Similarities in the biochemical changes between solar UV exclusion and GA application in Amaranthus caudatus.

Seedlings of Amaranthus caudatus grown under UV exclusion filters (-UV -B <320nm; -UV -B/A <400nm) in the ambient solar radiation showed an enhancement in growth. This was accompanied by reduction in the synthesis of betacyanin but enhancement in the level of amino acids and proteins. The growth promotion and the accompanying biochemical changes were similar to the external application of GA3 to the seedlings under ambient solar radiation. The results are discussed in the light of similarities between UV exclusion and GA3 application in terms of diversion of amino acid precursors towards enhanced primary metabolism.