Rhizosphere-associated microbiota of Canavalia ensiformis in sulfentrazone bioremediation.

The objective of this study was to determine the efficiency of the microbial rhizosphere (Canavalia ensiformis) in the phytoremediation of sulfentrazone using quantification methods (CO2 evolution, microbial biomass carbon, and metabolic quotient) and identification of bacteria (PCR-DGGE technique). The experiment was conducted in a completely randomized design, in a 2x4 factorial scheme, with four replications. The treatments were composed of rhizospheric soil (cultivated with C. ensiformis) and non-rhizosphere soil (uncultivated soil); and four levels of contamination by sulfentrazone (0, 200, 400, and 800 g ha-1 a.i.). The microbiota associated with the rhizosphere of C. ensiformis efficiently reduced sulfentrazone residues in the soil, with better performance at the dose of 200 g ha-1 a.i. Using the PCR-DGGE technique allowed the distinction of two profiles of bacteria in the rhizospheric activity of C. ensiformis. The second bacterial profile formed was more efficient in decontaminating soil contaminated with sulfentrazone residue. The microbiota associated with the rhizosphere of C. ensiformis has an efficient profile in decontaminating soils with residues equivalent to 200 g ha-1 a.i. the herbicide sulfentrazone.

Phytoremediation of soils contaminated with herbicide residues is a viable technique for decontamination of the environment.Canavalia ensiformis has an efficient profile in the decontamination of soils with residue equivalent to 200 g ha⁻¹ a.i. of the herbicide sulfentrazone.The PCR technique and microbial respiration used to analyze the diversity and estimate the bacterial population of a soil are viable tools to evaluate the phytoremediation potential of the microbiota associated with plant species.

Crops with potential for diclosulam remediation and concomitant bioenergy production.

The objective of this work was to evaluate crops for their ability to phytoremediate diclosulam residues in the soil and produce lignocellulosic ethanol. Physiological characteristics, biomass production, soil cover rate, fermentable sugar production and lignocellulosic ethanol production potential of the crops were evaluated in soil with diclosulam residues. The experimental design was a randomized block with four replications. The treatments were arranged in a 4 × 2 factorial scheme with the following crops as the first factor: Avena sativa, Canavalia ensiformis, Mucuna aterrima, and Pennisetum glaucum. The second factor was the presence or absence of the herbicide diclosulam in the soil (30 g ha-1). The physiological variables of the plant species were not affected by the presence of diclosulam; the soil cover of P. glaucum was lower in the area with diclosulam, with a value of 26%. The levels of glucose were not affected by the presence of diclosulam in A. sativa, C. ensiformis, and M. aterrima, indicate not change the estimated yield of ethanol for this species. Avena sativa and Pennisetum glaucum have the potential to phytoremediate soils containing diclosulam residues, with concomitant lignocellulosic ethanol production ability.

Phytoremediation of soils with herbicide residues is a viable tool and has been increasingly widespread throughout the world. The use of plant species capable of making the soil feasible for successive plantings sensitive to previously applied residual herbicides is a way to optimize agricultural production. However, there are few studies in which vegetable biomass used in the phytoremediation process is used. Thus, our study is innovative because it seeks to combine phytoremediation with the production of bioethanol, ensuring even more sustainable agriculture.

Potential Distribution of and Sensitivity Analysis for Urochloa panicoides Weed Using Modeling: An Implication of Invasion Risk Analysis for China and Europe.

Urochloapanicoides P. Beauv. is considered one of the most harmful weeds in the United States and Australia. It is invasive in Pakistan, Mexico, and Brazil, but its occurrence is hardly reported in China and European countries. Species distribution models enable the measurement of the impact of climate change on plant growth, allowing for risk analysis, effective management, and invasion prevention. The objective of this study was to develop current and future climate models of suitable locations for U. panicoides and to determine the most influential climatic parameters. Occurrence data and biological information on U. panicoides were collected, and climatic parameters were used to generate the Ecoclimatic Index (EI) and to perform sensitivity analysis. The future projections for 2050, 2080, and 2100 were modeled under the A2 SRES scenario using the Global Climate Model, CSIRO-Mk3.0 (CS). The potential distribution of U. panicoides coincided with the data collected, and the reliability of the final model was demonstrated. The generated model identified regions where the occurrence was favorable, despite few records of the species. Sensitivity analysis showed that the most sensitive parameters of the model were related to temperature, humidity, and cold stress. Future projections predict reductions in climate suitability for U. panicoides in Brazil, Australia, India, and Africa, and an increase in suitability in Mexico, the United States, European countries, and China. The rise in suitability of China and Europe is attributed to predicted climate change, including reduction in cold stress. From the results obtained, preventive management strategies can be formulated against the spread of U. panicoides, avoiding economic and biodiversity losses.

Mabea fistulifera and Zeyheria tuberculosa can be indicated for phytoremediation programs of soils contaminated with hormonal herbicides.

Hormone-like herbicides, used for large crops, can contaminate non-target areas with their waste. The objective of this study was to evaluate the tolerance of Mabea fistulifera and Zeyheria tuberculosa to 2,4-D + picloram herbicides by means of morphological and anatomical evaluations. The experiment was performed in a greenhouse in a 4 × 2 factorial scheme. The first factor was the control (without herbicide) and three doses (0.166; 0.333, and 0.666 L ha-1) of the herbicide Tordon® (402 g L-1 2,4-D + 103.6 g L-1 picloram) and the second factor, the species Mabea fistulifera and Zeyheria tuberculosa. The number of M. fistulifera leaves was lower after treatment with the highest dose of the 2,4-D + picloram mixture. The herbicide rates did not influence the number of Z. tuberculosa leaves. The higher dose of 2,4-D + picloram caused a more than 50% reduction in leaf area. Toxicity increased linearly as a function of the doses of the 2,4-D + picloram mixture. Changes in the leaf anatomy of the two species treated with herbicides were observed; however, the roots did not show any changes. Mabea fistulifera and Zeyheria tuberculosa can be recommended for phytoremediation programs in areas contaminated by the herbicides 2,4-D + picloram.

