Effect of plant growth regulators on in vitro germination and micropropagation of Brazmbl (Perovskia abrotanoides), a medicinal plant

The aim of this study was to obtain a suitable combination of hormones including naphthalene acetic acid (NAA) with benzyl aminopurin (BAP) or kinetin (KIN) to lower seed dormancy of Peroveskia abrotanoides، studying in vitro organogenesis and evaluation of antioxidant activity of shoots and roots. The seeds were sterilized and cultured on Murashige and Skoog medium (MS) containing BAP or KIN (at 0، 1، 2. 5 and 5 mg/L concentrations) and NAA (at 0، 0. 1، 0. 25 and 0. 5 mg/L concentrations). All experiments were done based on factorial design in a randomized block design with at least five replicas. Germination percent was estimated after 30 days and number of shoots and leave، leaf area، root and shoot length were determined after 80 days. The highest germination percent (93%) was obtained by 5 mg/L KIN and 2. 5 mg/L KIN + 0. 1 mg/L NAA treatments which was indicative of the role of the cytokinin on the seed dormancy breaking. Effect of BAP on rising shoot number was greater than KIN (30 shoots after 2. 5 mg/L BAP treatment). In contrast to NAA that was inhibitor of shoot induction in P. abrotanoides، number of the shoots was reduced to half by addition of it to the media. The highest value of leaf area (15 mm2) was obtained by treated seeds in the media supported with NAA alone. The highest percentage of callus induction (80%) was obverved on media containing 0. 25 or 0. 5 mg/L NAA in combination with 2. 5 mg/L BAP or KIN. Intermediate concentration of the studied cytokinins alone or with intermediate concentration of NAA، such as 2. 5 mg/L KIN + 0. 25 mg/L NAA، had the highest effect on rosmarinic acid storage in de novo organs (75. 21 mg/g DW). While، the induced organs was grown on the media that supplemented just with NAA had less antioxidant activity and rosmarinic acid content.