Department of Functional Sciences, “Victor Babeş” University of Medicine and Pharmaceutics, Timişoara, Romania
Abstract. The present study investigates the influence of ultrasound exposure on the germination capacity of the seeds of the plant Lotus corniculatus L. The seeds were grouped in four size categories according to their diameter: mixed sizes, small seeds, medium seeds and large seeds. Ultrasounds were applied to aliquots of about 100 seeds. For ultrasound treatment, the seeds were transferred into a sample holder, placed contact with the magnetostrictive transducer of an ultrasound generator of fixed frequency, f = 20 kHz, and adjustable power. Each group was exposed to various ultrasound intensities, ranging from 0.11 W/cm2 to 2.72 W/cm2, and various exposure times, ranging from 10 seconds to 160 seconds. Following ultrasound treatment, the germination capacity of the seeds was evaluated after 21 days, 31 days and 137 days. We have also performed an extensive statistical evaluation of the obtained data. Multiple quadratic correlations have been established between the physical parameters of the applied ultrasounds and the germination capacity of the seeds. Based on these correlations, the optimal exposure conditions were identified for each size category. According to the analyis, for medium-sized seeds the largest germination capacity (86.11%) is obtained for an ultrasound intensity of 1.46 W/cm2 applied for 72.3 seconds. For large seeds the best germination capacity (81.85%) is obtained for an ultrasound intensity of 1.79 W/cm2 applied for 62.3 seconds.
Key words: ultrasounds, germination, quadratic correlations, Lotus corniculatus L.