Phytoremediation of soils contaminated with herbicides is a recent and viable tool for environmental decontamination and for the protection of water resources. Mabea fistulifera and Zeyheria tuberculosa can be used to compose riparian forests and retain the arrival of herbicides in the water. Plant anatomy and morphological characteristics are viable tools to assess the tolerance and phytoremediation potential of plant species. Mabea fistulifera and Zeyheria tuberculosa are tolerant to the presence of hormonal herbicides. In this way, they can be used to recover natural areas close to the cultivation areas where the herbicides 2,4-D and picloram are used.

Morphoanatomical injuries in Pistia stratiotes L. (Araceae) as a result of exposure to clomazone in water.

Contamination of water sources due to herbicide is of great concern. Clomazone is a pesticide with a high contamination potential which could possibility lixiviate to water streams. Changes caused by residual herbicide include flora modifications which are generally detrimental for some species. The lack of morphological studies performed in aquatic plants exposed to herbicide-contaminated environments has encouraged the development of our research. For the first time, we present a study that aimed to evaluate leaf injuries visible to the naked eye as well as microscopical effects which may be caused by clomazone on Pistia stratiotes. Pistia stratiotes was subjected to five concentrations of clomazone. Our analysis showed leaf injuries, especially after 15 days of clomazone application. Hormesis was observed when the water lettuce was subjected to the lower concentrations. Total leaf area showed increase following by reduction while injured until reaching the highest concentration. Although the concentrations of clomazone tested in our study are not lethal to water lettuce, such herbicide have still caused morphoanatomical damages on leaves which advocates for the use of P. stratiotes as a bioindicator of the presence of herbicides such as clomazone in water.

Multivariate analysis reveals significant diuron-related changes in the soil composition of different Brazilian regions.

Sorption and desorption determine the amount of an herbicide in soil solution. Therefore, knowledge of the sorption and desorption coefficients in different soils is an essential factor to estimate the potential for environmental contamination by herbicides. We evaluated the feasibility of multivariate and linear discriminant analyses to predict the sorption and desorption capacity of a soil for diuron, one of the most used herbicides on sugarcane plantations. The adsorptive capacity in twenty-seven Brazilian soil samples was estimated using the sorption constant (Kfs) and desorption constant (Kfd) obtained by the Freundlich isotherms. The regression model was created from the sorbed and nonsorbed concentrations of diuron in soils. Ultra-performance liquid chromatography was applied to quantify the diuron concentrations. The multivariate analysis separated the soils into four groups considering the similarity of the following attributes: pH, organic matter, clay, and base saturation. The groups showed a similar pattern of sorption and desorption for diuron: Lom-Lclay: low sorption (5.9 ± 1.2) and high desorption (10.9 ± 0.6); Lclay: low sorption (7.5 ± 1.1) and high desorption (11.4 ± 1.3); Hom-Hclay: high sorption (11.2 ± 1.2) and low desorption (13.8 ± 1.2); HpH-Hclay: high sorption (10.1 ± 1.1) and medium desorption (11.5 ± 1.4). Linear discriminant analysis of these soil attributes was used to classify other soils described in the literature with adsorption capacity. This analysis was able to identify soils with high and low sorption using the pH, organic matter, clay, and base saturation, demonstrating the enormous potential of the technique to group soils with different contamination risks for subterranean waters. Sugarcane crops in northeastern Brazil showed a higher pollution risk through the leaching of diuron. Multivariate analysis revealed significant diuron-related changes in the soil composition of different Brazilian regions; therefore, this statistical analysis can be used to improve understanding of herbicide behavior in soils.

Tolerance to the herbicide clomazone and potential for changes of forest species / Uso de espécies florestais para diminuição do resíduo de clomazone no ambiente

Clomazone has excelled among Brazilian non-target-site herbicides with high environmental impact. Its high solubility in water can result in leaching, contaminating groundwater and watercourses with possible riparian forest degradation. This situation can be mitigated by phytoremediation process. This study aimed to identify tree species tolerant to clomazone aiming to use them in bioremediation programs. Twelve forest species were evaluated: Inga marginata Willd, Handroanthus serratifolius (A.H. Gentry) S. Grose, Jacaranda puberula Chan, Cedrela fissilis Vell, Calophyllum brasiliense Cambess, Psidium myrsinoides Berg, Tibouchina granulosa Cogn, Caesalpinia ferrea Mart ex. Tul, Caesalpinia pluviosa DC, Terminalia argentea Mart & Zucc, Schinopsis brasiliensis Eng and Schizolobium parahyba (Vell). The statistical analysis was performed in a completely randomized block design with four replications. Three clomazone applications were made each 20 days (60, 80 and 100 days after planting); each application was equivalent to one-half of the recommended rate (2.0 L ha-1). The evaluated parameters were plant height, stem diameter, leaf number, leaf area and dry biomass. The forest species survived the clomazone application; and I. marginata, C. ferrea and S. brasiliensis showed increased tolerance to this herbicide, demonstrating potential for phytoremediation of areas contaminated by clomazone.

Entre os herbicidas com elevado impacto ambiental em sítios não alvo no Brasil, o clomazone tem se destacado. A alta solubilidade desse herbicida em água pode resultar em lixiviação, ocasionando contaminação de mananciais de água subterrânea e cursos d'água, com possível degradação de matas ciliares. Esta circunstância pode ser mitigada por meio de processos de fitorremediação. Este trabalho objetivou identificar espécies arbóreas tolerantes ao clomazone visando utiliza-las em programas de biorremediação. Foram avaliadas doze espécies florestais: Inga marginata Willd, Handroanthus serratifolius (A.H. Gentry) S.Grose, Jacaranda puberula Chan, Cedrela fissilis Vell, Calophyllum brasiliense Cambess, Psidium myrsinoides Berg, Tibouchina granulosa Cogn, Caesalpinia ferrea Mart ex. Tul, Caesalpinia pluviosa DC, Terminalia argentea Mart & Zucc, Schinopsis brasiliensis Eng e Schizolobium parahyba (Vell) Blake. Foi utilizado o delineamento em blocos ao acaso com quatro repetições. Foram feitas 3 aplicações do herbicida clomazone com intervalos de 20 dias (aos 60, 80 e 100 dias após o plantio), cada aplicação foi correspondente a metade da dose comercial de 2.0 L ha-1. Foram avaliados a altura da planta, o diâmetro do caule, o número de folhas, a área foliar e o acúmulo de biomassa seca. Constatou-se que todas as espécies sobreviveram à aplicação de clomazone, contudo I. marginata, C. ferrea e S. brasiliensis apresentaram maior tolerância ao herbicida, demonstrando potencial para o uso em programas de fitorremediação de áreas contaminadas pelo clomazone.

