Enhancing Seed Germination of Four Crop Species Using an Ultrasonic Technique

Abstract

A laboratory experiment was conducted to determine the effect of ultrasound (US) treatment on seed germination of chickpea, wheat, pepper and watermelon. All tests were carried out at 40 kHz in a water bath ultrasonic device varying two factors, treatment duration (5, 10, 15, 30, 45 or 60 min) and germination temperature (15 or 20 • C). Parallel tests were run in which seeds were soaked in water without sonication in order to eliminate the effect of water from US test results. The effects of US on seed germination varied between crops and were more obvious on germination speed, expressed as germination rate index (GRI), rather than on germination percentage (GP). In particular, US treatment significantly increased the GRI of chickpeas, wheat and watermelon, resulting in a maximum increase of 133% (at 45 min), 95% (30 min) and 45% (5 min), respectively, above control seeds. The beneficial effects of US on the GRI of these crops were observed at both 15 and 20 • C, suggesting that US treatment offers a practical priming method to overcome the slow germination that may occur at low temperatures. Water-soaking treatment improved the GP of both chickpea and pepper seeds by 59 and 24%, respectively, compared to the control but neither water nor US had any positive effect on pepper GRI. Post-treatment measurement of moisture content of these seeds produced variable results depending on crop species and US treatment duration. Results of this research indicated that US treatment effectively enhanced speed of germination of chickpea, wheat and watermelon seeds. This increase in speed of germination may improve early field establishment of these crops in the semiarid Mediterranean region and thus needs further investigation. The US technique may also be very useful for plant propagators in nurseries to achieve fast seedling establishment of watermelon.

Modeling Analysis on Germination and Seedling Growth Using Ultrasound Seed Pretreatment in Switchgrass

“…When a longer time, greater temperature, or ultrasound output power is used, physical or chemical damage occurs, which is caused by the pressure induced by the ultrasonic wave. Ultrasound treatments longer than 5 min had a negative impact on pepper germination rates [27]. The heavily damaged region was observed within 200 min from the ginger particle surface when ultrasound was used [39].…”

Physical Factors for Plant Growth Stimulation Improve Food Quality

“…Different cultures were subjected to ultrasonic stimulation: pepper, tomatoes and cucumbers (Markov et al 1987), fodder beans (Rubtsova 1967), radish (Shimomura, 1990), corn (Hebling et al 1995), carrot (Aladjadjiyan 2002b), chickpea, wheat, pepper, and watermelon (Goussous et al 2010), ornamental trees (Aladjadjiyan 2003a(Aladjadjiyan , 2003b, barley (Yaldagard et al 2008a(Yaldagard et al , 2008b(Yaldagard et al , 2008c.…”

Combining Ionizing Irradiation and Ultrasound Technologies: Effect on Beans Hydration and Germination

“…Regarding the effect of ultrasound, this technology is well referenced due to its capacity to improve germination. In fact, many works have reported this improvement for different seeds and grains, such as chickpeas, wheat and pepper (Goussous, Samarah, Alqudah, & Othman, ), barley kernels (Miano et al., ), rice kernels (Ding et al., ), mung beans (Miano et al., ), grass seeds (Liu et al., ), and red rice (Ding et al., ). The main attributed mechanisms of this improvement reported in those published works are the acceleration of mass transfer (water, gases, and nutrients) and the acceleration of metabolism by the activation of enzymes, the acceleration of nutrients mobilization, or other physiological effect.…”