LED illumination and plant growth regulators’ effects on growth and phenolic acids accumulation in Moluccella laevis L. in vitro cultures

Abstract

Moluccella laevis L. (Lamiaceae) is an annual ornamental plant, naturally occurring in the areas of Western and Central Asia (Irano-Turanian area). It is a popular ornamental species, but its phytochemical profile remains poorly studied. This study presents the first report on in vitro cultures of M. laevis. The influence of two types of illumination and plant growth regulators (PGRs) supplementation on the morphogenetic response and the content of phenolic compounds were examined. Shoots were cultured on Murashige and Skoog (MS) solid basal medium. White light or photosynthetic active radiation (PAR) as well as three concentrations of 6-benzylaminopurine (BA) 2, 3 or 4 µM and one of the three auxins: 1-naphthaleneacetic acid (NAA), indole-3-acetic acid (IAA) or 4-amino-3,5,6-trichloropicolinic acid (picloram—PIC) at concentration of 0.5 µM were used for shoot proliferation. The highest number of axillary shoots per explant (3.4) was obtained for shoots grown on MS medium supplemented with 3-µM BA and 0.5-μM NAA under PAR light. However, the effect of PGRs treatment on shoot growth and development was stronger than the influence of light. The phytochemical analysis using Ultra-Performance Liquid Chromatography–Mass Spectrometry allowed identification of four hydroxycinnamic acids (caffeic, ferulic, rosmarinic, chlorogenic) and two cyanidin glycosides (cyanidin 3-O-galactoside, and cyanidin 3-O-malonylglucoside) in shoot clusters and callus tissue.