Aspectos biológicos de Tetranychus ludeni Zacher, 1913 (Acari: Tetranychidae) alimentados com folhas de batata-doce pulverizadas com o 2,4-D / Biological aspects of Tetranychus ludeni Zacher, 1913 (Acari: Tetranychidae) fed on sweet potato leaves sprayed with 2,4-D

Batata-doce [Ipomoea batatas (L.) Lam.] apresenta grande versatilidade de usos no Brasil. Com a ampliação das áreas de cultivo, essa espécie estará sujeita à contaminação por herbicidas. Eventualmente, organismos não alvos podem ser expostos aos resíduos. O objetivo deste trabalho foi avaliar aspectos biológicos do ácaro Tetranychus ludeni alimentado com folhas de batata-doce pulverizadas com diferentes doses do herbicida 2,4-D. O experimento foi conduzido no Laboratório de Controle Biológico da Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM), em Diamantina, Minas Gerais. Foram utilizadas 175 fêmeas de T. ludeni e 6 doses de 2,4-D, em g.ha-1 (8,06; 20,15; 40,30; 80,60; 201,50; e 806,00), mais o tratamento-controle com água destilada. Adotou-se delineamento inteiramente casualizado, com sete tratamentos e cinco repetições, contendo cinco fêmeas de T. ludeni em cada repetição. Foram avaliados a mortalidade inicial do ácaro em 24 h, o número de ovos, as ninfas e a longevidade das fêmeas. Os dados foram submetidos à análise de variância, sendo as médias significativas analisadas pelo teste de Duncan. Observou-se que doses maiores desse herbicida podem aumentar a mortalidade e reduzir a longevidade das fêmeas de T. ludeni.

Sweet potato [Ipomoea batatas (L.) Lam.] presents great versatility of uses in Brazil. With the expansion of crop areas, this species is subject to contamination by herbicides. Eventually, non-target organisms can be exposed to residues . The aim of this study was to evaluate biological aspects of the mite Tetranychus ludeni fed on sweet potato leaves sprayed with different doses of the herbicide 2,4-D. The experiment was conducted at the Biological Control Laboratory of Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM), Diamantina, Minas Gerais, Brazil. Altogether, 175 females of T. ludeni and six doses of 2,4-D, in g.ha-1 (8.06, 20.15, 40.30, 80.60, 201.50, and 806,00) were used, plus the control done with distilled water. It was adopted a completely randomized design with seven treatments and five replications with five females each. Early mortality of T. ludeni (24 h), the number of eggs, nymphs and longevity of females were evaluated. Data were subjected to analysis of variance, being the significant mean analyzed by Duncan test. It was observed that high doses of the herbicide may increase the mortality and decrease longevity of females of T. ludeni.

Aspectos biológicos de Tetranychus ludeni Zacher, 1913 (Acari: Tetranychidae) alimentados com folhas de batata-doce pulverizadas com o 2,4-D / Biological aspects of Tetranychus ludeni Zacher, 1913 (Acari: Tetranychidae) fed on sweet potato leaves sprayed with 2,4-D

Batata-doce [Ipomoea batatas (L.) Lam.] apresenta grande versatilidade de usos no Brasil. Com a ampliação das áreas de cultivo, essa espécie estará sujeita à contaminação por herbicidas. Eventualmente, organismos não alvos podem ser expostos aos resíduos. O objetivo deste trabalho foi avaliar aspectos biológicos do ácaro Tetranychus ludeni alimentado com folhas de batata-doce pulverizadas com diferentes doses do herbicida 2,4-D. O experimento foi conduzido no Laboratório de Controle Biológico da Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM), em Diamantina, Minas Gerais. Foram utilizadas 175 fêmeas de T. ludeni e 6 doses de 2,4-D, em g.ha-1 (8,06; 20,15; 40,30; 80,60; 201,50; e 806,00), mais o tratamento-controle com água destilada. Adotou-se delineamento inteiramente casualizado, com sete tratamentos e cinco repetições, contendo cinco fêmeas de T. ludeni em cada repetição. Foram avaliados a mortalidade inicial do ácaro em 24 h, o número de ovos, as ninfas e a longevidade das fêmeas. Os dados foram submetidos à análise de variância, sendo as médias significativas analisadas pelo teste de Duncan. Observou-se que doses maiores desse herbicida podem aumentar a mortalidade e reduzir a longevidade das fêmeas de T. ludeni.(AU)

Sweet potato [Ipomoea batatas (L.) Lam.] presents great versatility of uses in Brazil. With the expansion of crop areas, this species is subject to contamination by herbicides. Eventually, non-target organisms can be exposed to residues . The aim of this study was to evaluate biological aspects of the mite Tetranychus ludeni fed on sweet potato leaves sprayed with different doses of the herbicide 2,4-D. The experiment was conducted at the Biological Control Laboratory of Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM), Diamantina, Minas Gerais, Brazil. Altogether, 175 females of T. ludeni and six doses of 2,4-D, in g.ha-1 (8.06, 20.15, 40.30, 80.60, 201.50, and 806,00) were used, plus the control done with distilled water. It was adopted a completely randomized design with seven treatments and five replications with five females each. Early mortality of T. ludeni (24 h), the number of eggs, nymphs and longevity of females were evaluated. Data were subjected to analysis of variance, being the significant mean analyzed by Duncan test. It was observed that high doses of the herbicide may increase the mortality and decrease longevity of females of T. ludeni.(AU)

