Foliar Absorption and Translocation of Herbicides from Aqueous Solution and Treated Soil

Abstract

It has been suggested that soil treated with a herbicide and subsequently carried by wind and deposited on plant foliage can cause crop injury. This study compared foliar uptake and translocation of herbicides applied to plants as an aqueous solution or in herbicide-treated soil. Leaves of 3-wk-old seedling alfalfa, grape, and pea were treated with14C-labeled thifensulfuron, chlorsulfuron, glyphosate, 2,4-D, and bromoxynil. Significant amounts of all herbicides were absorbed by pea, alfalfa, and grape from the aqueous solutions, whereas very limited absorption occurred from herbicide-treated soil. Prolonged and multiple exposure to herbicide-treated soil did not increase herbicide uptake. High relative humidity enhanced herbicide absorption from aqueous solutions but not from herbicide-treated soil. All herbicides except bromoxynil were readily translocated in alfalfa, grape, and pea. Limited quantities of herbicides were absorbed from herbicide-treated soil by plant foliage, and this small amount is unlikely to cause crop damage.

2,4-D Past, Present, and Future: A Review

“…When the humidity increased from 40 to 90%, 2,4-D uptake was 11% greater in grapes (Vitis vinifera cv. Lemberger), but translocation was not affected (Al-Khatib et al 1992a). Water Stress.…”

“…Less uptake was observed in 5-wk-old field bindweed (Convolvulus arvensis L.) seedlings compared with 6-and 16-wk-old mature plants, but greater translocation occurred in seedlings (Agbakoba and Goodin 1969). Grapes grown in the field had 26% less uptake compared with grapes grown in the greenhouse and was attributed to cuticle differences (Al-Khatib et al 1992a). Leaf and Cell Factors.…”

“…A study of cuticle composition and chemistry found a wide variability among several plant species ranging in sensitivity, but a relationship with 2,4-D uptake was not found (Baker and Bukovac 1971). Even with varying leaf characteristics, differences in 2,4-D uptake were not found at 1, 3, or 7 d after application in alfalfa (Medicago sativa), grape, and pea (Al-Khatib et al 1992a). It was initially theorized that 2,4-D uptake correlated with the amount of stomatal openings (Pallas 1960).…”

Efeito de doses reduzidas de glyphosate e paraquat simulando deriva na cultura do sorgo

“…Os parâmetros avaliados no florescimento foram: área foliar e matéria seca da parte aérea por planta, altura da planta e teor de clorofila. Aos 7, 14 e 21 dias após a aplicação dos tratamentos foi avaliado o grau de toxicidade das plantas (Al-Khatib et al, 1992;Wall, 1994), variando de 0 a 100%, correspondendo respectivamente a ausência de toxicidade e 100% de sintoma nas plantas. Na colheita, foram avaliados estande final, peso de panículas, rendimento de grãos e peso de 1.000 grãos.…”

Método alternativo de avaliação da absorção de atrazine por plantas de Brachiaria plantaginea

“…A absorção foliar é comumente medida pela aplicação de gotículas de herbicidas radiomarcados nas folhas, medindo-se a radiação remanescente na superfície foliar em vários intervalos de tempo após a aplicação por meio da lavagem da folha (Al Khatib et al, 1992;Gaskin & Holloway, 1992;Green et al, 1992;Roggenbuck et al, 1994;Hsiao et al, 1996;Wahlers et al, 1997;Sprague et al, 1999). Um cuidado importante nessa técnica envolve a escolha do solvente para lavagem da superfície foliar.…”