HORMONES OF ALGAE - PRESENT STATE OF KNOWLEDGE .1. RESEARCH AND TENTATIVES FOR IDENTIFICATION OF AUXINS

The effect of phycological extracts on algae in culture and on other plants as well as the effect of extracts of other plants on algae show that the growth of these thallophytes is probably controlled by substances of hormonal nature. This hypothesis is strengthened by experiments on tropisms, periodisms, regeneration, polarity and apical control. The presence of active substances has been indicated by the oat coleoptile growth test. Other recent experiments have revealed the presence of several auxins in the thallus of numerous algae belonging to various taxonomical, anatomical, physiological and ecological units and at different stages of development. These experiments have been used, with more or less certainty, to identify phenyl acetic acid, indolyl-3-acetic acid and various other indolic compounds (such as tryptophan, indolyl-3-carboxylic acid, indolyl-3-pyruvic acid, indolyl-3-glycollic acid, indolyl-acetonitril, indolyl-ethyl acetate, indolyl-aldehyde, indolyl-acetamide, tryptamine, bound indolic auxins...). These experiments have revealed other stimulating plant growth substances but their chemical nature is still unknown. Distribution and partition of auxins in the thallus of a few species have been well studied along with their anabolic and catabolic properties.