Aspectos biológicos de Tetranychus ludeni Zacher, 1913 (Acari: Tetranychidae) alimentados com folhas de batata-doce pulverizadas com o 2,4-D / Biological aspects of Tetranychus ludeni Zacher, 1913 (Acari: Tetranychidae) fed on sweet potato leaves sprayed with 2,4-D

Batata-doce [Ipomoea batatas (L.) Lam.] apresenta grande versatilidade de usos no Brasil. Com a ampliação das áreas de cultivo, essa espécie estará sujeita à contaminação por herbicidas. Eventualmente, organismos não alvos podem ser expostos aos resíduos. O objetivo deste trabalho foi avaliar aspectos biológicos do ácaro Tetranychus ludeni alimentado com folhas de batata-doce pulverizadas com diferentes doses do herbicida 2,4-D. O experimento foi conduzido no Laboratório de Controle Biológico da Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM), em Diamantina, Minas Gerais. Foram utilizadas 175 fêmeas de T. ludeni e 6 doses de 2,4-D, em g.ha-1 (8,06; 20,15; 40,30; 80,60; 201,50; e 806,00), mais o tratamento-controle com água destilada. Adotou-se delineamento inteiramente casualizado, com sete tratamentos e cinco repetições, contendo cinco fêmeas de T. ludeni em cada repetição. Foram avaliados a mortalidade inicial do ácaro em 24 h, o número de ovos, as ninfas e a longevidade das fêmeas. Os dados foram submetidos à análise de variância, sendo as médias significativas analisadas pelo teste de Duncan. Observou-se que doses maiores desse herbicida podem aumentar a mortalidade e reduzir a longevidade das fêmeas de T. ludeni.(AU)

Sweet potato [Ipomoea batatas (L.) Lam.] presents great versatility of uses in Brazil. With the expansion of crop areas, this species is subject to contamination by herbicides. Eventually, non-target organisms can be exposed to residues . The aim of this study was to evaluate biological aspects of the mite Tetranychus ludeni fed on sweet potato leaves sprayed with different doses of the herbicide 2,4-D. The experiment was conducted at the Biological Control Laboratory of Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM), Diamantina, Minas Gerais, Brazil. Altogether, 175 females of T. ludeni and six doses of 2,4-D, in g.ha-1 (8.06, 20.15, 40.30, 80.60, 201.50, and 806,00) were used, plus the control done with distilled water. It was adopted a completely randomized design with seven treatments and five replications with five females each. Early mortality of T. ludeni (24 h), the number of eggs, nymphs and longevity of females were evaluated. Data were subjected to analysis of variance, being the significant mean analyzed by Duncan test. It was observed that high doses of the herbicide may increase the mortality and decrease longevity of females of T. ludeni.(AU)

Lethal concentration of glyphosate for juveniles of curimatã-pacu / Concentração letal do glifosato para juvenis de curimatã-pacu

This study aimed to determine the lethal concentration of glyphosate (CL50) for juveniles of curimatã-pacu, Prochilodus argenteus. The experiment was conducted in CODEVASF- Três Marias, MG, Brazil, during 96 h, using 240 juvenile fish (standard length 6.4 ± 8.47 cm and weight 8.98 ± 3.91 g), distributed in six herbicide concentrations: 0, 5, 10, 15, 20 and 40 mg.L-1 in a completely randomized design with four replications. Each 24 h was observed the animal's behavior and the mortality rate, and 48, 72 and 96 h CL50 was estimated. The CL50 of glyphosate at 48, 72 and 96 h were 20.88, 19.91 and 19.09 mg.L-1, respectively. The herbicide provoked lethargic swimming of the fish.

Neste trabalho objetivou-se determinar a CL50 do herbicida glifosato (CL50) para curimatã-pacu, Prochilodus argenteus. O experimento foi realizado na CODEVASF de Três Marias, MG, Brasil, onde teve a duração de 96 h, utilizando-se 240 juvenis de curimatãpacu (comprimento padrão de 6,4 ± 8,47 cm; e peso de 8,98 ± 3,91 g). Os animais foram submetidos a seis concentrações do herbicida: 0, 5, 10, 15, 20 e 40 mg.L-1 em delineamento inteiramente casualizado com quatro repetições cada. A cada 24 h foi observado o comportamento dos animais e a taxa de mortalidade, e em 48, 72 e 96 h foram estimadas as CL50. A CL50 de glyphosate em 48, 72 e 96 h foi 20,88; 19,91 e 19,09 mg.L-1, respectivamente. O herbicida provocou natação errática nos peixes.

Lethal concentration of glyphosate for juveniles of curimatã-pacu / Concentração letal do glifosato para juvenis de curimatã-pacu

This study aimed to determine the lethal concentration of glyphosate (CL50) for juveniles of curimatã-pacu, Prochilodus argenteus. The experiment was conducted in CODEVASF- Três Marias, MG, Brazil, during 96 h, using 240 juvenile fish (standard length 6.4 ± 8.47 cm and weight 8.98 ± 3.91 g), distributed in six herbicide concentrations: 0, 5, 10, 15, 20 and 40 mg.L-1 in a completely randomized design with four replications. Each 24 h was observed the animal's behavior and the mortality rate, and 48, 72 and 96 h CL50 was estimated. The CL50 of glyphosate at 48, 72 and 96 h were 20.88, 19.91 and 19.09 mg.L-1, respectively. The herbicide provoked lethargic swimming of the fish.(AU)

Neste trabalho objetivou-se determinar a CL50 do herbicida glifosato (CL50) para curimatã-pacu, Prochilodus argenteus. O experimento foi realizado na CODEVASF de Três Marias, MG, Brasil, onde teve a duração de 96 h, utilizando-se 240 juvenis de curimatãpacu (comprimento padrão de 6,4 ± 8,47 cm; e peso de 8,98 ± 3,91 g). Os animais foram submetidos a seis concentrações do herbicida: 0, 5, 10, 15, 20 e 40 mg.L-1 em delineamento inteiramente casualizado com quatro repetições cada. A cada 24 h foi observado o comportamento dos animais e a taxa de mortalidade, e em 48, 72 e 96 h foram estimadas as CL50. A CL50 de glyphosate em 48, 72 e 96 h foi 20,88; 19,91 e 19,09 mg.L-1, respectivamente. O herbicida provocou natação errática nos peixes.(AU)

