COLD CATHODE FLUORESCENT LAMPS (CCFL - Diagnosis Press

1497Biotechnol. & Biotechnol. eq. 23/2009/4

Article DOi: 10.2478/v10133-009-0019-1 A&eB

Keywords: ccFl, light source, micropropagation, CymbidiumAbbreviations: CCFL – cold cathode fluorescent lamp; CCFL-ELU – CCFL edge light unit; mCCFL-ELU – multiple CCFL-ELU; dtCCFL-LU – direct type CCFL light unit; HFL – heat fluorescent lamp; PPFD – photosynthetic flux density

Biotechnol. & Biotechnol. eq. 2009, 23(4), 1497-1503

IntroductionLight in plant micropropagationthe challenges facing world food production in developed and developing countries are quite different. in the latter, while populations are struggling to meet food demand, in the former there is a constant race to develop novel technologies to increase production while decreasing costs. One technology used in the production of plants, a fundamental starting block for addressing world food production, is micropropagation. the mass production of nutritionally important plants is achievable through the strict control of biotic and abiotic factors in vitro, or tissue culture. one of the most important abiotic factors that influences the successful establishment and subsequent development of a plant culture is light.

The most common form by which light is provided to plant tissue cultures in both research and industry is through the use of heat fluorescent lamps or HFLs, although the multiplication of plants have been studied intensively using fluorescent, incandescent, luminescent (sodium high pressure) and light-emitting diode (LED) lighting sources. HFLs are sometimes also referred to as neon tubes, cool white fluorescent lamps, or, depending on their shape and format, warm white fluorescent lamps (21).

A

Wall sideCulture shelf surface

130 cm

General fluorescent lamps (40W)

45 c

m

Aisle side


130 cm


45 c

m


130 cm


45 c

m

Aisle side

90％～100％ 80％～90％ 70％～80％

40％～50％ 30％～40％

60％～70％

50％～60％

Fig.1 AFig.1 A

B

90％～100％ 80％～90％ 70％～80％

40％～50％ 30％～40％

60％～70％

50％～60％

1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 1 1 0 1 2 00

5

1 0

1 5

2 0

2 5

3 0

3 5

4 0

4 5

長手方向　[c m ]130 cmAisle side

45 c

m

1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 1 1 0 1 2 00

5

1 0

1 5

2 0

2 5

3 0

3 5

4 0

4 5

長手方向　[c m ]130 cmAisle side

45 c

m

130 cmAisle side

45 c

m

Wall sideCulture shelf surface dtCCFL-LU

Fig. 1BFig. 1B

Fig. 1. PPFD distribution of HFL (A) and CCFL (B) on normal culture shelf surface

Although the individual costs of hFls are low and the market is well implemented, as their name suggests, these lamps emit heat during the production of light (35). in addition, the distribution of photosynthetic photon flux density (PPFD) from an hFl is not uniform on the culture shelf, unlike that from ccFls (Fig. 1A vs 1B). Most importantly, and central to our manuscript, is the fact that since hFls emit heat, plant cultures cannot be placed close to the light source as they would surely become damaged or suffer from photostress.

COLD CATHODE FLUORESCENT LAMPS (CCFL): REVOLUTIONARY LIGHT SOURCE FOR PLANT MICROPROPAGATION

M. tanaka1, A. norikane1, t. Watanabe2

1Kagawa University, Faculty of Agriculture, Department of Applied Biological Science, Miki-cho, Japan2Harison Toshiba Lighting Corp., Imabari-City, Japancorrespondence to: Michio tanakae-mail: [email protected]

ABSTRACTCold cathode fluorescent lamps or CCFLs are widely used in electro-domestic products, and for the first time ever, in this study, they have been applied to the in vitro culture of a plant, in this case, a difficult-to-propagate ornamental hybrid Cymbidum Forest Garden ‘#6’, which is also one of the most popular potted orchids in Japan. The red (R): blue (B) ratios could be manipulated in CCFLs, and the ideal and most effective R:B ratio was R80%+B20%, giving rise to highest mean plant fresh weight and plant height. Moreover, three different designs and forms of the CCFL were as effective or superior to conventional heat fluorescent lamps, or HFLs. This preliminary data sheds hope for a novel lighting system to substitute conventional HFLs in plant micropropagation due to its unique properties: longer life and lower energy consumption, small diameter, low heat generation, and the possibility of controlling the R:B ratio, something which is impossible to achieve in HFLs.

