Stimulating endogenous hormone content by plant extracts: increased in vitro regeneration of flax (Linum usitatissimum) cultivars

In the MS medium containing flax plant extract, the endogenous GA and IAA hormone content in the explant tissues is stimulated and a high regeneration rate and rooting are achieved.

In vitro regeneration efficiency is directly related to the endogenous hormone level of the plant. In this context, the potential regeneration efficiency of explants can be maximized by utilizing the endogenous plant hormone content in in vitro tissue culture studies. In this study, the effects of plant extracts obtained from flax (Linum usitatissimum L.) varieties were investigated on the in vitro regeneration capacity, rooting performance and tissue hormone content of flax cultivars. The Clark, Madaras and 1886 Sel. varieties were used as explants and plant extract sources. Abscisic acid (ABA), gibberellic acid (GA) and indole-3-acetic acid (IAA) contents of plant extracts were analyzed by the HPLC method. In vitro regeneration experiments were carried out in Murashige and Skoog (MS) media containing four different plant extract doses (0, 5 ml l⁻¹, 10 ml l⁻¹ and 15 ml l⁻¹) and chemical control. Tissue endogenous GA and IAA contents were determined in two stages as shoot regeneration (SH) and rooting stage (RH). Differences were observed in the examined regeneration parameters and endogenous hormone content among the varieties. The best shoot regeneration rate in all varieties was obtained from the medium containing 10 ml l⁻¹ plant extract. Besides, the best rooting rate for all varieties was determined in the medium containing 15 ml l⁻¹ plant extract. The high GA content of SH tissues decreased in the RH stage. On the other hand, the tissue IAA content was high in the RH stage, and the GA content decreased or remained constant. The effect of the plant extract on the endogenous hormone content was higher than the chemical control. The results obtained proved that the phytohormone content of the plant extract increased regeneration success by stimulating the endogenous hormone content in the tissues. Determining the effect of plant extracts on tissue regeneration will contribute to evaluating these components as bio-fertilizers or bio-stimulants.