Crescimento e nutrição de mudas de abacaxizeiro Imperial associadas com o fungo Piriformospora indica e aplicação de herbicidas / Growth and nutrition of Imperial pineapple nursery plants associated with the fungus Piriformospora indica and herbicide application

A baixa oferta de mudas sadias e com qualidade tem sido um obstáculo para o crescimento da abacaxicultura no Brasil. A pesquisa foi realizada com o objetivo de avaliar a associação micorrízica, o crescimento e absorção de nutrientes em mudas micropropagadas de abacaxizeiro Imperial inoculadas com o fungo Piriformospora indica em cultivo com a aplicação de herbicidas. Foi utilizado o esquema fatorial 2 x 4, sendo os fatores duas inoculações: mudas inoculadas com o fungo P. indica e sem inoculação e quatro doses de herbicidas: 0; 1,5; 3,0 e 6,0 L ha-1 para o ametryn, 0; 1,6; 3,2; 6,4 L ha-1 para o diuron e 0; 0,4; 0,8 e 1,6 L ha-1 para o sulfametrazone, distribuídos no delineamento inteiramente casualizado, com três repetições. As doses dos herbicidas foram aplicadas ao substrato antes do plantio das mudas. A inoculação com o fungo P. indica foi feita no momento do plantio, colocando-se no substrato discos de micélio de 5 mm, contendo estruturas fúngicas. Aos 150 dias após a inoculação foi feita a análise da colonização micorrízica, dos teores de N, P e K e do crescimento das mudas. Os dados foram submetidos à análise de variância, regressão polinomial e comparação de médias, a 5% de probabilidade. Foi observada a associação do fungo P. indica com as mudas de abacaxizeiro Imperial com a aplicação de todos os herbicidas. As mudas associadas com o fungo apresentaram maiores...(AU)

The low supply of healthy and quality nursery plants has been an obstacle to the growth of pineapple crop in Brazil. The research was carried out with the aim of evaluating mycorrhizal association, growth and nutrient uptake of Imperial micropropagated pineapple plants inoculated with the fungus Piriformospora indica in cultivation with herbicide application. The 2 x 4 factorial scheme was used, being the factors the two inoculations: inoculated nursery plants with the fungus P. indica and without inoculation and four doses of herbicides: 0, 1.5, 3.0 and 6.0 L ha-1 for ametryn, 0, 1.6, 3.2, 6.4 L ha-1 for diuron and 0, 0.4, 0.8 and 1.6 L ha-1 for sulfametrazone distributed in a completely randomized design with three replications. The doses of herbicides were applied to substrate before planting. The inoculation with the fungus P. indica was made at the time of planting, placing in the substrate 5 mm mycelial discs containing fungal structures. At 150 days after inoculation evaluations were made by analysis of colonization, determination of N, P and K levels and of nursery plants growth. Data were subjected to analysis of variance and regression. The association of fungus P. indica with Imperial pineapple nursery plants was observed with the application of all herbicides. Imperial pineapple nursery plants associated with P. indica fungus showed higher levels of nutrients...(AU)

Nicandra physalodes growth at different concentrations of N, P and K / Crescimento de Nicandra physalodes em resposta à adubação com N, P e K

Nicandra physalodes (L.) Gaertn. is a weed that frequently infests Brazilian agricultural areas. Knowledge of the plants response to competition, in the form of nutrient availability in soil, is fundamental to management of agroecosystems. This study aimed to evaluate the effect of concentrations of N, P and K on the growth of N. physalodes. The experiment was carried out in greenhouse conditions, using a randomized complete block design with split-plot arrangement (4 x 10), with three replications. The main plots were four combinations of N, P and K: (L1) 0, 0.3 and 17.2 mg dm-3; (L2) 30, 450.3 and 75.4 mg dm-3; (L3) 60, 900.3 and 133.4 mg dm-3; and (L4) 120, 1800.3 and 249.68 mg dm-3. Subplots were used for 10 different harvest times: 26, 33, 40, 47, 54, 61, 76, 91, 106 and 121 days after emergence (DAE). The dry matter, dry matter partitioning, leaf area, relative growth rate, height and photochemical efficiency of photosystem II were measured in N. physalodes plants at each harvest time. Overall, the leaves showed higher total dry matter accumulation up to 61 DAE. After that, the reproductive organs showed higher accumulation. Increasing concentrations of N, P and K resulted in higher plant height and dry matter of N. physalodes. Moreover, doubling the nutrient levels resulted in a proportional increase in dry matter accumulation. However, N. physalodes showed lower growth under natural soil fertility conditions (L1 treatment). Thus, increasing concentrations of N, P, and K promoted higher growth of N. physalodes. Biomass distribution was not changed by fertilization. There is evidence that N. physalodes could adapt easily in fertile soil. Thus, this species has greater competitive potential in high fertility soils.(AU)

A Nicandra physalodes (L.) Gaertn. é uma planta daninha que infesta com frequência áreas agrícolas brasileiras. O conhecimento do comportamento das plantas frente aos fatores de competição, como a disponibilidade de nutrientes no solo, é fundamental para direcionar o manejo dos agroecossistemas. Nesse contexto, objetivou-se avaliar o efeito de doses de N, P e K no crescimento de N. physalodes. O experimento foi conduzido em casa de vegetação, em delineamento de blocos casualizados arranjado em parcelas subdivididas, com três repetições. Nas parcelas foram aplicadas as doses de N, P e K: 0, 0,3 e 17,2 (D1); 30, 450,3 e 75,4 (D2); 60, 900,3 e 133,4 (D3); 120, 1800,3 e 249,68 mg dm-3 (D4) e nas subparcelas as épocas de colheita (26, 33, 40, 47, 54, 61, 76, 91, 106 e 121 dias após emergência (DAE)). Avaliou-se a matéria seca, área foliar, distribuição da matéria seca, taxa de crescimento relativo, altura e a eficiência fotoquímica do fotossistema II das plantas de N. physalodes. De maneira geral, as folhas apresentaram maior participação no acúmulo de matéria seca total até os 61 DAE; posteriormente, órgãos reprodutivos apresentaram maior participação. O aumento das doses de N, P e K proporcionou maior altura e produção de matéria seca da planta daninha, sendo que quando se dobrou as doses dos nutrientes aplicados observou-se aumento proporcional em acúmulo da matéria seca. Porém, ao ser cultivada nas condições de fertilidade natural do solo (tratamento D1), N. physalodes apresentou baixas taxas de crescimento. Conclui-se que o aumento das doses de N, P e K promove aumento do crescimento de N. physalodes, no entanto, o padrão de distribuição de biomassa não é alterado pela adubação. Essa espécie adapta-se bem a solos férteis, assim, pode-se considerar que a mesma tem maior potencial competitivo em solos de alta fertilidade.(AU)

