TIBA 2,3,5-triiodobenzoic

Nardi et al. (1994), by using two inhibitors of auxin (TIBA = 2,3,5-triiodobenzoic acid and PCIB = 4-chlorophenoxy-isobutyric acid), demonstrated in Nicotiana plumbaginifolia that the LMS component of humic matter is the fraction endowed with auxin-like activity, although the pathways followed by IAA and the LMS fraction in inducing their effects may be somewhat different. Humic matter, IAA, and IAA inhibitors stimulated peroxidase activity in tobacco. When the Nicotiana tissues were treated with the humic fraction and IAA, there was a minor polymorphism in the esterase isoenzymes. The presence of both TIBA or PCIB together with LMS or IAA restored the esterase profile obtained from control tissues. 

The iodine anologue of TBA, 2,3,5-triiodobenzoic acid (TIBA), is of similar activity but is no longer manufactured or marketed. 

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