Características micromorfológicas de biótipos de capim‑arroz resistente e suscetível ao quinclorac

Abstract

Resumo -O objetivo deste trabalho foi avaliar o efeito do quinclorac nas características anatômicas de folhas e raízes de biótipos de capim-arroz (Echinochloa spp.), resistente e suscetível a este herbicida, por meio de avaliações micromorfométricas. As plantas foram cultivadas em vasos de plástico com capacidade de 250 cm 3 . As imagens dos cortes foram obtidas com microscópio de luz equipado com sistema U-Photo, acoplado à câmera digital conectada a microcomputador. Na seção transversal da lâmina foliar e das raízes, utilizouse objetiva de 10X, tendo-se avaliado 20 cortes/campos por planta, com dez medições por corte e quatro repetições por tratamento. Observaram-se diferenças entre os biótipos resistente e suscetível, tanto na ausência quanto na presença do quinclorac. O biótipo resistente apresenta lâmina foliar pouco afetada pelo herbicida; no entanto, há modificação na constituição dos tecidos radiculares com a formação mais acentuada de aerênquima. O biótipo suscetível também apresenta formação de aerênquima quando tratado com o quinclorac, mas em quantidade inferior à observada no biótipo resistente.Termos para indexação: Echinochloa, Oryza sativa, análises micromorfométricas. Micromorphological characteristics of barnyardgrass biotypes resistant and susceptible to quincloracAbstract -The objective of this work was to evaluate the effect of quinclorac on anatomical traits of leaves and roots of barnyardgrass (Echinochloa spp.) biotypes, susceptible and resistant to this herbicide, by micromorphometric assessments. Plants were grown in plastic pots with 250 cm 3 capacity. The images of plant sections were obtained with a light microscope equipped with a U-Photo system, coupled to a digital photo camera connected to a microcomputer. For cross-sections of leaf blades and roots, 10X objectives were used, and 20 sections/fields per plant were evaluated, with ten measurements per section and four replicates per treatment. Differences were observed between resistant and susceptible biotypes, both in the absence and in the presence of quinclorac. The resistant biotype shows leaf blades that are less affected by the herbicide; however, there are changes in root tissue constitution with increased aerenchyma formation. The susceptible biotype also shows formation of aerenchyma when treated with quinclorac, but in lower levels than those observed for the resistant biotype.

Manejo de Sagittaria montevidensis resistente aos mecanismos de ação da ALS e do FSII com saflufenacil associado a diferentes adjuvantes

“…This could contribute to the reduced translocation of the product, although this is not among the most probable causes of resistance in that biotype. In the literature, there is little information concerning the possible effects about the micromorphological characteristics of herbicide resistant weed biotypes, developed from the resistance mechanisms by the plant (Ferreira et al, 2012). Therefore, it becomes complex to predict how different resistant biotypes of the same species will behave when sprayed with herbicides that this populations may be susceptible.…”

Anatomical Changes on the Stem and Leaves of Solanum lycopersicum Caused by Different Concentrations of Picloram + 2,4-D, in Two Different Types of Soil

“…In Brazil, the influence of herbicides on plant morphology has been studied, such as the application of trifuralin, pedimentalin and 2,4-D on Euphorbia heterophylla (Deuber et al, 1977), of lactofen on soybean (Damião Filho et al, 1992), of nicosulfuron on maize (Môro and Damião Filho, 1999), of glyphosate on eucalyptus (Santos et al, 2008), of 2,4-D, diquat and glyphosate on Polygonum lapathifolium (Costa et al, 2011), of quinclorac on junglerice (Ferreira et al, 2012), of diquat, glyphosate and imazapyr on the leaf anatomy of Brachiaria subquadripara (Belo et al, 2011), among others.…”