Root growth of Arabidopsis thaliana (L.) Heynh. treated with humic acids isolated from typical soils of Rio de Janeiro state, Brazil

Abstract

Root Growth of Arabidopsis thaliana (L.) Heynh. treated with humic acids isolated from typical soils of Rio de Janeiro State, BrazilHumic substances isolated from soil organic matter had been used as stimulators of plant metabolism. Arabidopsis thaliana (L.) Heynh. with only five chromosomes, short cycle and size, is an important model to evaluate the physiological effects of these substances, which are qualitatively and quantitatively influenced by morphogenesis, mineralogy and chemistry of soils. The objective of this study was to evaluate the ambience effects on bioactivity of humic acids. A and B horizons of four typical soils of the North Fluminense were sampled. After isolation and purification, humic acids were applied to plants in increasing concentrations. The number and length of lateral roots and main root length were evaluated and, subsequently, the concentrations of maximum stimulation were determined by dose-response curves and regression equations. The results showed that more stable humic acids isolated from soil in less advanced stages of weathering, high activity clay and high base saturation resulted in better physiological stimulants for Arabidopsis.Key words: Soil genesis, chemistry and fertility, humic substances, bioactivity, Arabidopsis thaliana. Crescimento radicular de plantas de Arabidopsis thalaiana tratadas com ácidos húmicos isolados de diferentes solos típicos do Estado do Rio de JaneiroAs substâncias húmicas isoladas da matéria orgânica do solo têm sido usadas como estimuladores do metabolismo vegetal. As plantas de Arabidopsis thaliana (L.) Heynh. com apenas cinco cromossomos, ciclo curto e tamanho reduzido, aparecem como modelo para avaliar os efeitos fisiológicos dessas substâncias, as quais são qualitativa e quantivamente influenciadas pela morfogênese, mineralogia e química dos solos. Avaliar os efeitos dessas ambiências na bioatividade de ácidos húmicos foi o objetivo principal do presente trabalho. Para isso, foram amostrados os horizontes A e B de quatro solos típicos da Região Norte Fluminense. Após o isolamento e purificação, ácidos húmicos foram usados em concentrações crescentes nas plantas. O número e comprimento de raízes laterais e o comprimento da raiz principal foram avaliados e, posteriormente, determinadas as concentrações de máxima estimulação, obtidas por meio das curvas de dose resposta e das equações de regressão ajustadas. Os resultados mostraram que ácidos húmicos mais estáveis, isolados de solos em estádio de intemperismo menos avançado, com argila de alta atividade e alta saturação por bases resultaram em melhores estimulantes fisiológicos das plantas de Arabidopsis.Palavras-chave: Gênse, química e fertilidade do solo, substâncias húmicas, bioatividade, Arabidopsis thaliana.

Corn initial vigor in response to humic acids from bovine manure and poultry litter

“…Among the technologies available for corn production, it is worth to mention the use of improved seeds in combination with the optimization of other factors affecting production, i.e., integrated nutrition management, plant protection, and irrigation. Recently developed technologies incorporate the use of plant growth regulators to stimulate plant metabolism and increase the efficiency of light, water and nutrients use (BALDOTTO et al, 2012a;BALDOTTO, 2013). However, the effect of this technology on corn yield has not been studied extensively.…”

“…The effect of these substances was reported to be analogous to auxins in stimulating and accelerating the growth of roots and aerial parts (BALDOTTO et al, 2012a;BALDOTTO, 2013). For most crops, greater response of plants to humic and fulvic acids occurs at concentrations between 10 and 20 mmol L -1 of C, which are used, for instance, for treatment of seeds, stem cuttings, and in post-planting sprays.…”

“…For most crops, greater response of plants to humic and fulvic acids occurs at concentrations between 10 and 20 mmol L -1 of C, which are used, for instance, for treatment of seeds, stem cuttings, and in post-planting sprays. At higher concentrations, the effect stabilizes and tends to decrease, sometimes being even detrimental when compared to no applications (BALDOTTO et al, 2009;BALDOTTO et al, 2012a;BALDOTTO, 2013;CANELLAS et al, 2006;SILVA et al, 2011). Nardi (2002 and Baldotto (2011) reviewed about the effects of humic substances on diferent plants.…”

Produtividade da alface (Lactuca sativa L.) em resposta à aplicação de ácidos húmicos e bactérias diazotróficas, em condições de campo

“…Ao emergir, as raízes laterais causam injúrias que podem funcionar como porta de entrada e proliferação dessas bactérias. Isso aumenta a possibilidade de efeitos benéficos que elas podem promover (Baldotto et al, 2011b;Canellas & Olivares, 2014).…”

Growth and production of ornamental sunflower grown in the field in response to application of humic acids

“…BALDOTTO et al (2009;2012;2013) found that humic acid applications close to 20mmol L -1 C to gladiolus bulbs, pineapple seedlings and croton cuttings concentrations increased the biomass. The positive effects on the accumulation of shoot matter in humic acid treated sunflower plants can be explained by different physiological factors such as increased synthesis of chlorophyll (BALDOTTO et al, 2009), increased nutrient uptake (NARDI et al, 2002), growth promotion of the root system (BALDOTTO et al, 2011) and the formation of root hairs (SILVA et al, 2011).…”