Excess iron on growth and mineral composition inEugenia unifloraL.

Abstract

Excesso de ferro sobre o crescimento e a composição mineral emEugenia uniflora L. 1Excess iron on growth and mineral composition in Eugenia uniflora L. ABSTRACT -Iron, although an essential micronutrient, when present in excess can cause a reduction in the growth, and hence the productivity, of plants. The aim of this study was to evaluate the absorption, accumulation and distribution of Fe, and its consequences on growth and mineral composition in young plants of Eugenia uniflora L.. The plants were exposed to different concentrations of Fe, 0.045 (control), 1.0 and 2.0 mM, applied in the form of Fe-EDTA in Hoagland's pH 5.0 nutrient solution for 15, 30 and 45 days, when the number of leaves, shoot height, primary root length, dry mass of the roots, stems and leaves, and the levels of chlorophyll, total carotenoids and minerals were evaluated. Plants exposed to the treatments with 1.0 and 2.0 mM Fe showed an increase in levels of the element in the leaves, stem and roots, compared to the control plants, especially after 45 days of exposure. Under that condition, the plants exhibited typical symptoms of Fe toxicity, characterised by leaf bronzing, darkening of the roots, a reduction in the number of leaves, shoot height, length of the main root, dry matter production and the levels of chloroplast pigments. Excess Fe modified biomass partitioning and caused a reduction in the levels of P, Zn, Cu and Mn, especially in the roots. In addition to the direct effect of excess Fe, the resulting nutritional disorder may be associated with restrictive effects on initial vegetative growth in plants of Eugenia uniflora L..

Tolerance of Marandu Grass to Excess Iron and Manganese

“…Other toxicity studies with Fe and Mn in other cultures obtained different results. Jucoski et al (2016), evaluating the excess of iron on the growth of pitangueira (Brazilian cherry), submitted to concentrations of 1.0 and 2.0 mM, noted that the plants presented leaf spots of yellow/brownish color that evolved into necrotic lesions, as described in the literature. Stein et al (2014) observed similar symptoms in different rice cultivars, such as discoloration and necrosis in older leaves.…”

“…Different authors describe that when subjected to high concentrations of Fe, plants of different species can develop tolerance mechanisms, where part of the Fe will not be absorbed, being accumulated in the superficial part of the root and another part destined for the old leaves, and this factor may result in less nutrient absorption (Audebert and Sahrawat, 2000;Zhang et al, 2016). Besides the low nutrient absorption the roots may present reddish coloration when subjected to high doses of Fe as observed by Jucoski et al (2016). According to Siqueira-Silva et al ( 2012), the darkening of the roots indicates deposition of iron oxide or phenols.…”

“…Fe toxicity can vary according to the species it was submitted. Dobermann e Fairhurst (2000) found results starting at 300 mg kg -1 for rice culture; Jucoski et al (2016) found symptoms of toxicity in Fe contents in leaves between 120 and 229 mg kg -1 of Fe in Eugenia uniflora L, with reduction in both leaves and roots. There was a higher concentration of Mn in the treatment where the highest dose of nutrient was applied (8x the recommended dose), followed by treatment with application of Mn (4x the recommended dose), which differed from treatment with application of the appropriate dose of nutrients (Table 1).…”

Nutritional Efficiency and Morphophysiological Aspects With Growth in the ‘Okinawa Roxo’ Peach Rootstock

“…However, under the conditions of the present study, the mean Fe content was within the ideal range (2945.00 to 4292.33 μg plant -1 ) for Prunus persica (Souza et al, 2015), except in the plants from T3 and T4, where it was below the ideal range (Table 4). It is known that Fe plays an important role in the activation of enzymes, acting as a prosthetic group (Jucoski et al, 2016). In addition, Fe catalyses chlorophyll biosynthesis, being one of the enzymes responsible for its formation (Yilmaz & Gökmen, 2016).…”

Physiological Responses and Absorption of Metals in Itallian Ryegrass Leaves Cultivated With Sewage Sludge and Its Relationships With Organic Acids

“…37 Os sintomas citados em outros estudos incluem manchas amareladas em folhas de soja, amarelecimento de folhas de pitangueira, diminuição do comprimento radicular em trigo, redução no crescimento da raiz em aroeira, manchas marrons a aparecimento de necroses nas folhas de batata doce, além de diminuições do crescimento e outros. [37][38][39][40][41] O Zn é um dos micronutrientes menos abundantes nos solos brasileiros, sendo mais comum encontrarmos problemas causados pela 35 , Juiz de Fora possui duas sazonalidades bem distintas, uma mais chuvosa e quente (que compreende os meses de março e abril) e outra mais seca e com temperaturas baixas (iniciando no mês de maio) que afetam a concentração de alguns nutrientes. Essas diferenças na qualidade do LE poderiam afetar a distribuição de nutrientes e metais potencialmente tóxicos na espécie, com reflexo na translocação para a parte aérea.…”