Vitamins and Nitrogen Requirements of Orchis Laxiflora Lamk.

Summary Orchis laxiflora Lamk. grown from seeds in asymbiotic cultures has a special need for thiamine which is necessary for its development; riboflavin though it has a favourable influence on germination is unable to replace it. The requirement of this orchid for a nitrogen source can be satisfied with casamino acids; no mineral nitrogen source can play the same role, but in presence of the organic source, the addition of ammonium nitrogen is an improving factor while nitric nitrogen is unfavourable.