Hidden deficiency of nickel in soybean: assessment and control
Year: 2018
Type: dissertation
Abstract: Studies on nickel (Ni) fertilization in cultivated plants are remarkably \nnew, although their positive effects have been reported since the early 1980s. This \nelement, emerging as a micronutrient, takes place in the enzymes urease, in plants, \nand hydrogenase, in microorganisms. So, legume plants, due to their symbiotic \nassociation with diazotrophic bacteria, may be one of the species most affected by \nNi deficiency in agricultural soils. The most important legume species currently \ncultivated is soybean, an important source of food on the world`s scenario. Thus, \npractices that lead to a more efficient and sustainable production of this species \nare aimed to ensuring the current and the future food security. In the first paper, \nwe followed the evidence of Ni deficiency presented in the literature and associate \nthem with the low natural contents of this element commonly found in agricultural \nsoils, and, thus, we confirmed the occurrence of Ni deficiency also in soybean \nplants. However, in this species, Ni deficiency occurred as a hidden deficiency. \nTo detect this event, we cultivated 17 soybean genotypes, which are commonly \ncultivated by farmers, with and without the supply of Ni in greenhouse and field, \nevaluating their physiology, metabolism and production. Therefore, we noticed \nthat fertilization with this micronutrient maximized all evaluated points, even \nwithout expressing leaf symptoms of the Ni deficiency. In the second paper, we \nstarted from the selection of genotypes previously done, which discriminated \nthem as to their responsiveness to Ni fertilization. To the most responsive \ngenotype, we offered the fertilization with increasing doses of this micronutrient \nin order to establish the concentrations that would provide the ranges of \nundernutrition, adequate development and toxicity. As expected, the genotype \ntested required a higher concentration of Ni to reach its maximum development, \nand curiously, the nitrogen-fixing bacteria associated with these, too. To reach this \nconclusion, we evaluated the genotype development following the supply of the \nNi doses and how the concentrations of Ni and activity of the root nodules \naccompanied them. With the developed works, we provide not only ways to detect \nthe hidden deficiency that occurs in the new soybean genotypes, but also how to \ncircumvent this limitation by provision of adequate doses for the maximum \ndevelopment of soybean plants.
Author: Freitas, Douglas Siqueira
Language: English
Subfield: Plant Science
Domain: Life Sciences
SDG: Zero hunger
Open Access status: green
OpenAlex ID: W2934630739