The Effects of Ultrasound on Multiple Shoot Regeneration from Sainfoin (Onobrychis sativa) Shoot Apex

Ultrasound has multiple industrial, medical and biotechnological applications. Ultrasound increases membrane permeability and causes several biological effects in plant cells. In this research, the effects of ultrasound on survival and growth of the sainfoin shoot apex explants were investigated. For this, shoot apex explants were exposed to ultrasonic waves (Frequency 37 kHz) for 0, 20, 30, 40, 50, 60, 90, 120, 180, 240 and 300 seconds in a ultrasonic bath and then cultured on MS medium supplemented with 0.1 mg/l IBA and 3 mg/l BAP. Results showed that the percentage of shooting (explants with shoot growth) significantly reduced by ultrasound treatment, but percentage of multiple shoots, number of shoots per explants and percentage of callusing significantly increased. Control treatment (without ultrasound) showed the highest percentage of shooting with the lowest callus induction and percentage of explants vitrification. The highest percentage of callus induction (60.98% and 61.11%) was observed in higher sonication dosages (180 and 240 seconds). While, the highest percentage of multiple shoots, number of shoots per explants and percentage of explants vitrification were obtained in 30 seconds ultrasound treatment. Increasing ultrasound treatment duration decreased viability of plant cells and tissues, and as a result reduced shooting of explants.