THE IRRADIATION OF ENERGETIC WILLOW CUTTINGS BY LASER LIGHT. CHEMICAL, TECHNICAL AND CALORIMETRIC ANALYSIS OF BIOMASS.

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1 Section Advances in Biotechnology THE IRRADIATION OF ENERGETIC WILLOW CUTTINGS BY LASER LIGHT. CHEMICAL, TECHNICAL AND CALORIMETRIC ANALYSIS OF BIOMASS. PhD. Mateusz Jakubiak AGH University of Science and Technology in Krakow, Poland ABSTRACT The article presents issues related to the growth stimulation of some plant species, using a low power laser light. This technology could be helpful in increasing the yield and germination energy as well as accelerating development and growth of plants. The presented experiment was part of a wider research on the effects of laser light on the different varieties of energetic willow (Salix sp.). The aim of this particular experiment was to ascertain whether the selected laser stimulation parameters of willow cuttings could enhance and accelerate the production of biomass without changing wood properties relevant to the energetic use. The Salix viminalis Turbo cuttings were used as biological material. Two devices were used as the sources of coherent light: laser - wave length: λ = 670 nm and laser diode - wave length: λ = 473 nm. Willows had been cultivated for two years. The willow shoots were collected after the second growing season. Wood samples of control and experimental groups were dried and the calorimetric analysis have been made. Additionally, the analysis of technical parameters as well as carbon, hydrogen and sulfur content of the harvested wood were carried out. The results clearly indicate that stimulation by low power lasers with parameters of irradiation properly chosen for the Salix viminalis Turbo can significantly speed up growth of plants without changing the chemical and technical characteristics and the calorific value of biomass. Keywords: willow biomass, laser stimulation, irradiation, energetic willow, calorific value INTRODUCTION - APPLICATION OF LASER STIMULATION The use of physical factors for controlled influence on different plants and vegetables during growth and storage is a modern trend of combining the intensification of plant technologies with the ecological requirements. The application of physical methods of plants stimulation can speed up efforts to improve the natural environment and its rational management as well as could be a solution for agriculture without the use of genetic engineering. Physical methods for increasing plants production are based on use of different physical factors for seeds or seedlings treatment. The major goal is increasing of the yield, germination energy and accelerating development and growth of plants. Moreover, the stimulation may effect in resistance to unfavorable environmental conditions [1, 6, 11]. 543

2 14 th SGEM GeoConference on Nano, Bio and Green Technologies for Sustainable Future The studies on the effects of physical stimulation of plants mainly include factors such as electromagnetic waves, laser light, magnetic field as well as the ultrasound and ionizing radiation [1, 6, 15]. Plants sensitivity to the influence of these physical factors has been developed during their evolution. These physical factors are elements of their natural environment. All living processes taking place in plants cells are highly dependent on energy exchange between the cell and the environment. The physical methods are useful for plants able to vegetate at a higher energy level. The mechanism of energy changes is based on the fact that physical methods increase the energy account by internal transformation of energy. The core of physical methods is the energy supply. Absorbed energy is converted into chemical energy, which is used for growth and development of plants. Stimulation of the seed and seedlings effects in increasing the energy balance, intensification of the materials exchange and the growth processes activation. The use of low-power laser light is one of the physical methods of plants stimulation. The invention of lasers in the 60 of the last century resulted in development of new field of science. Research on the use of lasers in various fields of technology is still being intensively developed. These interdisciplinary studies search for new possibilities of laser light application. One of the new technologies is the use of low-power lasers for stimulation of biological materials. Light has a profound effect on plant growth and development. Light is a necessary condition for photosynthesis and the sensitivity of plants to light is well known. Plants are sensitive not only to light intensity but also to its spectral composition. Absorption spectra for chlorophyll a and chlorophyll b result in slightly different absorptions of visible light. The two kinds of chlorophyll in plants complement each other in absorbing light. Plants are able to satisfy their energy requirements by absorbing mostly light of wavelength corresponding to blue color ( = nm) and red color ( = nm) [10]. Due to this fact, red and blue light best stimulates photosynthetic metabolism. The use of these light wavelengths for irradiation could be particularly efficient in the stimulation of autotrophic growth characteristics. Light Amplification by Stimulated Emission of Radiation - LASER is a specific light source. Unlike traditional light sources such as incandescent or discharge lamps, lasers are generators or amplified light wave. Depending on the design and purpose lasers can generate electromagnetic radiation of ultraviolet, visible light and infrared. The general scheme of the construction and characteristics of the generated light are the same. What is important, is that the laser light is strengthened by stimulated emission of radiation. This emission is a process of interaction of light with matter. The quantum state of the atom, ion or molecule is changing. An excited atom or molecule releases photon by collision with another photon. Lasers differ from other sources of light because the emitted light has high degree of spatial and temporal coherence. Laser light is uniformly polarized, monochromatic and highly directional. It is emitted as a relatively narrow beam in a specific direction. Laser can easily radiate emission line of very little width. This results in very high power in a narrow region of the spectrum. Devices emitting laser light used for photostimulation of plants could be classified in three different types. They differ in the state of emitting medium: solid, gaseous, semiconductor. Lasers can emit light of wavelength corresponding to different colors. The ruby and helium-neon lasers emit light of wavelength corresponding to red colors. The YAG:Nd 544

