{"id":10400,"date":"2024-02-09T12:37:52","date_gmt":"2024-02-09T15:37:52","guid":{"rendered":"https:\/\/ilsabrasil.com.br\/?p=10400"},"modified":"2024-02-09T12:39:28","modified_gmt":"2024-02-09T15:39:28","slug":"absorcao-e-distribuicao-dos-micronutrientes-pelas-plantas","status":"publish","type":"post","link":"https:\/\/ilsabrasil.com.br\/en\/absorcao-e-distribuicao-dos-micronutrientes-pelas-plantas\/","title":{"rendered":"Absorption and distribution of micronutrients by plants"},"content":{"rendered":"

\u00a0 \u00a0 \u00a0 \u00a0 \u00a0\u00a0Micronutrients, which include B, Cl, Cu, Fe, Mn, Mo, Ni and Zn, are required by plants in very low concentrations for adequate growth and reproduction. However, despite their low concentrations within plant tissues and organs, micronutrients are as important as macronutrients for plant nutrition. At these low concentrations, micronutrients are essential for plant growth and development, acting as constituents of cell walls (B) and cell membranes (B, Zn), as constituents of enzymes (Fe, Mn, Cu, Ni), as enzyme activators (Mn, Zn) and in photosynthesis (Fe, Cu, Mn, Cl) (<\/span>KIRKBY<\/span>; <\/span>R\u00d6MHELD, 2007).<\/span><\/p>\n

\u00a0 \u00a0 \u00a0 \u00a0 \u00a0\u00a0Inadequate micronutrient content in crops, which limits their growth and can go unnoticed, not only has a direct effect on crop development but also reduces the efficiency of use of fertilizers containing macronutrients. In addition, micronutrients (Cu, Mn, Zn, B) are particularly involved in the reproductive phase of plant growth and, consequently, in determining the productivity and quality of the harvested crop (<\/span>KIRKBY<\/span>; <\/span>R\u00d6MHELD, 2007). <\/span>Micronutrients can be applied directly to the soil, through fertigation, foliar fertilization or seed treatment (<\/span>GON\u00c7ALVES et al., 2019).<\/span><\/p>\n

\u00a0 \u00a0 \u00a0 \u00a0 \u00a0\u00a0Due to the difficulty in uniformly distributing micronutrients through fertilization, given the small amounts required, seed treatment via pelletization represents a viable alternative for fertilization (Ohse et al., 2001). In addition to its low costs and smaller amount of fertilizer required, the application presents greater uniformity of distribution (Parducci et al., 1989) and good utilization by the plant, proving to be an effective and easy-to-perform practice. The application via seed treatment is based on the translocation of the applied micronutrients to the future plant (Cheng, 1985), especially when environmental conditions restrict root growth. However, it is important that the producer follows the recommendations for use and dosage during treatment, since high concentrations of salts near the seed can harm seedling emergence (Pessoa, 2000).\u00a0<\/span><\/p>\n

\u00a0 \u00a0 \u00a0 \u00a0 \u00a0\u00a0In situations where the micronutrient has low mobility in the plant, as in the case of Zn, B and Cu, it can be applied via foliar application, ensuring a greater supply of demand and allocation to the vegetative parts (Lawson et al., 2015).\u00a0<\/span><\/p>\n

\u00a0 \u00a0 \u00a0 \u00a0 \u00a0\u00a0For technical and economic reasons, foliar applications or seed treatment can be performed together with applications of fungicides, insecticides, herbicides and beneficial microorganisms, without compromising the quality and performance of the plants. According to Bays et al. (2007), in a study carried out with soybean crops, the joint application of fungicides, micronutrients (Co, Mo and B) and polymer ensured better uniformity in the treatments and did not compromise the quality and performance of the seeds up to the limit of 2 mL of micronutrients per kilogram of seeds, proving to be highly efficient.<\/span><\/p>\n

\u00a0 \u00a0 \u00a0 \u00a0 \u00a0\u00a0An alternative is soil application, which can be done by broadcasting (with or without incorporation), applied in the hole or in the seeding furrow, aiming to increase their concentration in the soil solution. However, it is necessary that the sources of micronutrients used are dissolved in the soil at a speed compatible with the absorption rate by the roots and, applied in regions close to them, due to the low mobility of some micronutrients, mainly in clayey soils (<\/span>GON\u00c7ALVES et al., 2019).<\/span><\/p>\n

\u00a0 \u00a0 \u00a0 \u00a0 \u00a0\u00a0Fertigation can also be used, combining two main factors essential for plant growth and development: water and nutrients. Its advantages include reduced labor requirements, reduced soil compaction, reduced machine traffic within the area, good uniformity of fertilizer distribution, application at the time the plant needs it, ease of division, reduced soil erosion and reduced physical damage to the crop (Bernardo et al., 2008).<\/span><\/p>\n

\u00a0 \u00a0 \u00a0 \u00a0 \u00a0\u00a0The lower concentrations of micronutrients are reflected in their function as constituents of prosthetic groups in metalloproteins and as activators of enzymatic reactions. Their presence in prosthetic groups allows them to catalyze redox processes by electron transfer (mainly the transition elements Fe, Mn, Cu and Mo). Micronutrients also form enzyme complexes by binding the enzyme to the substrate (e.g. Fe and Zn). It is now also known that several micronutrients (Mn, Zn, Cu) are present in superoxide dismutase (SD) isoenzymes, which act as scavenging systems to eradicate toxic oxygen radicals in order to protect biomembranes, DNA, chlorophyll and proteins. For the nonmetals B and Cl there are no well-defined enzymes or other essential organic compounds that contain these micronutrient elements. However, it is now established that B is an essential constituent of cell walls (<\/span>KIRKBY<\/span>; <\/span>R\u00d6MHELD, 2007).<\/span><\/p>\n

Table 1 \u2013 Main functions of plant micronutrients.<\/span><\/p>\n

\"Tabela
Source: (KIRKBY; R\u00d6MHELD, 2007).<\/figcaption><\/figure>\n

Basic description of micronutrients:<\/b><\/p>\n