1498 Biotechnol. & Biotechnol. eq. 23/2009/4

Consequently, culture space cannot be optimized and cooling, often through energy-expending air conditioners, is required to maintain a stable temperature for plant growth and culture maintenance.

in a bid to defeat these limitations and weaknesses of the hFl, a novel light source has been developed and applied, in preliminary results, to the in vitro culture and micropropagation of a commercially important, difficult-to-propagate and popular hybrid orchid Cymbidium Forest Garden “#6”.

Development of the CCFL: contrast with HFLCCFLs (cold cathode fluorescent lamps) as a light source is not novel, and its use is quite wide and varied (car navigation system displays, note-book type PCs, PDAs, liquid crystal monitors and widescreen LCD TVs, all as backlighting (14), although it has never been applied to plant biotechnology in any format.

the ccFl tube is unique (Fig. 2). it has a small diameter (1.6-3.0 mm), long life (~50 000 h), low heat generation and thus lower costs caused by lower electric consumption (in fact, in terms of electric consumption, under the same light intensity, ccFls > hFls when plants and light are equidistant or ccFls < hFls when ccFls are brought close to the plantlets, which is not possible with hFls, and it is possible to control the red (R):blue (B) ratio (see merits and importance below), something which has not been achieved at a commercial scale in hFls, even though such a control is possible (6). the importance of controlling the R:B ratio (mainly through the use of LEDs) and its clear effects on plant growth has been demonstrated for Cymbidium (12, 24), strawberry (20), lettuce (10), Rehmannia glutinosa (7), chrysanthemum (15), rice (18), and wheat (5).

Hg Gas Phospor ElectrodeGlassHg Gas Phosphor Glass ElectrodeHg Gas Phospor ElectrodeGlassHg Gas Phosphor Glass ElectrodeHg Gas Phosphor Glass Electrode

Fig. 2

Fig. 2. ccFl schematic diagram

Harison Toshiba Lighting Corp. developed three types of ccFl light sources, all of which use the ccFl, but differ in their structural design: 1) ccFl edge light unit, or ccFl-elU (Fig. 3A), 2) multiple ccFl-elU or mccFl-elU (Fig. 3B), and 3) direct type CCFL light unit, or dtCCFL-LU (Fig. 3C). While CCFL-ELU is the prototype and ideal for lab-based experiments, the mCCFL-ELU and dtCCFL-LU are applicable to mass-scale micropropagation. In CCFL-ELU, the specific design allows a maximum amount of light to be reflected and refracted back in the direction of the plant (Fig. 4). in contrast, in the HFL, light is dissipated, lost and not utilized by the plant. More details on the difference between hFl and ccFl are available at the web page provided in the reference section (6) (in Japanese only).

A

Fig. 3A

B

Fig. 3B

c

Fig. 3C

Fig. 3. (A) ccFl edge light unit or ccFl-elU. (B) Multiple ccFl edge light unit or mCCFL-ELU. (C) Direct type CCFL light unit or dtCCFL-LU

ハウジングケース

冷陰極蛍光ランプ

反射板

厚さ６ｍｍ

反射シート

拡散シート

導光板

印刷散乱ドット

出射光

Housing caseReflector sheet

Print diffuser dot

Light pipe (acrylic resin)

Diffuser

Reflector

CCFL

Light6 mm thick

Fig. 4

Fig. 4. ccFl edge light unit scheme

Light and photoautotrophic micropropagationAs mentioned above, light is most probably the most important factor affecting the outcome of a plant culture. the medium and


its constituents are also extremely important. All plants are, by nature, photoautotrophic, that is, they produce complex organic compounds from simple inorganic molecules using energy from light or inorganic chemical reactions, i.e. photosynthesis. For photosynthesis, plants primarily use light from the 400-500 (blue) and 600-700 (red) nm wavelengths, corresponding to photosystem (PS) II and PS I (9). It is possible to enhance the growth of plants successfully under a CO2-enriched environment, without the use of a sugar (primarily sucrose), or photoautotrophic propagation. this has been demonstrated for several plants, specifically in hybrid Cymbidium (11, 13, 24, 25, 28, 29, 31, 32), eucalyptus (19, 26), strawberry (20), and sweet potato (4) in studies originating from our group of researchers. Kozai et al. in 1987 first reported on the photoautotrophic growth of Cymbidium cv. ‘Reporsa’ (16). Kozai et al. (17) succinctly summarized the theory and different cases of photoautotrophic culture systems. A discussion of this topic is, however, beyond the scope of this manuscript.

