sole carbon and energy source was isolated from a soil used for grown wheat with a long-term history of herbicide use in Beijing, China. The strain BJ71 was identified as Cupriavidus campinensis based on its 16S rRNA sequence analysis and morphological, physiological, and biochemical characteristics. The degradation characteristics of strain BJ71 were evaluated. The optimal conditions for 2,4-D degradation were as follows: pH 7.0, 30 °C, 3% (v/v) inoculum size, and an initial 2,4-D concentration of 350 mg L−1. Up to 99.57% of the 2,4-D was degraded under optimal conditions after 6 days of incubation. Strain BJ71 was also able to degrade quizalofop and fluroxypyr. This is the first report of a 2,4-D-degrader containing tfdA gene that can utilize these two herbicides. In a biodegradation experiment, 87.13% and 42.53% of 2,4-D (initial concentration, 350 mg kg−1) was degraded in non-sterile and sterilized soil inoculated with BJ71, respectively, after 14 days. The 2,4-D degradation was more rapid in a soil microcosm including BJ71 than in a soil microcosm without BJ71. These results indicate that strain BJ71 is a potential candidate for the bioremediation of soil contaminated with the herbicide 2,4-D.

ESTABLECIMIENTO DEL SISTEMA DE REGENERACIÓN POR EMBRIOGÉNESIS SOMÁTICA DE Azadirachta indica A. Juss. / Establishment of Regeneration System for Somatic Embryogenesis of Azadirachta Indica A. Juss.

Azadirachta indica, es una planta con múltiples aplicaciones tanto forestal como farmacológica. Por ende, el establecimiento del sistema de cultivo in vitro por embriogénesis somática ofrece diversas y variadas ventajas, tales como obtener plantas altamente productivas en metabolitos. En este estudio, se utilizaron secciones foliares y cotiledonares, inducidas en medios MS (1962) suplementados con: BAP sólo y combinado con ANA / 2,4-D, TDZ sólo y con ABA. La regeneración fue con MS sólo o con K + AIA y BAP + AIA. Como resultado se estableció un sistema eficiente con secciones de cotiledones, observándose organogénesis a bajas concentraciones de BAP, mientras a altos niveles de BAP (2,5 mg.L-1), así como con TDZ + ABA (0,02 + 1 mg.L-1) respectivamente favorecieron la embriogénesis somática primaria y secundaria en un 96 % y 71 % respectivamente. La regeneración fue 71 % con MS, mientras que el enraizamiento fue de 86,67 % con MS½, obteniéndose plantas completas a corto plazo.

Azadirachta indica, is a plant with multiple forest and pharmacological application. Therefore, the establishment of in vitro culture system for somatic embryogenesis offers several distinct advantages such as obtaining highly productive plant metabolites. In this study, were used sections cotyledon and leaf, induced on MS medium (1962) supplemented with: BAP alone and combined with NAA / 2,4-D, TDZ alone and ABA. Regeneration was with MS alone or with K + BAP + IAA and IAA. As a result was established an efficient system with cotyledon sections, being observed organogenesis at low concentrations of BAP, while high levels of BAP (2.5 mg.L-1) with 96 % and TDZ + ABA (0.02 + 1 mg.L-1) with 71 %, favoring the primary and secondary somatic embryogenesis. Regeneration was 71 % with MS; rooting was 86.67 % with MS½, presenting whole plants obtained short term.

Regeneration Procedure for Three Arachis hypogaea L. Botanicals in Uganda through Embryogenesis.

