However, in early studies of isolated
tissue cultures of plants, it was discovered that root cultures required
the addition of thiamine (Bonner, 1940). This suggested that
thiamine was formed in the leaves and transported to the roots and
such transport could also be shown (Bonner, 1942). These and following
findings of growth-promoting effects of thiamine additions
on stem growth of some plants, stimulated during a number of
years a strong interest in thiamine for applications in plant cultivation
(Rasmussen, 1999). Despite extensive studies, these early
experiments did however not confirm any general growth promoting
effects of thiamine additives.