The “Vitron”tM, a culture vessel with high gas permeability and light transmittance, has already shown success in the micropropagation of several commercially important plants (3, 4, 26, 27, 30).

Challenges to this researchThere are four main objectives of this study: 1) to introduce the concept of a ccFl, to show its merits and its current development to suit plant micropropagation; 2) to determine whether the ccFl can be used in the micropropagation of an important, popular and difficult-to-propagate ornamental, hybrid Cymbidium; 3) to ascertain if the CCFL can perform as well as the hFl in practice and to assess basic plant growth parameters based on the use of these two light systems; 4) to determine if the lab-based prototype (CCFL-ELU) is as effective as the up-scaled mccFl-elU and dtccFl-lU.

Materials and MethodsEstablishment of in vitro cultureHybrid Cymbidium Forest Garden ‘#6’ (Bio-U, Japan) shoots with three leaves and no roots were derived from shoot-tip cultures, established according to guidelines and recommendations for several hybrid Cymbidium (11, 13, 28, 29, 31, 32). Shoots were placed at one shoot per block on rockwool multiblocks® (Grodan, Denmark) with a total of 25 shoots per Vitron in a 5×5 block format (Fig. 5A, B, C). According to previously established protocols referenced above, 180 mL of sugar-free modified Vacin and Went medium was added to each Vitron (34). Photoautotrophic cultures were provided with 3000 µmol mol-1 co2 and maintained at 250c under a 16-h photoperiod with a light intensity of 45 µmol m-2 s-1 provided by either of the light systems described next.

A

Fig. 5 B

B

“ V itron ”90

120

110

140

CCFL光源ユニット

培地支持体

培養容器

Unit: mm

CCFL edge light unit

Culture vesselthe “Vitron”

Substrate

Fig. 5 A

c

Fig. 5 C

Fig. 5. (A) Film culture vessel, ‘Vitron’. (B) CCFL edge light unit installed on the ‘Vitron’. (C) Cymbidium Forest Garden ‘#6’ shoots planted into the rockwool multiblock

Testing the light source: CCFL vs HFLIn Experiment 1, different red (R):blue (B) ratios of CCFL-ELU (Harison Optical Research Inc., Japan) were tested: R90%+B10%, R80%+B20%, R70%+B30% and R60%+B40%. Since only red light causes excessive elongation, and since >40% blue light causes stunting (see (18) and references therein), R>90% and B>40% were not tested. In Experiment 2, HFL (Homo Lux, Matsushita Electric Industrial Co., Japan) lamps were pitted against CCFL-ELU. In Experiment 3, mccFl-elU and dtccFl-lU were pitted against hFl.

Plant growth parameters assessedPlant height and shoot fresh weight were determined for all treatments. 90-day old plantlets (n = 25) were used to assess these parameters.


Energy expenditure: CCFL vs HFLthe total electric power consumption of dtccFl-lU and hFl were assessed in a commercial biological environmental-controlled chamber (Micropropagation chambertM, nK System, Osaka, Japan) after 100 hours. HFLs were placed on three shelves while ccFls were placed on either 3 or 6 shelves within each chamber since these numbers of shelves (and the distances between them) mirror the realistic application in commercial plant micropropagation systems.Statistical analysisThe experiments had one replicate per treatment, with 5×5 blocks such that n=25. Data was recorded at 90 days after culture, which corresponds to a growth of well-developed Cymbidium plants ready for acclimatization (33).

Results and DiscussionThe importance of light in micropropagationThe micropropagation of any plant species is entirely dependent on biotic and abiotic factors. Among the most important abiotic factors are light and carbon source since plants are autotrophic organisms. The quality of light, in particular the effect of the blue to red light ratio has already been demonstrated (non-exhaustive list) for chrysanthemum (15), Cymbidium (12, 24), lettuce (10), pepper (1), Rehmannia glutinosa (7), spinach, raddish and lettuce (36), rice (18), strawberry (20), and wheat (5), albeit with LEDs. In some of those studies, as in this one using CCFLs, a 80% red and 20% blue light ratio resulted in taller plants than when hFls were used (Fig. 6, Fig. 7, Fig. 8), independent of the light source used (Fig. 9, Fig. 10, Fig. 11, Fig. 12). In most of the literature, however, mostly descriptive results are reported and no real physiological mechanistic explanation has been provided and in many cases blue is considered to be supplemental. in all of these studies the basal premise is the same, i.e. that blue light is vital for the growth and development of higher plants since blue light photoreceptors are involved in several photomorphogenic events (2). When blue light was supplemented to a red-LED base in wheat, stomatal conductance and photosynthetic rates increased (5) although a similar experimental design did not yield increased photosynthetic rate in lettuce despite greater stomatal opening (36), indicating that the response to blue LEDs is not standard.

