Glyphosate is the most widely used herbicide in the world. In sugarcane, it is used as a herbicide when applied at its field rate, but it is also used as ripener when applied as low doses. However, the effects of glyp...Glyphosate is the most widely used herbicide in the world. In sugarcane, it is used as a herbicide when applied at its field rate, but it is also used as ripener when applied as low doses. However, the effects of glyphosate on plant metabolism and sugarcane growth are not fully understood. This study aimed to evaluate the metabolic changes and the effects on sugarcane plant growth caused by the application of different doses of glyphosate. Sugarcane plants were grown in a greenhouse and subjected to glyphosate applications at doses of 7.2;18;36;72;180;360 and 720 g a.e. ha-1. Plants grown without an herbicide application were used as a control. Plants from each treatment were collected at 2, 7, 14, and 21 days after treatment (DAT) application to quantify the levels of shikimic acid, quinic acid, shikimate-3-phosphate, glyphosate, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), phenylalanine, tyrosine, and tryptophan. Visual evaluations of plant intoxication were performed at the same time as the collection of plants, and the quantification of their shoot dry biomass was performed at 21 DAT. At doses of glyphosate greater than 72 g a.e. ha-1, increases in the levels of shikimic acid, quinic acid, and shikimate-3-phosphate occurred and AMPA was detected in the plants. Initially, glyphosate caused increases in the plant levels of phenylalanine and tyrosine at doses of 72 and 180 g a.e. ha-1, although a decrease in the levels of aromatic amino acids subsequently occurred at and above the doses of 72 or 180 g a.e. ha-1. The doses ranging from 7.2 to 36 g a.e. ha-1 promoted an increase in plant shoot biomass, and doses greater than 72 g a.e. ha-1 caused significant reductions in dry mass.展开更多
We aimed to study the response of Conyza sumatrensis to different doses of glufosinate, intrapopulation variation in sensitivity to the herbicide, and the heritability of phenotypic response, and model the evolution o...We aimed to study the response of Conyza sumatrensis to different doses of glufosinate, intrapopulation variation in sensitivity to the herbicide, and the heritability of phenotypic response, and model the evolution of resistance. Three studies were conducted in the greenhouse with two repetitions. First, we tested doses of glufosinate (0, 50, 100, 200, 400, 800 g a.i. ha-1) plus a nontreated check, with four replications. Second, we examined the range in sensitivity of 44 plants to 200 g a.i. ha-1 glufosinate. Third, we evaluated the sensitivity of the progeny of six glufosinate-treated plants to 200 g a.i. ha-1 glufosinate. Plant response was evaluated visually and the ammonium content in leaf tissues was measured. Glufosinate at 400 g a.i. ha-1 caused the highest injury to C.sumatrensis plants. Ammonia accumulation occurred in response to glufosinate treatment, regardless of dose. Ammonia accumulation was correlated strongly with the level of visible plant injury;thus, it is a good indicator of herbicide efficacy. Sensitivity to glufosinate was highly variable within the population. Plants with high ammonia concentration (high injury) after treatment with glufosinate produced progenies that also had high ammonia concentrations after herbicide treatment. The variation in ammonia accumulation among siblings was high. Simulating the exclusion of plants that accumulated more ammonia produced a population that is expected to be less sensitive to glufosinate in the next generation. The stronger the selection pressures by a simulated treatment with glufosinate, the greater the reduction in ammonia accumulation in the progeny and expected sensitivity to glufosinate.展开更多
Globally,the area of land cultivated with genetically modified(GM)crops has increased a thousand-fold over the last two decades.Although this technology has become important for food production,the regulatory framewor...Globally,the area of land cultivated with genetically modified(GM)crops has increased a thousand-fold over the last two decades.Although this technology has become important for food production,the regulatory frameworks that underpin these outcomes are based on a list of requirements for a risk assessment that differ from country to country.In recent years,policymakers have had the opportunity to learn from the controversies over transgenics to create effective regulatory milestones for emerging technologies,allowing them to reach their potential for a more sustainable agriculture,ensuring food security.In Brazil,Law No.11.105 of 24 March 2005 established a framework with four main organizations responsible for risk assessment and management.However,most of new breeding technologies did not exist at that time and were not considered in this law.In2016,Normative Resolution No.16 of the National Biosafety Technical Commission(CTNBio)was established to address this gap based on the evaluation of the products obtained through these techniques(termed Innovative Precision Improvement Techniques in the resolution),in a case-by-case consultation system.Briefly,if the product is designated to be a GM,the developer will have to go through the biosafety requirements and will be approved only after CTNBio risk assessment.If the product is designated not to be GM(for the purposes of the legislation),then it can be registered using the existing procedures.Currently,152 GM products are commercially approved in Brazil.In 2018,CTNBio assessed the first consultation on commercial release of plants generated using the new breeding technologies and has subsequently approved six products.It is expected that many institutions would be able to participate in Brazilian and world markets,developing and introducing new biotechnological solutions and products through a more sustainable approach and without facing public disapproval,a common issue for GM crops.展开更多
基金funded by the Sao Paulo Research Foundation(FAPESP).
