Determination of growth characteristics and quality of Nigella sativa L. affected by mycorrhizal fungi symbiosis and ultrasonic waves

A field experiment was carried out in the research farm of Shahrood University to study the effects of ultrasonic waves and mycorrhizal fungi on quantitative and qualitative characteristics of Black seed (Nigella sativa L.) in 2012. The experiment was conducted as factorial based on randomized complete block design with three replications. The treatments included: mycorrhizal inoculation at three levels of control (non-inoculated), recommended level and twice the recommended level as well as five exposure duration of ultrasonic waves (42 kHz) including control, 3, 5, 7 and 9 minutes. According to the results, seed yield, 1000 seed weight, root colonization percentage, biological yield and harvest index were affected by mycorrhizal fungi. Essential oil percentage and yield were significantly affected by mycorrhizal inoculation. The highest essential oil percentage was obtained from application of twice the recommended level of mycorrhizal inoculum (1.1 %). No significant difference was found for seed yield and 1000 seed weight between two inoculum treatments. Plant height, seed yield, biological yield, 1000 seed weight and essential oil percentage and yield were increased by exposure to the ultrasonic waves. The highest value of seed yield and 1000 seed weight was obtained from 7- min of exposure to ultrasonic waves (696.3 kg.ha-1 and 2.7g). Results showed that the interaction effects of mycorrhiza and ultrasonic were significant on plant height, number of capsules per plant, and essential oil percentage. The highest essential oil percentage was obtained from 9-min of ultrasonic exposure and non-inoculated treatment as well as 3-min of ultrasonic exposure and the use of mycorrhiza.