Abstract
For the purpose of checking possible conversion of dihydrothiamine into thiamine during germination and growth of plants, either the wheat grains, previously immersed in a dihydrothiamine solution, were germinated or the grains, previously germinated, were maintained in the cotton-sponge containing dihydrothiamine solution. In both cases dihydrothiamine was decomposed to a great extent ; a small portion of dihydrothiamine and a negligible amount of thiamine were detected in grains. Incubation of dihydrothiamine with homogenate of germinated wheat grains for 22 hours resulted also in decomposition of dihydrothiamine and practically no formation of thiamine, while incubation with the boiled homogenate showed a similar decomposition of dihydrothiamine. Homogenates of sprouts of soy beans or green beans, onions and spinachs destructed dihydrothiamine on incubating them with dihydrothiamine. Thus dihydrothiamine was proved to be unstable and decomposed easily on its contact with vegetable protein and the hypothesis of dihydrothiamine as a precursor of thiamine biosynthesis was not probable.
