About the Speaker

Dr. Ehara serves as the Director of the International Center for Research and Education in Agriculture and as a Professor at the Graduate School of Bioagricultural Sciences, Nagoya University. From 1999 to 2000, he conducted research as a visiting scientist at the Royal Botanic Gardens, Kew, supported by the Royal Society– Japan Society for the Promotion of Science fellowship. Between 2011 and 2015, he contributed to Mie University as Vice President for International Affairs. In 2008, he was honored with the Academic Award from the Japanese Society for Tropical Agriculture (JSTA) in recognition of his ecophysiological and phylogenetic research on the sago palm. Dr. Ehara was elected President of the Society of Sago Palm Studies in 2016 and Vice President of the JSTA in 2020. 

Abstract

Phenotypic Changes Induced by the Application of Low-Temperature Plasma Treatments in Crops and Related Species

The effects of exposing dry seeds to plasma at room temperature using a helium jet device were investigated. Plasma treatment for 1-5 minutes could modify the first and second phases of water absorption (the physical water absorption and the germination preparation) in Vigna seeds compared to the control. The 3-minute treatment significantly increased leaf DW, top/root ratio, leaf weight ratio, and leaf area ratio (LAR). The 5-minute treatment tended to increase root DW, while root weight ratio and net assimilation rate (NAR) were significantly higher. In the 3-minute treatment, relative growth rate (RGR) increased with a rise in LAR, whereas in the 5-minute treatment, RGR primarily depended on NAR. In rice seedlings germinated from plasma-treated seeds, seedling emergence, plant height, and stem number were significantly greater in the treated plot compared to the control for approximately two months after germination. The cumulative water consumption of rice plants by the booting stage was also significantly higher in the treated plants. During the early growth stage, the phenotypes of rice seedlings, particularly the root system, were improved with longer irradiation times among 1 to 10-minutes. The differences in phenotypes between seedlings from treated seeds and those from untreated seeds were particularly evident under drought stress. Plasma treatment of seeds also reduced the accumulation of reactive oxygen species in seedlings, alleviating oxidative stress.