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CA-3060371-C - METHOD FOR INCREASING AMOUNT OF PHENOLIC COMPOUND IN PLANT

CA3060371CCA 3060371 CCA3060371 CCA 3060371CCA-3060371-C

Abstract

An object of the present invention is to provide a method that can effectively/efficiently increase the amount of a phenolic compound such as a polyphenol. The invention provides a method for increasing an amount of a phenolic compound in a plant, or a method for producing a plant containing an increased amount of a phenolic compound, the method comprising irradiating the/a plant with ultraviolet light, wherein a fluence at wavelengths of 270 to 290 nm is 1500 to 50000 µmol/m and a fluence at wavelengths of 310 to 400 nm is less than 50% of that at wavelengths of 270 to 290 nm.

Inventors

  • Atsushi Okazawa
  • Yasuo Fujikawa
  • Tomohiro TSURUMOTO

Assignees

  • NICHIA CORPORATION

Dates

Publication Date
20260505
Application Date
20180427
Priority Date
20170428

Claims (14)

  1. 32 CLAIMS 1. A method for increasing an amount of a phenolic compound in a seedling, adult plant or harvested plant, the method comprising: irradiating the seedling, adult plant or harvested plant or parts thereof 5 with ultraviolet light, wherein a fluence at wavelengths of 270 to 290 nm is 1500 to 50000 μmol/m2 and a fluence at wavelengths of 310 to 400 nm is less than 50% of that at wavelengths of 270 to 290 nm, wherein the ultraviolet light at wavelengths of 270 to 290 nm is irradiated at a photon flux density of 0.01 to 100 μmol/m2/s, and wherein the ultraviolet light has a wavelength 10 spectrum with a peak wavelength at 280 ± 5 nm and a half-width of 5 to 15 nm; and placing the seedling, adult plant or harvested plant or parts thereof in the dark for 12 hours or more after the irradiation.
  2. 2. The method according to claim 1, wherein the fluence at wavelengths of 310 to 400 nm is less than 10% of that at wavelengths of 270 to 290 nm.
  3. 3. The method according to claim 1, wherein a fluence at wavelengths of 300 to 400 nm is less than 50% of that at wavelengths of 270 to 290 nm. 20
  4. 4. The method according to any one of claims 1 to 3, wherein light at wavelengths of 270 to 290 nm is irradiated at a photon flux density of 1 to 5 μmol/m2/s.
  5. 5. The method according to any one of claims 1 to 4, wherein a fluence at wavelengths of 200 to 260 nm is less than 20% of that at wavelengths of 270 to 290 nm. CA 3060371 33
  6. 6. The method according to any one of claims 1 to 5, wherein a fluence at wavelengths of 200 nm or more and less than 270 nm is less than 10% of that at wavelengths of 270 to 290 nm.
  7. 7. The method according to any one of claims 1 to 6, wherein the ultraviolet light is emitted from a LED.
  8. 8. The method according to any one of claims 1 to 7, wherein the ultraviolet light is irradiated to the seedling, adult plant or harvested plant or 10 parts thereof in a dark place.
  9. 9. The method according to any one of claims 1 to 8, wherein the seedling, adult plant or harvested plant or parts thereof is placed in the dark for 48 hours or more and less than 288 hours. 15
  10. 10. The method according to any one of claims 1 to 9, wherein the seedling, adult plant or harvested plant belongs to the family Brassicaceae, Berberidaceae, Theaceae, Fabaceae, Rutaceae or Vitaceae.
  11. 11. The method according to any one of claims 1 to 10, wherein the seedling, adult plant or harvested plant is selected from Arabidopsis thaliana, Podophyllum peltatum, Camellia sinensis, Glycine max, Citrus sudachi, Vitis spp., Brassica oleracea var. capitata, Brassica oleracea var. italica, Brassica rapa var. perviridis, Brassica rapa subsp. chinensis, Raphanus sativus var. 25 longipinnatus, Brassica rapa subsp. rapa, Solanum lycopersicum, Solanum melongena, Fragaria x ananassa, Lactuca sativa and Perilla frutescens var. crispa. CA 3060371 34
  12. 12. The method according to any one of claims 1 to 11, wherein the phenolic compound is a polyphenol.
  13. 13. The method according to claim 12, wherein the polyphenol is a 5 flavonoid.
  14. 14. The method according to claim 13, wherein the flavonoid is an anthocyanin. CA 3060371

