Bozena Sera

Germination of Chenopodium Album in Response to Microwave Plasma Treatment

The seeds of Lambs Quarters (Chenopodium album agg.) were stimulated by low-pressure discharge. The tested seeds were exposed to plasma discharge for different time durations (from 6 minutes to 48 minutes). Germination tests were performed under specified laboratory conditions during seven days in five identical and completely independent experiments. Significant differences between the control and plasma-treated seeds were observed. The treated seeds showed structural changes on the surface of the seat coat. They germinated faster and their sprout accretion on the first day of seed germination was longer. Germination rate for the untreated seeds was 15% while it increased approximately three times (max 55%) for seeds treated by plasma from 12 minutes to 48 minutes.

How various plasma sources may affect seed germination and growth

Germination and early growth of buckwheat (Fagopyrum aesculentum) after low-temperature plasma discharge treatment in air gas generated in various devices were tested. Three pre-treatment times were used: 180 s, 300 s and 600 s. Seed cultivation was carried out in laboratory conditions. Number of germinating seeds was counted, length and weight of seedling sprouts were measured. The data were analysed with two-way ANOVA: a significant influence of the type of plasma apparatus, time of exposure and combination of both factors were found. A positive effect on germination and early growth was observed after the application of GlidArc device (low-temperature plasma generated in air gas under atmospheric pressure between two electrodes). The opposite effect of surface dielectric barrier discharge (SDBD) apparatus, which is characterized by plasma with high power density, was observed. Shorter pre-treatment times for SDBD device must be therefore used. Effects of seed germination and early growth of seeds strongly depended on the type of the used plasma apparatus.

EFFECT OF LOW-TEMPERATURE PLASMA TREATMENT ON THE GROWTH AND REPRODUCTION RATE OF SOME PLANT PATHOGENIC BACTERIA

Atmospheric pressure plasmas have received much attention lately as a promising physical tool for biological decontamination and sterilization. Two phytopathogenic bacterial species, Clavibacter michiganensis subsp. michiganensis and Erwinia amylovora, and one cosmopolitan bacterium, Escherichia coli (control), were employed to study the bacterial growth mechanism after exposure to the atmospheric pressure GlidArc plasma. The results have shown that low-temperature plasma treatment affects all three bacterial species by slowing down growth and reproduction rate. After plasma treatment, both Gram-negative bacteria (E. coli and E. amylovora) reached their maximum growth sooner than the Gram- positive C. michiganensis subsp. michiganensis. This is however caused by a longer cultivation period of Clavibacter bacterial genus. The application of GlidArc plasma is a suitable treatment that can be used in agriculture for plant protection.

Hemp (Cannabis sativa L.) seeds after plasma treatment

This experiment was focus to increase the germination and growth of hemp seed by using cold plasma discharge. The seeds of three hemp cultivars (Finola, Bialobrzeskie, and Carmagnola) were pre-treated in Plasonic AR-550-M and GlidArc apparatuses for three time expositions (180 s, 300 s, and 600 s). Commercial Plasonic AR-550-M apparatus was not suitable for plasma pre-treatment, because all seeds were obviously under a big stress. GlidArc device was suitable. GlidArc plasma pre-treatment positively affected the seeds of the cultivar Finola in all tested expositions above all. Seedling acceleration on the fifth day of the experiment showed higher values than control sample (153% in length and 127% in weight of seedlings). Although tested cultivars were taxonomically very similar, high differences in response to plasma pre-treatment were found.