Antonio Juárez-Maldonado

Use of Iodine to Biofortify and Promote Growth and Stress Tolerance in Crops

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.

Application of nanoelements in plant nutrition and its impact in ecosystems

Nanotechnology has great potential, as it can enhance the quality of life through its applications in various fields like agriculture and the food system. Around the world it has become the future of any nation. But we must be very careful with any new technology to be introduced regarding its possible unforeseen related risks that may come through its positive potential. However, it is also critical for the future of a nation to produce a trained future workforce in nanotechnology. In this process, to inform the public at large about its advantages is the first step; it will result in a tremendous increase in interest and new applications in all the domains will be discovered. With this idea, the present review has been written. There is great potential in nanoscience and technology in the provision of state-of-the-art solutions for various challenges faced by agriculture and society today and in the future. Climate change, urbanization, sustainable use of natural resources and environmental issues like runoff and accumulation of pesticides and fertilizers are the hot issues for today’s agriculture. This paper reviews some of the potential applications of nanotechnology in the field of agriculture and recommends many strategies for the advancement of scientific and technological knowledge currently being examined.

Cu Nanoparticles absorbed on chitosan hydrogels positively alter morphological, production, and quality characteristics of tomato

Use of nanoparticles as nano copper (nCu) may be useful in agriculture. The objective of the present study was to evaluate responses in plant growth and antioxidants in tomato fruits upon application of nCu absorbed on chitosan hydrogels. The study was performed in two stages. The first stage, with tomato seedlings, was done to determine the most appropriate nCu concentration. nCu was absorbed on a chitosan hydrogel at 100 mg nCu kg-1 of hydrogel, and five different treatments of hydrogel were applied to the substrate prior to transplantation: 0.3, 0.15, 0.06, 0.03 and 0.015 g L-1, plus a control. The second stage evaluated the best treatment results from the previous stage, a chitosan treatment without nCu and a control. Effects of the treatments on antioxidants in the leaves and fruit were evaluated, along with fruit quality. The results from the first stage demonstrated that 0.06 g L-1 nCu-chitosan hydrogel treatments had better results. Outcomes from the second stage demonstrated that treatment with nCu had the best results for most of the plant growth variables, with differences in catalase activity in the leaves and lycopene concentration in the fruit. Application of chitosan hydrogels with nCu was favorable to tomato growth and quality.

Effects of Chitosan–PVA and Cu Nanoparticles on the Growth and Antioxidant Capacity of Tomato under Saline Stress

Chitosan is a natural polymer, which has been used in agriculture to stimulate crop growth. Furthermore, it has been used for the encapsulation of nanoparticles in order to obtain controlled release. In this work, the effect of chitosan–PVA and Cu nanoparticles (Cu NPs) absorbed on chitosan–PVA on growth, antioxidant capacity, mineral content, and saline stress in tomato plants was evaluated. The results show that treatments with chitosan–PVA increased tomato growth. Furthermore, chitosan–PVA increased the content of chlorophylls a and b, total chlorophylls, carotenoids, and superoxide dismutase. When chitosan–PVA was mixed with Cu NPs, the mechanism of enzymatic defense of tomato plants was activated. The chitosan–PVA and chitosan–PVA + Cu NPs increased the content of vitamin C and lycopene, respectively. The application of chitosan–PVA and Cu NPs might induce mechanisms of tolerance to salinity.

Selenium and Sulfur to Produce Allium Functional Crops

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.

Macro-nutrient uptake dynamics in greenhouse tomato crop

ABSTRACT This study verified the concentration over time of nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur (N, P, K, Ca, Mg, and S) in the leaves, stems, fruits, and roots of tomato plants. An indeterminate growth variety with ball-type fruits suited for greenhouse cultivation was used. The results showed that the distribution of minerals in the different organs of the plant varies over time. The minerals N, P, and K showed a tendency to decrease their concentration, while the concentration of Ca and S increased and that of Mg remained constant over time. The leaves had the highest concentrations of N, P, K, Ca, and Mg. The concentrations of K, for both leaf and stem, ranged between 20 and 30 g kg−1. N and K were the most extracted minerals, while P was the least extracted mineral. The information presented in this paper allows a better fertilization plan for growing tomatoes inside greenhouses.

