Lílian Estrela Borges Baldotto

Adventitious rooting in cuttings of croton and hibiscus in response to indolbutyric acid and humic acid

Adventitious rooting of ornamental plants can be accelerated by the application of growth regulators, such as auxin. Humic acids, organic matter in soil and organic compounds also have a biostimulant effect. This work evaluated the rooting in cuttings of croton ( Codianeum variegatum L. Rumph) and hibiscus (Hibiscus rosa-sinensis L) in response to the application of different concentrations of indolbutyric acid (IBA) and humic acid (HA). The experiment was carried out in a greenhouse. Apical stem cuttings were treated with solutions at concentrations of: 0, 250, 500, 1000, 2000 mg L -1 IBA and 0, 10, 20, 30, 40 mmol L -1 HA carbon isolated from vermicomposting. Forty-five days after the applications, the cuttings were removed from the pots containing carbonized rice hull and the following variables were measured: rooting number, length and width of leaves, fresh and dry matter of root and aerial part and root area. The results were subjected to analysis of variance and the qualitative and quantitative effects of the treatments were compared by contrast and regression, respectively. Regression equations were used to determine the maximum efficiency level of root dry matter according to IBA and HA. Higher accumulation of root dry matter was recorded for the treatments with the doses 579 mg L -1 IBA and 14 mmol L -1 HA and 970 mg L -1 IBA and 50 mmol L -1 HA for root cuttings of croton and hibiscus, respectively. It was found that the application of eiher IBA or HA at the indicated doses accelerates rooting in cuttings of croton and hibiscus and contributes to the formation of vigorous plants.

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

As substâncias humicas isoladas da materia orgânica do solo tem 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 fisiologicos dessas substâncias, as quais sao qualitativa e quantivamente influenciadas pela morfogenese, mineralogia e quimica dos solos. Avaliar os efeitos dessas ambiencias na bioatividade de acidos humicos foi o objetivo principal do presente trabalho. Para isso, foram amostrados os horizontes A e B de quatro solos tipicos da Regiao Norte Fluminense. Apos o isolamento e purificacao, acidos humicos foram usados em concentracoes crescentes nas plantas. O numero e comprimento de raizes laterais e o comprimento da raiz principal foram avaliados e, posteriormente, determinadas as concentracoes de maxima estimulacao, obtidas por meio das curvas de dose resposta e das equacoes de regressao ajustadas. Os resultados mostraram que acidos humicos mais estaveis, isolados de solos em estadio de intemperismo menos avancado, com argila de alta atividade e alta saturacao por bases resultaram em melhores estimulantes fisiologicos das plantas de Arabidopsis.

Gladiolus development in response to bulb treatment with different concentrations of humic acids

Gladiolus is an ornamental species produced for cut flowers and propagated by corms. The early flowering and increase in the number of flower buds, besides the production of commercial corms are constant challenges to be addressed in the crop improvement. Commercial production of ornamentals is technologically accelerated by means of growth regulators. Among them, the auxins stand out for their key role in the adventitious rooting and cell elongation. Alternatively, the humic substances present in the organic matter also have biostimulating effect, which is very similar to the auxinic effect. Therefore, this work aimed to study the growth and development of gladiolus in response to application of different concentrations of humic acids (HA) isolated from vermicompost. Corms were soaked for 24 hours in solutions containing 0, 10, 20, 30 and 40 mmol L-1 of C from HA. The corms were planted in 10-dm3 plastic bags filled with substrate and kept in a greenhouse. Growth of shoots and roots was evaluated. The results showed that the use of HA accelerates growth, and anticipates and increases flowering of Gladiolus.

