FNS  Vol.3 No.3 , March 2012
Elevated Concentrations of Dietarily-Important Trace Elements and Macronutrients in Edible Leaves and Grain of 27 Cowpea (Vigna unguiculata L. Walp.) Genotypes: Implications for Human Nutrition and Health
Abstract: Legumes are a good source of calories, protein and mineral nutrients for human nutrition and health. In this study, the edible leaves and grain of 27 field-grown cowpea genotypes were assessed for trace elements and macronutrient den-sity at Manga in the Sudano-Sahelian zone of Ghana in 2005 and 2006, using inductively coupled plasma-mass spectrometry. The genotypes differed markedly in their accumulation of trace elements and major nutrients in edible leaves and grain. Except for P, the concentrations of K, Ca, Mg, S and Na were much higher in edible cowpea leaves than grain in 2005. A similar pattern was observed for Ca, Mg, S, Na in 2006. However, more dramatic variations were found in the micronutrient concentrations between edible cowpea leaves and grain. The levels of the trace elements Fe, Cu, Zn, Mn and B were sometimes 2- to 20-fold greater in leaves than grain of cowpea. Furthermore, there were strong genotypic differences in mineral density of cowpea leaves and grain. For the major nutrients, for example, IT93K-2045-29 and IT90K-59 accumulated greater concentrations of P, K, Ca, S and Na in both edible leaves and grain in 2006, while ITH98-46, which showed the least macronutrient density, exhibited the highest concentrations of Fe, Zn, Cu, Mn and B in edible leaves, as well as Fe, Cu and Mn in grain. These results have implications for cowpea breeding, as well as for human nutrition and health.
Cite this paper: A. Belane and F. Dakora, "Elevated Concentrations of Dietarily-Important Trace Elements and Macronutrients in Edible Leaves and Grain of 27 Cowpea (Vigna unguiculata L. Walp.) Genotypes: Implications for Human Nutrition and Health," Food and Nutrition Sciences, Vol. 3 No. 3, 2012, pp. 377-386. doi: 10.4236/fns.2012.33054.

[1]   P. A. Sanchez, A. M. N. Izac, I. Valencia and C. Pieri, “Soil Fertility Replenishment in Africa,” In: S. A. Breth, Ed., Achieving greater impact from research investments in Africa, Sasakawa Africa Association, Mexico City, 1996.

[2]   P. Drechel, D. Kunze and F. Penning de Vries, “Soil Nutrient Depletion and Population Growth in Sub-Saharan Africa: A Malthusian Nexus?” Population and Environment, Vol. 22, No. 4, 2001, pp. 411-423. doi:10.1023/A:1006701806772

[3]   R. Lal, “Soil Degradation as a Reason for Inadequate Human Nutrition,” Food Science, Vol. 1, No. 1, 2009, pp. 45-57. doi:10.1007/s12571-009-0009-z

[4]   U.E. MacIntyre, H. S. Kruger, C. S. Venter and H. H. Vorster, “Dietary Intakes of an African Population in Different Stages of Transition in the North West Province, South Africa: The THUSA Study,” Nutrition Research, Vol. 22, No. 3, 2002, pp. 239-256.

[5]   J. M. MacKeown, P. E. Cleaton-Jones and S. A. Norris, “Nutrient Intake among a Longitudinal Group of Urban Black South African Children at Four Interceptions between 1995 and 2000 (Birht-to-Ten Study),” Nutrition Research, Vol. 23, No. 2, 2003, pp. 185-197. doi:10.1016/S0271-5317(02)00489-X

[6]   D. Labadarios, N. P. Steyn, C. Mgijima and N. Daldla, “Review of the South African Nutrition Policy 1994-2002 and Targets for 2007: Achievements and Challenges,” Nutrition, Vol. 21, 2005, pp. 100-108. doi:10.1016/j.nut.2004.09.014

[7]   H. C. Sch?nfeldt and N. Gibson, “Healthy Eating Guidelines in the South African Context,” Journal of Food Composition and Analysis, Vol. 22, Suppl. 1, 2009, pp. S68-S73.

[8]   R. D. Graham, D. Senadhira, S. Beebe, C. Iglesias and I. Montasterio, “Breeding for Micronutrient Density in Edible Portions of Staple Food Crops: Conventional Approaches,” Field Crop Research, Vol. 60, No. 1, 1999, pp. 57-80. doi:10.1016/S0378-4290(98)00133-6

[9]   R. M. Welch and R. D. Graham, “Breeding Crops for Enhanced Micronutrient Content,” Trend in Food Science and Technology, Vol. 245, No. 1, 2002, pp. 191209.

[10]   H. E. Bouis, “Micronutrient Fortification of Plants through Plant Breeding: Can It Improve Nutrition in Man at Low Cost?” Proceedings of Nutritional Society, Vol. 62, No. 2, 2003, pp. 403-411. doi:10.1079/PNS2003262

[11]   M. B. Zimmermann and R. F. Hurrell, “Improving Iron, Zinc and Vitamin A Nutrition through Plant Biotechnology,” Current Opinion in Biotechnology, Vol. 13, No. 2, 2002, pp. 142-145. doi:10.1016/S0958-1669(02)00304-X

[12]   J. Kubota, “Copper Status of United States Soils and Forage Plants,” Agronomy Journal, Vol. 75, 1983, pp. 109-119. doi:10.2134/agronj1983.00021962007500060014x

[13]   G. A. Pedersen, G. E. Brink and T. E. Fairbrother, “Nutrient Uptake in Plant Parts of Sixteen Forage Fertilized with Poultry Litter: Nitrogen, Phosphorus, Potassium, Copper and Zinc,” Agronomy Journal, Vol. 94, No. 4, 2002, pp. 895-904.