Aims: A procedure was developed for embryogenesis from embryo explants derived from mature seeds of freshly harvested Serenut 4T, Serenut 1R and Acholi-white groundnut cultivars representing the three broad groundnut botanical classifications. Methodology: This study explored the use of mature embryo axes as explants for somatic embryogenesis, and determined the factors that affect regeneration of three Ugandan groundnut cultivars. Freshly harvested mature seeds of the three groundnut cultivars were collected and the embryo explants were initiated on 3 media namely; Murashige and Skoog (MS) basal media with varying concentrations of the growth regulator 2,4-Dichlorophenoxy acetic acid (2,4-D); Chu N6 basal medium with vitamins (N6); and Callus Induction Medium (CIM). The shoot formation and elongation medium contained MS basal medium supplemented with indolebutyric acid (IBA) and 6- Benzylamminopurine (BAP) in isolation, and BAP in combination with a-naphthaleneacetic acid (NAA) and indoleacetic acid (IAA). For root induction, elongated shoots were transferred to MS medium supplemented with various combinations of NAA with IBA, BAP and a combination of IBA and Kinetin. Results and Conclusion: Different concentrations of 2,4-D elicited different callogenesis responses in the cultivars with Acholi white (Valencia botanical) and Serenut 4T (Spanish botanical) giving the optimal response at 5mg/l whereas Serenut 1R (Virginia botanical) showed best response at a concentration of 30 mg/l. N6 and CIM supported callogenesis in Acholi white (AW) and Serenut 4T only. In all cultivars, maximum root production was gained when using MS medium supplemented with NAA- 1 mg/l and IBA -2.0 mg/l. On the other hand, for Serenut 1R and Serenut 4T, BAP 2.5 mg/l; NAA 0.5 mg/l combination yielded higher shoot regeneration percentage whereas for AW BAP 3 mg/l; NAA 0.5 mg/l supported maximum shoot production.This is the first ever report of successful regeneration of the three groundnuts botanicals in Uganda. These results are likely to facilitate genetic transformation of three preferred Ugandan groundnut varieties.

Rapid propagation of Paris polyphylla var. chinensis / 中草药

Objective: The roots of Paris polyphylla var. chinensis were used as explants to establish a rapid propagation technique. Methods: The effects of hormone 6-BA, 2,4-D, NAA, IBA, KT, IAA, ceftriaxone, activated carbon, etc on callus induction, differentiation of adventitious bud, and formation of adventitious roots were studied to find out the best culture medium formulation by using MS as basic culture medium. Results: The best medium for callus induction of P. polyphylla var. chinensis was MS + 6-BA 1.0 mg/L + NAA 1.5 mg/L + 2,4-D 3.0 mg/L, and the best medium for differentiation of adventitious bud was MS + 6-BA 3.0 mg/L + IAA 0.3 mg/L + KT 1.0 mg/L + ceftriaxone 300 mg/L, while the best medium for formation of adventitious roots was 1/2 MS + IBA 0.5 mg/L + NAA 0.1 mg/L + activated carbon 0.5%. The tissue cultured seedling was moved to sterile water for 5 d when the first leaf emerged and four adventitious roots appeared, then the seedling was transplanted into the soft soil. The tissue cultured seedling would grow strongly with 100% survival rate. Conclusion: The adventitious bud is inducted and then the root from bare-root seedling is cultured on the basis of obtained callus. Finally the best conditions to foster the tissue cultured seedling of P. polyphylla var. chinensis have been screened.

Effects of the 2, 4-D herbicide on gills epithelia and liver of the fish Poecilia vivipara / Efeitos do herbicida 2, 4-D no epitélio das brânquias e no fígado do peixe Poecilia vivípara

The 2,4-dichlorophenoxyacetic acid, usually named 2,4-D is one of the most widely used herbicides in the world. Acute toxicity of 2,4-D herbicide was investigated through its effects on guppies (Poecilia vivipara Bloch et Schneider 1801). Fish were exposed to the herbicide at concentrations of 10, 20 and 40µl per liter of water for 24 hours to determine its effects on gills and liver epithelia. The estimated LC50 was 34.64µl of 2,4-D per liter of water. Histochemical analyses and Feulgen's reaction were conducted to detect glycoconjugates and DNA, respectively, in gills and liver epithelia. Histochemistry revealed qualitative variations of glycoconjugates present on mucous cells and granules. The four types of mucous cells contained neutral granules, acids, or both. Increasing amounts of syalomucins were observed from the control group to the group exposed to the highest concentration of 2,4-D, suggesting increased mucous viscosity and the formation of plaques that could inhibit gas exchange and osmoregulation. Lamellar fusion observed in the group exposed to 40µl of 2,4-D suggests a defense mechanism. Hepatocytes showed vacuolization in the 10 and 20µl/L groups. The 40 µl/L group showed normal hepatocytes as well as changed ones, many Ito cells, micronuclei, and nuclear swelling. These effects may be associated with toxicity or adaptative processes to cellular stress. The data from this study indicates the importance of assessing similar risks to aquatic species and suggests that Poecilia vivipara is an adequate biological model for analysis of environmental contamination.

