Thiamine (vitamin B1) is a water soluble vitamin that is essential
in the cellular primary metabolism. It is a coenzyme that in the form
of thiamine pyrophosphate is involved in essential reactions in carbohydrate
metabolism, such as glycolysis, Krebs cycle and the pentose
phosphate cycle. It is generally assumed that the plants
produce their own vitamins in quantities sufficient that they should
not suffer vitamin deficiency. However, in early studies of isolated
tissue cultures of plants, it was discovered that root cultures required
the addition of thiamine (Bonner, 1940).