Photonic multilayer structure of Begonia chloroplasts enhances photosynthetic efficiency


Enhanced light harvesting is an area of interest for optimizing both natural photosynthesis and artificial solar energy capture1,2. Iridescence has been shown to exist widely and in diverse forms in plants and other photosynthetic organisms and symbioses3,4, but there has yet to be any direct link demonstrated between iridescence and photosynthesis. Here we show that epidermal chloroplasts, also known as iridoplasts, in shade-dwelling species of Begonia5, notable for their brilliant blue iridescence, have a photonic crystal structure formed from a periodic arrangement of the light-absorbing thylakoid tissue itself. This structure enhances photosynthesis in two ways: by increasing light capture at the predominantly green wavelengths available in shade conditions, and by directly enhancing quantum yield by 5–10% under low-light conditions. These findings together imply that the iridoplast is a highly modified chloroplast structure adapted to make best use of the extremely low-light conditions in the tropical forest understorey in which it is found5,6. A phylogenetically diverse range of shade-dwelling plant species has been found to produce similarly structured chloroplasts79, suggesting that the ability to produce chloroplasts whose membranes are organized as a multilayer with photonic properties may be widespread. In fact, given the well-established diversity and plasticity of chloroplasts10,11, our results imply that photonic effects may be important even in plants that do not show any obvious signs of iridescence to the naked eye but where a highly ordered chloroplast structure may present a clear blue reflectance at the microscale. Chloroplasts are generally thought of as purely photochemical; we suggest that one should also think of them as a photonic structure with a complex interplay between control of light propagation, light capture and photochemistry.

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Figure 1: Blue leaf iridescence and iridoplasts in Begonia.
Figure 2: Optical properties and modelling of iridoplast structure.
Figure 3: Enhanced absorption at reflectance sideband.
Figure 4: Chlorophyll fluorescence images and quantum yield of Begonia plastids.


  1. 1

    Bermel, P., Luo, C., Zeng, L., Kimerling, L. C. & Joannopoulos, J. D. Improving thin-film crystalline silicon solar cell efficiencies with photonic crystals. Opt. Express 15, 16986–17000 (2007).

    CAS  Article  Google Scholar 

  2. 2

    Mihi, A. & Míguez, H. Origin of light-harvesting enhancement in colloidal-photonic-crystal-based dye-sensitized solar cells. J. Phys. Chem. B 109, 15968–15976 (2005).

    CAS  Article  Google Scholar 

  3. 3

    Holt, A. L., Vahidinia, S., Gagnon, Y. L., Morse, D. E. & Sweeney, A. M. Photosymbiotic giant clams are transformers of solar flux. J. R. Soc. Interface 11, 20140678 (2014).

    Article  Google Scholar 

  4. 4

    Glover, B. J. & Whitney, H. M. Structural colour and iridescence in plants: the poorly studied relations of pigment colour. Ann. Bot. 105, 505–511 (2010).

    Article  Google Scholar 

  5. 5

    Gould, K. S. & Lee, D. W. Physical and ultrastructural basis of blue leaf iridescence in four Malaysian understory plants. Am. J. Bot. 83, 45–50 (1996).

    Article  Google Scholar 

  6. 6

    Endler, J. A. The color of light in forests and its implications. Ecol. Monogr. 63, 1–27 (1993).

    Article  Google Scholar 

  7. 7

    Sheue, C.-R. et al. Bizonoplast, a unique chloroplast in the epidermal cells of microphylls in the shade plant Selaginella erythropus (Selaginellaceae). Am. J. Bot. 94, 1922–1929 (2007).

    Article  Google Scholar 

  8. 8

    Graham, R. M., Lee, D. W. & Norstog, K. Physical and ultrastructural basis of blue leaf iridescence in two neotropical ferns. Am. J. Bot. 80, 198–203 (1993).

    Article  Google Scholar 

  9. 9

    Nasrulhaq-Boyce, A. & Duckett, J. G. Dimorphic epidermal cell chloroplasts in the mesophyll-less leaves of an extreme–shade tropical fern, Teratophyllum rotundifoliatum (R. Bonap.) Holtt.: a light and electron microscope study. New Phytol. 119, 433–444 (1991).

    Article  Google Scholar 

  10. 10

    Kirchhoff, H. Architectural switches in plant thylakoid membranes. Photosynth. Res. 116, 481–487 (2013).

    CAS  Article  Google Scholar 

  11. 11

    Pribil, M., Labs, M. & Leister, D. Structure and dynamics of thylakoids in land plants. J. Exp. Bot. 65, 1955–1972 (2014).

    CAS  Article  Google Scholar 

  12. 12

    Vukusic, P. & Sambles, J. R. Photonic structures in biology. Nature 424, 852–855 (2003).

    CAS  Article  Google Scholar 

  13. 13

    Sun, J., Bhushan, B. & Tong, J. Structural coloration in nature. RSC Adv. 3, 14862–14889 (2013).

    CAS  Article  Google Scholar 

  14. 14

    Thomas, K. R., Kolle, M., Whitney, H. M., Glover, B. J. & Steiner, U. Function of blue iridescence in tropical understorey plants. J. R. Soc. Interface 7, 1699–1707 (2010).