3 Section Advances in Biotechnology laser emits green light, argon - blue and nitrogen laser ultraviolet. Semiconductor lasers emit visible and infrared light and carbon dioxide laser - far-infrared [1, 7]. Laser diodes emitting light with similar characteristic to laser light are also used for plants photostimulation. The advantage of laser diodes is their much lower price compared to lasers. These sources of laser light have been used alone or in combined forms, in single or several irradiation sequences. The laser light wavelength most frequently used in the biostimulation process is corresponding to the red and blue color [7, 16]. It was found that the effect of stimulation depended on the following parameters: the light wavelength, the exposition to irradiation (time and mode) and the energy density. The values of irradiation parameters must be chosen individually for the particular biological material. The values depend on the aim of stimulation, the irradiated part of the plant (seeds, seedlings), as well as on the species and variety [1, 4, 8]. Interdisciplinary research studies on the application of low intensity laser stimulation of different biological material proved, that the photostimulation of plants is based on the relation between the polarized monochromatic laser beam and the photoreceptors absorbing it, which activate numerous biological reactions [1]. The energy from the laser light absorbed in the seed and seedlings triggers physiological and biochemical processes, due to the transformation of light energy into chemical energy. The effects of stimulation by coherent light are related to the quantum of energy absorption of laser radiation by certain biologically active compounds or cellular organelles. Irradiation could increase certain enzymes activity, mainly those involved in the cells energetic processes. Research studies proved that the effects of a low-power lasers light on the biological material have non-specific character. It was found that coherent and monochromatic light is able to cause effects of biostimulation on different organisms like bacteria, algae, protozoans, animals as well as on in vitro animals and plant cells cultures and in vivo vascular plants cells cultures [2, 4, 7]. Laser light stimulation could also cause changes in the degree of elements accumulation in plant cells. An increase or, conversely, reduction of accumulation of some elements in irradiated plants tissues may be caused by different algorithms of irradiation [4]. Since first reports in the 60' of previous century there have been numerous studies on applying lasers in agriculture and these have shown the potentiality of its application in this field. The number of studies has increased in last two decades, studies are conducted in many scientific centers at various countries. The experimental work on the use of laser light stimulation of agricultural plants mainly include pre-sowing treatment of seeds. The energy absorbed form the laser beam is converted into chemical energy, which is used for growth and development of plants. Increased energy potential of the seeds affects the physiological processes in the germinating seeds. Possible effects include not only better and faster germination and accelerated ripening but also increased disease and frost resistance. Furthermore, appropriately selected parameters of seeds photostimulation can also increase the percentage of germinating seeds. Research conducted on the agricultural use of laser light showed that pre-sowing laser stimulation could be a factor increasing seed quality and, what is very important, accelerating the early phase of growth. There are numerous studies that show positive effects of presowing laser irradiation, both in cereals (eg. maize, wheat, rice, barley) and in vegetables, such as: cucumbers, tomato, eggplant, lettuce, peas, etc. and other agricultural plants like sugar beets, alfalfa, vetch, white lupine or perennial ryegrass. 545

