, Volume 32, Issue 4, pp 951–965 | Cite as

Dark chlorophyll synthesis may provide a potential for shade tolerance as shown by a comparative study with seedlings of European larch (Larix decidua) and Norway spruce (Picea abies)

  • Tibor Stolárik
  • Vladimíra Nožková
  • Lukáš Nosek
  • Andrej PavlovičEmail author
Original Article


Key message

The ability to green in the dark represents a trait providing shade tolerance in seedlings of Norway spruce.


In contrast to angiosperm plants, gymnosperms possess two different enzymes for the reduction of protochlorophyllide to chlorophyllide: dark-operative, light-independent protochlorophyllide oxidoreductase (DPOR), consisting of three subunits: ChlL, ChlN and ChlB, and light-dependent protochlorophyllide oxidoreductase (LPOR). European larch seedlings (Larix decidua Mill.), in contrast to Norway spruce (Picea abies Karst.), accumulate only very low amounts of chlorophylls in the dark due to an inactive DPOR enzyme. In this study, we used these two species to investigate the advantage of the co-existence of two protochlorophyllide oxidoreductases on chlorophyll synthesis under different light conditions. We found that under deep shade conditions, the larch seedlings are partially etiolated with a low quantum yield of photosystem II photochemistry caused by inefficient LPOR function under that subliminal irradiance concomitant with an inactive DPOR enzyme. In contrast, spruce accumulated a significant amount of chlorophylls under deep shade conditions due to the co-existence of active DPOR and LPOR enzymes. Moreover, although PSII developed in the dark had an inactive oxygen-evolving complex, even very low irradiance is sufficient for photoactivation of PSII, as proved by the high quantum yield of photosystem II (Fv/Fm) and the disappearance of the K-step in chlorophyll a fluorescence induction under deep shade conditions in spruce. We did not find any advantage of having DPOR enzyme under high light conditions, which is consistent with the decreasing abundance of DPOR subunits with increasing light intensities. Thus, the presence of an active DPOR enzyme may represent a molecular basis for shade tolerance in coniferous seedlings.


Chlorophyll Larix decidua (European larch) Light acclimation Shade Picea abies (Norway spruce) 



This work was supported by the National Program of Sustainability I (Grant LO1204) of the Ministry of Education, Youth and Sports of the Czech Republic. We are very thankful to Dr. Michal Martinka and Dr. Marek Vaculík, Department of Plant Physiology, Faculty of Natural Sciences, Comenius University in Bratislava (Slovak Republic) for invaluable material help and excellent advice during sample preparation for transmission electron microscopy and to Prof. Yuichi Fujita (Nagoya, Japan) for providing antibodies against DPOR.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Supplementary material

468_2018_1688_MOESM1_ESM.jpg (509 kb)
Photoactivation experiments at a light intensity of 20 μmol m-2 s-1 PAR in L. decidua (A) and P. abies (B). Chlorophyll a fluorescence rise measured at excitation light intensity of 7000 μmol photons m−2 s−1 PAR (650 nm) in dark-grown spruce cotyledons that were illuminated (20 μmol photons m−2 s−1, PAR) for different time periods (0, 1, 5 min and 1 h as indicated). Seedlings were dark-adapted for 30 min before the fluorescence measurement. Curves are normalized to F0 level, vertically shifted and plotted on a logarithmic time scale. The vertical lines indicate the position of K-step. Presented data are representatives of a total of 4–5 measurements. The values below each curve indicate average FV/FM, means ± s.d., n = 4-5 (JPG 509 KB)
468_2018_1688_MOESM2_ESM.jpg (568 kb)
Photoactivation experiments at a light intensity of 100 μmol m-2 s-1 PAR in L. decidua (A) and P. abies (B). Chlorophyll a fluorescence rise measured at excitation light intensity of 7000 μmol photons m−2 s−1 PAR (650 nm) in dark-grown spruce cotyledons that were illuminated (100 μmol photons m−2 s−1, PAR) for different time periods (0, 1, 5 min and 1 h as indicated). For details see legend of Fig.S1 (JPG 568 KB)
468_2018_1688_MOESM3_ESM.jpg (431 kb)
Photoactivation experiments at a light intensity of 1400 μmol m-2 s-1 PAR in L. decidua (A) and P. abies (B). Chlorophyll a fluorescence rise measured at excitation light intensity of 7000 μmol photons m−2 s−1 PAR (650 nm) in dark-grown spruce cotyledons that were illuminated (1400 μmol photons m−2 s−1, PAR) for different time periods (0, 1, 5 min and 1 h as indicated). For details see legend of Fig.S1 (JPG 431 KB)
468_2018_1688_MOESM4_ESM.jpg (84 kb)
Average number of thylakoids per granum. Means ± s.d., n = 10 (JPG 84 KB)
468_2018_1688_MOESM5_ESM.docx (14 kb)
Supplementary material 5 (DOCX 14 KB)


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Copyright information

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Authors and Affiliations

  1. 1.Department of Biophysics, Centre of Region Haná for Biotechnological and Agricultural Research, Faculty of SciencePalacký University in OlomoucOlomoucCzech Republic

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