Effect of potassium silicate on epidemic components of powdery mildew on melon

The effects of silicon (Si) supplied in the form of potassium silicate (PS) were evaluated on epidemic components of powdery mildew of melon under greenhouse conditions. The PS was applied to the roots or to leaves. In the first experiment, epidemic components were evaluated after inoculation with Podosphaera xanthii. In the second experiment, the disease progress rate was evaluated on plants subjected to natural infection. The area under the disease progress curve was reduced by 65% and 73% in the foliar and root treatments, respectively, compared to control plants, as a consequence of reductions in infection efficiency, colony expansion rate, colony area, conidial production and disease progress rate. However, root application of PS was more effective than foliar application in reducing most of the epidemic components, except for infection efficiency. This can be explained by the high Si concentration in leaf tissues with root application, in contrast to the foliar treatment where Si was only deposited on the external leaf surfaces. The effects of PS reported in this study demonstrated that powdery mildew of melon can be controlled, and that the best results can be achieved when PS is supplied to the roots.

Peat palynomorphs from Eugenio de Melo, middle valley of Paraiba do Sul River, Sao Paulo, Brazil.

Peat palynomorphs from Eugenio de Melo, middle valley of Paraiba do Sul River, Sao Paulo, Brazil. This paper presents palynomorphs identified in the peats of the Eugenio de Melo region, the middle valley of the Paraiba do Sul River, Sao Paulo State. The samples were collected at intervals of 10 cm from a core with 3.90 m deep, aged between 11400-11220 and 490-290 cal. years B.P. Three types of algae were identified and presented, and ten spores, two gymnosperm pollen grains and thirty-nine angiosperms were described, with their own ecological information.

O canteiro do poeta-arquiteto: a conduta criativa de João Cabral de Melo Neto à luz de seus manuscritos

Neste artigo repensamos a metáfora do "poeta-engenheiro", ou "poeta-arquiteto", que geralmente caracteriza o processo criativo de João Cabral de Melo Neto, à luz de uma leitura genética de manuscritos de A educação pela pedra. Veremos que o "arquiteto" da metáfora provém da teoria de Le Corbusier, na qual o desenho (a concepção) determina o canteiro (a execução). No entanto, a análise de transformações de estruturas por meio de reformulações textuais nos manuscritos do poeta mostra que, por vezes, o projeto, ou intenção, se transforma nos trabalhos da página-canteiro.