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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Towards soil management with Zn and Mn: estimates of fertilisation efficacy of Citrus trees

Texto completo
Autor(es):
Hippler, F. W. R. [1] ; Boaretto, R. M. [1] ; Quaggio, J. A. [2] ; Azevedo, R. A. [3] ; Mattos, Jr., D. [1]
Número total de Autores: 5
Afiliação do(s) autor(es):
[1] Inst Agron, Ctr Citricultura Sylvio Moreira, BR-13490970 Sao Paulo - Brazil
[2] Inst Agron Estado Sao Paulo, Ctr Solos & Recursos Ambientais, Campinas, SP - Brazil
[3] Escola Super Agr Luis Dequeiroz, Dept Genet, Piracicaba, SP - Brazil
Número total de Afiliações: 3
Tipo de documento: Artigo Científico
Fonte: Annals of Applied Biology; v. 166, n. 3, p. 484-495, MAY 2015.
Citações Web of Science: 11
Resumo

Nutrient management recommendations for fruit crops lack the understanding of the efficiency of soil fertilisation with manganese (Mn) and zinc (Zn), which could substitute, in part, the traditional foliar applications. Fruit yield of trees in response to Zn and Mn supply via soil may be limited either by sorption reactions with soil colloids or low solubility of fertilisers. We investigated the effects of fertiliser sources and rates of Mn and Zn applied to soils with different sorption capacities on nutrient uptake, biochemical responses and biomass of Citrus. Two experiments were carried out with 2-year-old sweet orange trees that received applications of Mn or Zn. The first experiment evaluated the application of Mn fertilisers (MnCO3 and MnSO4) at three levels of the nutrient (0, 0.7 and 3.5gplant(-1) of Mn) in two types of soil (18.1% and 64.4% of clay, referred to as sandy loam and clay soils, respectively). The second experiment, likewise, evaluated Zn fertilisers (ZnO and ZnSO4) and nutrient levels (0, 1.0 and 5.0gplant(-1) of Zn). Application of Mn and Zn increased nutrient availability in the soils as well as leaf nutrient concentrations in the trees. The lowest rates, 0.7gplant(-1) of Mn and 1.0gplant(-1) of Zn, both as sulphate, were sufficient to supply these micronutrients to sufficient levels in leaves, flowers and fruits. Metal toxicity to plants occurred with higher doses of both nutrients and to a large extent in the sandy soil. In this case, protein bands lower than 25kDa were observed as well a decrease on leaf chlorophyll content. In the clay soil, despite increased micronutrient concentrations in the plant, responses were less pronounced because of higher adsorption of metals in the soil. Superoxide dismutase (SOD, EC 1.15.1.1) isoenzyme activity was determined by non-denaturing polyacrylamide gel electrophoresis (PAGE). The Cu/Zn-SOD isoenzymes increased with increased Zn rates, but in contrast, when Mn was applied at the highest rate, the activity of Cu/Zn-SODs decreased. The SOD activity pattern observed indicated increased production of superoxide and consequently an oxidative stress condition at the highest rates of Zn and Mn applied. The results demonstrated that the soil application of Mn and Zn can supply nutrient demands of orange trees, however the low solubility of fertilisers and the high sorption capacity of soils limit fertilisation efficiency. On the contrary, application of sulphate source in sandy soils may cause excess uptake of Mn and Zn and oxidative stress, which impairs the photosynthetic apparatus and consequently tree growth. (AU)

Processo FAPESP: 10/17589-9 - Eficiência da aplicação e do uso de micronutrientes metálicos em citros
Beneficiário:JOSE ANTONIO QUAGGIO
Linha de fomento: Auxílio à Pesquisa - Regular
Processo FAPESP: 10/02981-0 - Eficiência da aplicação de micronutrientes metálicos via solo em citros
Beneficiário:Franz Walter Rieger Hippler
Linha de fomento: Bolsas no Brasil - Mestrado