A toxicidade aguda do herbicida 2,4-D foi investigada através dos efeitos no peixe Poecilia vivípara (Bloch et Schneider, 1801). Grupos de peixes foram expostos ao herbicida nas concentrações de 10, 20 e 40µl por litro de água, durante 24 horas. As brânquias e o fígado foram estudados. A concentração letal média (CL50) do herbicida para a espécie em questão foi de 34,64µl/l. Foram realizadas colorações histoquímicas e coloração de Feulgen para identificar glicoconjugados e DNA, respectivamente, nos tecidos acima citados. Os métodos histoquímicos revelaram os tipos de glicoconjugados presentes nas células mucosas e nos grânulos. Os quatro tipos de células mucosas apresentaram glicoconjugados neutros, ácidos, ou ambos em um mesmo tipo celular. Observou-se a presença crescente de sialomucinas do grupo controle até o grupo exposto a maior concentração de 2,4-D, sugerindo aumento da viscosidade do muco e, consequentemente, formação de placas que impedem as trocas gasosas e a osmorregulação. A fusão lamelar observada no grupo exposto a 40µl de 2,4-D sugere ser um mecanismo de defesa. Os hepatócitos apresentaram processo de vacuolização nos grupos 10 e 20µl/l. No grupo de 40µl/l, observou-se a presença de células de Ito, micronúcleos e hepatócitos normais e outros com edema nuclear. Este estudo indica a importância da avaliação de riscos semelhantes a espécies aquáticas e sugere a espécie Poecilia vivipara como modelo biológico adequado para análises de contaminação ambiental.

Callus culture development of two varieties of Tagetes erecta and carotenoid production

Background The properties of natural pigments, such as antioxidants, functional, medical, and nutraceutical, have demonstrated the advantages of these natural compounds over synthetic ones. Some products are accepted only when they are pigmented with natural, food-quality colorants: for example poultry products (manly marigold flower extracts). Carotenoids such as β-carotene, β-criptoxanthin and lutein are very attractive as natural food colorants due to their antioxidant and pro-vitamin activities which provide additional value to the target products. Marigold (Tagetes erecta) is an Asteraceous ornamental plant native to Mexico, and it is also important as a carotenoid source for industrial and medicinal purposes but nowadays its production is destined mainly for ornamental purposes. Results Friable callus of T. erecta yellow flower (YF) and white flower (WF) varieties was induced from leaf explants on Murashige and Skoog (MS) medium supplemented with 9.0 µM 4-dichlorophenoxyacetic acid (2,4-D) and 8.8 µM benzyladenine (BA). Calluses developed from both varieties were different in pigmentation. Extract characterization from callus cultures was carried out by high-performance liquid chromatography (HPLC). This analytical process detected several carotenoids; the main pigments in extracts from YF callus were lutein and zeaxanthin, whereas in the extracts of the WF callus the main pigments were lutein, zeaxanthin, β-cryptoxanthin and β-carotene. Callus cultures of T. erecta accumulated pigments even after several rounds of subculture. Conclusions WF callus appeared to be a suitable candidate as a source of different carotenoids, and tested varieties could represent an alternative for further studies about in vitro pigment production.

