Treatment of Common Sunflower (Helianthus annus L.) Seeds with Radio-frequency Electromagnetic Field and Cold Plasma Induces Changes in Seed Phytohormone Balance, Seedling Development and Leaf Protein Expression

Abstract

Treatment of plant seeds with electromagnetic fields or non-thermal plasmas aims to take advantage of plant functional plasticity towards stimulation of plant agricultural performance. In this study, the effects of pre-sowing seed treatment using 200 Pa vacuum (7 min), 5.28 MHz radio-frequency cold plasma (CP −2, 5, and 7 min) and electromagnetic field (EMF −5, 10, 15 min) on seed germination kinetics, content of phytohormones, morphometric parameters of seedlings and leaf proteome were assessed. CP 7 min and EMF 15 min treatments caused 19–24% faster germination in vitro ; germination in the substrate was accelerated by vacuum (9%) and EMF 15 min (17%). The stressors did not change the seed germination percentage, with exception of EMF 5 min treatment that caused a decrease by 7.5%. Meanwhile both CP 7 min and EMF 15 min treatments stimulated germination, but the EMF treatment resulted in higher weight of leaves. Stressor-specific changes in phytohormone balance were detected in seeds: vacuum treatment decreased zeatin amount by 39%; CP treatments substantially increased gibberellin content, but other effects strongly varied with the treatment duration; the abscisic acid content was reduced by 55–60% after the EMF treatment. Analysis of the proteome showed that short exposure of seeds to the EMF or CP induced a similar long-term effect on gene expression in leaves, mostly stimulating expression of proteins involved in photosynthetic processes and their regulation.

Cold Plasma Treatment of Sunflower Seeds Modulates Plant-Associated Microbiome and Stimulates Root and Lateral Organ Growth

“…However, the protein expression pattern induced by DBD type plasma source was very different from the previous results obtained using low-pressure capacitively coupled plasma (Mildaziene et al, 2019). While the latter method had no significant effect on root protein abundance (Mildaziene et al, 2019), in the current study, extensive protein expression variation was detected in seedling roots upon DBD type CP treatment. The difference might arise from the presence of atmospheric pressure air in the DBD type CP that is a source of abundant reactive species generated during seed treatment.…”

“…Protein abundance differences induced by CP treatment were consistent but had a characteristically low amplitude which had been observed in studies on low intensity stress (eustress) stimuli such as low intensity UV-B treatment (Aksoy et al, 2010), or low-pressure capacitively coupled plasma or electromagnetic field treatment of sunflower seeds (Mildaziene et al, 2019). However, the protein expression pattern induced by DBD type plasma source was very different from the previous results obtained using low-pressure capacitively coupled plasma (Mildaziene et al, 2019). While the latter method had no significant effect on root protein abundance (Mildaziene et al, 2019), in the current study, extensive protein expression variation was detected in seedling roots upon DBD type CP treatment.…”

Seed priming with cold plasma improved seedling performance, secondary metabolism, and expression of deacetylvindoline O‐acetyltransferase gene in Catharanthus roseus

“…Acceleration in root development in primed seedlings (especially lateral roots) is responsible for upcoming facilitated growth, regardless of the utilized priming technique . In addition to well‐characterized mechanisms such as changes in seed coat and water uptake, recent reports indicate the molecular, physiological, anatomical, and hormonal modifications in the plasma‐treated seedlings. These mechanisms can individually and/or synergistically influence the plant growth and development programme.…”

“…The plasma‐derived UV photons and bioactive signalling molecules can individually or synergistically trigger particular signalling routes, thereby reprogramming intracellular metabolism . For instance, Mildažienė et al also displayed changes in the hormonal status following plasma utilization. It is crystal clear that phytohormones are the main regulators of plant growth, development, metabolism, and nuclear transcription.…”

Seed treatment with cold plasma and electromagnetic field induces changes in red clover root growth dynamics, flavonoid exudation, and activates nodulation

“…Seed phytohormone extracts were prepared and analyzed as described before. [ 25 ] Seeds were powdered using a batch mill Tube‐Mill with a disposable grinding chamber (IKA). Seed powder (1 g) was mixed with 5 ml of 85% methanol and incubated in a shaker for 24 h at 4°C.…”