Ultrasonic Priming and Sprouting

• Ultrasonic seed priming is a useful pre-sowing technique to replenish seeds with water and nutrients and to stimulate germination.
• Sonication is an efficient technique for breaking seed dormancy and improving the germination characteristics.
• Hielscher ultrasonic equipment can be precisely controlled for reliable outcome of seed germination and priming.

Ultrasonic Seed Priming, Germination and Sprouting

Ultrasonic seed priming refers to a process of treating seeds with ultrasound waves at approx. 20 kHz in water or other suitable nutrient solutions to enhance their germination and early growth. A rapid germination and seedling emergence are critical factors for a successful establishment of plants and crops. Dormancy breaking and germination stimulation are important for proliferation and early production of plant seedlings. Ultrasonication of seeds in water, nutrient solution or an osmoticum improves the germination rate and speed and show a higher germination percentage than untreated seeds.

 
 

Advantages of Ultrasonic Seed Priming

Intense ultrasound of approx. 20kHz show significant impact on the seed coat as well as on the mass transfer and intracellular processes. Below, you can find details about the major effects of sonication on seeds and their related benefits.

• Increased germination rate: Ultrasonic seed priming can improve seed germination rates by breaking down seed dormancy, increasing water uptake, and activating enzymes that promote seed growth. Since sonication can activate enzymes within the seed that are responsible for breaking down stored nutrients and initiating germination.
• Increasing water uptake: Sonication can perforate the seed coat and cell walls, so that the seed can subsequently increase its permeability to water and improve water and nutrient uptake. This gives primed seeds an advantage especially in dry or nutrient-depleted soil.
• Accelerated seedling emergence: Ultrasound treatment for seed priming can reduce the time it takes for seedlings to emerge from the soil, which can be particularly beneficial in situations where a quick establishment of crops is desired. By breaking down the seed coat and improve water permeability, promoting the swelling and germination of seeds, ultrasound can interrupt seed dormancy.
• Enhanced seedling growth: Ultrasonic seed priming can stimulate the growth of seedlings by promoting the development of roots, stems, and leaves. This can result in stronger, healthier plants with better yields.
• Improved seedling tolerance to stress: Ultrasonic seed priming increases the ability of seedlings to withstand environmental stressors such as drought, salinity, and high temperatures.
• Reduced seedling mortality: Ultrasonic seed priming can reduce seedling mortality rates by promoting uniform germination and early growth, which can help to prevent the loss of seedlings due to uneven emergence or poor growth.

Due to these positive effects, ultrasonically induced seed priming and germination improves the quality and quantity of crops leading to more successful germination, reducing production costs, and increasing sustainability in agriculture.

Ultrasonic Priming

Priming of seeds in osmotica such as mannitol, polyethylene glycol (osmopriming), saline solutions (e.g., CaCl₂, NaCl or CaSO₄) (halopriming) and in water (hydropriming) can be easily improved by the application of ultrasound waves. Ultrasonically induced shell fragmentation, perforation and enlargement of the pore size of seeds lead to a higher water and nutrient retention capacity in seeds and grains resulting in improved hydration. Sonication improves the mass transfer between the seed and the surrounding solution resulting in an increased uptake of solution (i.e. water, nutrients etc.) into the seed is achieved. Ultrasonically assisted priming is an economical, simple and a safe technique for increasing the capacity of seeds to osmotic adjustment and enhancing seed germination, seedling establishment and crop production under stressed conditions.
Furthermore, ultrasonication causes endosperm modification, such as starch degradation by sonication, which increases the rate of enzyme-catalyzed hydrolysis reactions within the seeds. An increased enzyme activity and hydrolysis accelerates germination and embryo growth as result of the ultrasonic treatment.
Read more about ultrasonic priming here!

Ultrasonicators for Seed Priming and Germination

Hielscher Ultrasonics supplies ultrasonic equipment for improved seed priming including hydro-priming, osmo-priming, and halo-priming. Compact ultrasonicators for R+D and lab work allow for testing and establishing the optimum ultrasonic process parameters, whilst industrial-grade ultrasonic equipment are implemented in the large-scale treatment of commercially traded seeds in a convenient and highly efficient flow-through ultrasonic priming treatment.
In order to improve germination of seed by sonication, precisely controllable and adjustable ultrasonic systems are required. Since ultrasound waves are used to stimulate physiological activities of vegetal cells, the intensity of sonication must be adapted to the specific type of seed and cultivar. Hielscher ultrasonic systems can be set to mild amplitudes delivering the cavitation and/or oscillation required to prime seeds for optimal germination and vigour. Seed treatment can be applied in batch as well as in continuous flow mode. The broad spectrum of accessories allow for the easy integration of ultrasound into existing premises.
Hielscher ultrasonic systems increase the potential for high seedling performance after sowing.

The table below gives you an indication of the approximate processing capacity of our ultrasonicators:

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Literature/References

• Yaldagard M.; Reza Mortazavi S.A.; Tabatabaie F. (2008): Application of Ultrasonic Waves as a Priming Technique for Accelerating and Enhancing the Germination of Barley Seed: Optimization of Method by the Taguchi Approach. Journal of The Institute for Brewing Vol. 114, Issue1, 2008. 14-21.
• Machikowa T.; Kulrattanarak T.; Wonprasaid S. (2013): Effects of Ultrasonic Treatment on Germination of Synthetic Sunflower Seeds. World Academy of Science, Engineering and Technology International Journal of Agricultural and Biosystems Engineering Vol:7, No:1, 2013.
• Nazari M.; Eteghadipour M. (2017): Impacts of Ultrasonic Waves on Seeds: A Mini-Review. Agri Res & Tech Volume 6 Issue 3 – April 2017.