Ultrasound technology supplements zinc in soybean seeds and increases the photosynthetic efficiency of seedlings

Strategies to increase the concentration of essential micronutrients for the plant cycle have made a remarkable contribution to agriculture. Ultrasonic waves have the potential to increase cell wall permeability and enhance the chemical composition of seed tissues. In this context, the aim of this study was to verify if it is possible to increase the zinc (Zn) supplementation of soybean seeds through their controlled exposure to ultrasonic waves with improvements in the photosynthetic efficiency (Fv/Fm) of the resulting seedlings. Initially, we investigated the impact of ultrasonic waves on the physical, physiological and spectral parameters of soybean seeds. Next, the seeds were treated with Zn and analyzed by X-ray fluorescence spectroscopy to better understand the kinetics of Zn uptake. Finally, we evaluated the germination, vigor, pigments and photosynthetic performance of seedlings. The main results showed that ultrasound modifies the structure of the seed coat without interfering with the dynamics of water absorption and the germination capacity of the seeds. The changes promoted by the technology favor Zn supplementation of more than 100 % in the seeds. In addition, the resulting seedlings show Fv/Fm values 92.7 % higher than the control, and an increase in chlorophyll fluorescence, initial fluorescence, and anthocyanin. We show that ultrasonic wave technology combined with Zn treatment improves the performance of soybean seeds, producing seedlings with superior photosynthetic efficiency.