Abstract
Polyamines (PAs) are polycationic compounds found in all living organisms and play crucial roles in growth and survival. We here show the 'Polyamine and paraquat (PQ) transport assay' protocol, which can be used to examine the uptake activity of PA/PQ transporters. We have used this protocol to demonstrate that PUT3 in Arabidopsis is a polyamine transporter and is able to take up spermidine and its analog paraquat.