Surface barrier discharge pre-sowing treatment of winter wheat seeds in a three-electrode arrangement with dc bias

Abstract

In the present work, the experimental results of reaction of morphological indicators (sprout and root length, number of roots, 3-day germination) of seedlings of high quality winter wheat seeds treated by plasma byproducts in the three-electrode system of surface dielectric barrier discharge with dc bias on the third electrode in humid air of atmospheric pressure at different polarity of the bias voltage are shown. The treatment was carried out for 15 min in a strip electrode system (eight 1 mm width strips with 4 mm distance between them, a sinusoidal voltage of 2.7 kV (rms) with a frequency 23 kHz) made on a corundum ceramic barrier (1 mm thickness) with the additional third electrode which is a stainless steel grid distant 10 mm from the surface of the dielectric barrier. Direct-current bias of 8 kV of positive or negative polarity was applied to the third electrode. Seeds were located on the surface of the third electrode. The treatment was also carried out with vibration of the system (the imitation of seeds movement along the third electrode). It is shown that the efficiency of treatment depends on the month of carrying it out. It was succeeded to get a reliable stimulation with weak control. With strong control (potential sowing months) it was not obtained. The imposing of dc bias in any considered case is less efficient than plasma products affection without bias. The vibration of electrode system leads to seeds damage during the treatment and notable germination reduction.