Hemp (Cannabis sativa L.) seeds after plasma treatment Božena Šerá, Iveta Gajdová, Bogdan Gavril, Eugen Hnatiuc, Michal Šerý, Petr Špatenka Institute of Nanobiology and Structural Biology of GCRC, Academy of Sciences of the Czech Republic, Na Sádkách 7, 37005 Č. Budějovice, Czech Republic; "Gh. Asachi" Technical University of Iaşi, Faculty of Electrical Engineering, Iaşi, Romania; Apollonia University of Iaşi, 11 Pacurari Street, Iaşi 6600, Romania; Department of Physics, Pedagogical Faculty, University of South Bohemia in České Budějovice, Jeronýmova 10, 37115 Č. Budějovice, Czech Republic
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[email protected] Abstract- 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.
I.
INTRODUCTION
Hemp (Cannabis L.) is a genus of flowering annual plants indigenous to Central and South Asia. It is used by men for a long time. Hemp has been used for fibre (textile and paper industry, engineering), for seed and seed oils (food, engineering), for medicinal purposes, and as a soft drug [1-3]. “Industrial hemp” is represented by species of Cannabis sativa. Its used varieties have been developed to contain minimal levels of THC (terpeno-phenolic compound: tetrahydrocannabinol). Recently, the interest of farmers grows in unconventional plants and alternative procedures. Hemp seems to be a re-discovered plant good used in pharmacy or energetic [4]. On the ground of previous experiments with seeds of various plant species, we know that plasma pre-treatment may positive affect the vitality of growing seeds [5-8]. The aim of this experiment was to test three cultivars of hemp species and to find the best way how to pre-treat seeds before the sowing. Research was focused on effect of two cold plasma treatments (including various time expositions) on germination and early growth of hemp seed.
978-1-4673-1653-8/12/$31.00 '2012 IEEE
II.
MATERIAL AND METHODS
Three cultivars of hemp seeds (Cannabis sativa L.) were obtained from the civil association KONOPA: cv. Carmagnola, cv. Finola, and cv. Bialobrzeskie. For plasma pre-treatment we used two plasma devices. The first was the Gliding-arc discharge (GlidArc) device consisting of two divergent electrodes. The second was the commercial apparatus Plasonic AR-550-M, which generates downstream microwave plasma (DMP). Three different time expositions were used in both apparatuses: 180 s, 300 s, 600 s. GlidArc: The aluminium electrodes, having a thickness of 2 mm, were connected to an AUPEM power converter supplied from the power grid at 50 Hz through an adjustable power transformer. In operation, the discharge ignites in the area where the distance between the electrodes is minimal and as it moves along the edges of the electrodes, it elongates and finally extinguishes. This gliding motion is achieved using a flow of gas injected along the symmetry axis of the electrode ensemble through a nozzle of a 0.6 mm inner diameter. The flow of gas helps maintain the parameters within the limits proper to cold plasma due to deionization phenomenon, preventing the transition of discharges from electric arc regime. Parameters of the discharges are also maintained in the cold plasma specific range due to the special power supply, having a fast-dropping outlet characteristic. This feature helps maintain the current in the circuit at relatively low values [9]. The treated samples were placed under the electrodes (distance of 250 mm). The temperature in the target area did not exceed 50○C for the longest exposure time. Air with water vapour obtained from an air compressor and passed through a flask with deionised water was used as working gas. The gas flow rate was 10 L/min. The active species produced by the discharge were transfered towards the exposed seeds through the flow of gas that „blows” the discharges. DMP: The apparatus was equipped with a cylindrical vacuum aluminium chamber (10 L) and was evacuated with the rotary pump. The downstream microwave power-source
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Plasonic MAL 1200 was connected to the vacuum chamber (working pressure 140 Pa). The power-source consisting of a mineral corundum tube was placed in the center of the microwave resonator (2.45 MHz). The air was introduced into one end of the vacuum chamber and the other end led into the reactor chamber. Other used parameters: magnetron input 500 W, flow rate 3.3 ml/s. The detailed configuration is described in [10-11]. A glass Petri dish (20 cm diameter) with tested seeds was placed on the bottom of the vacuum chamber, ca. 10 cm under the plasma output (temperature about 25°C). Seed germination (%) 115 100 85
length of the seedlings accretions and their dry-mass weight were collected on the 6th day of the cultivation. III.
RESULTS
Differences in response to the treatment between apparatuses, among tested cultivars and among time expositions were found. A positive/neutral effect was observed in all measured characteristics after GlidArc plasma pre-treatment. On the other hand, a negative/neutral effect was found after DMP pre-treatment (Fig. 1). The longest seedlings were recorded after GlidArc plasma pre-treatment in all time exposures in cultivars of Finola and Bialobzeskie. The highest seedlings were recorded after GlidArc plasma pre-treatment in all time exposures in cultivars of Finola and Carmagnola. Plasma pre-treatment DMP was destructive effect for all tested hemp cultivars.
