Search

O arroz tem uma grande capacidade de absorver silício (Si) nas raízes, que se acumula na parte aérea da planta, acompanhando o fluxo da transpiração. Este estudo teve como objetivo avaliar como o Si e a calagem afetam a fitometria e o teor de silício em plantas de arroz (Oryza sativa L.). Foi aplicado um total de 5 g de calcário por vaso contendo 5 kg de solo. As doses de silício foram: 0; 0,25; 0,50; 0,75 e 1 g por vaso com e sem correção, com quatro repetições. Cinco sementes foram semeadas por vaso e a fertilização foi realizada de acordo com a necessidade da colheita. Após dois meses, o material vegetal foicoletado, seco em estufa a 60 ° C e o teor de silício foi analisado. Os dados foram submetidos à análise de variância e regressão utilizando o software Sisvar. Os resultados mostraram que a calagem proporcionoumaior absorção de Si pelas plantas. Plantas que não foram submetidas à calagem apresentaram aumentostanto na massa seca quanto na verde. As doses de silício resultaram em um aumento linear na produção demassa de broto verde e massa seca de plantas de arroz.

In Brazil, the status of chlorine (Cl) nutrition in plants is still poorly studied. The micronutrient Cl plays an important role in cultures such as coconut and oil palm trees. This study aimed to evaluate the status of chlorine nutrition in oil palm trees as a function of planting age, which ranged from two to eight years of cultivation. The experiment was conducted in Tailândia, state of Pará, Brazil. The soil of the area is characterized as Yellow Latosol of medium texture. A total of four oil palm trees were sampled for each age and the following variables were analyzed: leaf, petioles, rachis, palm heart, arrows, stipe, male inflorescences, peduncles, spikelets and fruits, as well as the accumulated, recycled and immobilized levels of Cl. Oil palm trees proved to be demanding in Cl and the accumulation in the different vegetative organs increased with the development of the plant. The stipe was the main storing vegetative organ of this micronutrient. The highest demand of Cl (16.9-26.0 g/kg) occurred in the palm heart, while for male inflorescence, the values ranged from 3.3-4.1 g/kg of Cl. The levels of Cl recycled by the plant were higher than the immobilized and exported levels considering the development up to 4 years of age. After this age, the levels of recycled Cl are lower than those immobilized. As for the amount of Cl exported by clusters in 8-year-old plants, the values were 3.2 and 1.3 times lower than the recycled and immobilized levels, respectively.