Structural interaction between GFP-labeled diazotrophic endophytic bacterium Herbaspirillum seropedicae RAM10 and pineapple plantlets 'Vitória'

The events involved in the structural interaction between the diazotrophic endophytic bacterium Herbaspirillum seropedicae, strain RAM10, labeled with green fluorescent protein, and pineapple plantlets ‘Vitória’ were evaluated by means of bright-field and fluorescence microscopy, combined with scanning electron microscopy for 28 days after inoculation. After 6 hours of inoculation, H. seropedicae was already adhered to the roots, colonizing mainly root hair surface and bases, followed by epidermal cell wall junctions. Bacteria adherence in the initial periods occurred mainly in the form of solitary cells and small aggregates with pleomorphic cells. Bacteria infection of root tissue occurred through the cavities caused by the disruption of epidermal cells during the emergence of lateral roots and the endophytic establishment by the colonization of intercellular spaces of the cortical parenchyma. Moreover, within 1 day after inoculation the bacteria were colonizing the shoots. In this region, the preferred sites of epiphytic colonization were epidermal cell wall junctions, peltate scutiform trichomes and non-glandular trichomes. Subsequently, the bacteria occupied the outer periclinal walls of epidermal cells and stomata. The penetration into the shoot occurred passively through stoma aperture followed by the endophytic establishment on the substomatal chambers and spread to the intercellular spaces of spongy chlorenchyma. After 21 days of inoculation, bacterial biofilm were seen at the root hair base and on epidermal cell wall surface of root and leaf, also confirming the epiphytic nature of H. seropedicae.

Aclimatização de orquídea (Cymbidium sp.) em resposta à aplicação de ácidos húmicos

The acclimatization of in vitro propagated orchid is a slow process that can be benefited from the use of bio-stimulants, such as humic substances. This study investigated the growth of Cymbidium sp. in response to application of humic acids extracted from organic compounds poultry litter (AHcf) and manure (AHeb) during the acclimatization period. The plants were immersed in solutions of 0, 10, 20, 30 and 40mmol L-1 of C from AHcf and AHeb and acclimatized in a greenhouse. After 150 days, the plants were collected for measurement of variables: number of leaves, plant height, stem diameter, root and shoot fresh weight, root, shoot and total dry matter and root shoot ratio. Data were submitted to analysis of variance, regression analysis and contrast. The results showed increased accumulation of total dry matter of the plants with the application of concentration of 18.75mmol L-1 of C AHcf and 3.77mmol L-1 of C AHeb with increments in the control 21 and 28%, respectively. It is concluded that the use of humic acids at the indicated doses accelerates the growth of plantlets propagated in vitro of Cymbidium sp. favoring the reduction of time required for acclimatization.

Initial performance of pineapple and utilization of rock phosphate applied in combination with organic compounds to leaf axils

Rock phosphates have low solubility in water, but good solubility in acid. The use of or ganic compounds together with these phosphorus sources applied to the basal leaf axils of pineapple can increase the solubility of this phosfate source and increase the P availability to the crop. A greenhouse experiment was conducted using Araxa rock phosphate (10 g) in combination or not with solutions containing increasing concentrations of humic acids (0 to 40 mmol L -1 of carbon), with or without citric acid (0.005 mmol L -1 ), applied to basal leaf axils of pineapple cv. Perola. Growth and nutritional characteristics of aerial plant parts were assessed. Growth rates of aerial parts and N, P , K, Ca and Mg contents increased curvilinearly with increasing concentration of carbon in the form of humic acids. Maximum values were found for the concentration of 9.3 mmol L -1 of carbon combined with 0.005 mmol L -1 of citric acid and natural phosphate.

Estoque e frações de carbono orgânico e fertilidade de solo sob floresta, agricultura e pecuária

O entendimento dos fenomenos de trocas de carbono entre solo, agua e atmosfera e fundamental para o manejo e a conservacao de ecossistemas naturais e agrarios. Os objetivos deste trabalho foram determinar os estoques de carbono orgânico, as suas fracoes e a fertilidade do solo sob os manejos florestal (mata remanescente), integrando agricultura e florestas (eucalipto e cutieira) e em monoculturas agricola (sob pivo central) e pastoril (braquiaria), na Bacia do Rio Paraopeba, em Florestal-MG, visando a propor indicadores para a avaliacao de manejo e conservacao do solo. As amostras de solo foram coletadas em remanescente de mata nativa (Mata), em area agricola cultivada sob irrigacao de pivo central (Pivo) e em areas de cultivo de Corymbia citriodora (Corymbia citriodora (Hook.) K.D. Hill & L.A.S. Johnson) (Eucalipto), Joannesia princeps Vell. (Cutieira) e Brachiaria decumbens Stapf (Pasto), nas profundidades de 0 a 20 e 20 a 40 cm. Os resultados indicaram que as estimativas dos estoques e de estabilidade do carbono orgânico aumentaram com a fertilidade do solo. Os sistemas florestais, principalmente a Mata, acompanhada pelos sistemas de manejo do solo integrando florestas a pastagem, em comparacao com o cultivo continuo ou a monocultura de pastagem, apresentaram estoques de carbono maiores, mais estaveis e menos soluveis, com formas mais aromaticas e hidrofobicas (maior relacao AH/AF), indicando menor potencial de lixiviacao de carbono para o sistema aquatico adjacente.

