ENRICHMENT OF SOME B-VITAMINS IN PLANTS WITH APPLICATION OF ORGANIC FERTILIZERS

A review of the literature showed that plants grown with organic ferti lizers often contain higher concentrations of vitamins B-1 (thiamin) a nd B-12 (cyanocobalamin) as compared with plants grown with inorganic fertilizers. Since plant roots were recently shown to be able to absor b B-1 and B-12, it was thus suspected that organic fertilizers (such a s manure of diverse sources or sewage sludges which often contain rela tively high concentrations of several vitamins) introduce additional v itamins into the soil which in turn leads to increased vitamins in the plants. This possibility was studied by measuring the B-12 content in the seeds of soybean and barley and in the leaves of spinach plants g rown in soils amended with pure B-12 Or COW dung (which is naturally r ich in B-12) The addition of pure B-12 or cow dung did not after the B -12 content in the soybean seeds but significantly increased that in t he barley kernels and in the spinach leaves. For example, the addition of cow dung at the rate of 10 g kg(-1) increased the B-12 content in barley kernels by more than threefold (from 2.6 to 9.1 ng g(-1) DW) an d in spinach leaves by close to twofold (from 6.9 to 17.8 ng g(-1) DW) . Long-term addition of organic fertilizers to the soil also significa ntly increased the soil content of this vitamin. Since plants cannot s ynthesize B-12 and thus plant foods are normally fully devoid of (or h ave very low concentrations of) this vitamin, the finding that plants grown with organic fertilizers may contain relatively higher concentra tions of this vitamin may have nutritional consequences in that the co nsumption of these plants by humans would inadvertently increase their intake of this vitamin. This may be of special benefit to people livi ng by choice or by necessity on strict vegetarian diets who are known to be in danger of B-12 deficiency.