Efeito residual de herbicidas mimetizadores de auxinas no teor de clorofila da lab-lab

Todos os textos, informa??es e resultados apresentados s?o de inteira responsabilidade dos autores.Parte da disserta??o do segundo autor, financiado pelo Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq), Funda??o de Amparo ? Pesquisa do Estado de Minas Gerais (FAPEMIG) e Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES).Objetivou-se com este trabalho avaliar o efeito residual dos herbicidas triclopyr, 2,4-D e a mistura 2,4-D + picloram no teor de clorofila total de plantas de lab-lab. O experimento foi dividido em duas etapas. A primeira parte foi conduzida em uma ?rea de pastagem infestada por plantas daninhas pertencente ? UFVJM, em Couto de Magalh?es de Minas ? MG. A segunda etapa foi realizada em casa de vegeta??o no Campus JK da UFVJM, em Diamantina ? MG. O delineamento experimental adotado foi inteiramente ao acaso, com quatro repeti??es. Os tratamentos foram tr?s herbicidas: triclopyr (960 g ha-1 do equivalente ?cido triclopyr); 2,4-D (1340 g ha-1 do equivalente ?cido 2,4-D) e a mistura 2,4-D + picloram (720 + 192 g ha-1 do equivalente ?cido 2,4-D + picloram) aplicados na dose recomendada pelos fabricantes, mais testemunha sem aplica??o. Foi utilizado o Dolichos lablab (lab-lab) como esp?cie indicadora. As aplica??es dos herbicidas foram realizadas em condi??es ambientais adequadas, utilizando um pulverizador costal, com bico de jato plano (leque) TT 110 02 e press?o constante de 200 kPa. Aos 40 e 280 dias ap?s a aplica??o do herbicida (DAA) foram coletados aleatoriamente, em cada parcela, amostras de solo na profundidade de 0 a 20 cm. Aos 20, 27, 34 e 40 dias ap?s a semeadura (DAS), foram determinados os teores de clorofila total. Aos 40 DAA, foi observada redu??o nos teores de clorofila total aos 20 DAS nas plantas de lab-lab cultivadas em solos tratados com os herbicidas estudados. O tratamento com aplica??o da mistura 2,4-D + picloram aos 40 DAA resultou na morte das plantas de lab-lab a partir dos 20 DAS. Entretanto, os solos coletados aos 280 DAA indicam uma redu??o do res?duo da mistura 2,4- D + picloram, pois, foram observados menores teores de clorofila na lab-lab. Os herbicidas 2,4-D e triclopyr apresentaram baixo efeito residual nas plantas de lab-lab, entretanto, foi observado longo efeito residual no solo para a mistura 2,4-D + picloram.The aim of the study was to evaluate the residual effect of the herbicides triclopyr, 2,4-D, and the combination of 2,4-D + picloram on the total chlorophyll content of the lablab bean plants. The experiment was divided in two parts. The first part was conducted on a pasture area infested by weeds that belongs to the UFVJM, in Couto de Magalh?es de Minas ? MG. The second part was managed in a greenhouse in the Campus JK of the UFVJM, in Diamantina ? MG. The experimental design was in randomized block, with four repetitions. The treatments were three herbicides: triclopyr (960 g ha-1 of the acid triclopyr equivalent); 2,4-D (1340 g ha-1 do of the 2,4-D acid equivalent), and the combination 2,4-D + picloram (720 + 192 g ha-1 of the acid 2,4-D + picloram acid equivalent) applied on the dose recommended by the manufacturer, one more witness without application. It was utilized the Dolichos lablab (lablab bean) as the indicator species. The application of the herbicides were conducted on adequate environmental conditions, using a costal spray, with a flat fan nozzle (fan) TT 110 02, and constant pressure of 200 kPa. At 40 and 280 days after application of the herbicide (DAA) were randomly collected, in each portion, soil samples on the width of 0 to 20 cm. At 20, 27, 34, and 40 days after sowing (DAS), were determined the total chlorophyll content. At 40 DAA, was observed a reduction on the total chlorophyll content at 20 DAS on the lablab bean plants cultivated on soils treated with the studied herbicides. The treatment with application of the combination of 2,4-D + picloram at 40 DAA resulted on the death of the lablab bean plants starting at the 20 DAS. However, the soils collected at 280 DAA indicate a reduction of the residue of the combination 2,4-D + picloram, were observed lower chlorophyll content in the lablab bean. The herbicides 2,4-D and triclopyr presented small residual effect on the lablab bean plants, however was observed long residual effect on the soil for the combination 2,4-D + picloram

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio