Effect of benzyladenine and indolebutyric acid on ultrastructure, glands formation, and essential oil accumulation in Lavandula dentata plantlets

Abstract

Lavandin (Lavandula dentata) axillary buds were grown in Linsmaier-Skoog (LS) medium solidified with 10 % bactoagar (control) and supplemented with 0.1 mg dm-3 benzyladenine (BA), 0.1 mg dm-3 indolebutyric acid (IBA) or both plant growth regulators. In the studied conditions the axillary buds developed into plantlets. The addition of BA inhibited the formation of glands by 44 % as compared with the control plantlets and also inhibited their development: these plantlets had the highest number of unbroken glands (in pre-secretory state) when compared with plantlets grown in the other conditions. The presence of BA stimulated chloroplast formation, and increased the content of essential oils by 150 % with respect to the control plantlets. It also increased their secretion, and the number of lipid droplets in the chloroplasts, cytosol and plasmalemma. On the contrary, the presence of IBA decreased the essential oil concentration in plantlets by 31 % when compared with the control ones and inhibited their secretion capacity.