Efeito do alumínio sobre a absorção, o acúmulo e o fracionamento do fósforo em sorgo

Abstract

Efeito do alumínio sobre a absorção do fósforo em sorgo Bragantia RESUMOO trabalho teve como objetivo estudar o efeito do Al sobre a absorção, o acúmulo e o fracionamento do P em duas cultivares de sorgo. As plantas foram expostas a níveis tóxicos de Al durante dez dias e, então, colhidas e determinados o crescimento em tamanho e produção de massa seca, os teores de Al e de P total e as diversas formas de P nas duas partes das plantas. Avaliou-se, também, o efeito do Al sobre a absorção de P pelas raízes de plantas intactas. O Al reduziu o crescimento da raiz seminal e a produção de matéria seca de raízes e parte aérea nas duas cultivares, especialmente na sensível. Os teores de Al e de P total aumentaram nas raízes, mas não foram modificados na parte aérea nas duas cultivares. A absorção de P, entretanto, decresceu na presença de Al nas duas cultivares, principalmente na sensível. O Al, de modo geral, modificou as concentrações das várias formas de P solúvel (P i e P org ) e insolúvel (P RNA e P residual ), exceto a da forma P LIP . Algumas dessas modificações parecem ser importantes e podem estar relacionadas com o mecanismo de tolerância ao Al em sorgo.Palavras-chave: tolerância ao Al, Sorghum bicolor, fosfato inorgânico, fosfato orgânico. ABSTRACT ALUMINUM EFFECT ON UPTAKE, ACCUMULATION AND FRACTIONATION OF PHOSPHORUS IN SORGHUMThe objective of this work was to evaluate Al effect on uptake, accumulation and fractionation of P in two sorghum cultivars. Plants were treated with toxic levels of Al during ten days and then they were harvested and growth, dry matter yield, Al and total P contents and concentrations of the various P forms in the two parts of the plants were determined. Aluminum effect on P uptake was also evaluated in intact plants. Aluminum reduced the growth of the seminal root and dry matter yield in roots and tops of both cultivars, especially in the sensitive one. Aluminum and P contents increased in roots but did not change in the top of both cultivars. Phosphate uptake by roots, however, decreased in the presence of Al in both cultivars, especially in the sensitive one. Aluminum, in general, changed concentrations of all soluble (P i e P org ) and insoluble P forms (P RNA e P residual ), except of the P LIP form. Some of these modifications seem to be important and may be related to Al tolerance mechanism in sorghum.

Aluminum stress tolerance in potato genotypes grown with silicon

“…1 and 2). This reduction in root growth has been observed in several studies with other plant species (Pereira et al 2008;Liu et al 2012;Freitas et al 2017). Because of the inhibition in root growth, shoot growth is negatively affected and this leads to a reduction in dry weight.…”

Release of Phosphorus Forms from Cover Crop Residues in Agroecological No-Till Onion Production

“…This is because most of the P in plant tissue is found in inorganic forms (Casali et al, 2011;Marschner, 2012) and the inorganic P in the tissue makes up the labile compartment. These results corroborate with those obtained by Fernandes et al (2000), Pereira et al (2008), Casali et al (2011), and Oliveira et al (2016), who noticed that most of the tissue P is found in the soluble inorganic form in well-nourished plants grown in soil with sufficient nutrient content.…”

Effects of silicon on aluminum toxicity in upland rice plants

“…Because Al toxicity affects the root growth, it also affects the nutrient uptake. These effects were also observed in sorghum plants in which Al modified the kinetic constants of root P uptake, thereby decreasing the uptake of P (Pereira et al 2008).…”