Antioxidant enzmmes activity in embryogenic and non-embryogenic tissues in sugarcane / Actividad de enzimas antioxidantes en tejidos embriogénicos y no embriogénicos de caña de azúcar

The objective of this work was to induce direct somatic embryogenesis from segments of immature leaves of the RB872552 variety of sugarcane and to correlate this morphogenic event with oxidative stress. Two previously described protocols were utilized for the induction of somatic embryogenesis in sugarcane with different supplementations of the culture medium and different incubation conditions. For the conversion of embryos into plants was used MS medium without phytoregulators. Histological analyses and activity of antioxidant enzymes were also conducted for the embryogenic and non-embryogenic tissues. The formation of somatic embryos was obtained in 81 % of the explants with the combination of regulators 2,4-D (2,4-dichlorophenoxyacetic acid)and BAP (6-benzylaminopurine) when incubated under 16 h photoperiod. With regards to the antioxidant enzymes, there was increased activity of peroxidase and an increase in the soluble protein content in embryogenic tissues, whereas lower activities of polyphenol oxidase and catalase appeared in these tissues compared to nonembryogenic tissues. It could be inferred that oxidative stress plays an important role in the induction of somatic embryogenesis in sugarcane.

El objetivo de este trabajo fue inducir la embriogénesis somática directa en segmentos de hojas jóvenes en la variedad de caña de azúcar RB872552, e investigar la correlación de este evento morfogénico con el estrés oxidativo. Se utilizaron dos protocolos de inducción de embriogénesis somática, previamente descritos para caña de azúcar, con distintas suplementaciones en el medio de cultivo y en las condiciones de incubación. Para la conversión de embriones en plantas se utilizó el medio MS sin fitoreguladores. Se realizaron además análisis histológicas y de actividad enzimática antioxidante en tejidos embriogénicos y no embriogénicos. La formación de embriones somáticos ocurrió en 81 % de los explantes, con la combinación de los reguladores de crecimiento 2,4-D (ácido 2,4-diclorofenoxiacético) y BAP (6-bencilaminopurina) e incubación bajo un fotoperiodo de 16 h. Respecto a las enzimas antioxidantes, se observó un incremento en la actividad de peroxidasa y en el contenido de proteínas solubles en los tejidos embriogénicos, mientras que la polifenoloxidasa y la catalasa presentaron valores más bajos de actividad en estos tejidos, en comparación con los no embriogénicos. Se podría inferir que el estrés oxidativo juega un papel importante en la inducción de la embriogénesis somática en caña de azúcar.

Reproductive toxicity of 2,4-D butylate to male mice / 中国比较医学杂志

Objective To explore the reproductive toxicity of 2,4-D butylate to the testis in male mice.Methods Forty-eight ICR male mice were randomly divided into four groups : the control group, and three 2,4-D butylate experimental groups (10, 20, 40 mg/kg), 12 mice in each group.2,4-D butylate was intragastrically administered once a day and six days per week for five weeks .At the end of the exposure, the activities of total antioxidant capacity (T-AOC), Na+ K+-ATPase, Ca+ + Mg+ +-ATPase, lactate dehydrogenase (LDH) and succinate dehydrogenase (SDH) in testis homogenate were measured by spectrophotometry .Results The activity of T-AOC was gradually decreased with the increase of doses, with a significant difference between the high dose group and other groups .The activities of LDH in the moderate and high dose groups were significantly lower than those of the low dose group and control group , and there was a significant difference between the high dose group and moderate dose group .The activities of SDH in the testis was gradually decreased with the increase of the 2,4-D butylate dose, showing significant differences between the high dose group and the moderate dose and control groups , and between the high and moderate dose groups and the low dose group . The activities of Na +K +-ATPase in the moderate and high dose groups were significantly lower than that of the control and low dose group.The activities of Ca++Mg++-ATPase was significantly lower in the experimental groups than that in the control group.Conclusion Exposure to 2,4-D butylate has certain toxic effect on the testicular tissue in male mice .

Somatic embryogenesis of Neoglaziovia variegata (Arruda) Mez, an important source of fiber from native Brazilian bromeliads

Neoglaziovia variegata (Arruda) Mez, a Bromeliad endemic to the Brazilian Caatinga and source of fiber for many different products, is considered an endangered species. Leaf and stem segments were cultivated on Murashige and Skoog (MS) medium with combinations of 2,4- dichlorophenoxyacetic acid (2,4-D) (0, 9, 18 and 27 µM) and glutamine (0, 50, 100, 150, 200 mg L-1) for the induction of embryogenic calli. Leaf segments did not present a favorable response for the combinations analyzed. The best response for embryogenic calli frequency with the best distribution of somatic embryos on the surface and better conversion rate was obtained using the stems explants in the medium containing 18 µM 2,4-D and 100 mg L-1 glutamine. The embryogenic calli obtained from the different induction media were transferred to MS medium supplemented with 30 g.L-1 sucrose, 2.4 g.L-1 Phytagel®, 0.53 µM α-naphthalene acetic acid (NAA) and 0.88 µM of 6-benzylaminopurine (BAP). The regenerated plants presented normal growth; however, many embryos did not fully develop.

