Beyond Conventional Auxins: Evaluating DCPE and DCP Pulse Applications for Enhanced Rooting in <i>Lavandula angustifolia</i> Mill.

Abstract

Efficient adventitious root formation is crucial for Lavandula angustifolia Mill. propagation. This study evaluated the effects of continuous and short-duration pulse applications (1 min, 1 h, and 1 day) of the auxin dichlorprop (DCP) and its prodrug dichlorprop-2-ethylhexyl ester (DCPE) at varying concentrations on adventitious rooting and callus formation. DCPE generally proved more effective than DCP in promoting rooting, especially at lower concentrations, with continuous application of 0.1 µM DCPE yielding the highest number of adventitious roots. Notably, a brief 1 min pulse of 2.5 µM DCPE induced superior rooting, including high root number and weight, while minimizing callus formation compared to longer exposures. In contrast, 1 h pulse treatments showed a positive correlation between auxin concentration and root number but led to substantial callus development. These findings highlight DCPE’s potential as an efficient auxin source for lavender propagation, likely due to its rapid hydrolysis to active DCP within plant tissues, facilitating systemic distribution. The enhanced rooting achieved with short pulse treatments offers significant implications for optimizing commercial propagation for this economically important aromatic plant.

Keywords

• adventitious rooting
• auxin prodrugs
• <i>L. angustifolia</i>
• auxin pulse treatment
• in vitro propagation