Influence of Exposure to Ultrasonic Waves for 5 min on Seeds of Helianthus annuus L.

This work evaluated the influence of ultrasound application on the germination and emergence of seeds of the species Helianthus annuus L., (sunflower), adopting some parameters such as Germination Percentage (%G), Emergence Percentage (%E), Germination Speed Index (GSI), Emergence Speed Index (ESI), Average Germination Time (AGT) and Average Emergence Time (AET). The following treatments were used: T1, T2 and T3 with 75 seeds each by 1 MHz frequency, and 0.5; 1.0 and 1.5 W/cm2 of intensity respectively. In T4, T5 and T6 the same intensities were applied at a frequency of 3 MHz in 75 seeds in each treatment and Control Group - GC did not receive application. All applications followed 5 min in duration. After application, the seeds were immersed in aqueous solution for 10 min for disinfection and, later, washed in distilled water for the same period. They were immersed in distilled water with 2.5 times its weight for 24 h. They were sown one day after ultrasound application, conditioned in plastic bags with a 1:1 ratio of sand and clay. T1 performed better than the control group in G% = 60 and E% = 40. The 3 MHz groups were below CG for germination, except for AGT. As for emergence, they obtained better values in everything in relation to the CG. T2 was the worst treatment in all parameters and could be discarded in further studies. More experiments are needed with different doses and a greater number of seeds to obtain greater accuracy in the technique, which is widely explored.