Effects of the ingestion of 2, 4 Dichlorophenoxyacetic acid on jejunal myenteric neurons in rats

2,4 dichlorophenoxyacetic acid (2,4-D) is a systemic herbicide. The effects of different levels of 2,4-D on some animal organ systems have been examined, but little is known about its role in the enteric nervous system. The purpose of this study was to verify the effects of 2,4-D administration on the density and morphometry of jejunal myenteric neurons in rats. Ten male rats were assigned to control (C) and experimental (E) groups. For 15 days, group E received, via gavage, 5 mg of 2,4-D.kg–1 body weight. On the 16th day, the animals were sacrificed by a lethal dose of thiopental, and the jejunum was removed by laparotomy and used to obtain whole mount preparations for Giemsa staining and NADPH-diaphorase (NADPHd+) histochemistry to identify neurons. The density and cell body area of the myenteric neurons was measured. In the total neuronal population, the neuronal density/mm2 of the jejunum in groups E and C was equivalent, and the cell body area of the rats in group E was lower (p < 0.05) than that of those in group C. For NADPHd+ neurons, the neuronal density did not differ between the groups, although the cell body area was larger (p < 0.05) in group E. It was concluded that even though 2,4-D does not alter the neuronal density in the rat jejunum, it induces cell body atrophy in the general population of neurons and hypertrophy of the NADPHd+ nitric oxide producing neurons without promoting cell death.

Establishment of an efficient callus induction and plant regeneration system in Pakistani wheat (Triticum aestivum) cultivars

Four commercially grown wheat varieties of Pakistan, namely Inqilab-91, Chakwal-97, Tatara and Manthar were used for this investigation. For callus induction different concentrations of 2,4-Dichlorophenoxyaceticacid (2,4-D) along with 0.1 mg/L of Kinetin were evaluated. For regeneration initially different concentrations of Indole-3-Acetic Acid (IAA) and 6-BenzylAminoPurine (BAP) were tested. Best hormone combinations were further subjected to Kinetin and 6-ã-ã-dimethylallylaminopurine (2iP). For Inqilab-91, Chakwal-97 and Manthar, 3 mg/L of 2,4-D was found optimum, which induced 83.25 percent, 77.75 percent and 95.20 percent of embryogenic calli, respectively. Maximum callus induction (97.18 percent) was observed in Tatara when 2 mg/L of 2,4-D was used. As regard to regeneration, Inqilab-91, Chakwal-97 and Manthar showed maximum regeneration on media containing 0.1 mg/L IAA, 0.4 mg/L Kinetin and 0.5 mg/L 2iP, regenerating 87.25 percent, 81.75 percent and 68.75 percent respectively. For Tatara maximum regeneration of 12.25 percent was obtained on 0.1 mg/L IAA and 2 mg/L of BAP. Presently optimized regeneration method holds promise for facilitating the deployment of agronomical important trait through genetic transformation for the improvement of this important food crop.

Toxicity of herbicides to cyanobacterial isolates.