Description

DESCRIPTION METHOD FOR INCREASING AMOUNT OF PHENOLIC COMPOUND IN PLANT TECHNICAL FIELD [0001] The present invention relates to a method for increasing the amount of a phenolic compound in a plant and a method for producing a plant having an 10 increased content of a phenolic compound. BACKGROUND ART [0002] Phenolic compounds (such as polyphenols) in plants are found to have 15 various bioactivities such as antioxidant, antibacterial and blood pressure elevation inhibitory activities, and therefore have been attracting increasing attention with rising health consciousness. Thus, techniques have been developed for increasing the amount of a phenolic compound in a plant. Among them, there is a great interest in 20 techniques for increasing the amount of flavonoids in plants by irradiation with ultraviolet light, because plants are believed to synthesize flavonoids having a maximum absorption in the ultraviolet region so as to escape the impacts of ultraviolet light in the sunlight. [0003] 25 For example, Patent Document 1 pertains to a method for increasing the content of a polyphenol in a "harvested" plant by irradiating it with ultraviolet light at the specific wavelengths (of between 240 and 320 nm both inclusive, or of between 300 and 400 nm both inclusive). Patent Document 1 discloses that the appropriate ultraviolet fluence is between 0.5 and 50 J / cm2 (both inclusive) per day and that the wavelength(s) of ultraviolet light to be irradiated to harvested plants should be selected in accordance with the maximum absorption wavelength of a polyphenol of interest. 5 (0004] Patent Document 2 pertains to a method for increasing the content(s) of an ascorbic acid and/ or polyphenols in a cultivated monocotyledon (particularly, sprouted Welsh onion) by irradiating it with ultraviolet light at wavelengths of 280 to 380 nm and with a peak at around 312 nm. Patent 10 Document 2 discloses that the appropriate ultraviolet intensity is 0.1 to 1.0 mW·cm-2 . (0005] Non-Patent Document 1 reports that Arabidopsis plants were exposed to narrowband UV-B radiation (280 to 320 nm; peak wavelength: 312 nm; 15 830 mW /m2/s) continuously for 1 or 4 days to investigate the impacts of UVB stress on the plants and an increase of anthocyanins and flavonols was observed in the plants exposed to ultraviolet for 1 day or more. CITATION LIST 20 PATENT LITERATURE [0006) Patent Document 1: Japanese Patent Application Publication No. 2004-121228 Patent Document 2: Japanese Patent Application Publication 25 No. 2008-086272 NON-PATENT LITERATURE [0007) Non-Patent Document 1: Kusano et al., The Plant Journal, 2011, 67, 2 354-369 SUMMARY OF INVENTION TECHNICAL PROBLEM 5 [0008] As described above, it is known that the exposure of a plant to ultraviolet light (UVA or UVB) increase in the amount of a phenolic compound in the plant. Meanwhile, it is also known that ultraviolet light is harmful to not only plants but organisms in general. The ultraviolet light used in the 10 conventional art has a relatively wide wavelength band, and the emission spectrum of such a UV lamp as used in Non-Patent Document 1 has a peak wavelength at 312 nm but is broad, as illustrated in Figure 9 for example. The determination of the exact wavelengths of ultraviolet light contributing to increasing phenolic compounds allows for an efficient increase 15 in the amount of the compounds in plants while reducing the adverse effects caused by exposure to ultraviolet light. Thus, there is still a need for a method that can effectively/ efficiently increase the amount of a phenolic compound such as a polyphenol in a plant. 20 SOLUTION TO PROBLEM [0009] The present inventors investigated the wavelengths and the fluence contributing to increasing phenolic compounds. As a result, the inventors have found that ultraviolet light at specific wavelengths, which are shorter 25 than the conventionally known wavelengths, is effective in increasing phenolic compounds, while conventionally used ultraviolet light includes light at wavelengths that do not contribute to increasing phenolic compounds and, what is worse, can cause a decrease in the abundance of the compounds, 3 thereby completing the present invention. (0010] The invention provides a method for increasing an amount of a phenolic compound in a plant, the method comprising irradiating the plant 5 with ultraviolet light, wherein a fluence at wavelengths of 270 to 290 nm is 1500 to 50000 μmol/m2 and a fluence at wavelengths of 310 to 400 nm is less than 50% of that at wavelengths of 270 to 290 nm. The invention also provides a method for producing a plant containing an increased amount of a phenolic compound, the method comprising 10 irradiating a plant with ultraviolet light, wherein a fluence at wavelengths of 270 to 290 nm is 1500 to 50000 μmol/m2 , while a fluence at wavelengths of 310 to 400 nm is less than 50% of that at wavelength 270 to 290 nm. The invention also provides a lighting device for use in increasing an amount