Respostas fisiológicas da mandioca à aplicação de herbicidas / Cassava physiological responses to the application of herbicides

A análise da fluorescência da clorofila a vem sendo utilizada para melhorar o entendimento dos mecanismos da fotossíntese, bem como, na avaliação da capacidade fotossintética alterada por estresses bióticos ou abióticos. Objetivou-se com esse trabalho avaliar a sensibilidade de plantas de mandioca a herbicidas com diferentes mecanismos de ação, bem como, os danos causados pela aplicação desses herbicidas no aparato fotossintético destas plantas. Para isso foi montado um experimento no delineamento em blocos casualizados, com quatro repetições no arranjo fatorial (10 x 4), sendo  o primeiro fator referente aos herbicidas utilizados (bentazon, clomazone, fomezafen, fluazifop-p-buthyl, glyphosate, nicossulfuron, clorimuron, a mistura fluazifop-p-buthyl + fomesafen, sulfentrazone e  testemunha), o segundo fator às épocas de avaliação (aos 2, 9, 16 e 23 dias após a aplicação dos herbicidas). Os herbicidas avaliados afetaram de forma diferenciada as plantas de mandioca, sendo que, o glyphosate e sulfentrazone promoveram a morte das plantas. Os herbicidas clomazone, fomesafen, fluazifop-p-buthyl e chlorimuron-ehtyl causaram baixa intoxicação as plantas de mandioca e não afetaram a relação Fv/Fm e a ETR. No entanto, para o nicossulfuron e a mistura fluazifop-p-buthyl + fomesafen os valores da Fv/Fm estiveram abaixo do ideal nas primeiras épocas de avaliação mas as plantas tratadas com...(AU)

Analysis of chlorophyll a fluorescence has been used to improve the understanding of the mechanisms of photosynthesis, as well as in the evaluation of plant photosynthetic capacity altered by biotic or abiotic stresses. The objective of this study was to evaluate the sensitivity of cassava plants to herbicides with different mechanisms of action, as well as the damage caused by the application of herbicides on the photosynthetic apparatus of these plants. An experiment was conducted in a randomized block design with four replications. The treatments were constituted of the application of the following post- emergence herbicides in cassava: bentazon, clomazone, fomesafen, fluazifop-p-buthyl, glyphosate, nicosulfuron, chlorimuron, fluazifop-p-buthyl + fomesafen, sulfentrazone, besides a control without application. The visual intoxication and chlorophyll a fluorescence assessments were performed at 2, 9, 16 and 23 days after herbicide application. The herbicides evaluated affected differently the cassava plants. Sulfentrazone and glyphosate promoted plant death. Herbicides clomazone, fomesafen, fluazifop-p-buthyl and chlorimuron-ehtyl caused low toxicity to cassava plants and did not affect the ratio Fv / Fm and ETR. However, for the mixture nicossulfuron and fluazifop-p-buthyl + fomesafen values of Fv / Fm were suboptimal in the first evaluation times but plants treated with the...(AU)

Respostas fisiológicas da mandioca à aplicação de herbicidas / Cassava physiological responses to the application of herbicides

A análise da fluorescência da clorofila a vem sendo utilizada para melhorar o entendimento dos mecanismos da fotossíntese, bem como, na avaliação da capacidade fotossintética alterada por estresses bióticos ou abióticos. Objetivou-se com esse trabalho avaliar a sensibilidade de plantas de mandioca a herbicidas com diferentes mecanismos de ação, bem como, os danos causados pela aplicação desses herbicidas no aparato fotossintético destas plantas. Para isso foi montado um experimento no delineamento em blocos casualizados, com quatro repetições no arranjo fatorial (10 x 4), sendo  o primeiro fator referente aos herbicidas utilizados (bentazon, clomazone, fomezafen, fluazifop-p-buthyl, glyphosate, nicossulfuron, clorimuron, a mistura fluazifop-p-buthyl + fomesafen, sulfentrazone e  testemunha), o segundo fator às épocas de avaliação (aos 2, 9, 16 e 23 dias após a aplicação dos herbicidas). Os herbicidas avaliados afetaram de forma diferenciada as plantas de mandioca, sendo que, o glyphosate e sulfentrazone promoveram a morte das plantas. Os herbicidas clomazone, fomesafen, fluazifop-p-buthyl e chlorimuron-ehtyl causaram baixa intoxicação as plantas de mandioca e não afetaram a relação Fv/Fm e a ETR. No entanto, para o nicossulfuron e a mistura fluazifop-p-buthyl + fomesafen os valores da Fv/Fm estiveram abaixo do ideal nas primeiras épocas de avaliação mas as plantas tratadas com...