[14]   M. R. Broadley, H. C. Bowen, H. L. Cotterill, J. P. Hammond, M. C. Meacham, A. Mead and P. J. White, “Variation in the Shoot Calcium Content of Angiosperms,” Journal of Experimental Botany, Vol. 54, No. 368, 2003, pp. 1431-1446. doi:10.1093/jxb/erg143

[15]   N. K. Fageria, “Dry Matter Yield and Shoot Nutrient Concentration of Upland Rice, Common Bean, Corn, and Soybean Grown in Rotation on an Oxisol,” Communication in Soil Science and Plant Analysis, Vol. 35, 2004, pp. 961-964. doi:10.1081/CSS-120030572

[16]   R. S. Gibson, “Technological Approaches to Combating iron Deficiency,” European Journal of Clinical Nutrition, Vol. 51, 1997, p. S27

[17]   B. Mulvihill and P. A. Morrissey, “An Investigation of Factors Influencing the Bioavailability of Non-Haem Iron from Meat Systems,” Irish Journal of Agriculture and Food Research, Vol. 37, 1998, pp. 219-226.

[18]   E. Forssard, M. Bucher, F. Machler, A. Mozafar and R. Hurrell, “Potential for Increasing the Content and Bioavialability of Fe, Zn, and Ca in Plants for Human Nutrition,” Journal of Science, Food and Agriculture, Vol. 80, No. 7, 2000, pp. 861-879. doi:10.1002/(SICI)1097-0010(20000515)80:7<861::AID-JSFA601>3.0.CO;2-P

[19]   R. M. Welch and R. D. Graham, “Agriculture: The Real Nexus for Enhancing Bioavailable Micronutrients in Food Crops,” Journal of Trace Elements in Medicine and Biology, Vol. 18, 2005, pp. 299-307. doi:10.1016/j.jtemb.2005.03.001

[20]   Food and Agriculture Organization FAO, “FAOUNESCO Soil Map of the World, World Soil Resource Rome,” Food and Agriculture Organization, Rome, Report 60, 1990.

[21]   A. Ataro, R. I. McCrindle, B. M. Botha, C. M. E. McCrindle and P. P. Ndibewu, “Quantification of Trace Elements in Raw Cow’s Milk by Inductively Coupled Plasma Mass Spectrometry (ICP-MS),” Food Chemistry, Vol. 111, No. 1, 2008, pp. 243-248. doi:10.1016/j.foodchem.2008.03.056

[22]   Fertilizer Society of South Africa FSSA, “Manual of Soil Analysis Methods,” Fertilizer Society of South Africa, South Africa Pretoria, 1974, p. 37.

[23]   StatSoft Inc., “STATISTICA Data Analysis Software System, Version 7.1,” 2005.

[24]   R. Bressani, “Nutritive Value of Cowpea,” In: S. R. Singh and R.O. Rachie, Eds., Cowpea Research, Production and Utilization, Wiley, Winchester, 1985, pp. 353-359.

[25]   S. S. Nielsen, T. A. Ohler and C. A. Mitchell, “Cowpea Leaves for Human Consumption: Production, Utilization and Nutrient Composition,” In: B. B. Singh, R. A. J. Moham, K. E. Dashiell and L. E. N. Jackai, Eds., Advances in Cowpea Research, International Institute of Tropical Agriculture, IITA, Nigeria, Ibadan, 1997, pp. 326-332.

[26]   B. C. Donovan, M. A. McNiven, J. A. McLeod and D. M. Anderson, “Protein Quality of Two Cultivars of Lupin Seeds Evaluated in Weaning Rats,” Animal Feed Science and Technology, Vol. 33, No. 1-2, 1991, pp. 87-95. doi:10.1016/0377-8401(91)90048-W

[27]   F. J. Nell, F. K. Siebrits and J. P. Hayes, “Studies on the Nutritive Value of Cowpeas (Vigna unguiculata),” South African Journal of Animal Science Vol. 22, 1992, pp. 157-160.

[28]   K. K. Ayisi, R. J. Nkgapele and F. D. Dakora, “Nodule Formation and Function in Six Varieties of Cowpea (Vigna unguiculata L. Walp) Grown in a Nitrogen-Rich Field Soil in South Africa,” Symbiosis, Vol. 28, 2000, pp. 17-31.

[29]   F. Kurdali, F. Al-Ain and M. Al-Shamma. “Nodulation, Dry Matter Production, and N2 Fixation by Fababean and Chickpea as Affected by Soil Moisture and Potassium Fertilizer,” Journal of Plant Nutrition, Vol. 25, No. 2, 2002, pp. 355-368. doi:10.1081/PLN-100108841

[30]   R. C. Abaidoo, H. H. Keyser, P. W. Singleton, K. E. Dashiell and N. Sanginga, “Population Size, Distribution, and Symbiotic Characteristics of Indigenous Bradyrhizobium sp. That nodulate TGx Soybean Genotypes in Africa,” Applied Soil Ecology, Vol. 35, No. 1, 2007, pp. 57-67. doi:10.1016/j.apsoil.2006.05.006

[31]   F. Pule-Meulenberg, C. Gyogluu, J. B. Naab and F. D. Dakora, “Symbiotic N Nutrition, Bradyrhizobial Biodiversity and Photosynthetic Functioning of Six Inoculated Promiscuous-Nodulating Soybean Genotypes,” Journal of Plant Physiology, Vol. 168, No. 6, 2011, pp. 540-548. doi:10.1016/j.jplph.2010.08.019