4 14 th SGEM GeoConference on Nano, Bio and Green Technologies for Sustainable Future However, several researches shown that the seeds of vegetables are more sensitive and susceptible to laser stimulation than cereals. Positive effects of vegetables seeds irradiation are more synchronous germination and accelerated ripening. Moreover, a higher biological value of fruits and an increased content of nutrients is specific result of the photostimulation of agricultural seeds [1, 4, 6, 7, 9]. Research on the use photostimulation of biological material was also conducted on industrial plants and other organisms. The aim was to study the possibility of using biostimulation of biological material to improve the natural environment [4]. Laboratory and field studies have shown that it was possible to increase the resistance to stress conditions of different plants species by using properly chosen algorithms of laser irradiation. It was found that laser stimulation of seeds and seedlings may cause an increase of resistance to unfavorable environmental conditions. It could also cause changes in the degree of accumulation of elements in plant cells [4]. An equipment was constructed to automate the process of photostimulation of seeds and seedlings. Several different devices were constructed independently in different research centers. The first example of application of pre-sowing laser seeds stimulation by divergent beam method is a Polish device developed and patented by Dygdała and Koper [5]. SOLAR-2M, yet another device for seed photostimulation, was constructed by a team of Institute of Information Technologies at Bulgarian Academy of Sciences [3]. MATERIAL AND METHOD The presented experiment was part of a wider research on the effects of laser light on the different varieties of energetic willow (Salix sp.). The purpose was to verify that the photostimulation method can be helpful in the implementation of activities related to the biological reclamation of wasteland and degraded brownfields. The aim of this study was to ascertain whether the selected laser stimulation parameters of willow cuttings could improve their physical fitness as well as enhance and accelerate the production of biomass. Photostimulation algorithms were based on the following parameters: wavelength, energy density, duration and mode of exposure. The parameters were chosen on the basis on the results of preparatory hydroponic experiments, previous field experiments and on studies on other plant material. Selected species of energetic willow could be suitable for cultivation on wastelands and postindustrial areas. These species are resistant for diseases and adverse environmental conditions. Large and rapid growth of biomass is an important advantage when using willows in reclamation. The biological material used in this experiment were Salix viminalis Turbo cuttings. This variety, resistant to disease and tolerant to pests, was created at The Chair of Plant Breeding and Seed Production of The University of Warmia and Mazury in Olsztyn. Additionally, it gives a very high yield of dry wood which is why the biomass collected after a vegetation season can be used as a source of renewable energy. The following devices were used in the experiment as the sources of coherent light: - impulse medical laser (ML): Marp Electronic Type D68-1, emitting pulsating light, wave length: =670 nm, power: 20 mw. - blue laser diode (BD): wave length: =473 nm, power: 20 mw, 546