Initial growth of maize in response to application of rock phosphate, vermicompost and endophytic bacteria

Devido a alta exigencia energetica e demanda por recursos nao renovaveis para a producao de fertilizantes quimicos, somadas, ainda, ao impacto ambiental provocado pelo uso de tais produtos, e importante a intensificacao de pesquisas com insumos agricolas de base biologica. O uso de bacterias endofiticas fixadoras de nitrogenio e solubilizadoras de fosfatos pode disponibilizar esses nutrientes para as plantas a partir do ar e de fontes fosfatadas pouco soluveis, como fosfatos de rochas. O objetivo deste trabalho foi avaliar a nutricao e o crescimento inicial de milho (Zea mays L.) em resposta a inoculacao de bacterias endofiticas fixadoras de nitrogenio e solubilizadoras de fosfato de rocha, em formulacao simples ou mista, aplicadas com vermicomposto. As plantas de milho dos tratamentos contendo bacterias, tanto as diazotroficas quanto as solubilizadoras de fosfato, quando comparadas as do controle, apresentaram maiores teores foliares de nitrogenio e fosforo no milho, acompanhados por caracteristicas de crescimento mais elevadas. A aplicacao de vermicomposto apresentou efeito sinergico quando combinada com as bacterias endofiticas. Dessa forma, a inovacao da combinacao dos fatores estudados pode contribuir para o desenvolvimento inicial do milho.

Initial performance of corn in response to treatment of seeds with humic acids isolated from bokashi

The humified organic matter presents bioactivity similar to the auxinic effect. As bokashi is produced by a special process of humification, information is needed about the bioactive potential of its humic acids. The objective of this work was studying the initial performance of corn-indicator plants in response to the application of different concentrations of humic acids isolated from bokashi. The corn seeds were treated for 16 hours with solutions containing 0, 10, 20, 30, 40 and 80 mmol L-1 of C in the form of humic acids. Then, the seeds were planted in pots of 1 dm3 containing corrected and fertilized soil, in greenhouse. Growth characteristics of shoot and root systems were evaluated. The results showed that the humic acids extracted from bokashi had positive effects on the initial performance of corn.

Acclimation of croton and hibiscus seedlings in response to the application of indobultiric acid and humic acid for rooting

The vegetative propagation of ornamental plants can be accelerated by applying plant growth regulators. Amongst them, the use of auxins, plant hormones with physiological effects on cell elongation and rooting have stood out. Alternatively, the application of humic acids, bioactive fraction of soil organic matter, also results in increases in rooting cuttings of ornamental plants. The objective of this work was to study the growth characteristics and the nutritional contents of croton and hibiscus plants during acclimation of seedlings in response to different concentrations of indolebutyric acid (IBA) and humic acid (HA) applied to cuttings for rooting. The experiment was conducted in greenhouse, and the apical stem cuttings were treated with solutions with concentrations of 0, 250, 500, 1000 and 2000 mg L-1of IBA and 0, 10, 20, 30 and 40 mg L-1 of C from HA. At 45 days of rooting in carbonized rice husk, they were individually transferred to plastic bags of 2.0 dm3 containing a mixture of soil: sand: manure (2: 1: 1) as substrate. At 90 days of acclimation, the plants were collected for measurement of growth and nutritional variables. The results showed that the application of the IBA stimulates the absorption of nutrients and growth of croton cuttings and transplanted hibiscus, contributing to formation of vigorous seedlings. A similar response occurred with the application of HA in hibiscus cuttings