文摘Glyphosate is the most widely used herbicide in the world. In sugarcane, it is used as a herbicide when applied at its field rate, but it is also used as ripener when applied as low doses. However, the effects of glyphosate on plant metabolism and sugarcane growth are not fully understood. This study aimed to evaluate the metabolic changes and the effects on sugarcane plant growth caused by the application of different doses of glyphosate. Sugarcane plants were grown in a greenhouse and subjected to glyphosate applications at doses of 7.2;18;36;72;180;360 and 720 g a.e. ha-1. Plants grown without an herbicide application were used as a control. Plants from each treatment were collected at 2, 7, 14, and 21 days after treatment (DAT) application to quantify the levels of shikimic acid, quinic acid, shikimate-3-phosphate, glyphosate, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), phenylalanine, tyrosine, and tryptophan. Visual evaluations of plant intoxication were performed at the same time as the collection of plants, and the quantification of their shoot dry biomass was performed at 21 DAT. At doses of glyphosate greater than 72 g a.e. ha-1, increases in the levels of shikimic acid, quinic acid, and shikimate-3-phosphate occurred and AMPA was detected in the plants. Initially, glyphosate caused increases in the plant levels of phenylalanine and tyrosine at doses of 72 and 180 g a.e. ha-1, although a decrease in the levels of aromatic amino acids subsequently occurred at and above the doses of 72 or 180 g a.e. ha-1. The doses ranging from 7.2 to 36 g a.e. ha-1 promoted an increase in plant shoot biomass, and doses greater than 72 g a.e. ha-1 caused significant reductions in dry mass.
文摘We aimed to study the response of Conyza sumatrensis to different doses of glufosinate, intrapopulation variation in sensitivity to the herbicide, and the heritability of phenotypic response, and model the evolution of resistance. Three studies were conducted in the greenhouse with two repetitions. First, we tested doses of glufosinate (0, 50, 100, 200, 400, 800 g a.i. ha-1) plus a nontreated check, with four replications. Second, we examined the range in sensitivity of 44 plants to 200 g a.i. ha-1 glufosinate. Third, we evaluated the sensitivity of the progeny of six glufosinate-treated plants to 200 g a.i. ha-1 glufosinate. Plant response was evaluated visually and the ammonium content in leaf tissues was measured. Glufosinate at 400 g a.i. ha-1 caused the highest injury to C.sumatrensis plants. Ammonia accumulation occurred in response to glufosinate treatment, regardless of dose. Ammonia accumulation was correlated strongly with the level of visible plant injury;thus, it is a good indicator of herbicide efficacy. Sensitivity to glufosinate was highly variable within the population. Plants with high ammonia concentration (high injury) after treatment with glufosinate produced progenies that also had high ammonia concentrations after herbicide treatment. The variation in ammonia accumulation among siblings was high. Simulating the exclusion of plants that accumulated more ammonia produced a population that is expected to be less sensitive to glufosinate in the next generation. The stronger the selection pressures by a simulated treatment with glufosinate, the greater the reduction in ammonia accumulation in the progeny and expected sensitivity to glufosinate.
文摘Globally,the area of land cultivated with genetically modified(GM)crops has increased a thousand-fold over the last two decades.Although this technology has become important for food production,the regulatory frameworks that underpin these outcomes are based on a list of requirements for a risk assessment that differ from country to country.In recent years,policymakers have had the opportunity to learn from the controversies over transgenics to create effective regulatory milestones for emerging technologies,allowing them to reach their potential for a more sustainable agriculture,ensuring food security.In Brazil,Law No.11.105 of 24 March 2005 established a framework with four main organizations responsible for risk assessment and management.However,most of new breeding technologies did not exist at that time and were not considered in this law.In2016,Normative Resolution No.16 of the National Biosafety Technical Commission(CTNBio)was established to address this gap based on the evaluation of the products obtained through these techniques(termed Innovative Precision Improvement Techniques in the resolution),in a case-by-case consultation system.Briefly,if the product is designated to be a GM,the developer will have to go through the biosafety requirements and will be approved only after CTNBio risk assessment.If the product is designated not to be GM(for the purposes of the legislation),then it can be registered using the existing procedures.Currently,152 GM products are commercially approved in Brazil.In 2018,CTNBio assessed the first consultation on commercial release of plants generated using the new breeding technologies and has subsequently approved six products.It is expected that many institutions would be able to participate in Brazilian and world markets,developing and introducing new biotechnological solutions and products through a more sustainable approach and without facing public disapproval,a common issue for GM crops.