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IV. Finola
Bialobrzeskie
Carmagnola
Finola
Bialobrzeskie
DMP
5 min
10 min
3 min
5 min
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Carmagnola
GlidArc
Length of seedling (%) 130 100 70 40
Finola
Bialobrzeskie
Carmagnola
Finola
Bialobrzeskie
DMP
10 min
5 min
3 min
10 min
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3 min
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Carmagnola
GlidArc
Weight of seedling (%) 125 100 75
50 25
Finola
Bialobrzeskie DMP
Carmagnola
Finola
Bialobrzeskie
10 min
5 min
3 min
10 min
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3 min
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0
Carmagnola
GlidArc
Fig. 1. Germination and growth of hemp seeds after plasma pre-treatment on the 5th day of the cultivation.
The germination and early-growth tests were run under laboratory conditions. We used 30 seeds of one pre-treated cultivar, KA0/80 filter paper, 6 ml of distilled water for one plastic Petri dish of 9 cm in diameter. Each pre-treatment was repeated five times, so 150 seeds were used for one pretreatment. The data about number of germinating seeds,
DISCUSSION
Apparatus generated GlidArc plasma is more suitable for plasma pre-treatment of seeds than DMP apparatus. This corresponds to results from the experiment with buckwheat [12]. We do not if a taxonomical level of the treated seeds is as important as a matter of quantity of energy displayed (used apparatus). The data was obtained on 3rd, 4th and 5th day of seed cultivation, but the data from 5th day has the highest informative value for the plant ecology. Characteristics of germination and early growth from the 5th day of the test are shown in Fig. 1. The best germination was recorded at cultivar Finola after GlidArc pre-treatment (more than 105 % in comparison with the control sample) and the worst one at cultivar Carmagnola after DMP pre-treatment (small than 60 % in comparison with the control sample). The best taxon of the tested cultivars seems to be the cultivar Finola, because it grew after GlidArc pre-treatment significantly better than control sample. On 5th day, length and weight of Finola seedlings was even 153 % and 127% respectively (5 min exposition) (Fig. 1). After DMP plasma pre-treatment, the measured values are for cultivar Finola the least destructive (Fig. 1). The worst plant hemp of the tested cultivars seems to be the cultivar Carmagnola. It is very interesting that so large differences in response to plasma treatment were found in one plant species of Cannabis sativa. The sensitivity to plasma pre-treatment was between cultivars of Finola and Carmagnola highly visible. Previous simulation experiments were conducted with species that were taxonomically different [8,9,11]. V.
CONCLUSION
Downstream microwave plasma pre-treatment is not suitable for seed modification of hemp plants. Positive stimulations of seed germination and early growth were found above all in cultivar Finola after GlidArc plasma pre-
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treatment. The length and weight of the seedlings were larger by 53 % and 27 % respectively in comparison with the control sample. REFERENCES [1] D. M. Alden, J. L. R. Proops, and P. W. Gay, “Industrial hemp’s double dividend: a study for the USA,” Ecolog. Econom., vol. 25, pp. 291-301, 1998. [2] J. C. Callaway, “Hempseed as a nutritional resource: An overview,” Euphytica, vol. 140, pp. 65-72, 2004. [3] R. Pertwee, “Pharmacological and therapeutic targets for Δ9tetrahydrocannabinol and cannabidiol,” Euphytica, vol. 140, pp. 73-82, 2004. [4] T. R. Fortenbery and M. Bennett, “Opportunities fro Commercial Hemp Production,” Rev. Agricult. Econ., vol. 26, no. 1, pp. 97-117, 2004. [5] J. C. Volin, F. S. Denes, R. A. Young, and S. M. T. Park, “Modification of seed germination performance through cold plasma chemistry technology,” Crop Sci., vol. 40, no. 6, pp. 1706-1718, Nov./Dec. 2000. [6] M. Q. Yin, M. J. Huang, B. Z. Ma, and T. C. Ma, “Stimulating effects of seed treatment by magnetized plasma on tomato growth and yield,” Plasma Sci. Technol., vol. 7, no. 6, pp. 3143-3147, Dec. 2005. [7] B. Šerá, V. Straňák, M. Šerý, M. Tichý, and P. Špatenka, “Germination of Chenopodium album in response to microwave plasma treatment,” Plasma Sci. Technol., vol. 10, no. 4, pp. 506-511, Aug. 2008. [8] A. E. Dubinov, E. M. Lazarenko, and V. D. Selemir, “Effect of glow discharge air plasma on grain crops seed,” IEEE Trans. Plasma Sci., vol. 28, no. 1, pp. 180-183, Feb. 2000. [9] B. Gavril, E. Hnatiuc, B. Sera, I. Hruskova, S. Padureanu, and C. Hăisan, “Possibilities of performing treatments on seeds using cold plasma discharges,” in XIXth Symposium on Physics of Switching Arc, Brno: University of Technology, 2011, pp. 189-192. [10] M. Šerý, P. Špatenka, J. Pavlik, and J. Messelhauser, “Chromatic monitoring of downstream microwave plasma source,” Czech. J. Phys., vol. 50, pp. 481-486, 2000, Suppl. 3. [11] B. Šerá, P. Špatenka, M. Šerý, N. Vrchotová, and I. Hrušková, “Influence of plasma treatment on corn germination and early growth,” IEEE Trans. Plasma Sci., vol. 38, no. 10, pp. 2963-2968, Oct. 2010. [12] B. Šerá, I. Gajdová, M. Černák, B. Gavril, E. Hnatiuc, D. Kováčik, V. Kříha, J. Sláma, M. Šerý, and P. Špatenka, “How various plasma sources may affect seed germination and growth,” IEEE Trans. Plasma Sci., 2012, accepted.