5 Section Advances in Biotechnology There were 30 cuttings prepeared per group. Seedlings in the experimental groups were exposed to laser light with different parameters before planting. Irradiation was intermittent. The total time of exposure to laser light was 90 seconds for every experimental group. The distance from the light source to the biological material was 20 cm and the light beam was perpendicular to the surface of the material. The cuttings used in experiment were divided into four groups of the same quantity: - control group of unirradiated cuttings, marked as C, - experimental group, irradiated by blue laser diode, total exposure time of 90 seconds (3 sequences of 30 seconds), marked as BD. - experimental group, irradiated by impulse medical laser, total exposure time of 90 seconds (3 sequences of 30 seconds), marked as ML. - experimental group, irradiated by impulse medical laser, total exposure time of 45 seconds (3 sequences of 15 seconds) and also irradiated by blue laser diode, total exposure time of 45 seconds (3 sequences of 15 seconds), marked as ML/BD, After the second growing season willow shoots were collected. Wood samples of each group, prior to the calorimetric analysis, have been dried at room temperature. The analyses of carbon, hydrogen and sulfur content of the wood has also been made. The analyses of the suitability of biomass for energy purposes is based on the following standards: PN/G analysis of moisture content. PN/G the ash content was assessed by the classical method of burning at a temperature of 815 C. PN-ISO 562: 2000 the volatile matter content was performed at 900 C PN-ISO 351: total sulfur content and ash sulfur content PN/G the contents of carbon and hydrogen in the biomass are estimated by the high fuel combustion PN-ISO 1928: the heat of combustion and calorific value. RESULTS AND DISCUSSION The results of experiments can make a basis to create optimal photostimulation parameters of willow cuttings for enhancement and acceleration the production of biomass. Significant differences in the increase of biomass in experimental groups were found. Chemical, technical parameters values as well as calorific value from a control group and experimental groups were comparable (Tab. 1.). The average weight (Fig. 1.) of harvested shoots from the control group (C) was g (SD g), group BD g (SD 55.6 g), group ML g (SD g) and group ML/BD g (SD g). In comparison with the control group differences in weight of shoots in experimental groups ML and ML/BD are statistically significant. 547

6 14 th SGEM GeoConference on Nano, Bio and Green Technologies for Sustainable Future Tab. 1. Technical, calorimetric and chemical analysis of harvested biomass from control (C) and experimental groups: BD, ML and ML/BD. Group C BD ML ML/BD Technical analysis Free moisture (W ex ) [%] 49,2 48,7 50,2 49,5 Moisture (W) [%] 4, ,9 Ash (A) [%] 1,4 1,4 1,3 1,4 Volatile matter (V) [%] 74,78 74,49 74,53 74,5 Calorimetric analysis Calorific value Q i [kj*kg -1 ] Chemical analysis Carbon (C) [%] 46,7 48,1 48,5 46,8 Hydrogen (H) [%] 5,94 5,92 5,99 5,78 Sulfur (S) [%] 0,24 0,28 0,32 0,2 Fig. 1. The average weights [g] of harvested shoots from control (C) and experimental groups: BD, ML and ML/BD. The results of experiment confirmed that stimulation by low power lasers with parameters of irradiation properly chosen for the Salix viminalis Turbo can significantly speed up growth of plants. Results clearly indicate that the best growth may be achieved using stimulation by impulse medical laser emitting wave length: λ=670 nm, with irradiation total time of 90 seconds (3 sequences in 30 seconds). A similar effect of 548

