Cell cycle inhibition of potato root tips treated with Imazethapyr

Imazethapyr inhibits the progression of the cell cycle in potato (Solanum tuberosum L.) root tips. A variety of existing methods were developed and adapted for the determination of mitotic index in potatoes. Significantly lower numbers of mitotically dividing cells were recorded after just 30 min of incubation with imazethapyr (0.35 μM) and the effect was characterised as an inhibition of mitotic entry. Imazethapyr inhibits a key enzyme in the biosynthesis of the branched-chain amino acids, valine, leucine and isoleucine. The inhibition of mitotic entry can be considered to be a secondary manifestation of a primary metabolic change induced by imazethapyr.