Improving Germination of Mustard (Brassica nigra) and Bok choi (Brassica rapa subsp. chinensis) through Priming using Plasma Activated Water (PAW)

The study explores Plasma Activated Water (PAW) or water directly exposed to Atmospheric Pressure Plasma (APP) as priming agent to improve seed germination and vigor of Mustard and Bok Choi. Seeds were primed using distilled water exposed to APP for two minutes (Treatment 1) and five minutes (Treatment 2) using APP jet. These treatments were compared to positive control (untreated distilled water, Treatment 3) and negative controls (no priming, Treatment 4). The parameters on the priming agent (PAW) observed were physicochemical properties (pH, electric conductivity (EC), total dissolved solids (TDS), resistivity, and oxidation reduction potential (ORP)). Seeds were soaked in the priming agent for 6hr followed by 8hr air-drying before seed germination test using top-of-paper (TP) method. The study was laid out using CRD, replicated thrice with two (2) subsamples with 100 seeds per subsample. Germinated seeds were counted from first to seventh day. Seed germination, germination rate index, mean germination time, and germination speed were measured. Data was analyzed using ANOVA and Tukey's Honest Significant Difference. In terms of PAW's properties, both PAW are acidic, with high EC, TDS, ORP and low resistivity as compared to untreated distilled water. Significantly, higher germination percentage, more uniform and faster germination with shorter germination time were observed on seeds presoaked in PAW (regardless of water exposure to APP) compared to the controls for both Mustard and Bok Choi. This shows that PAW is effective as priming agent to increase germinability and vigor of Bok Choi and Mustard. Specifically, distilled water exposed to APP for 2 mins is sufficient to improve germination and vigor of Mustard and Bok choi seeds.