Evaluation of ultrasound technology to break seed dormancy of common lambsquarters (Chenopodium album)

Abstract

Although seed dormancy is advantageous for annual plants in the wild, unsynchronized germination in the laboratory leads to increased error in measurements. Therefore, techniques to promote and synchronize germination are routinely used. Ultrasound is one of the newest methods for breaking dormancy in weed seeds. We have investigated whether ultrasonic waves can be used to break seed dormancy of common lambsquarters (Chenopodium album), a highly competitive annual weed that leads to significant reduction of yields of corn, soybeans, and sugar beets. Ultrasonic waves with frequency of 35 kH were applied for 0 (control), 5, 10, 15, and 30 min using a completely randomized design. The results showed that the use of ultrasound waves generally enhanced the traits under investigation in the treated samples compared with the control sample. The maximum enhancement of germination percentage (180%), seedling dry weight (78%), and seedling vigor index I (271%) and II (392%) was seen in the common lambsquarters samples treated with ultrasound for 15 min and seedling length (40%) at 30 min compared with the control samples. Radical lengths were not statistically different from controls under any treatment and plumule length only increased marginally. These changes are reflected in seedling vigor index I and II measurements. For some of these traits, increasing the length of ultrasound treatment to 30 min had negative effects. These results demonstrate that ultrasound technology can be used as a quick, and efficient nondestructive method to break seed dormancy in common lambsquarters.

Evaluation of techniques to break seed dormancy in Redroot pigweed (Amaranthus retroflexus)

“…Our data show that pretreating seeds with ultrasound effectively promoted germination percentage and rate (Figure 1, Table 2). This finding is consistent with previous studies in other species that have utilized ultrasound to promote seed germination (Babaei-Ghaghelestany et al, 2020;Ding et al, 2018;Kratovalieva et al, 2012;Miano et al, 2015;Rifna et al, 2019). For example, Ding Ultrasound treatments are believed to induce changes in the seed coat, facilitating influx or efflux of water and mineral elements into cells (Miano et al, 2015;Qin et al, 2012) and/or to increase the activity of alpha-amylase enzyme and therefore the rate of starch metabolism (Yaldagard et al, 2007(Yaldagard et al, , 2008.…”

“…To evaluate the efficacy of ultrasound treatment, we used methods developed by Babaei‐Ghaghelestany et al. ( 2020 ). Redroot pigweed seeds were exposed to ultrasonic waves for 10, 20, 30, and 40 min to evaluate this treatment.…”

“…These different treatments were chosen not only because they are the standard laboratory methods recommended for breaking seed dormancy and promoting seed germination by the International Seed Testing Association (ISTA, 2018 ) they also mimic what seeds would experience during changes in temperature in wet soil (cold stratification), alter levels of the hormone that is well known to promote germination (application of gibberellic acid), or methods that variously alter seed coat physiology or permeability (hot water and sulfuric acid). Additionally, we consider ultrasound, which uses sound frequencies in the inaudible range (20–100 kHz) and improves germination rate by stimulating the seed cell wall (Babaei‐Ghaghelestany et al., 2020 ; Ding et al., 2018 ; Rifna et al., 2019 ). These methods have all been successfully used to break the dormancy of other weed species (Alebrahim et al., 2011 ; Alshallash, 2018 ; Chadha et al., 2019 ; Fallahi et al., 2016 ; Humphries et al., 2018 ; Kępczyński et al., 2017 ; Nadjafi et al., 2006 ; Rahnama‐Ghahfarokhi & Tavakkol‐Afshari, 2007 ).…”

Seed germination and seedling development assisted by ultrasound: gaps and future research directions

“…Another study in the same species showed that sonication (20 kHz and 350 W) for 5 min stimulated seedlings but was less efficient than thermal scarification in terms of GP and germination rate index (GRI) 96 . Furthermore, the germination of other dormant seeds, including orchid ( Calanthe discolor ) 60 and lamb's quarters ( Chenopodium album ) 54 were also positively affected by different ultrasound systems. Contrarily, sonication treatment failed to stimulate the germination of dormant seeds of Xylopia emarginata 95 …”

Effects of High Intensity Ultrasound Stimulation on the Germination Performance of Caper Seeds

“…Many studies have tried to improve caper seed germination and to break the possible physical dormancy with different types of scarifications (mechanical, chemical, thermal or biological) [5][6][7][8] and to break the physiological dormancy with the use of gibberellic acid (GA 3 ) and potassium nitrate [9][10][11][12]. The ultrasound application has been used in seed germination studies of both cultivated plants and weeds [13][14][15][16][17][18], but it is one of the least-studied methodologies in caper seeds.…”