Fig.6

Fig. 6. Growth of Cymbidium Forest Garden ‘#6’ plantlets under various blue to red CCFL ratios. From left to right: R90%+B10%; R70%+B30%; R80%+B20%; R60%+B40%. There is little difference among culture conditions in this picture and the actual culture co close together at an inter-vessel distance much less than the real culture conditions

Fig. 7

Fig. 7. In vitro growth of Cymbidium Forest Garden ‘#6’ plantlets cultured under various blue to red CCFL ratios (from left to right, R60%+B40%; R70%+B30%; R80%+B20%; R90%+B10%)

CCFL vs HFL lighting systemsAlmost every single plant tissue culture study published has used HFLs to provide light, and although the PPFD can be controlled, the greatest weakness of hFls is, however, their emission of heat (35) and their uneven light distribution, although this fact has never been published nor examined (perhaps for obvious reasons); the greater the PPFD value required, the greater the heat emission (following basic first and second laws of thermodynamics). This directly impacts production and maintenance costs, with most plant cultures requiring a 16-h photoperiod over several weeks or months. Moreover, since heat is emitted by HFLs, the distance between the light source and the plant container is extremely limited, usually with a 20-40 cm distance to prevent scalding and damage to plant parts and cultures, caused by radiant heat (8) and at an ultrastructural level by photooxidative damage induced by excess light (22). What the CCFL does is to provide a light source that emits much less heat through its unique properties. this allows plants or cultures to be placed very close to the light source. In the case of the CCFL-Vitron system used in this study, the CCFL can be as close as 5-10 mm from the plant (as opposed to 20-30 cm in commercial production systems that use HFLs). This increases the per-unit production value and decreases the energy costs by as much as 42.4% compared with hFls (Table 1).

The balance between photosynthesis and photoinhibition is fine and although the process is not fully understood there are several clues that can assist us in better understanding some of the reaction of photoautotrophic plants in vitro. When the sucrose content is decreased in the medium, and when the PPFD and/or co2 concentration is increased, photosynthesis tends to increase, which contributes to the overall plantlet biomass. However, the absorption of excessive photons by leaves may lead to higher photoinhibition and lower carbon gain (discussed by (23) and references therein). This photoinhibition is brought about by photodamage, mainly to PSII, whether using white light or photochromatic light (8, 22).

Measurement of the PPFD in both CCFL and HFL lighting systems indicated that CCFLs provide uniform distribution of light over the culture shelf than conventional hFl cultures shelves (Fig. 1A vs 1B). CCFL (in any one of the three designs) performed as effectively (assessed by plant fresh weight and plant height), if not better, than conventional hFls in the micropropagation of a commercially important and


difficult-to-propagate hybrid Cymbidium Forest Garden ‘#6’. The results of the three experiments described next are initial, provisional results subject to repetition and verification with the same cultivar and other Cymbidium hybrids.

Experiment 1: blue to red ratios of CCFL-ELUThe most effective red (R):blue (B) ratio was R80%+B20% (Fig. 6, Fig. 7, Fig. 8) in terms of plant fresh weight. Plants were taller in R90%+B10% but this morphology is considered to be abnormal for commercial Cymbidium production. Plants cultured with B >30% were stunted.

0

100

200

300

400

500

600

700

R60%+B40% R70%+B30% R80%+B20% R90%+B10%

Ｔｏ

ｐ f

resh

weig

ht

(mg)

Ｔｏｐｆｒｅｓｈ weight

Ｐｌａｎｔ height

Ｐｌａ

ｎｔ

ｈｅｉｇ

ｈｔ

(cm

)

0

4

8

12

Fig. 8

Fig. 8. effects of various blue to red ccFl ratios on the in vitro growth of Cymbidium Forest Garden ‘#6’ plantlets. Values represent means ± SE

Fig. 9

Fig. 9. In vitro growth of Cymbidium Forest Garden ‘#6’ plantlets cultured under CCFL and HFL (left, CCFL-ELU; right, HFL)

Experiment 2: CCFL-ELU vs HFLThe ideal R:B ratio of R80%+B20% assessed in Experiment 1 was implemented in the ccFl-elU. ccFl-elU was more effective than hFl in terms of plant fresh weight and plant height (Fig. 9, Fig. 10).