The herbicides most commonly used in Turkey are trifluralin (a,a,a-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine), 2,4-D (2,4- dichlorophenoxyacetic acid), and linuron [3-(3,4-dichlorophenyl)-N-methoxy-N-methylurea]. The effects of these three herbicides on the growth of 10 threatened aquatic cyanobacterial isolates were tested by using 9-day exposure experiments at concentrations of 50-200 mg l-1 for trifluralin and 2,4-D and 0.05-1 mg l-1 for linuron. Concentrations of herbicides that elicited a 50% growth reduction over 9 days (EC50) were 136-882 mg l-1 trifluralin, 122-747 mg l-1 2,4-D, and 0.002-0.714 mg l-1 linuron. Synechocystis sp. H6 was more tolerant to the three herbicides than the other isolates of cyanobacteria. Chroococcus sp. S27 , Microcystis sp. S17 , and Synechococcus sp. S24 were the most sensitive to trifluralin, 2,4-D, and linuron, respectively. There has been increasing awareness about using cyanobacteria as pollution control agents. The present study indicated that as the concentrations of the these herbicides were increased, significant changes were recorded in cyanobacterial growth rates. Results obtained from this comparative study allow the choice of suitable herbicides for agricultural practices based on their effects on cyanobacterial growth.

Calogênese e teores de fenóis e tatinos totais em barbatimão [stryphnodendron adstringens (Mart. ) coville] / Callogenesis and contents of total phenols and tannins in barbatimão [Stryphnodendron adsrtingens (Mart. ) Coville]

Atualmente, culturas de células ou de suspensões celulares têm sido frequentemente empregadas para produzir fitoterápicos com maiores concentrações de princípios ativos. O barbatimão é uma importante espécie medicinal do Cerrado, com taninos nas cascas do caule. Objetivando-se induzir calos em barbatimão e avaliar os teores de fenóis e taninos totais, explantes foliares foram inoculados em meio MS suplementado com 30 g L-1 sacarose e acrescidos de 2,4-D (0; 4,52; 9,05; 18,10 μM ) e BAP (0; 4,44; 8,88; 17,75 μM ), na presença e ausência de luz. A calogênese ocorreu em meios contendo 2,4-D, na presença de luz. O número de calos não variou com as concentrações de 2,4-D e maiores valores de matérias fresca e seca de calos e teores de fenóis totais foram observados em meios com 9,05 μM e 18,10 μM de 2,4-D, na presença e ausência de luz. Com BAP, a calogênese ocorreu na ausência de luz, com maior produção de calos na presença de 4,44 e 8,88 μM de BAP e maiores valores de matéria fresca e seca em meios com 4,44 μM de BAP. Calos crescidos em meios suplementados 4,44 e 17,75 μM de BAP apresentaram maiores teores de fenóis totais. Não se detectaram taninos, independente do regulador empregado.

Recently, cell cultures and cell suspensions have been frequently employed to produce phytotherapics with high amounts of active principles. Barbatimão is a native species from the Cerrado, with tannins in the stem bark. In order to induce callus in barbatimão and evaluate the content of total phenols and tannins, leaf explants were inoculated on MS medium, supplemented with sucrose 30 g L¹ and 2,4-D (0, 4.52, 9.05, 18.10 μM ) and BA (0, 4.44, 8.88, 17.75 μM ), in the presence and absence of light. The callogenesis occurred on medium containing 2,4-D, in the presence of light. The callus number did not alter with the different concentrations of 2,4-D but higher values of dry and fresh matter of the callus and total phenol contents were observed in medium with 9.05 μM and 18.10 μM of 2,4-D, independently of the light treatment. In treatments with BA, the callogenesis occurred in the absence of light and higher callus induction was observed in medium supplemented with 4.44 and 8.88 μM BA in the absence of light and higher values of dry and fresh matter of the callus were observed in medium increased with 4.44 μM BA. Callus grown on medium supplemented with 4.44 and 17.75 μM BA showed higher total phenol content. Tannins were not detected independently of the regulator used.

Efecto del herbicida ácido 2, 4-Diclorofenoxiacético sobre la fimbriación de bacterias uropatógenas / Effect of the herbicide 2, 4-Dichlorophenoxyacetic acid on fimbriation of uropathogenic bacteria