Plant Nutrition and Agronomic Management to Obtain Crops With Better Nutritional and Nutraceutical Quality

Abstract The nutritional and nutraceutical quality of crops depends on different compounds, such as vitamins, trace elements, phenolic compounds, terpenoids, and pigments. The compounds in plant foods pass from crops to animal and human consumers, exerting beneficial effects in terms of less oxidative stress and lower rates of degenerative diseases. Similarly, the nutraceuticals that accumulate in plants before harvest contribute to the quality of processed products obtained from the crops. This biochemical set is synthesized and accumulated in the plant cells, and it is under genetic and environmental control. These nutraceutical components are important players that act as metabolites, cofactors, antioxidants, and stabilizers of membranes and macromolecules. The profiles and concentrations of nutraceuticals change in response to environmental stimuli, and their synthesis is dependent on the induction of gene expression in response to environmental elicitation. Agricultural practices, including mineral nutrition, biofortification, the manipulation of the environment, and the use of biochemical and microbial elicitors allow substantial improvements in their nutritional and nutraceutical quality. In this chapter, we specify the different growing systems, fertilizer management, the use of natural or synthetic elicitors and the soil and climate conditions that lead to the production of crops with better nutritional and nutraceutical qualities.

Nanometals as Promoters of Nutraceutical Quality in Crop Plants

Abstract In plants, animals, and humans, metals have various functions as enzyme cofactors and coadjuvants of the cellular redox balance and electron transfer. Metals in crops improve stress tolerance and increase nutritional and nutraceutical quality. Various studies have reported that the addition of metallic elements to plants is possible in nanometric or ionic form. In both forms, the built-in element metabolism covers the needs for plant growth. However, nanomaterials offer several advantages compared with the same elements in their ionic form: an increase in stress tolerance, additional antioxidant capacity, and a higher concentration of phytochemicals, which result in higher nutraceutical quality. Additionally, nanomaterials can be used in agriculture to increase plant tolerance to certain pathogens and abiotic stresses. Focusing on the environmental fate of nanomaterials and their transference into the ecological food web, most researches in the past addressed nanometals as industrial pollutants but investigated their agricultural application substantially less often. The challenge for agricultural research is not only to elucidate the effects of nanometals on crops but also to understand their impact on the soil, the environment, and animal and human health.

Dynamic Modeling of Silicon Bioavailability, Uptake, Transport, and Accumulation: Applicability in Improving the Nutritional Quality of Tomato

Silicon is an essential nutrient for humans, additionally is beneficial for terrestrial plants. In plants Si enhances tolerance to different types of stress; in humans, it improves the metabolism and increases the strength of skeletal and connective tissues as well as of the immune system. Most of the Si intake of humans come from edible plants creating a double benefit: first, because the absorption of Si increases the antioxidants and other phytochemicals in plants, thereby increasing its functional value, and second because the higher concentration of Si in plants increases intake in human consumers. Therefore, it is desirable to raise the availability of Si in the human diet through the agronomic management of Si accumulator species, such as corn, wheat, rice, soybeans, and beans. But also in such species as tomatoes, carrots, and other vegetables, whose per capita consumption has increased. However, there are few systematized recommendations for the application and management of Si fertilizers based on the physicochemical factors that determine their availability, absorption, transport, and deposition in cells and tissues. This study presents updated information about edaphic and plant factors, which determine the absorption, transport, and deposition rates in edible organs. The information was integrated into an estimated dynamic model that approximates the processes previously mentioned in a model that represents a tomato crop in soil and soilless conditions. In the model, on the other hand, was integrated the available information about key environmental factors related to Si absorption and mobilization, such as the temperature, pH, and soil organic matter. The output data of the model were compared against information collected in the literature, finding an adequate adjustment. The use of the model for educational or technical purposes, including the possibility of extending it to other horticultural crops, can increase the understanding of the agronomic management of Si in plants.

Effect of iodine application on antioxidants in tomato seedlings

El yodo es un micronutriente benefico; sin embargo, aun se desconoce su funcion metabolica. El objetivo de este trabajo fue evaluar el efecto de la aplicacion de yodo sobre la biomasa y la concentracion de antioxidantes en plantulas de jitomate. Se hicieron aplicaciones de yodo en forma de yoduro (I-) y yodato de potasio (IO3-), a concentraciones de 1 μM diariamente y 100 μM cada dos semanas, directo al sustrato o por aspersion foliar a plantulas de jitomate var. Rio Grande, bajo condiciones de invernadero. Se analizo el efecto del yodo sobre los antioxidantes enzimaticos: superoxido dismutasa, catalasa, ascorbato peroxidasa y glutation peroxidasa, asi como la concentracion de antioxidantes no enzimaticos: ascorbato, glutation y fenoles totales. Ningun tratamiento con I- o IO3- tuvo efecto negativo sobre la biomasa de las plantulas. Ademas, se encontro que los tratamientos de I- aplicado cada dos semanas, tanto via foliar como al sustrato, asi como IO3- y I- empleados via foliar diariamente, mostraron disminucion de 54 al 86 % en la actividad enzimatica de superoxido dismutasa, sin evidenciar cambios en las enzimas restantes. Por otro lado, en la concentracion de los antioxidantes no enzimaticos, el ascorbato y glutation presentaron un aumento de 22 y 85 %, respectivamente; en ambos casos con aplicacion diaria de I- por aspersion foliar. Los fenoles no mostraron cambios en los diferentes tratamientos