Browsing by Author "Lucena, Juan J."
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- Alleviation of Fe-induced chlorosis of soybean plants grown in calcareous soil by a freeze-dried iron fertilizer containing siderophores produced by Rhizobium radiobacterPublication . Arcas, Alejandra; Sadeghi, S. Maryam; Lucena, Juan J.; Vindeirinho, João M.; Soares, Eduardo V.; Soares, Helena M. V. M.; López-Rayo, SandraThe concerns about the unsustainability of traditional synthetic Fe chelates lead to the search for new environmentally friendly alternatives, such as siderophores-based fertilizers. In this work, the focus was on the evaluation of a bio-based Fe-chelate fertilizer obtained from the culture of the siderophore-producer bacterium Rhizobium radiobacter. The suitability of a freeze-dried fertilizer formulated from a R. radiobacter culture labeled with 57Fe to alleviate Fe chlorosis in soybean plants cultivated in calcareous soil was analyzed and the new potential Fe fertilizer was evaluated in comparison to the traditional synthetic chelate o,oEDDHA/57Fe3+. This natural chelate was able to maintain chlorophyll content stable during all the pot trials and presented greater Fe concentration in the remaining soil fractions serving as an Fe pool for a long time whereas o,oEDDHA/57Fe3+ could supply Fe quickly. The new bio-based Fe siderophore fertilizer, derived from R. radiobacter culture, could be a green substitute to conventional synthetic chelates to address Fe chlorosis in calcareous soil conditions.
- Evaluation of the Efficacy of Two New Biotechnological-Based Freeze-Dried Fertilizers for Sustainable Fe Deficiency Correction of Soybean Plants Grown in Calcareous SoilsPublication . Ferreira, Carlos M. H.; López-Rayo, Sandra; Lucena, Juan J.; Soares, Eduardo V.; Soares, Helena M. V. M.Currently, fertilization with synthetic chelates is the most effective agricultural practice to prevent iron (Fe) deficiencies in crops, especially in calcareous soils. Because these compounds are not biodegradable, they are persistent in the environment, and so, there is the risk of metal leaching from the soils. Thus, new, more environment-friendly efficient solutions are needed to solve iron-deficiency-induced chlorosis (IDIC) in crops grown in calcareous soils. Therefore, the central aim of this work was to prepare new freeze-dried Fe products, using a biotechnological-based process, from two siderophores bacterial (Azotobacter vinelandii and Bacillus subtilis) cultures (which previously evidenced high Fe complexation ability at pH 9) and test their capacity for amending IDIC of soybean grown in calcareous soils. Results have shown that A. vinelandii iron fertilizer was more stable and interacted less with calcareous soils and its components than B. subtilis one. This behavior was noticeable in pot experiments where chlorotic soybean plants were treated with both fertilizer products. Plants treated with A. vinelandii fertilizer responded more significantly than those treated with B. subtilis one, when evaluated by their growth (20% more dry mass than negative control) and chlorophyll development (30% higher chlorophyll index than negative control) and in most parameters similar to the positive control, ethylenediamine-di(o-hydroxyphenylacetic acid). On average, Fe content was also higher in A. vinelandii-treated plants than on B. subtilis-treated ones. Results suggest that this new siderophore-based formulation product, prepared from A. vinelandii culture, can be regarded as a possible viable alternative for replacing the current nongreen Fe-chelating fertilizers and may envisage a sustainable and environment-friendly mending IDIC of soybean plants grown in calcareous soils.