Micronutrient homeostasis in plants for more sustainable agriculture and healthier human nutrition.

The provision of sustainable, sufficient, and nutritious food to the growing population is a major challenge for agriculture and the plant research community. In this respect, the mineral micronutrient content of food crops deserves particular attention. Micronutrient deficiencies in cultivated soils and plants are a global problem that adversely affects crop production and plant nutritional value, as well as human health and well-being. In this review, we call for awareness of the importance and relevance of micronutrients in crop production and quality. We stress the need for better micronutrient nutrition in human populations, not only in developing but also in developed nations, and describe strategies to identify and characterize new varieties with high micronutrient content. Furthermore, we explain how adequate nutrition of plants with micronutrients impacts metabolic functions and the capacity of plants to express tolerance mechanisms against abiotic and biotic constraints. Finally, we provide a brief overview and a critical discussion on current knowledge, future challenges, and specific technological needs for research on plant micronutrient homeostasis. Research in this area is expected to foster the sustainable development of nutritious and healthy food crops for human consumption.

Revegetation of the acidic, As contaminated Jales mine spoil tips using a combination of spoil amendments and tolerant grasses.

A combination of metal immobilising agents and metal tolerant plants has been utilised in order to reduce the environmental impact of the acidic metal contaminated Jales mine spoil tips. The addition of Beringite (a modified aluminosilicate), steel shots (iron bearing material) and organic matter as spoil amendments resulted in changes in arsenate (As) concentrations and pH of spoil material and improved plant growth. The application of Beringite increased both pH and plant available As concentrations. A 4-year follow up of the spoil analysis demonstrated that the effect of the spoil treatments was stable following treatments, however, the effectiveness did not increase any more after 2 years. The use of metal tolerant grasses in combination with spoil treatments resulted in a rapid and effective revegetation of the As contaminated Jales mine spoils. Colonisation and reproduction of Agrostis castellana and Holcus lanatus was most successful when the substrate contained a combination of all three additives. Plant performances could be enhanced by supplementation of a phosphate fertiliser. The rapid reproduction of the two grass species makes them very suitable for revegetation purposes. Agrostis castellana and Holcus lanatus apparently exhibited a level of metal- and As-tolerance sufficient for survival on untreated spoil, but in the first stages of revegetation the use of spoil amendments was found to be essential. Organic matter in combination with Beringite and/or steel shots resulted in decreased As in the aboveground biomass, protecting possible grazers and predators from undesirable levels of As.