Information regarding auxin metabolism will most likely lead to genetic and chemical manipulation of endogenous hormone levels resulting in desirable growth and differentiation of important crop species. Now although basipetal transport appears to predominate in coleoptiles and shoots it is probably not as stirct as once thought. Movement of the compound should be driven by metabolic forces. This is also true for auxin transport because metabolic inhibitors and anaerobic conditions block auxin transport. The compound should be able to move against a concentration gradient.
Auxins can move very rapidly against concentration gradients in a basipetal direction.
The transport system should show specificity for a certain compound. The plus form is more active and is transported better than the minus form. Specific inhibitors of auxin transport such as 2,3,5-triiodobenzoic acid mimic auxin and therefore block its transport. The compound being transported should show a saturation effect, when all trans- port sites are saturated the addition of more plant growth substance should have no effect. Auxin transport has been shown to be saturable in many test systems.