0

100

200

300

400

500

600

700

ＣＣＦＬ eｄｇｅ light ＨＦＬ

Ｔｏ

ｐ f

resh

weig

ht　

(mg)

Ｔｏｐｆｒｅｓｈ weight


0

4

8

12

Ｐｌａ

ｎｔ

ｈｅｉｇ

ｈｔ

(cm

)

Fig. 10

Fig. 10. effects of ccFl on the in vitro growth of Cymbidium Forest Garden ‘#6’ plantlets. Values represent means ± SE

Experiment 3: mCCFL-ELU and dtCCFL-LU vs HFLThe ideal R:B ratio of R80%+B20% assessed in Experiment 1 was implemented for the mccFl-elU and dtccFl-lU. mccFl-elU and dtccFl-lU were as effective as hFl in terms of plant fresh weight and plant height (Fig. 11, Fig. 12).Fig. 11

Fig. 11. In vitro growth of Cymbidium Forest Garden ‘#6’ plantlets cultured under different CCFL light sources and HFL (from left to right: mCCFL-ELU; dtCCFL-ELU; HFL)

TABLE 1comparison of electric power consumption of different light sources installed in a biological environmental-controlled chamber

Light sourceAir conditioner

(kWh) Lighting(kWh)

Total(kWh)

Per shelf(kWh)

Cooler HeaterhFl1 (3 shelves) 8.3 4.6 16.9 29.8 9.9ccFl2 (6 shelves) 9.2 2.2 22.9 34.3 5.71- hFl installed in a biological environmental-controlled camber2- ccFl installed in a biological environmental-controlled cambereach chamber was operated for 100 hours


Fig. 12

0

100

200

300

400

500

600

700

Ｍｕｌｔｉ-eｄｇｅ light ＣＣＦＬ

ＤｉｒｅｃｔＣＣＦＬ HFL

Ｔｏ

ｐ f

resh

weig

ht

(m

g) Ｔｏｐｆｒｅｓｈ weight


Ｐｌａ

ｎｔ

ｈｅｉｇ

ｈｔ

(cm

)

0

4

8

12

Fig. 12. Effects of different CCFL types on the in vitro growth of Cymbidium Forest Garden ‘#6’ plantlets. Values represent means ± SE

Energy expenditure: CCFL vs HFLdtCCFL-LU uses 42.4% less energy per shelf than HFLs when 6 shelves are used, respectively (Table 1). Since the Vitron can be placed very close to the CCFL light source, 6 shelves are recommended, a situation which is impossible under hFls.

Conclusionsthe ccFl is a strong candidate to substitute conventional HFLs or more expensive LEDs as a lighting system for plant micropropagation. It has many useful properties which allow for maximized production while reducing costs. Cost analysis and some basic data on an orchid in this study indicate the positive potential of this new light source in plant biotechnology. Through the provisional results of this study, whose primary objective is to introduce the CCFL system for plant micropropagation, dtccFl-lU has several advantages: low cost, long life (when compared with mccFl-lU), low power consumption, high airflow, light weight and thinness. thus, dtccFl-lU is recommended because the growth of Cymbidium plantlets cultured under both ccFl sources was not different. This experimental system will be re-tested with the same cultivar and other Cymbidium cultivars in future studies as well as with other plant species.

AcknowledgementsThe authors thank Dr. J. A. Teixeira da Silva, Department of Applied Biological Science, Faculty of Agriculture, Kagawa University for critical reading and revision of the manuscript.

REFERENCES1. Brown C.S., Schuerger A.C., Sager J.C. (1995) J. Am.

Soc. Hortic. Sci., 120(5), 808-813.2. Christie J.M. and Briggs W.R. (2001) J. Biol. Chem.,

276(15), 11457-11460.3. Giang D.T.T. and Tanaka M. (2004) Prop. Ornamental

Plants, 4(2), 41-47.4. Giang D.T.T., Tanaka M., Teixeira da Silva J.A. (2006)

Acta hortic., 205-210.

