Variation of antioxidative activity and growth enhancement of Brassicaceae induced by low-pressure oxygen plasma

Abstract

The mechanism of growth enhancement induced by active oxygen species generated in an oxygen plasma is investigated. The plant growth enhancement induced by the active oxygen species would relate to an antioxidative activity, which is one of the biological responses. The amount of generated active oxygen species is varied by the oxygen gas pressure in a low-pressure RF glow discharge plasma. The antioxidative activity of sprouts of Brassicaceae induced by the oxygen plasma is maximized at pressures between 30 and 40 Pa, whereas the antioxidative activity becomes small at around 60 and 80 Pa. The pressure dependence of the antioxidative activity of sprout stems is opposite to that of the stem length of the sprouts. The growth enhancement would be induced by the increase in the concentration of active oxygen species in plants owing to the decrease in the amount of antioxidative substances.

DNA Microarray Analysis of Plant Seeds Irradiated by Active Oxygen Species in Oxygen Plasma

“…) are produced due to the lower-energy electrons. 9,10 was varied within a range of several tens of Pa. Also, the chemical indicator shows generation of active oxygen species in the afterglow region of the chamber.…”

“…Germination 9 When seeds that were irradiated by active oxygen species under particular conditions grew, stem and root lengths were longer than those of seeds without irradiation. 10 Figure 2 shows tendencies of the light emission intensity of excited oxygen molecule O 2 ( 1 + g ), antioxidative activity, and the full length of radish sprout varying gas pressure. Student t-tests were performed between lengths of untreated and plasma irradiated radish sprouts.…”

“…2 has a peak at the same pressure, 40 Pa. An inverse relationship was observed between the intensity of O 2 ( 1 + g ) and the full length of radish sprout as the oxygen gas pressure changed. 10 At 40 Pa pressure, the growth of plants was suppressed pression of growth factor led to expression of antioxidative genes, and large quantity of antioxidative substances was produced. On the other hand, irradiation of an appropriate amount of active oxygen species at < 20 Pa or > 60 Pa oxidized thiol compounds related to biological reactions in cells. )…”

“…4,5 Recently, plant germination and growth regulations has been observed when plant seeds are irradiated by active oxygen species produced by oxygen plasmas. [6][7][8][9][10][11] induced by active oxygen species are the redox reactions of thiol compounds. [12][13][14][15][16][17] When plant seeds are irradiated by active oxygen species generated by oxygen plasma, thiol 9, 18 major thiol compound in living organisms is thioredoxin, 16,19 which plays roles as an oxygen sensor and a scavenger of excess active oxygen species.…”

Plasma-assisted agriculture: history, presence, and prospects—a review

“…The advantage of using low-pressure plasma lies in the possibility of tuning the density and energy of species exposed to plasma. This was investigated by Ono and Hayashi using 13.56-MHz oxygen glow discharge generated at 10-100 Pa to treat Brassicaceae seeds [120]. The variation in pressure led to the generation of different oxygen states; for example, in the range 10-40 Pa, the optical emission spectroscopy confirmed the presence of singlet excited oxygen molecules and oxygen atoms.…”