Changes in diffusible indole-3-acetic acid from various parts of tulip plant during rapid elongation of the flower stalk

In order to chemically identify the putative indole-3-acetic acid (IAA) and to confirm the native source of auxins account for rapid elongation of the floral stalk of tulip, we examined diffusible IAA from various parts of tulip plant during rapid elongation of the flower stalk. IAA was identified in the diffusates collected from the leaves, internodes, and floral organs with gas chromatography (GC)–mass spectrometry. The amount of diffusible IAA from different plant organs followed the order of that the internodes > flower organs > leaves during the period of rapid elongation of the floral stalk. The diffusible IAA from internodes reached its peak amount at different time than did diffusible IAA from the flower. The results obtained indicated that the top internode is probably the major source of auxins account for rapid elongation of the flower stalk.