7 Section Advances in Biotechnology biomass growth was achieved in experimental group irradiated by impulse medical laser and blue laser diode. The parameters important for biomass use for energy purposes are very similar in all groups. Comparing with the data from other studies, calorific value is on the standard level for one-year shoots of willows. However, the ash content in all groups is very low. The one-year-old willow shoots wood has calorific value - 17 MJ*kg -1 and ash - 6,89% [12]. The calorific value of dry biomass of one year old shoots of different energetic plants is lower. For example, Virginia fanpetals (Sida hermaphrodita Rusby) stems has 15.1 MJ*kg -1 [15]. The literature data published by researchers working on the energetic willows show that using a suitable system of plants cultivation it is possible to increase the calorific value. In addition, willow crops harvest on a three-year or five -year rotation may result in calorific value of almost 20 MJ*kg -1 [13, 14] Acknowledgements The article was published within the scope of AGH-UST statutory research for the Department of Environmental Management and Protection No REFERENCES [1] Aladjadjiyan A. Physical Factors for Plant Growth Stimulation Improve Food Quality, In: A. Aladjadjiyan (ed.) Food Production - Approaches, Challenges and Tasks, InTech Europe, pp , [2] Chen YP., Yue M., Wang XL. Influence of He Ne laser irradiation on seeds thermodynamic parameters and seedlings growth of Isatis indogotica. Plant Science, Vol.168, Is. 3, Elsevier Ireland Ltd., pp , [3] Dinoev S. Laser a controlled assistant in agriculture. Problems of Engineering Cybernetics and Robotics, No 56, Bulgarian Academy Of Sciences, Sofia, pp 86-91, [4] Dobrowolski J.W., Śliwka M., Mazur R. Laser biotechnology for more efficient bioremediation, protection of aquatic ecosystems and reclamation of contaminated areas. Journal of Chemical Technology and Biotechnology Vol. 87, Is. 9, Society of Chemical Industry, pp , [5] Dygdała Z., Koper R. The device for pre-stimulation of seeds with laser light. Patent UPRP, No , 1993 [In Polish]. [6] Dziwulska-Hunek A., Kornarzyński K., Matwijczuk A., Pietruszewski S., Szot B. Effect of laser and variable magnetic field simulation on amaranth seeds germination. International Agrophysics 23, pp , [7] Hernandez A.C., Dominguez P.A., Cruz O.A., Ivanov R., Carballo C.A., Zepeda B.R. Laser in agriculture. International Agrophysics 24, pp , [8] Jakubiak M., Śliwka M. Research on effects of laser light stimulation on selected strains of energetic willow. Polish Journal of Environmental Studies Vol. 18 No. 3A, pp , [9] Klimont K. The effects of biostimulation by laser irradiation on sowing value of seeds and yield of some crop plants. Bulletin of Plant Breeding and Acclimatization Institute No 242, pp ,

8 14 th SGEM GeoConference on Nano, Bio and Green Technologies for Sustainable Future [10] Solomon E. P., Berg L. R., Martin D. W. Biology. Seventh edition. Thomson Learning, [11] Sommer A. P., Franke R-P. Plants grow better if seeds see green. Naturwissenschaften - The Science of Nature, Vol. 93, Is. 7, Springer-Verlag, pp , [12] Stolarski M., Wróblewska H., Cichy W., Szczukowski S., Tworkowski J. Chemical composition and calorific value of basket willow wood obtained from arable lands willow coppice. Drewno. Prace naukowe. Doniesienia. Komunikaty. Vol. 48 No. 174, pp. 5-16, [13] Stolarski M., Szczukowski S., Tworkowski J. Characteristic of biomass from willows cultivated under Eco-salix system in energetic aspect. Problemy Inżynierii Rolniczej 1/2010, pp , [14] Stolarski M. J., Szczukowski S., Tworkowski J., Krzyżaniak M. Cost of heat energy generation from willow biomass. Renewable Energy Vol. 59, Elsevier Ltd., pp , [15] Sujak A., Dziwulska-Hunek A., Kornarzyński K. Compositional and nutritional values of amaranth seeds after pre-sowing He-Ne laser light and alternating magnetic field treatment. International Agrophysics, 23, pp 81-86, [15] Szyszlak-Bargłowicz J., Piekarski W. Calorific value of biomass from Virginia fanpetals (Sida hermaphrodita Rusby) stems depending on humidity. Inżynieria Rolnicza 8(117)/2009 pp , [16] Śliwka M., Jakubiak M. The application of the innovative biotechnology in hydrobotanical wastewater treatment plants. Polish Journal of Environmental Studies vol. 18 no. 3A, pp ,

Degraded Lands Biological Reclamation using Modern Methods of Stimulating the Growth of Selected Varieties of Willows (Salix sp.)

Degraded Lands Biological Reclamation using Modern Methods of Stimulating the Growth of Selected Varieties of Willows (Salix sp.) Mateusz Jakubiak* Department of Management and Protection of Environment