A breakthrough in the study of polar auxin transport proved to be the results obtained through the use of molecular biology techniques - characteristics of the respective mutants , cloning of genes AUX1 and PIN , encoding putative auxin transport carriers that control dokomórkowy and extracellular transport of the hormone. Specific demonstrated by immunocytochemistry , polar location of these proteins in cells, stem and root of Arabidopsis thaliana. It was also found that the location of PIN proteins may be subject to dynamic changes ( vesicular transport ) and their distribution in the plazmalemmie controlled by elements of the cytoskeleton . Additional information on polar auxin transport in a survey , using its inhibitors - fitotropiny . Although it is not entirely clear polar auxin transport mechanism in a photo- and grawitropizmie plants, in the light of the test results, an asymmetric distribution of auxin in the cells during operation of the respective stimuli may be due to the transport of the targeted hormone , regulated by specific localized auxin transport carriers .