Iodine is not considered essential for land plants; however, in some aquatic plants, iodine plays a critical role in antioxidant metabolism. In humans, iodine is essential for the metabolism of the thyroid and for the development of cognitive abilities, and it is associated with lower risks of developing certain types of cancer. Therefore, great efforts are made to ensure the proper intake of iodine to the population, for example, the iodization of table salt. In the same way, as an alternative, the use of different iodine fertilization techniques to biofortify crops is considered an adequate iodine supply method. Hence, biofortification with iodine is an active area of research, with highly relevant results. The agricultural application of iodine to enhance growth, environmental adaptation, and stress tolerance in plants has not been well explored, although it may lead to the increased use of this element in agricultural practice and thus contribute to the biofortification of crops. This review systematically presents the results published on the application of iodine in agriculture, considering different environmental conditions and farming systems in various species and varying concentrations of the element, its chemical forms, and its application method. Some studies report beneficial effects of iodine, including better growth, and changes in the tolerance to stress and antioxidant capacity, while other studies report that the applications of iodine cause no response or even have adverse effects. We suggested different assumptions that attempt to explain these conflicting results, considering the possible interaction of iodine with other trace elements, as well as the different physicochemical and biogeochemical conditions that give rise to the distinct availability and the volatilization of the element.

Agriculture stands to benefit from nanotechnology in areas such as combating pests and pathogens, regulating the growth and quality of crops, and developing intelligent materials and nanosensors. The objective of this paper is to provide an overview of the use of nanomaterials (NMs) and nanoparticles (NPs) in plant nutrition, highlighting their advantages and potential uses, but also reviewing their possible environmental destination and effects on ecosystems and consumers. NPs and NMs have been shown to be an attractive alternative for the manufacture of nanofertilizers (NFs), which are more effective and efficient than traditional fertilizers. Because of their impact on crop nutritional quality and stress tolerance in plants, the application of NFs is increasing. However, there are virtually no studies on the potential environmental impact of NPs and NMs when used in agriculture. These studies are necessary because NPs and NMs can be transferred to ecosystems by various pathways where they can cause toxicity to organisms, affecting the biodiversity and abundance of these ecosystems, and may ultimately even be transferred to consumers.

Nanotechnology represents an opportunity to improve the use of elements in agriculture. Selenium is an element that is beneficial to plants and essential to the human diet. The size of nanoparticles gives them characteristics that can enhance the benefits that selenium provides to plants. The objective of the present study was to determine the effects of selenium nanoparticles on the growth, antioxidant responses, and fruit quality of tomato developed under NaCl stress. Four doses of selenium nanoparticles (1, 5, 10, and 20 mg L−1) under NaCl stress, only NaCl, and a control were evaluated. The results showed that the impact of salinity on the growth of the tomato crop can be reduced with the application of selenium nanoparticles. However, the amount of both enzymatic and non-enzymatic compounds significantly increased in the leaves and fruits of tomato. The results suggest that the application of selenium nanoparticles generated a positive effect against salinity in the tomato crop; moreover, it had a positive impact on the content of beneficial biocompounds for human health in tomato fruits.

Abstract:Tomatoes are important for human diet due to their content of bioactive compounds. However, is little known about behavior of these compounds during fruit shelf life. The goal of this research was to evaluate the effects on bioactive compounds of tomato fruits stored during different times and conditions, obtained from tomato plants developed under conditions of saline stress and with the application of copper nanoparticles. Four treatments were evaluated: foliar spray of copper nanoparticles (250 mg L −1 ) with or without saline stress, only saline stress, and the absolute control. The results show that application of copper nanoparticles has a positive effect on the accumulation of bioactive compounds such as total phenols, β-carotene, and vitamin C. The saline stress during the development of tomato plants causes a decrease of the bioactive compounds as well as antioxidant capacity in tomato fruits. However, this negative effect can be reduced with the application of copper nanoparticles. The application of copper nanoparticles may be a technique to increase and maintain the content of bioactive compounds in tomato fruits and can be an effective alternative to diminish the negative effects on bioactive compounds caused by saline stress.

Selenium is an element that must be considered in the nutrition of certain crops since its use allows the obtaining of biofortified crops with a positive impact on human health. The objective of this review is to present the information on the use of Se and S in the cultivation of plants of the genus Allium. The main proposal is to use Allium as specialist plants for biofortification with Se and S, considering the natural ability to accumulate both elements in different phytochemicals, which promotes the functional value of Allium. In spite of this, in the agricultural production of these species, the addition of sulfur is not realized to obtain functional foods and plants more resistant; it is only sought to cover the necessary requirements for growth. On the other hand, selenium does not appear in the agronomic management plans of most of the producers. Including S and Se fertilization as part of agronomic management can substantially improve Allium crop production. Allium species may be suitable to carry out biofortification with Se; this practice can be combined with the intensive use of S to obtain crops with higher production and sensory, nutritional, and functional quality.

During the production of petroleum and gas a by-product, known as congenital water, is obtained, which varies in composition depending on the geological formation from which it is extracted. In the industrial process its composition is modified and then it is known as “produced water”. These waters can contain high concentrations of mineral salts that can potentially be used for crop fertilization. The aim of this study was to evaluate the effects of the application of produced water on the mineral contents of the plants and levels of BTEX and TPH in the fruits of greenhouse tomato cultivation. The produced waters used were derived from gas producing zone of Sabinas-Piedras Negras in northern Mexico. These waters were analyzed according to NOM-143-SEMARNAT-2003. Waters from three different stations, (Buena Suerte, Forasteros and Monclova 1), were mixed with fresh water to obtain the treatment waters used. As a control, we used a complete Steiner solution. The results showed that the produced waters modified the absorption of essential minerals in tomato plants; it was observed that the mineral concentration in plant tissues was highest in the control plants, except for Na, in which the plants irrigated with produced water had the highest concentrations. The treatments with produced waters also affected negatively the root length, leaf dry weight, stem dry weight, number of fruits per plant, and the dry weight of the fruits.

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