Božena Šerá was born in Jindřichův Hradec, the Czech Republic, in 1966. She graduated from the Charles University in Prague and received the Ph.D. degree in plant ecology from the University of South Bohemia in České Budějovice. She is a specialist in population biology of plant, above all in ecology of generative reproduction of high plants. Since 1998, she has been at the Institute of Systems Biology and Ecology, Academy of Sciences of the Czech Republic. Since 2011, she has worked at the Institute of Nanobiology and Structural Biology of GCRC, Academy of Sciences of the Czech Republic. She is presently focused on plant biotechnology.
Iveta Gajdová was born in Bechyně, the Czech Republic, in 1983. She graduated as the M.Sc. degree in applied measuring and computing technology from the University of South Bohemia in České Budějovice. Since 2009, she has been a technician worker at the Institute of Systems Biology and Ecology, Academy of Sciences of the Czech Republic. Since 2011, she has work at the Institute of Nanobiology and Structural Biology of GCRC, Academy of Sciences of the Czech Republic. She is focused on a bio-stimulation of seeds of high plant by chemical and physical treatments.
Bogdan Gavril was born in Roman, Romania in 1983. He received his BSc. in Electrical Engineering Specialization in 2007 and his MSc. degree in Electrical Advanced Systems in 2008, from the "Gh. Asachi" Technical University of Iasi. Since October 2008 he is a Ph.D. Student at "Gh. Asachi" Technical University of Iasi, Faculty of Electrical Engineering. His research interest is in the area of non – thermal plasma and its applications, biological applications for cold plasma discharges.
Eugen Hnatiuc was born in Piatra Neamt, Romania, in 1947. He received the B.E. degree in electrical engineering from the Electrical Engineering Faculty, Technical University of Iasi, Romania, in 1969. Since 1969 he has been sustaining research and teaching activities at the Electrical Engineering Faculty, Technical University of Iasi, Romania. His research interests include electrical apparatus, switching techniques, stationary and dynamic electromagnets behavior, electro-ecology, design of cold plasma reactors and cold plasma applications. Since 2011 he is responsible of biomedical applications of cold plasma at the Apollonia University of Iasi. Michal Šerý was born in České Budějovice, the Czech Republic, in 1963. He received the Master of Engineering degree in control systems and cybernetics from Department of Technical Cybernetics, the Czech Technical University in Prague. His main fields are application of electronics and information systems, technological applications, computer graphics and data
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visualization. Since 1994, he has been an assistant lecturer at the Department of Physics, Pedagogical Faculty, University of South Bohemia in České Budějovice. Petr Špatenka was born in České Budějovice, the Czech Republic, in 1954. He received the M.Sc. degree in physics and mathematics and the Ph.D. degree in plasma physics from the Faculty of Mathematics and Physics, the Charles University in Prague in 1978 and 1986, respectively. He was a Lecturer with the Faculty of Education, České Budějovice, the Czech Republic, in 1981. From 1991 to 1993, he was a Visiting Scientist with the group of Prof. H. Suhr at the Faculty of Chemistry, University of Tübingen, Germany. He became a Lecturer with the University of South Bohemia in České Budějovice in 1993, where he also became an Associate Professor in 1995 and a Full Professor in 2003. Since 2000, he has been the Director of the Surface Engineering Group, Department of Material Science, Technical University in Liberec, the Czech Republic. His research interests include plasma diagnostics, plasma chemical processes and their application for surface treatment, and deposition of functional coatings. He is an author or coauthor of over 70 peer-reviewed articles, several patents, and numerous conference contributions. He is the founder of PlasmaTech Ltd. and the president of SurfaceTreat Inc.
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