Biological detection auxins

Brassinolide was tested on 17 bioassays for growth substance. The results led to claims that brassinolide possesses a broad spectrum of biological activity, including gibberellin-, auxin- and cytokinin-like activity (32,34). These claims must be treated with some caution however, since the claimed "specificity of some of the bioassays selected is questionable. At present three bioassay techniques (35,36,37) are used routinely for the detection of brassinolide activity. All three assays are sensitive to auxin, which is a prerequisite for the detection of brassinolide-like compounds. This is not to say that brassinolide has auxin-like activity, but rather there seems to be an interaction of cooperative action between auxin and BR. 

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