Changes of 6-benzylaminopurine and 2,4-dichlorophenoxyacetic acid concentrations in plant tissue culture media in the presence of activated charcoal

Abstract

The rate of adsorption of 6-benzylaminopurine (BAP) and 2,4-dichlorophenoxyacetic acid (2,4-D) by activated charcoal (AC) from liquid and semi-solid tissue culture media was determined using 8-[14C]-BAP and 2-[14C]-2′,4′-D. For both liquid and semi-solid media an essentially constant ratio of free BAP: AC-bound BAP was reached between 5 and 10 days after preparation of the media. Pronounced increases in the level of available 2,4-D in the medium occurred, when either the initial BAP or 2,4-D level or both were raised to 5 × 10−4 M. When 2,4-D was used at 5 × 10−4 M the medium component sucrose (40 g l−1) caused a pronounced increase in available 2,4-D. Conversely the inclusion of the combined macro- and micronutrients markedly reduced the availability of free 2,4-D in the medium.