Navegando por Autor "Moreira, Wiler Ribas"
Agora exibindo 1 - 4 de 4
- Resultados por Página
- Opções de Ordenação
Item Effect of root and leaf applications of soluble silicon on blast development in rice(Bragantia, 2013-08-18) Cacique, Isaias Severino; Domiciano, Gisele Pereira; Moreira, Wiler Ribas; Rodrigues, Fabrício Ávila; Cruz, Maria Fernanda Antunes; Serra, Núria Sierras; Català, Ana BottaBlast, caused by Pyricularia oryzae, is the most important fungal disease of rice worldwide. This study aimed to compare root and foliar supply of soluble silicon (Si) on rice resistance to blast. The application of soluble Si to the roots increased Si concentration in leaf tissues as compare to plants grown in soil amended with calcium silicate. There was no increase in leaf Si concentration after soluble Si spray, regardless if the leaves were washed or not before analysis. X-ray microanalysis revealed that Si deposition was very similar on the leaf epidermis of plants sprayed with soluble Si, root amended with soluble Si or grown in soil amended with calcium silicate. The lesion size, the number of lesions per cm2 of leaf and the area under blast progress curve were reduced for rice plants grown in soil that received the application of soluble Si or was amended with calcium silicate. The results of this study showed that the supply of soluble Si to the roots or its spray onto to the rice leaves can decrease blast symptoms.Item Induction of resistance to Pyricularia oryzae in wheat by acibenzolar-S-methyl, ethylene and jasmonic acid(Tropical Plant Pathology, 2014-05) Rios, Jonas Alberto; Rodrigues, Fabrício Ávila; Debona, Daniel; Resende, Renata Sousa; Moreira, Wiler Ribas; Andrade, Camila Cristina LageThis study investigated the effects of acibenzolar-S-methyl (ASM), ethylene (ET) and jasmonic acid (JA) on the resistance of two wheat cultivars (BRS-229 and BR-18) to infection by Pyricularia oryzae. The treatments included spraying plants with ASM (300 mg L-1), ET (0.5 mM), JA (0.1 mM) and distilled water (control) 48 h before inoculation with P. oryzae. Malondialdehyde concentration, an indicative of oxidative damage to the lipids in the leaf cells, was significantly higher for plants sprayed with ASM compared to plants sprayed with JA and ET. Plants sprayed with JA and ET showed reduced values for the number of lesions per cm2 of leaf area and area under blast progress curve, but these hormones had no effect on the incubation period and lesion size (in mm). Plants sprayed with JA and ET showed reduce blast symptoms in comparison to plants sprayed with ASM due to greater peroxidase, polyphenoloxidase, chitinase and β-1,3-glucanase activities.Item Influência do magnésio na resistência do arroz à mancha parda(Bragantia, 2013-07-29) Resende, Renata Sousa; Moreira, Wiler Ribas; Rodrigues, Fabrício Ávila; Andrade, Camila Cristina Lage; Nascimento, Clístenes Williams AraujoA mancha parda, causada pelo fungo Bipolaris oryzae, é uma das principais doenças da cultura do arroz. Sabe-se que o magnésio (Mg) tem o potencial de reduzir a intensidade de algumas doenças em culturas de importância econômica e, portanto, o objetivo desse trabalho foi verificar o efeito de diferentes doses desse macronutriente na resistência do arroz à mancha parda. Para isto, plantas de arroz (cv. Metica-1) foram cultivadas em solução nutritiva contendo 0,25; 0,5; 1; 2 e 4 mmol.L^-1 de Mg. Foram avaliados o período de incubação (PI), o número de lesões (NL) por cm^2 de folha, a severidade da mancha parda e a concentração foliar de Mg. Os dados de severidade foram usados para calcular a área abaixo da curva do progresso da mancha parda (AACPMP). Outro experimento com as doses de 0,25; 2,5 e 4 mmol.L^-1 de Mg foi conduzido para determinar a concentração de aldeído malônico (MDA) e a atividade da quitinase (QUI), β-1,3-glucanase (GLU), peroxidase (POX), polifenoloxidase (PFO) e fenilalanina amônia-liase (FAL) em resposta à infecção por B. oryzae. Houve efeito linear positivo e linear negativo das doses crescentes de Mg, respectivamente, na concentração foliar de Mg e na AACPMP. Houve efeito quadrático das doses crescentes de Mg no PI e no NL por cm^2 de área foliar. Alta concentração de MDA e maior atividade da PFO ocorreram com a dose de 4 mmol.L^-1 de Mg. As atividades da QUI e da GLU não foram afetadas pelas doses de Mg. A maior atividade da POX ocorreu para as plantas supridas com as doses de 2,5 e 4 mmol.L^-1 de Mg. A FAL apresentou aumento significativo em atividade às 48 e 72 horas após inoculação com a dose de 4 mmol.L^-1 Mg. Os resultados desse estudo demonstram que a alta concentração foliar de Mg aumentou a resistência do arroz à infecção por B. oryzae principalmente por meio do aumento das atividades das enzimas de defesa.Item Photosynthesis impairments and excitation energy dissipation on wheat plants supplied with silicon and infected with Pyricularia oryzae(Plant Physiology and Biochemistry, 2017-10-26) Aucique-Pérez, Carlos Eduardo; Silva, Paulo Eduardo de Menezes; Moreira, Wiler Ribas; DaMatta, Fábio Murilo; Rodrigues, Fabrício ÁvilaConsidering the effect of silicon (Si) in reducing the blast symptoms on wheat in a scenario where the losses in the photosynthetic capacity of the infected plants is lowered, this study investigated the ability of using the incident light, the chloroplastidic pigments (chlorophylls and carotenoids) alterations and the possible role of carotenoids on the process of light dissipation on wheat plants non-supplied (-Si) or supplied (+Si) with Si and inoculated or not with Pyricularia oryzae. For + Si plants, blast severity was reduced compared to -Si plants. Reductions in the concentration of photosynthetic pigments (total chlorophyll, violanxanthin + antheraxanthin + zeaxanthin, β-carotene and lutein) were greater for inoculated -Si plants than for inoculated + Si ones. The α-carotene concentration increased for inoculated -Si and +Si plants in comparison to non-inoculated plants limiting, therefore, lutein production. Higher functional damage to the photosystem II (PSII) was noticed for inoculated -Si plants with reductions in the values of maximum quantum quenching, photochemical yield of PSII and electron transport rate, but higher values for quenching non-photochemical. This finding also contributed to reductions in the values of light saturated rate photosynthesis and light saturation point for -Si plants which was attenuated for inoculated + Si plants. Increase in dark respiration values occurred for inoculated plants than for non-inoculated ones. The Si supply to wheat plants, besides reducing blast severity, contributed to their better photosynthetic performance. Moreover, inoculated + Si plants coped with drastic losses of light energy dissipation processes (fluorescence and heat) by increasing the concentration of carotenoids which helped to maintain the structural and functional viability of the photosynthetic machinery minimizing, therefore, lipid peroxidation and the production of reactive oxygen species.