A Study on the Germination of Origanum acutidens L. Seeds Subjected to Pre-Treatment of Gibberellic Acid and Colchicine

Abstract

In Türkiye, the general name for aromatic plant species belonging to the Lamiaceae family is “thyme”. However, species containing thymol/carvacrol type essential oil are considered “thyme”. Origanum acutidens is one of the thyme species that grows endemic in the Northeastern Anatolia Region of Türkiye. The low germination rate of its seeds is one of the factors limiting the studies conducted on this plant. This study was conducted to investigate the effects of different doses of colchicine and gibberellic acid on germination in O. acutident seeds. Seeds collected from the plant’s natural habitat at the end of the flowering period were used as plant material. The experiment was planned as control (only distilled water) and treatments consisting of three different gibberellic acid (GA3) [100 ppm (GA1), 200 ppm (GA2) and 300 ppm (GA3)] and four different colchicine doses [0.01 mM (C1), 0.02 mM (C2), 0.04 mM (C3) and 0.08 mM (C4)]. The applications were kept at 25±1 ⁰C for 12 hours. After the waiting period, all seeds were filtered and placed, 50 seeds each, in 9 cm diameter petri dishes between two layers of sterile filter paper sheets. The experiment was carried out in 4 replications. Some parameters of the germination (Germination rate (GR), Germination time (GT), Average germination time (AGT)) and early seedling period (Embryonal root length (ERL), Number of embryonal roots (NER), Root fresh weight (RFW), Root dry weight (RDW), Grass sheath length (GSH)) were measured and the results were statistically evaluated. In general, the highest values obtained from all evaluated germination (92.0% GR and 1.7 day AGT) and early seedling parameters (10.4 cm ERL, 4.6 NER, 0.095 g RFW, 0.028 g RDW and 3.6 cm GSL) were found to belong to the GA3 application. The lowest values obtained from the relevant parameters were obtained with the C4 application. In our study, it was observed that gibberellic acid applications significantly increased germination in this plant and positively increased the parameters related to germination. Based on the study results, we think that colchicine stimulates germination at certain rates, but causes death by having a toxic effect in increasing doses.