ROLE OF MICRONUTRIENT IN HUMAN LIFE:
Fortification is the process of adding vitamins or minerals to foods to increase its overall nutritional value. A disquieting part of worlds population undergoes from “hidden hunger” the term used for micronutrient deficiencies because the symptoms often cannot be seen or felt. Body required very small quantities of vitamins and mineral elements for normal physical and mental development, their deficiency affected more than a third of the worlds population. The micronutrient deficiencies results in health damage, learning disabilities, cause death, harm reproduction, reduce intelligence, educability and academic achievement and damage work productivity and occupational choices. The most common deficiencies interfered with child growth and development which is sometimes permanent. Important micronutrients with public health significance include vitamin A, iron, iodine, B. complex vitamins and zinc (Johnson et al., 2004).
The concept of hidden hunger (deficiency of certain vitamins and micronutrient nutrients despite eating enough calories) has been well established in the last two decades (Nilson and Piza, 1998). As a result, the importance of micronutrient nutrition is increasing at a great stride.
Micronutrients include Zn, Fe, Mn, Cu, B, Mo, Co, Cu, Cl and Ni. However, each has a very narrow range of deficiency and toxicity (Imtiaz et al., 2010).
Fortification of food with micronutrients is an effective tool for reducing micronutrient malnutrition as part of a food-based approach. For fortification cereals as wheat flour, maize meal etc. are important micronutrient carriers because these are staple foods in many parts of the world and involved in many food preparations (Allen et al., 2006).
Micronutrient malnutrition affects more than half of the world population, particularly in developing countries. Biofortification, the delivery of micronutrients via micronutrient-dense crops, offers a cost effective and sustainable approach, complementing these efforts by reaching rural populations. Concerted international and national fortification and supplementation efforts to curb the scourge of micronutrient malnutrition are showing a positive impact, unfortunately without reaching the goals set by international organizations.
Zn deficiency causes serious health problems in human beings (Cakmak, 2008). Zinc deficiency has become fifth most important reason causing health problems in developing countries (WHO, 2002). More than 2.5 billion people globally are deficient of Zn element (Muller and Krawinkel, 2005).
Micronutrients are as important for the plant growth as are the macronutrients. Manganese (Mn) is an essential micronutrient involved in photosynthesis and as an enzyme antioxidant-cofactor. Greger (1999) reported that Mn is essential for reproduction, carbohydrate and lipid metabolism and in brain functioning. It also takes part in neurotransmitter synthesis and in the brain for several enzymes, such as the antioxidant enzyme superoxide dismutase as a cofactor (Golub et al., 2005). Central nervous system most critically disturbed by manganese and it stored into the brain non-haem iron portion of the globus pallidus and subthalamic nuclei (Aschner et al., 2006). In humans manganese deficiency causes anorexia, weakness and apathy (Huang et al., 1989).
Manganese is a crucial micronutrient in plants and human beings because it intricate in the structure of proteins and in enzymes as an activator. So manganese required for the normal growth, development, metabolism and reproduction in both plants and human beings because it act as a co-factor in many enzymes. Its deficiency cause severe abnormalities both in plants and humans.
Bioavailable micronutrients in the edible parts of staple crops at concentrations high enough to impact on human health can be obtained through breeding programmes provided that sufficient genetic variation for a given trait exists or through transgenic approaches. Research and breeding programmes are underway to enrich the major food staples in developing countries with the most important micronutrients: iron, pro vitamin A, zinc contents and folate (Johnson et al., 2005).
MICRONUTRIENTS APPLICATION METHODS
Plant nutrients can be made available by distinctive nutrient application practices; these consist of
1. Soil fertilization,
2. Nutripriming
3. Foliar spray
All of these application processes have some advantages and limitations (Ali et al., 2008). Soil and foliar applications are the most prevalent methods of micronutrient addition but the cost involved and difficulty in obtaining high quality micronutrient fertilizers are major concerns with these in developing countries. Micronutrients availability through foliar spray has resulted in high crop yield (Arif et al., 2006).
Micronutrient seed treatments, as seed priming and seed coating, are striking and easy substitute. Arif et al., (2007) found that micronutrient application through seed treatments improved the stand establishment, advances phonological events, increases yield and micronutrient grain contents.
In seed priming, seeds are partially hydrated to allow metabolic events to occur without actual germination, and then re-dried to permit routine handling (Bradford, 1986). Primed seeds germinate faster than non-primed, have better and more uniform germination (Farooq et al., 2006, 2009).
In seed coating, beneficial materials like nutrients, microbes, plant growth promoter and other materials are adhered to the seed with some material that is sticky in nature. Many experiments revealed that Zn coating has potential to improve the crop (Masuthi et al., 2009). Numerous reports showed that wheat (Wilhelm et al., 1988), rice and forage legumes yield improved by nutripriming (Sherrell, 1984).
To overcome the micronutrient deficiency the seed treatment is the suitable and most economical method. In crux, Mn plays very important role in the plant physiology. However, influence of Mn application and allopathic water extracts in improving the productivity and grain biofortification of rice and wheat has rarely been explored.
The authors are associated with the Department of Agronomy, University of Agriculture, Faisalabad, Pakistan.