Direct Determination of Plant-Growth Related Metabolites by Capillary Electrophoresis with Spectrophotometric UV Detection

The detection of plant hormones and growth regulators is of great interest for many biological studies especially in the determination of metabolites related to plan growth and differentiation. In this work, we propose a simple method based on capillary electrophoresis (CE) for the separation of different classes of plant growth regulators such as auxins, cytokinins, gibberelic acid and abscisic acid. CE with UV detection was used and the analytical conditions were as follows: phosphate buffer 25 mmol L-1, for all the measurements and the separation conditions pH 12 or 2.5, by hydrodynamic injection 5 s at 10 cm and separation voltage of 22 kV. The absorbance detection was fixed at either 220 nm or 270 nm depending on a given phytohormone class. Under these conditions, phytohormones (Indole-3-acetic acid (IAA), Gibberellic acid (GA(3)), Abscisic acid (ABA), picloram, zeatin and 6-Benzylaminopurine (BAP) were separated in approximately 3 to 5 min. The plant material used to verify the possibility of detection of hormone/plant growth regulators was citro (Citrus sinensis L. Osbeck) callus in the multiplication stage. In the plant tissue sample, zeatin was successfully detected. The results confirmed the potential use of CE as an efficient alternative and simple method to the classical procedures used for phytohormone detection in plant tissues.