Analysis of chlorophyll a fluorescence has been used to improve the understanding of the mechanisms of photosynthesis, as well as in the evaluation of plant photosynthetic capacity altered by biotic or abiotic stresses. The objective of this study was to evaluate the sensitivity of cassava plants to herbicides with different mechanisms of action, as well as the damage caused by the application of herbicides on the photosynthetic apparatus of these plants. An experiment was conducted in a randomized block design with four replications. The treatments were constituted of the application of the following post- emergence herbicides in cassava: bentazon, clomazone, fomesafen, fluazifop-p-buthyl, glyphosate, nicosulfuron, chlorimuron, fluazifop-p-buthyl + fomesafen, sulfentrazone, besides a control without application. The visual intoxication and chlorophyll a fluorescence assessments were performed at 2, 9, 16 and 23 days after herbicide application. The herbicides evaluated affected differently the cassava plants. Sulfentrazone and glyphosate promoted plant death. Herbicides clomazone, fomesafen, fluazifop-p-buthyl and chlorimuron-ehtyl caused low toxicity to cassava plants and did not affect the ratio Fv / Fm and ETR. However, for the mixture nicossulfuron and fluazifop-p-buthyl + fomesafen values of Fv / Fm were suboptimal in the first evaluation times but plants treated with the...

Nicandra physalodes growth at different concentrations of N, P and K / Crescimento de Nicandra physalodes em resposta à adubação com N, P e K

Nicandra physalodes (L.) Gaertn. is a weed that frequently infests Brazilian agricultural areas. Knowledge of the plants response to competition, in the form of nutrient availability in soil, is fundamental to management of agroecosystems. This study aimed to evaluate the effect of concentrations of N, P and K on the growth of N. physalodes. The experiment was carried out in greenhouse conditions, using a randomized complete block design with split-plot arrangement (4 x 10), with three replications. The main plots were four combinations of N, P and K: (L1) 0, 0.3 and 17.2 mg dm-3; (L2) 30, 450.3 and 75.4 mg dm-3; (L3) 60, 900.3 and 133.4 mg dm-3; and (L4) 120, 1800.3 and 249.68 mg dm-3. Subplots were used for 10 different harvest times: 26, 33, 40, 47, 54, 61, 76, 91, 106 and 121 days after emergence (DAE). The dry matter, dry matter partitioning, leaf area, relative growth rate, height and photochemical efficiency of photosystem II were measured in N. physalodes plants at each harvest time. Overall, the leaves showed higher total dry matter accumulation up to 61 DAE. After that, the reproductive organs showed higher accumulation. Increasing concentrations of N, P and K resulted in higher plant height and dry matter of N. physalodes. Moreover, doubling the nutrient levels resulted in a proportional increase in dry matter accumulation. However, N. physalodes showed lower growth under natural soil fertility conditions (L1 treatment). Thus, increasing concentrations of N, P, and K promoted higher growth of N. physalodes. Biomass distribution was not changed by fertilization. There is evidence that N. physalodes could adapt easily in fertile soil. Thus, this species has greater competitive potential in high fertility soils.

A Nicandra physalodes (L.) Gaertn. é uma planta daninha que infesta com frequência áreas agrícolas brasileiras. O conhecimento do comportamento das plantas frente aos fatores de competição, como a disponibilidade de nutrientes no solo, é fundamental para direcionar o manejo dos agroecossistemas. Nesse contexto, objetivou-se avaliar o efeito de doses de N, P e K no crescimento de N. physalodes. O experimento foi conduzido em casa de vegetação, em delineamento de blocos casualizados arranjado em parcelas subdivididas, com três repetições. Nas parcelas foram aplicadas as doses de N, P e K: 0, 0,3 e 17,2 (D1); 30, 450,3 e 75,4 (D2); 60, 900,3 e 133,4 (D3); 120, 1800,3 e 249,68 mg dm-3 (D4) e nas subparcelas as épocas de colheita (26, 33, 40, 47, 54, 61, 76, 91, 106 e 121 dias após emergência (DAE)). Avaliou-se a matéria seca, área foliar, distribuição da matéria seca, taxa de crescimento relativo, altura e a eficiência fotoquímica do fotossistema II das plantas de N. physalodes. De maneira geral, as folhas apresentaram maior participação no acúmulo de matéria seca total até os 61 DAE; posteriormente, órgãos reprodutivos apresentaram maior participação. O aumento das doses de N, P e K proporcionou maior altura e produção de matéria seca da planta daninha, sendo que quando se dobrou as doses dos nutrientes aplicados observou-se aumento proporcional em acúmulo da matéria seca. Porém, ao ser cultivada nas condições de fertilidade natural do solo (tratamento D1), N. physalodes apresentou baixas taxas de crescimento. Conclui-se que o aumento das doses de N, P e K promove aumento do crescimento de N. physalodes, no entanto, o padrão de distribuição de biomassa não é alterado pela adubação. Essa espécie adapta-se bem a solos férteis, assim, pode-se considerar que a mesma tem maior potencial competitivo em solos de alta fertilidade.

Crescimento e nutrição de mudas de abacaxizeiro Imperial associadas com o fungo Piriformospora indica e aplicação de herbicidas / Growth and nutrition of Imperial pineapple nursery plants associated with the fungus Piriformospora indica and herbicide application

A baixa oferta de mudas sadias e com qualidade tem sido um obstáculo para o crescimento da abacaxicultura no Brasil. A pesquisa foi realizada com o objetivo de avaliar a associação micorrízica, o crescimento e absorção de nutrientes em mudas micropropagadas de abacaxizeiro Imperial inoculadas com o fungo Piriformospora indica em cultivo com a aplicação de herbicidas. Foi utilizado o esquema fatorial 2 x 4, sendo os fatores duas inoculações: mudas inoculadas com o fungo P. indica e sem inoculação e quatro doses de herbicidas: 0; 1,5; 3,0 e 6,0 L ha-1 para o ametryn, 0; 1,6; 3,2; 6,4 L ha-1 para o diuron e 0; 0,4; 0,8 e 1,6 L ha-1 para o sulfametrazone, distribuídos no delineamento inteiramente casualizado, com três repetições. As doses dos herbicidas foram aplicadas ao substrato antes do plantio das mudas. A inoculação com o fungo P. indica foi feita no momento do plantio, colocando-se no substrato discos de micélio de 5 mm, contendo estruturas fúngicas. Aos 150 dias após a inoculação foi feita a análise da colonização micorrízica, dos teores de N, P e K e do crescimento das mudas. Os dados foram submetidos à análise de variância, regressão polinomial e comparação de médias, a 5% de probabilidade. Foi observada a associação do fungo P. indica com as mudas de abacaxizeiro Imperial com a aplicação de todos os herbicidas. As mudas associadas com o fungo apresentaram maiores...

