Role of Endogenous Auxins and Gibberellins in Growth-correlative Effects of Root Metabolism and in the Hypocotyl Regeneration of Flax Seedlings

Abstract

Summary The paper deals with studies on the phytohormonal nature of growth correlations in flax seedlings. The level of endogenous auxins increased while that of endogenous gibberellins decreased in cotyledons within 12 to 72 h after the amputation of roots (together with the hypocotyl base). This was probably associated with the well-known capacity of roots to inactivate auxins and biosynthesise gibberellins. Decapitation of plants below cotyledons resulted in the regeneration of adventitious buds on the hypocotyl stump. Prior to this regeneration, the level of endogenous auxins in this stump decreased while that of endogenous gibberellins increased. This explains inhibiting effects of exogenous auxin and promoting effects of exogenous gibberellin upon the hypocotyl regeneration demonstrated earlier.