| Negative Air Ions (NAT) were regarded as Air vitamin, growth hormone, longevity element. And its concentration was also designated as a key index to measure air quality. NAI not only had the function of dust-settling and sterilization, but also had function of disease prevention. It was good for health. After the "soot-type" and "type of photochemical smog" pollution, human beings was entering into the modern "indoor air pollution" as a symbol of the third generation of pollution period. Therefore, it significantly improved intramural air quality, by improving and retaining intramural NAI concentration. In this research, by conducting investigation in functional type plant to produce NAI efficiently and its generator by which plants could efficiently generate more NAI. Main results were as follows:Firstly, detection of NAI concentration generated by plants in natural state.Through investigation in 36 plants species as experimental material in sealed glass chamber with the dimensions 80x80x80cm, it was showed as following. In the 36 species, Mammillaria hahniana generated max NAI concentration (49 ion·com-3)in 24 hours,while Cymbidium sinense generated the low level(18 ion·com-3). Judging from the mean value in 24h, Sansevieria trifasciata produced the highest level (27 ion·com-3)which was 1.5 times as control sample. Most plants could steadily produce NAI in different times a day while some species could not. The ability to generate NAI was too week for plants in natural state to satisfy the need of human health. Therefore,it was urgent to develop a device which could stimulate plants to generate negative air ions efficiently.Secondly, The development of the plants Negative air ions generator which could stimulate plants to generate NAI efficiently. Based on analysis and research on the plants NAI generator, we confirmed the system construction, and developed a new efficient generator, which effectively resolved some key problems, such as the high voltage input, the anti-interference and stability of the figures display circuit, the adjustability of the output pulse peak voltage, the pulse interval and the pulse frequency. From which the equipment became more stable and practicable. Under different intensities of the pulsed electric field, the plant in generator could produce different concentration of NAI.Therefore, it was very important to study out the optimal parameters of the effectively NAI generation of each plant under different pulsed electric field.Thirdly, Studying out the typical optimal parameters of the effectively NAI generation of different CAM plants under different pulsed electric field. Experiments by using plants NAI generator to stimulate the rhizosphere of different types of plants in pulsed electric field. We found out that under the effect of the pulsed electric field, the CAM plants, which is short for the crassulacean acid metabolism, showed the best effects on generating NAI. We also detected the concentration of the NAI in different levels. The results as follows:(1)The concentration of NAI significantly increased when the rhizosphere soil of CAM plants was stimulated by the plants NAI generator.Under different intensities of pulsed electric field, the abilities of generating level of NAI were different, such as the Asparagus setaceus ’Nanus’was most significant, under the pulsed electric field (Um=20kV,T=0.5s,τ=65ms),the concentration of NAI was 2603613 ion·com-3, which was 108484 times in natural state. The orthogonal design of 3 factors(Average output voltage Um, Pulse interval T, and Pulse width τ,) and four levels were taken for studying the typical optimal parameters of the pulsed electric field for 19 different CAM plants which released NAI efficiently,Took Asparagus setaceus ’Nanus’ for example, its typical optimal parameters were Um=15kV,T=0.5 s,τ=35ms. (2)Under the stimulation of the pulsed electric field (the average output voltageUm=15kV, pulse intervalT=1.0s, the pulse widthτ=50ms), the average concentrations of the NAI of the Loam, clay and sand all improved, compared with the normal states. However, the growth was small. By contrast, the released quantity of the clay was the highest, was about 204 ion·com-3, which was 8.5 times in normal state, and the released quantity of the sand had 92 ion·com-3;which was the lowest.(3)Detections of the concentration of the NAI produced by the Asparagus setaceus ’Nanus’ in different conditions, such as were planted in the Loam, clay and sand under the same pulsed electric field. The concentration of the NAI was low and similar with in other soil conditions in natural state. For example,the mean(44 ion·com-3) as the highest level; But the concentration of the NAI produced by Asparagus setaceus’Nanus’planted in sand under the pulsed electric field (Um=15kV, T=1.0s, τ=50 ms) had reached to the level (886814 ion·com-3), which had the 20154 times as in the natural state in those three different conditions. Furthermore, the average concentration reached to 112229 ion·com-3,which was the lowest, that imposed by pulsed electric field for 20 minutes. So, the average concentration of the the Asparagus setaceus ’Nanus’ planted in loam could reached to a higher level than other two conditions when under the same pulsed electric field.Fourthly, The mechanism study on CAM plants produced NAI efficiently. The relationship between the leaf epidermis stomatal, voltage and ability to produce NAI of CAM plants were studied, the results showed that:(1)The leaf epidermis stomatal of most CAM plants was significantly amplified, and also generated more NAI when it was stimulated by pulsed electric field. The Chlorophytum comosum showed the best, whose leaf epidermis stomatal was expanded to 3471.88 μm2 when it was stimulated, it was 3.7 times in natural state. The concentration of NAI was 616480 ion·com-3 and it was 3425 times in natural state.(2)It was found that the voltage in the plants was attenuated different degree when some certain intensity pulsed electric field was applied to rhizosphere soil of CAM plants.The voltage of 14 plants was from 1.40kV-1.60kV, and the voltage of Asparagus setaceus ’Nanus’ was the highest which was 7.8 kV.So the higher voltage in plants, the more NAI generated. The concentration of NAI of Asparagus setaceus ’Nanus’ was 236307 ion·com-3 which was the highest in the 15 plants.The voltage of Kalanchoe blossfeldiana was 1.4 kV which was the lowest, while the concentration of negative air ions was 44 ion·com-3 which was also the lowest.(3)The voltage of plants was rapidly decreased when plants were connected to the earth or ground by wire. Plants were connected to the earth, most voltage was released to the earth, it was from 0.44 to 1.00 kV, and the amount of NAI was also dropped sharply. The Kalanchoe blossfeldiana was most outstanding, the voltage was 0 kV, the concentration of NAI was 13 ion·com-3, which was the same as in natural state. When it was connected to the ground, the voltage was from 0.00 to 0.56 kV, and the concentration of NAI was the same as in natural state.In spite of higher generation from some other plants, amplification is small.Fifthly, The development of the plants NAI generator. Based on the improvement and the perfection of the functional plants NAI generator, most different CAM plants were identified, by which 12 CAM plants were found which could produce NAI efficiently after stimulated under pulsed electric field, and the optimal parameters of 12 different CAM plants such as Asparagus setaceus ’Nanus’ produced NAI were identified,. Based on plants such as the Asparagus setaceus ’Nanus’ as the first-choose plants stimulated by plants NAI generator. In order to improve and perfect the matching technology and corollary equipment. |
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