**5. Perspectives and recommendations**

Expanding the list of elements used in the fertilization of plants cultivated in soil and in soilless systems will allow obtaining advantages for both agricultural producers and consumers. In particular, the use of the beneficial elements I, Se, and Si in crops for human consumption is expected to increase the functional quality of food, due to the increase in antioxidants that occur in response to the presence of these elements. On the other hand, the exogenous application of quantities as low as 50 μM of KIO3, 5 μM of Na<sup>2</sup> SeO4 , and 2 mM Na<sup>2</sup> SiO<sup>3</sup> in soilless crops provides enough to trigger an increase in antioxidants such as ascorbate, glutathione, and phenolic compounds, which give more reducing power useful to deal with various types of stress.

**References**

[1] Kabata-Pendias A. Trace Elements in Soils and Plants. Boca Raton, FL: CRC Press; 2011 [2] Fuge R. Soils and iodine deficiency. In: Selinus O. Essentials of Medical Geology: Revised

The Use of Iodine, Selenium, and Silicon in Plant Nutrition for the Increase of Antioxidants…

http://dx.doi.org/10.5772/intechopen.75069

163

[4] Shetaya WH, Young SD, Watts MJ, Ander EL, Bailey EH. Iodine dynamics in soils. Geo-

[5] Shand CA, Eriksson J, Dahlin AS, Lumsdon DG. Selenium concentrations in national inventory soils from Scotland and Sweden and their relationship with geochemical fac-

[6] Venturi S. Evolutionary significance of iodine. Current Chemistry & Biology. 2011;**5**:155-162

[7] Tolu J, Thiry Y, Bueno M, Jolivet C, Potin-Gautier M, Le Hécho I. Distribution and speciation of ambient selenium in contrasted soils, from mineral to organic rich. Science of

[8] Dai J-L, Zhu Y-G, Zhang M, Huang Y-Z. Selecting iodine-enriched vegetables and the residual effect of iodate application to soil. Biological Trace Element Research. 2004;

[9] Toan DQ, Li Z, Thu TTA, Wang D, Liang D. Role of organic acids on the bioavailability

[10] Tonacchera M, Dimida A, De Servi M, Frigeri M, Ferrarini E, De Marco G, Grasso L, Agretti P, Piaggi P, Aghini-Lombardi F, Perata P, Pinchera A, Vitti P. Iodine fortification of vegetables improves human iodine nutrition: In vivo evidence for a new model of iodine prophylaxis. The Journal of Clinical Endocrinology and Metabolism. 2013;**98**:

[11] Melzer SE, Chadwick OA, Hartshorn AS, Khomo LM, Knapp AK, Kelly EF. Lithologic controls on biogenic silica cycling in South African savanna ecosystems. Biogeochemistry.

[12] Struyf E, Smis A, van Damme S, Meire P, Conley DJ. The global biogeochemical silicon

[13] Gocke M, Liang W, Sommer M, Kuzyakov Y. Silicon uptake by wheat: Effects of Si pools

[14] Tavakkoli E, Lyons G, English P, Guppy CN. Silicon nutrition of rice is affected by soil pH, weathering and silicon fertilisation. Journal of Plant Nutrition and Soil Science.

and pH. Journal of Plant Nutrition and Soil Science. 2013;**176**:551-560

Edition. Dordrecht: Springer Netherlands; 2013. pp. 417-432

chimica et Cosmochimica Acta. 2012;**77**:457-473

the Total Environment. 2014;**479**:93-101

**101**:265-276

E694-E697

2012;**108**:317-334

2011;**174**:437-446

cycle. Silicon. 2010;**1**:207-213

tors. Journal of Geochemical Exploration. 2012;**121**:4-14

of selenium in soil: A review. Chemosphere. 2017;**184**:618-635

[3] Rodrigues FA, Datnoff LE. Silicon and Plant Diseases. Cham: Springer; 2015
