Use of zincon to study uptake and accumulation of zinc by zinc tolerant and hyperaccumulating plants

A quick and cheap method to digest plant material using 2% sulphosalicylic acid and to analyze the extract for zinc (Zn) using the colorimetric agent zincon is described. It is shown that the recovery of Zn is excellent, within 90% of that determined by nitric acid digestion and atomic absorption spectrophotometry (AAS). The sensitivity is similar to the AAS. Its usefulness for investigating Zn uptake by the Zn hyperaccumulator Cardaminopsis halleri is investigated. Almost 50% of the variation between samples is due to between-plant variance, with between-leaf variation making up a further 37%. Some of the between-leaf variance is due to age: young leaves contain less Zn than old leaves. In roots, root tips contain about twice as much Zn as root bases.