Diferenças no metabolismo das plantas que determinam resistência ao glyphosate em Conyza canadensis (L.) Cronquist
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Data
2016-03-30
Autores
Batista, Mariana Silveira [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
A planta daninha está entre as espécies de maior importância nos campos de diversas culturas. Por se tratar de uma espécie que apresenta alto poder de produzir milhares de sementes que tem se adaptado ao uso de herbicidas, seu estudo se torna de grande importância para amenizar os danos causados às culturas. O trabalho foi desenvolvido com o objetivo de estudar as características morfofisiológicas da espécie Conyza canadensis (L.) Cronquist quanto à resistência ao herbicida do grupo químico das glicinas substituídas em plantas com histórico de resistência. O experimento foi instalado e conduzido durante o segundo semestre de 2014 em condição de campo na área da Universidade Federal do Mato Grosso do Sul – Campus Chapadão do Sul. O delineamento experimental foi blocos casualizados, com 4 repetições, os tratamentos em esquema fatorial 5x5, totalizando 25 tratamentos. O fator A correspondeu ao estádio de desenvolvimento: Tamanho I – plantas com 5 cm de altura; Tamanho II - 10 cm de altura; Tamanho III – 15 cm de altura; Tamanho IV – 20 cm de altura; Tamanho V – 25 cm de altura. O fator B foram as doses do glyphosate: Dose I (sem aplicação) - Testemunha; Dose II (1200 g i.a ha-1); Dose III (2400 g i.a ha-1); Dose IV (3600 g i.a ha-1) e Dose V (4800 g i.a ha-1). Foram realizadas análises de crescimento das plantas: altura de plantas e diâmetro do caule, aos 0, 14 e 28 dias após a aplicação dos tratamentos e uma avaliação de altura de plantas remanescentes ou rebrota realizada aos 100 dias após a aplicação. Para a análise de perdas de transpiração de folhas destacadas e hidratadas as plantas estavam em fase vegetativa e coletadas no terço-médio das plantas aos 0, 4 e 8 DAA. Os dados foram submetidos à análise de variância e as medias dos tratamentos comparadas pelo Teste de Scott Knott a 5% de probabilidade. Concluiu-se que tanto o tamanho das plantas como as doses do glyphosate influenciaram na altura de plantas, no diâmetro da haste e nas perdas de transpiração da espécie Conyza canadensis (L.) Cronquist. A porcentagem de redução da altura das plantas de tamanho menor foi maior conforme as doses de glyphosate aumentaram em todos os períodos das avaliações. Plantas de tamanho menor transpiram mais do que plantas de tamanho maior sem a aplicação de herbicida. Para as perdas de transpiração, as plantas de menor tamanho que receberam a aplicação do glyphosate em doses maiores, transpiraram menos. As plantas de tamanhos maiores transpiraram mais quando submetidas a doses medianas do glyphosate quando comparadas as doses maiores.
The weed is among the species of greatest importance in the fields of different cultures. Because it is a species that has a high power to produce thousands of seeds that have adapted to the use of herbicides, their study becomes very important to mitigate the damage to crops. The work was to study the morphological and physiological characteristics of species Conyza canadensis (L.) Cronquist for resistance to the herbicide chemical group of glycines substituted in plants with a history of resistance. The experiment was installed and conducted during the second half of 2014 under field conditions at the Universidade Federal do Mato Grosso do Sul-Campus Chapadão do Sul. The experimental design was blocks randomized with four repetitions, the treatments in a factorial 5x5, totaling 25 treatments. The factor A corresponded to the stage of development: Size I - plants with 5 cm; Size II - 10 cm; Size III - 15 cm; Size IV - 20 cm; Size V - 25 cm. The factor B were the glyphosate doses: Dose I (without application) - witness; Dose II (1200 g a.i. ha-1); Dose III (2400 g a.i. ha-1); Dose IV (3600 g a.i. ha-1) and Dose V (4800 g a.i ha-1). Plant growth analysis were performed: plant height and stem diameter at 0, 14 and 28 days after application of treatments and an assessment height of remaining plants or regrowth held at 100 days after application. For the analysis of transpiration losses highlighted and hydrated leaves the plants were in vegetative stage and collected the third-medium plants at 0, 4:08 DAA. The data were submitted to analysis of variance and the averages of the treatments compared by Scott Knott test at 5% probability. It was concluded that both the size of the plants as glyphosate doses influence on plant height, stem diameter and the losses in perspiration of species Conyza canadensis (L.) Cronquist. The percentage reduction of the height of the smaller plants was higher as the glyphosate rates increased in all periods of evaluations. smaller plants transpire more than plants of large size without the application of herbicide. For transpiration losses, smaller plants that received the application of glyphosate in larger doses, transpired less. The larger size plants transpired more when subjected to glyphosate median doses when compared to higher doses.
The weed is among the species of greatest importance in the fields of different cultures. Because it is a species that has a high power to produce thousands of seeds that have adapted to the use of herbicides, their study becomes very important to mitigate the damage to crops. The work was to study the morphological and physiological characteristics of species Conyza canadensis (L.) Cronquist for resistance to the herbicide chemical group of glycines substituted in plants with a history of resistance. The experiment was installed and conducted during the second half of 2014 under field conditions at the Universidade Federal do Mato Grosso do Sul-Campus Chapadão do Sul. The experimental design was blocks randomized with four repetitions, the treatments in a factorial 5x5, totaling 25 treatments. The factor A corresponded to the stage of development: Size I - plants with 5 cm; Size II - 10 cm; Size III - 15 cm; Size IV - 20 cm; Size V - 25 cm. The factor B were the glyphosate doses: Dose I (without application) - witness; Dose II (1200 g a.i. ha-1); Dose III (2400 g a.i. ha-1); Dose IV (3600 g a.i. ha-1) and Dose V (4800 g a.i ha-1). Plant growth analysis were performed: plant height and stem diameter at 0, 14 and 28 days after application of treatments and an assessment height of remaining plants or regrowth held at 100 days after application. For the analysis of transpiration losses highlighted and hydrated leaves the plants were in vegetative stage and collected the third-medium plants at 0, 4:08 DAA. The data were submitted to analysis of variance and the averages of the treatments compared by Scott Knott test at 5% probability. It was concluded that both the size of the plants as glyphosate doses influence on plant height, stem diameter and the losses in perspiration of species Conyza canadensis (L.) Cronquist. The percentage reduction of the height of the smaller plants was higher as the glyphosate rates increased in all periods of evaluations. smaller plants transpire more than plants of large size without the application of herbicide. For transpiration losses, smaller plants that received the application of glyphosate in larger doses, transpired less. The larger size plants transpired more when subjected to glyphosate median doses when compared to higher doses.
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Palavras-chave
Buva, Seletividade, Glyphosate, Horseweed, Selectivity