Glyphosate drift affects arbuscular mycorrhizal association in coffee

Abstract

-Mycorrhizal association promotes better survival and nutrition of colonized seedling on field, and consequently, increasing of productivity. However, the weed management can interfere on this association, due to incorrect use of glyphosate. This work has assessed the effects of glyphosate drift on the growth and nutrition of arabica coffee plants (Catuaí Vermelho -IAC 99) colonized with arbuscular mycorrhizal fungi (AMF). The experiment was conducted in 2 x 5 factorial scheme, and included inoculated and non-inoculated plants, and five glyphosate subdoses (0.0, 57.6, 115.2, 230.4, and 460.8 g ha -1 of glyphosate), in randomized blocks with five replication. The inoculation was carried during the greenhouse phase of seedlings production with a mixture of Rhizophagus clarus and Gigaspora margarita, and after to transplanting, when the plants had seven pairs of leaves, glyphosate subdoses were applied. The product caused intoxication in up to 60% of non-inoculated and 45% on inoculated plants, when the highest dose of 460.8 g a.e. ha -1 was applied. A negative effect was noted on the growth and phosphorus content of coffee plants, this effect increased depending on glyphosate subdose, but regardless of inoculation. Glyphosate drift reduces the growth and nutrition of plants colonized by species of AMF and native fungi, negatively affecting root colonization of plants treated.Keywords: Coffea arabica, glyphosate drift, mycorrhiza, Rhizophagus clarus, Gigaspora margarita. (0; 57,6; 115,2; 230,4; e 460,8 RESUMO -A associação micorrízica favorece o estabelecimento, a sobrevivência no campo e a nutrição da planta hospedeira, levando por consequência, a maior crescimento e produtividade. Todavia, o manejo de plantas daninhas no cafeeiro pode interferir nessa associação, podendo o emprego incorreto do glyphosate influenciar nesses benefícios da associação. Avaliou-se neste trabalho efeito da deriva do herbicida glyphosate no crescimento e estado nutricional de plantas de café arábica (Catuaí Vermelho IAC 99) inoculadas com fungos micorrízicos arbusculares (FMAs). Para isso, utilizou-se esquema fatorial 2 x 5, sendo mudas inoculadas ou não inoculadas com FMAs e cinco subdoses de glyphosate

Evaluation of leaf and root absorptions of glyphosate in the growth of coffee plants

“…A different result was observed for barley [(Hordeum vulgare (Poaceae)] in hydroponics with an increase of 10 to 30% in the root-aerial part ratio (CEDERGREEN, 2008). The decrease in the root length along with the increase in the aerial part indicates a greater investment of photoassimilates for the leaves rather than to the root system (CARVALHO et al, 2014;FRANÇA et al, 2010a;SANTOS et al, 2008). This result suggests that coffee roots may be more affected after glyphosate drift and the distribution of resources in one organ may have priority over another depending on the species.…”

“…This is due to the fact that this herbicide is systemic and translocates through the path of photoassimilates from the leaves to the other parts, affecting the growth points such as root meristems (KRUSE et al, 2000). The growth of young plant roots was expanding and presented high cell division; thus, amino acids, hormones or enzymes that participate in these processes may have been inhibited with increased doses of the herbicide due to their translocation to the growth zone (CARVALHO et al, 2014). The presence of glyphosate in the Brachiaria roots was observed by darkening them (SANTOS et al, 2008) and the damage to the cotton roots, in hydroponics, included inhibition of development, deposition of a thick layer of dead cells and cellular exudates (PLINE et al, 2002).…”

“…The management of weeds in crops is essential in order to achieve greater productivity (SCHRÜBBERS et al, 2014;COSTA et al, 2017). Coffee trees are sensitive to the interference of invasive plants that, even at low densities, can cause decreases in nutritional content by competing for resources in the environment which makes them scarce for coffee plants and hinders harvesting and treatment (FRANÇA et al, 2010a;CARVALHO et al, 2014). The chemical control of weeds stands out for being more efficient; however, the reduced number of selective products to coffee culture increases the application of no selective herbicides such as glyphosate (SCHRÜBBERS et al, 2014).…”

Effect of glyphosate and P on the growth and nutrition of Coffea arabica cultivars and on weed control

“…The cultivars Catuaí-Amarelo/IAC-62 and Catuaí-Vermelho/IAC-144 accumulated more P and Ca when cultivated in soils with higher P content, but Catuaí-Amarelo/IAC-62 plants were more efficient in accumulating S and Mg in soils with higher P content. On the other hand, the application of glyphosate reduced the levels of N, P and K in leaves of Catucaí, Oeiras, Topázio 29 and Catuaí-Vermelho/IAC-99 30 , increased the Ca content of these cultivars 24 , 30 , and no affected the accumulation of N, P, K, Ca, Mg and S contents in Catuaí-Vermelho/IAC-144 31 . The nutrient accumulation of these cultivars was influenced by glyphosate (360 g ae ha −1 ) to which they were submitted.…”