Effect of plasma irradiation on germination of lettuce seeds with fluctuating dormancy*

Induction of response of plant seeds by irradiation with non-thermal atmospheric pressure plasma has attracted attention [1-3]. Many studies have shown a phenotypic correlation to plasma irradiation conditions (voltage, power, gas, etc.). However, the elucidation of the mechanism has just begun. To elucidate the mechanism, improving the reproducibility of the plasma irradiation effect on seeds is essential. This study deals with the dormant state of seeds to be irradiated with plasma. The sample is lettuce seeds. The seeds were irradiated with plasma at different storage periods. Scalable dielectric barrier discharge electrodes were used for plasma irradiation [4].  After irradiation, the seeds were used for germination tests. The germination rate was counted every 12 hours after imbibition. As a result, the germination rate at 12 hours was 10% at 0d of storage, but 50% at 40d, and then gradually decreased to 10% at 150d. This result indicates a dormancy fluctuation depending on the storage period. Plasma-irradiated seeds show improvement in germination characteristics earlier than seeds without plasma irradiation. Thus, it is important to construct an experimental system considering the dormancy as an important parameter. The presentation will discuss the dependency of plasma irradiation time on germination of seeds with fluctuating dormancy.

[1]P. Attri, et al., Processes 2020, 8, 1002. [2]P. Attri, et al., Jpn. J. Appl. Phys., 2021, 20, 040502. [3]P. Attri, et al., Agronomy 2022, 12, 482 [4]K. Koga, et al., Appl. Phys. Express 2016, 9, 016201.