The low supply of healthy and quality nursery plants has been an obstacle to the growth of pineapple crop in Brazil. The research was carried out with the aim of evaluating mycorrhizal association, growth and nutrient uptake of Imperial micropropagated pineapple plants inoculated with the fungus Piriformospora indica in cultivation with herbicide application. The 2 x 4 factorial scheme was used, being the factors the two inoculations: inoculated nursery plants with the fungus P. indica and without inoculation and four doses of herbicides: 0, 1.5, 3.0 and 6.0 L ha-1 for ametryn, 0, 1.6, 3.2, 6.4 L ha-1 for diuron and 0, 0.4, 0.8 and 1.6 L ha-1 for sulfametrazone distributed in a completely randomized design with three replications. The doses of herbicides were applied to substrate before planting. The inoculation with the fungus P. indica was made at the time of planting, placing in the substrate 5 mm mycelial discs containing fungal structures. At 150 days after inoculation evaluations were made by analysis of colonization, determination of N, P and K levels and of nursery plants growth. Data were subjected to analysis of variance and regression. The association of fungus P. indica with Imperial pineapple nursery plants was observed with the application of all herbicides. Imperial pineapple nursery plants associated with P. indica fungus showed higher levels of nutrients...

Influência do tamanho do vaso e época de avaliação sobre o crescimento do picão preto em competição com milho e soja / Influence of the cup size and time of evaluation on growth black jack in competition with corn and soybean

A avaliação dos efeitos da competição das plantas daninhas sobre o crescimento de culturas como milho e soja é efetuada por meio de ensaios em ambientes protegidos para maior precisão experimental e segurança nos resultados obtidos. Esses ensaios geralmente são feitos em recipientes (vasos) onde se testam os efeitos desejados em épocas após plantio. O tamanho do vaso quando pequeno pode limitar o desenvolvimento da planta pelo volume de substrato neles contido. No entanto, essa limitação está diretamente relacionada às espécies em desenvolvimento e ao tempo de avaliação. Assim objetivou-se com este trabalho verificar o efeito do volume de vasos na capacidade competitiva das plantas de picão-preto, milho e soja em diferentes épocas de avaliação. O milho apresentou-se mais competitivo com o picão-preto que a soja tanto nos diferentes tamanhos de vaso quanto nas diferentes épocas. Dentro do intervalo testado, recomenda-se o uso de vasos com volume de 16 dm3, devido à baixa tendência de estabilização das curvas do modelo proposto. Por este motivo também, pode-se afirmar que intervalos iguais ou inferiores a 60 dias são inadequados para os ensaios de competição das plantas de picão-preto com milho ou soja.

The evaluation of the effects of weed competition on growth from crops like corn and soybeans is done by testing in protected environments for increased accuracy and confidence in experimental results. These tests are usually done in containers (pots) where they test their desired times after planting. The small size of the vessel when could limit development of the plant the volume of the substrate contained therein. However, this limitation is directly related to the species in the development and evaluation time. Thus the objective of this work is to verify the effect of the volume of vessels in the competitive ability of plants black jack, corn and soybean at different sampling times. The corn had become more competitive with black jack soybean so that the vessel in different sizes and at different times. Within the range tested, it is recommended the use of vessels with a volume of 16 dm 3, due to the low tendency to stabilize model curves. For this reason, too, can say what intervals not exceeding 60 days are inadequate for field trials of plants black jack with corn or soybeans.

Atividade microbiana do solo, controle de plantas daninhas e crescimento da mandioca após a aplicação de herbicidas / Soil microbial activity, weed control and growth of cassava after application of herbicide

São poucas as informações na literatura sobre herbicidas para aplicação em pós-emergência da cultura da mandioca e seus possíveis impactos na atividade microbiana do solo. Dessa forma, objetivou-se com este trabalho avaliar o efeito da aplicação de herbicidas pós-emergentes em área total e dirigida na atividade microbiana de solo cultivado com mandioca, bem como seu efeito no controle das plantas daninhas e no crescimento inicial da cultura. O experimento foi conduzido em campo, no Distrito do Planalto, na cidade de Diamantina-MG. O delineamento experimental utilizado foi o de blocos casualizados, com quatro repetições e os tratamentos foram constituídos de uma testemunha capinada, uma testemunha cultivada sem o controle de plantas daninhas e a aplicação dos herbicidas: fluazifop-p-butil, fomesafen, glyphosate, paraquat e a mistura de herbicidas fluazifop-p-butil + fomesafem. De maneira geral, os herbicidas estudados apresentaram controle satisfatório das plantas daninhas presentes na área de plantio e causaram baixa intoxicação visual à mandioca. A mistura dos herbicidas fomesafen e fluazifop-p-butil promoveram um controle mais prolongado das plantas infestantes, mas com influência negativa à microbiota do solo. Os herbicidas paraquat e glyphosate apresentaram potencial para aplicação dirigida nas entrelinhas da mandioca.

There is little information in the literature on herbicides for post-emergence application of cassava and its potential impacts on soil microbial activity. Thus, the aim of this work was to evaluate the effect of postemergence herbicides in total area and direct microbial activity in soil cultivated with cassava, as well as its effect on weed control and early growth of the crop. The experiment was conducted in the field, in the Planalto District, the city of Diamantina-MG. The experimental design was a randomized block with four replications and treatments were made up of one weed control, one control grown without weed control and herbicide application: fluazifop-p-butyl and fomesafen, glyphosate, paraquat and the mixture herbicide fluazifop-p-butyl + fomesafem. In general, the herbicides showed satisfactory control of weeds in the planting area and caused low toxicity to visual cassava. The mixture of herbicides fomesafen and fluazifop-p-butyl promoted a more prolonged control of weeds, but with negative influence on soil microbes. The herbicide paraquat and glyphosate showed potential for application directed between the lines of cassava.