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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

NO3-/NH4(+) proportions affect cadmium bioaccumulation and tolerance of tomato

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Nogueirol, Roberta Correa [1] ; Monteiro, Francisco Antonio [2] ; de Souza Junior, Joao Cardoso [2] ; Azevedo, Ricardo Antunes [1]
Total Authors: 4
[1] Univ Sao Paulo, Dept Genet, ESALQ, POB 9, BR-13418900 Piracicaba, SP - Brazil
[2] Univ Sao Paulo, Dept Ciencia Solo, ESALQ, BR-13418900 Piracicaba, SP - Brazil
Total Affiliations: 2
Document type: Journal article
Source: Environmental Science and Pollution Research; v. 25, n. 14, SI, p. 13916-13928, MAY 2018.
Web of Science Citations: 3

With the growth of the world population, cadmium (Cd) concentration in the environment has increased considerably as a result of human activities such as foundry, battery disposal, mining, application of fertilizers containing toxic elements as impurities, and disposal of metal-containing waste. Higher plants uptake N as ammonium (NH4+), nitrate (NO3-), and many other water-soluble compounds such as urea and amino acids, and nourishing plants with N, providing part of it as NH4+, is an interesting alternative to the supply of this nutrient in the exclusive form of NO3- under Cd toxicity. The objective was to evaluate the influence of NO3-/NH4+ proportions on the development and tolerance of tomato plants grown under the presence of Cd in the culture medium. The experiment was conducted in a completely randomized block design in a 3 x 3 factorial arrangement consisting of three Cd rates (0, 50, and 100 mu mol L-1) and three NO3-/NH4+ proportions (100/0, 70/30, and 50/50) in the nutrient solution. To this end, we quantified the responses of the antioxidant enzymatic system and productive and functional changes in Solanum lycopersicum var. esculentum (Calabash Rouge). Shoot biomass production decreased with the maximum Cd rate (100 mu mol L-1) tested in the growth medium, whereas the NO3-/NH4+ proportions and other Cd rates did not significantly influence this variable. The lowest SPAD values were observed at the 100/0 NO3-/NH4+ proportion and in plants exposed to Cd. The largest accumulation of the metal occurred in the shoots at the NO3-/NH4+ proportion of 70/30 and at 100 mu mol L-1 Cd and in the roots at 100/0 NO3-/NH4+ and with 50 and 100 mu mol L-1 Cd. The concentration and accumulation of NO3- were highest at the NO3-/NH4+ proportion of 100/0 in the shoots and at 50/50 NO3-/NH4+ in the roots, whereas for NH4+ values were higher as the proportion of N supplied in the form of NH4(+) was increased. The nitrate reductase enzyme activity decreased with the Cd supply in the nutrient solution. The antioxidant system enzymes were activated as we increased the NO3-/NH4+ proportion and/or Cd rates added to the nutrient solution in both shoots and roots of the tomato plant, except for ascorbate peroxidase. Based on the results obtained, if the plant is to be used as a food source as is the case of tomato, the 100/0 NO3-/NH4+ proportion is the better alternative because it resulted in higher Cd accumulation in the root system over the translocation to the shoots and consequently to the fruit. (AU)

FAPESP's process: 15/20625-0 - Nitrate/ammonium relationship and Tanzania guinea grass tolerance to stress caused by copper
Grantee:João Cardoso de Souza Junior
Support type: Scholarships in Brazil - Master
FAPESP's process: 09/54676-0 - Oxidative stress induced by metals: new approaches
Grantee:Ricardo Antunes de Azevedo
Support type: Research Projects - Thematic Grants
FAPESP's process: 11/23019-3 - Study of the interaction soil-plant-aluminum using tomato varieties for tolerance to toxic elements
Grantee:Roberta Corrêa Nogueirol
Support type: Scholarships in Brazil - Post-Doctorate