5. Goins G.D., Yorio N.C., Sanwo M.M., Brown C.S. (1997) J. Exp. Bot., 48(312), 1407-1413.

6. GreatCHIP JAPAN, http://www.tlm.co.jp/web/gijyutu/ccfl.html

7. Hahn E.J., Kozai T., Peak K.Y. (2000) J. Plant Biol., 43(4), 247-250.

8. Hakala M., Tuominen I., Keranen M., Tyystjarvi T., Tyystjarvi E. (2005) Biochim. Biophys. Acta., 1706, 68-80.

9. Hall D.D. and Rao K.K. (1999) Cambridge Univ. Press, cambridge.

10. Hoenecke M.E., Bula R.J., Tibbitts T.W. (1992) HortScience, 27(5), 427-430.

11. Huan L.V.T., Takamura T., Tanaka M. (2004) Plant Science, 166(6), 1443-1449.

12. Huan L.V.T. and Tanaka M. (2004) environ. control Biol., 42, 57-64.

13. Huan L.V.T. and Tanaka M. (2004) J. Hort. Sci. Biotech., 79(3), 406-410.

14. Jinno M. and Motomura H. (2005) J. Plasma Fusion Res., 81(10), 801-803.

15. Kim S.J., Hahn E.J., Heo J.W., Paek K.Y. (2004) Sci. horticult., 101(1-2), 143-151.

16. Kozai T., Oki H., Fujiwara K. (1987) Symposium on plant micropagation in hort. ind., Arlon, Belgium, p. 135-141.

17. Kozai T., Afreen F., Zobayed S.M.A. (2005) Photoautotrophic (sugar-free medium) Micropropagation as a New Micropropagation and Transplant Production System, Springer, p. 316.

18. Matsuda R., Ohashi-Kaneko K., Fujiwara K., Goto E., Kurata K. (2004) Plant Cell Physiol., 45(12), 1870-1874.

19. Nhut D.T. (2002) environ. control in Biol., 40(2), 147-155.

20. Nhut D.T., Takamura T., Watanabe H., Okamoto K., Tanaka M. (2003) Plant Cell Tiss. Organ Cult., 73(1), 43-52.

21. Nhut D.T., Huong M.T.N., Khiem D.V., Teixeira da Silva J.A. (2006) J. Appl. Hort., 8(1), 15-20.

22. Ohnishi N., Allakhverdiev S.I., Takahashi S., Higashi S., Watanabe M., Nishiyama Y., Murata N. (2005) Biochemistry (N Y ), 44(23), 8494-8499.

23. Serret M.D., Trillas M.I., Matas J., Araus J.L. (2001) Photosynthetica, 39(2), 245-255.

24. Tanaka M., Takamura T., Watanabe H., Endo M., Yanagi T., Okamoto K. (1998) J. Hortic. Sci. Biotechnol., 73(1), 39-44.

25. Tanaka M., Yap D.C.H., Ng C.K.Y., Hew C.S. (1999) J. Hort. Sci. Biotech., 74(5), 632-638.

26. Tanaka M., Giang D.T.T., Murakami A. (2005) In Vitro Cell. Dev. Biol. Plant, 41(2), 173-180.


27. Teixeira da Silva J.A., Giang D.T.T., Tanaka M. (2005) Biotechnology, 4(3), 214-220.

28. Teixeira da Silva J.A., Yam T.W., Fukai S., Nayak N.R., Tanaka M. (2005) Prop. Ornamental Plants, 5(3), 129-136.

29. Teixeira da Silva J.A., Chan M.T., Sanjaya, Chai M.L., Tanaka M. (2006) Sci. Hortic., 109(4), 368-378.

30. Teixeira da Silva J.A., Giang D.D.T., Tanaka M. (2006) Photosynthetica, 44(1), 53-61.

31. Teixeira da Silva J.A., Singh N., Tanaka M. (2006) Plant cell tiss. organ cult., 84(2), 135-144.

32. Teixeira da Silva J.A., Giang D.T.T., Chan M.T., Sanjaya, Norikane A., Chai M.L., Chico Ruiz J., Penna

S., Granstrom T., Tanaka M. (2007) Orchid Sci. Biotech., 1(1), 15-23.

33. Teixeira da Silva J.A., Norikane A., Tanaka M. (2007) Acta hortic., 748, 207-214.

34. Vacin E.F., Went F.W. (1949) Bot. Gazz., 110, 605-613.35. Wikipedia, http://en.wikipedia.org/wiki/Fluorescent_

lamp36. Yorio N.C., Goins G.D., Kagie H.R., Wheeler R.M.,

Sager J.C. (2001) HortScience, 36(2), 380-383.

COLD CATHODE FLUORESCENT LAMPS (CCFL - Diagnosis Press

Documents