Existen algunos datos epidemiológicos que demuestran que, en poblaciones rurales, la frecuencia de lesiones inflamatorias de origen infeccioso en el riñón es mayor en individuos expuestos a pesticidas. Estudios previos han demostrado que el herbicida 2,4-D altera las propiedades de adherencia bacteriana a riñón, mediada por fimbrias de Escherichia coli uropatógena, si bien aún no se ha estudiado el mecanismo que podría estar involucrado. El 2,4-D demostró capacidad de generar uniones covalentes a proteínas de bacilos gram negativos. Debido a este hallazgo, se hipotetizó que la unión del herbicida a proteínas involucradas en la síntesis, exportación o ensamble de las subunidades fimbriales podía alterar la expresión de las fimbrias. En este trabajo se demuestra una unión covalente del herbicida a proteínas de membrana externa de Escherichia coli uropatógena y paralelamenteuna disminución de la fimbriación, determinada por tres técnicas diferentes: hemoaglutinación, cuantificación de proteínas de superficie y microscopía electrónica. Una conclusión importante está referida a que la exposición accidental detrabajadores rurales al 2,4-D en muy bajas dosis y durante un corto período de tiempo tendría un efecto protector de la pielonefritis por disminución de la fimbriación; mientras que los altos niveles de exposición predispondrían a la recurrencia del proceso infeccioso en el modelo de la pielonefritis ascendente no obstructiva en ratón (Balagué et al 2002). Probablemente los estudios epidemiológicos que asocian exposición a los herbicidas e infección renal estén relacionados con este último tipo de exposiciones.

Epidemiological data demonstrate, on rural populations, that the frequency of inflammatory lesions in renal tissue is higher for individuals exposed to pesticides. Previous studies demonstrated that the herbicide 2,4-D altered the bacterial adherence properties to renal tissue, mediated by fimbriae in uropathogenic Escherichia coli, but the mechanism involved is still unknown. The acid 2,4-D has the ability to perform covalent bonds to proteins in gram-negative bacteria. Because of this fact, we hypothesized that the 2,4-D acid binds proteins involved in the synthesis, export or ensemble of fimbrial subunits, modifying fimbrial expression. In this work we demonstrated a covalent bond of the herbicide to outer membrane proteins in uropathogenic E. coli and a paralleldecrease of fimbriation, assayed by three different methods: hemmaglutination, surface protein quantification and electronmicroscopy. An important conclusion is that the accidental exposure of rural workers to 2,4-D may have a protective effect by a decrease in fimbriation, when it is used in low doses and during a short period of exposure. But, it must be considered that high doses and several days of exposure had adverse effects, like recurrence of infection, in the mouse model of ascendingpyelonephritis (Balagué et al, 2002). Probably, the epidemiological studies that associate the herbicide exposure with renal infection were due to the last kind of exposure described.

Acute eye irritation study of a mixture of glyphosate isopropylamine salt and 2,4 D-isopropylamine.

This is an acute irritation study of the eye of a mixture of herbicides containing 240 g/l of glyphosate isopropylamine and 2,4 D-isopropylamine in the rabbits. This study was conducted according the methods as dercribed by the United States Environmental Protection Agency (EPA). Our results show that the combination of the herbicides causes mild conjunctivitis, mild chemosis, eye discharge and corneal injury. The ocular alteration, however, was reversible in nature.

Somatic embryogenesis from petiole in Eleutherococcus senticosus / 中草药

Objective The petiole of Eleutherococcus senticosus was used as somatic embryo,which is widely original plants with the pharmacological active components whose contents could be determined,the somatic embryo in E.senticosus was studied,the aim of this study is to provide the proof of E.senticosus species which have the higher yield of pharmacological active components.Methods Using the petiole of E.senticosus of three years old plants germinated somatic embryos within 15 d to observe the somatic embryogenesis of E.senticosus with the 2,4-D+BA medium.Results After cultured for 28 d with 2,4-D 1.5 mg/L+BA 1.0 mg/L,71.4% of the petiole somatic embryos were directly produced or 8.5 embryos in total were produced via callus.Both of the two methods could be used in the elicitation medium,but the percentage of indirect production was smaller.After transforming into the same or the lower concentration of 2,4-D medium,the somatic embryos gradually matured.At the same time,those of the new somatic embryos were also produced,the percentage of the somatic embryos which were produced by indirect way was increased with it.Conclusion Using the petiole of E.senticosus germination within 15 d could make somatic embryogenesis.It confirms that the somatic embryogenesis and the bodybmeryos inductivity depend on the 2,4-D and BA concentration.