    Article  Google Scholar 

  15. 15

    Lee, D. W. Nature's Pallete: The Science of Plant Colour (Univ. of Chicago Press, 2007).

    Google Scholar 

  16. 16

    Gebushuber, C. I. & Lee, D. W. in Encyclopedia of Nanotechnology (ed. Bhushan, B. ) 1790–1803 (Springer Netherlands, 2012).

    Google Scholar 

  17. 17

    Kirchhoff, H. Structural changes of the thylakoid membrane network induced by high light stress in plant chloroplasts. Philos. Trans. R. Soc. Lond. B. Biol. Sci. 369, 20130225 (2014).

    Article  Google Scholar 

  18. 18

    Pedersen, J., Xiao, S. & Mortensen, N. A. Slow-light enhanced absorption for bio-chemical sensing applications: potential of low-contrast lossy materials. J. Eur. Opt. Soc. 3 (2008).

  19. 19

    Nevo, R., Charuvi, D., Tsabari, O. & Reich, Z. Composition, architecture and dynamics of the photosynthetic apparatus in higher plants. Plant J. 70, 157–176 (2012).

    CAS  Article  Google Scholar 

  20. 20

    Murchie, E. H. & Lawson, T. Chlorophyll fluorescence analysis: a guide to good practice and understanding some new applications. J. Exp. Bot. 64, 3983–3998 (2013).

    CAS  Article  Google Scholar 

  21. 21

    Lawson, T., Oxborough, K., Morison, J. I. L. & Baker, N. R. Responses of photosynthetic electron transport in stomatal guard cells and mesophyll cells in intact leaves to light, CO2, and humidity. Plant Physiol. 128, 52–62 (2002).

    CAS  Article  Google Scholar 

  22. 22

    Lawson, T., Oxborough, K., Morison, J. I. L. & Baker, N. R. The responses of guard and mesophyll cell photosynthesis to CO2, O2, light, and water stress in a range of species are similar. J. Exp. Bot. 54, 1743–1752 (2003).

    CAS  Article  Google Scholar 

  23. 23

    Kouřil, R., Wientjes, E., Bultema, J. B., Croce, R. & Boekema, E. J. High-light vs. low-light: effect of light acclimation on photosystem II composition and organization in Arabidopsis thaliana. Biochim. Biophys. Acta Bioenerg. 1827, 411–419 (2013).

    Article  Google Scholar 

  24. 24

    Wientjes, E., Van Amerongen, H. & Croce, R. Quantum yield of charge separation in photosystem II: functional effect of changes in the antenna size upon light acclimation. J. Phys. Chem. B 117, 11200–11208 (2013).

    CAS  Article  Google Scholar 

  25. 25

    López-García, M. et al. Enhancement and directionality of spontaneous emission in hybrid self-assembled photonic-plasmonic crystals. Small 6, 1757–1761 (2010).

    Article  Google Scholar 

  26. 26

    Yeh, P., Yariv, A. & Hong, C.-S. Electromagnetic propagation in periodic stratified media. I. General theory. J. Opt. Soc. Am. 67, 423–438 (1977).

    Article  Google Scholar 

  27. 27

    Kirchhoff, H. et al. Dynamic control of protein diffusion within the granal thylakoid lumen. Proc. Natl Acad. Sci. USA 108, 20248–20253 (2011).

    CAS  Article  Google Scholar 

  28. 28

    FDTD Solutions v.8.15.736 (Lumerical Solutions, Inc., 2015);

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We would like to thank C. Kidner, M. Hughes (Royal Botanic Gardens Edinburgh) and C. Lundquist (Royal Botanic Gardens Kew) for Begonia species identification and tissue, and A. Kelly for Begonia collection maintenance and horticultural expertise. We thank S. Casson and L. Sandbach for contributions to pilot studies. We acknowledge the Wolfson Bioimaging Facility (University of Bristol) with thanks to D. Alibhai, J. Mantell and G. Tilly for assistance with imaging and also thank S. Vialet-Chabrand (University of Essex) for assistance with fluorescence microscopy. We also thank M.J. Cryan, T. Oliver and S. Nunez from the University of Bristol for fruitful discussion on the photonic side of photosynthesis. M.J. is funded by a NERC PhD studentship. R.O and M.L.G acknowledge EPSRC grant EP/N003381/1. We are grateful for funding from ERC project number 260920 (to H.M.W.).

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M.J., M.L-G., R.O. and H.M.W. conceived the experiments, M.J., O.-P.P. and M.L.-G. carried out iridoplast optical analysis, M.J., M.L.-G. and T.L. carried out the photosynthesis experiments, M.J., O.-P.P. and M.L.-G. carried out microscopy, M.L.-G. and R.O. designed and ran optical models, and M.J., M.L.-G., R.O. and H.M.W. wrote the manuscript, which all authors commented on.

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Correspondence to Heather M. Whitney.

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The authors declare no competing financial interests.

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Supplementary Figures 1–10, Supplementary References. (PDF 4011 kb)

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Jacobs, M., Lopez-Garcia, M., Phrathep, O. et al. Photonic multilayer structure of Begonia chloroplasts enhances photosynthetic efficiency. Nature Plants 2, 16162 (2016).

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