Zinc for the improvement of crop production and human health

Abstract

Zinc (Zn) is an exceptional micronutrient regarding itsrelevance in biological systems because it is the onlytrace metal represented in all classes of enzymes(Broadley et al. 2007). A large diversity of essentialcellular functions and metabolic pathways are directlyinfluenced by Zn including function and structural sta-bilityofproteins,integrityofbiologicalmembranesandprotection against reactive oxygen species (Cakmak,2000). Nearly 2800 proteins in biological systems re-quire Zn for their activity and structural stability(Andreini et al. 2009).It is, therefore, not surprising that crop plants showrapid and particular disturbances in growth and devel-opmentwhentheyaregrowingonlowZnsoils.Atleastone-third of the cultivated soils globally is estimated tocontain too low amounts of bioavailable Zn (Sillanpaaand Vlek 1985) for optimal crop production. Low bio-availability of Zn not only reduces plant productivity, italsoimpairsnutritionalqualityoftheharvestedproductsby lowering Zn density in seeds/grains.These problems in crop production, food qualityand human health associated with Zn deficiency andthe environmental issues related to Zn were addressedat the 3rd International Zinc Symposium held inHyderabad, India, 10–14 October, 2011, with 195participants from 30 countries. The event was jointlyorganized by the International Zinc Association (IZA),the International Fertilizer Industry Association (IFA),Fertilizer Association of India (FAI) and HarvestPlus.The symposium consisted of 6 sessions devoted tothe following topics.& human nutrition and health,& soil and crop management,& zinc fertilizers and crop nutrition,& plant physiology& genetics and molecular biology& environmental issuesThis short article summarizes the main findings ofthis symposium. Details of the findings and conclu-sions can be found in the articles in this special issue.Low Zn supply by soils to crops is becoming moreprominent due to the use of high yielding cultivarsand/or application of macronutrient fertilizers unbal-anced by Zn fertilization. In cropping areas with in-tensified farming, additional management practices(e.g., Zn fertilization) are often required to avoid Zndepletion of soils to sustain crop productivity andnutritional quality of the harvested product. The deter-mination of soil bioavailable Zn, however, is not