Ácido aconítico em sementes de espécies de plantas daninhas de diferentes locais

Abstract

2RESUMO -Plantas em estado vegetativo, como trigo ou aveia usados nos sistemas de cultivo de soja, podem produzir e liberar substâncias alelopáticas pelas suas raízes, afetando espécies de plantas daninhas, somando-se aos efeitos produzidos pelas suas palhadas. Experimentos foram conduzidos em laboratório com o objetivo de determinar os efeitos do ácido aconítico sobre as espécies de plantas daninhas amendoim-bravo (Euphorbia heterophylla), corda-deviola (Ipomoea grandifolia), picão-preto (Bidens pilosa) e guanxuma (Sida rhombifolia), provenientes de diferentes locais do Estado do Paraná. Os ensaios constaram de tratamentos com e sem ácido aconítico 2,5 mM L -1 . Corda-de-viola recebeu um pré-tratamento de escarificação com ácido sulfúrico. As sementes foram esterilizadas externamente com solução de hipoclorito de sódio a 2% durante dois minutos e enxaguadas. Em capela asséptica, em gerbox contendo meio de cultura de ágar, foram dispostas na superfície 50 sementes/ recipiente. Os experimentos foram conduzidos em câmara de germinação controlada. O delineamento utilizado foi o inteiramente casualizado, com quatro repetições. A origem das sementes teve influência nos resultados obtidos. A germinação das sementes foi afetada pelos efeitos do ácido aconítico na maioria dos locais. Ocorreu também a redução do crescimento das plântulas, sendo mais afetadas as raízes do que o caule, nas quatro espécies. O ácido aconítico apresenta efeitos alelopáticos sobre as sementes de diferentes espécies de plantas daninhas, variáveis com o local de origem, estimulando o crescimento de diferentes fungos endofíticos. Os efeitos do ácido aconítico podem traduzir-se na redução do período de sobrevivência dos bancos de sementes no solo.Palavras-chave: alelopatia, fungos endofíticos, banco de sementes, dinâmica de populações.ABSTRACT -Plants in vegetative state, such as wheat or oat used in soybean crops, may produce and release allellopathic substances through their roots, affecting weed species, complemented by the effects produced by straw. Experiments were carried out under laboratory conditions to determine the effects of aconitic acid on weed species such as wild poinsettia (Euphorbia heterophylla), morningglory (Ipomoea grandifolia), prickly sida (Sida rhombifolia) and beggarticks (Bidens pilosa) originated from different locations in the state of Paraná. Experiments consisted of treatments with and without AA 2,5 mM L -1 . Morningglory received a pre-treatment with sulfuric acid. The weed species seeds were sterilized externally using sodium hypochloride solution at 2% during two minutes and then rinsed. In an aseptic hood, in a gerbox containing agar medium, 50 seeds/container were placed on the surface. Experiments were arranged in a completely randomized design, with four replications, placed in a germination chamber. Seed origin influenced the results obtained. In general, seed germination was affected by aconitic acid in most locations. Growth reduction of seedlings was observed, with the roots being more affected than the s...

Phytosociology in agricultural areas submitted to distinct wintercropping management

“…Aconitic acid is a substance commonly exudated by grasses such as the Brachiaria species, which is responsible both for direct inhibition of plant growth (Putnan & DeFrank, 1983;Friebe et al, 1995) and for the growth stimulus of endophytic fungus capable of attacking seeds at the soil (Voll et al, 2004). According to Voll et al (2010), the aconotic acid affects the soil seed bank and its germination, which results in smaller competitive ability Phytosociology in agricultural areas submitted to distinct ... of the overall weed community against the crop present in the area.…”

Soil seed bank of plant species as a function of long-term soil management and sampled depth

“…Aconitic acid is a substance that is commonly exudated by grasses such as Brachiaria species, which is responsible both for direct inhibition of plant growth (Putnan & DeFrank, 1983;Friebe et al, 1995) and for growth stimulus of endophytic fungus capable of attacking seeds at the soil (Voll et al, 2004). According to Voll et al (2010), aconotic acid affects the soil seed bank and its germination, which results in smaller competitive ability of the overall weedy community against the crop at the area.…”

Influence of organo-mineral supplementation on the production of secondary metabolites in in vitro-germinated Bromelia balansae Mez.

“…Owing to reports regarding the optimal germination rates of "super seeds" at 95%(de Fátima B Coelho et al, 2011;Li et al, 2020;Su et al, 2017), our findings are thence remarkable for micropropagation purposes; especially when considering that B. balansae is a wild variety whose population is decreasing due to the advance of the monoculture of agricultural commodities in many regions. Nonetheless, the use of ethanol and sodium hypochlorite as disinfecting agents prior the incubation of the seeds in Murashige-Skoog medium seemingly allowed reliable in vitro germination of B. balansae whilst avoiding deleterious microbial contamination (Voll et al, 2010).…”