Selenium Isotope Studies In Plants Development And Validation Of A Novel Geochemical Tool And Its Application To Organic Samples

Selenium (Se), being an essential nutrient and a toxin, enters the food chain mainly via plants. Selenium isotope signatures were proved to be an excellent redox tracer, making it a promising tool for the exploration of the Se cycle in plants. The analytical method is sensitive on organic samples and requires particular preparation methods, which were developed and validated in this study. Plant cultivation setups revealed the applicability of these methods to trace plant internal processes.

Selenium (Se), being an essential nutrient and a toxin, enters the food chain mainly via plants. Selenium isotope signatures were proved to be an excellent redox tracer, making it a promising tool for the exploration of the Se cycle in plants. The analytical method is sensitive on organic samples and requires particular preparation methods, which were developed and validated in this study. Plant cultivation setups revealed the applicability of these methods to trace plant internal processes. This work was published by Saint Philip Street Press pursuant to a Creative Commons license permitting commercial use. All rights not granted by the work's license are retained by the author or authors.

The attraction of selenium isotopes as a paleoenvironmental tracer lies in the high redox potential of selenium oxyanions (SeIV and SeVI), the dominant species in the modern ocean. The largest isotopic fractionations occur during oxyanion reduction, which makes selenium isotopes a sensitive proxy for the redox evolution of our planet. As a case study we review existing data from the Neoarchean and Paleoproterozoic, which show that significant isotopic fractionations are absent until 2.5 Ga, and prolonged isotopic deviations only appear around 2.3 Ga. Selenium isotopes have thus begun to reveal complex spatiotemporal redox patterns not reflected in other proxies.

Crop plants growing under field conditions are constantly exposed to various abiotic and biotic stress factors leading to decreased yield and quality of produce. In order to achieve sustainable development in agriculture and to increase agricultural production for feeding an increasing global population, it is necessary to use ecologically compatible and environmentally friendly strategies to decrease the adverse effects of stresses on the plant. Selenium is one of the critical elements from the biological contexts because it is essential for human health; however, it becomes toxic at high concentrations. It has been widely reported that selenium can promote plant growth and alleviate various stresses as well as increase the quantity and quality of the yield of many plant species. Nonetheless, at high concentrations, selenium causes phytotoxicity. In the last decade, nanotechnology has emerged as a prominent tool for enhancing agricultural productivity. The production and applications of nanoparticles (NPs) have greatly increased in many industries, such as energy production, healthcare, agriculture, and environmental protection. The application of NPs has attracted interest for their potential to alleviate abiotic and biotic stresses in a more rapid, cost-effective, and more sustainable way than conventional treatment technologies. Recently, research related to selenium-NPs-mediated abiotic stresses and nutritional improvements in plants has received considerable interest by the scientific community. While significant progress was made in selenium biochemistry in relation to stress tolerance, an in-depth understanding of the molecular mechanisms associated with the selenium- and nano-selenium-mediated stress tolerance and bio-fortification in plants is still lacking. Gaining a better knowledge of the regulatory and molecular mechanisms that control selenium uptake, assimilation, and tolerance in plants is therefore vital and necessary to develop modern crop varieties that are more resilient to environmental stress. This book provides a comprehensive overview of the latest understanding of the physiological, biochemical, and molecular basis of selenium- and nano-selenium-mediated environmental stress tolerance and crop quality improvements in plants. It helps researchers to develop strategies to enhance crop productivity under stressful conditions and to better utilize natural resources to ensure future food security and to reduce environmental contamination. Finally, this book is a valuable resource for promoting future research into plant stress tolerance, and a reference book for researchers working on developing plants tolerant to abiotic and biotic stressors as well as bio-fortification and phytoremediation.

Selenium: Geobotany, Biochemistry, Toxicity, and Nutrition focuses on the properties, characteristics, reactions, applications, chemistry, and transformations of selenium. The book first offers information on the geological distribution of selenium, including the formation of seleniferous soils, chemical forms of selenium in soils, selenium in water, selenium on the sea floor and in sea water, and geobotany. The text then takes a look at selenium indicator in plants and accumulation of selenium by plants. Discussions focus on selenium accumulations in indicator plants; selenium accumulation in farm crops and native grasses; factors that influence selenium accumulation in plants; and identification of indicators by germination tests. The manuscript elaborates on selenium poisoning in animals and prevention and control of selenium poisoning. Acute selenium poisoning, chronic selenium poisoning by inorganic selenium, and recognition of poisonous range plants are also discussed. The text also examines selenium in nutrition and the chemistry of selenium. The publication is a valuable source of data for readers interested in the study of selenium.

The biological importance of selenium has been firmly established by scientists for its intricate roles in various biochemical and physiological mechanisms related to animal and human health. To evaluate different facets of selenium in today’s complex environment and to provide a worldwide platform for multi-disciplinary selenium researchers, the 6th International Conference on Selenium in the Environment and Human Health was held from 27 to 30 October 2019 in Yangling/Xi’an, China. This proceedings volume brings together 103 extended abstracts prepared by contributors from academia, industry, and governmental agencies in 18 countries, including some most recent research findings among different selenium research disciplines from cell molecular and plant biology, geochemistry, biofortification, to environmental and health management. Selenium researchers worldwide provide extraordinary new knowledge on selenium in the peer-reviewed texts contained within this book.