Differential Mechanisms of Photosynthetic Acclimation to Light and Low Temperature in Arabidopsis and the Extremophile Eutrema salsugineum
Photosynthetic organisms are able to sense energy imbalances brought about by the overexcitation of photosystem II (PSII) through the redox state of the photosynthetic electron transport chain, estimated as the chlorophyll fluorescence parameter 1-q , also known as PSII excitation pressure. Plants e...
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| Published in: | Plants (Basel) Vol. 6; no. 3; p. 32 |
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| Main Authors: | , , , , |
| Format: | Journal Article |
| Language: | English |
| Published: |
Switzerland
MDPI AG
09-08-2017
MDPI |
| Subjects: | |
| Online Access: | Get full text |
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| Summary: | Photosynthetic organisms are able to sense energy imbalances brought about by the overexcitation of photosystem II (PSII) through the redox state of the photosynthetic electron transport chain, estimated as the chlorophyll fluorescence parameter 1-q
, also known as PSII excitation pressure. Plants employ a wide array of photoprotective processes that modulate photosynthesis to correct these energy imbalances. Low temperature and light are well established in their ability to modulate PSII excitation pressure. The acquisition of freezing tolerance requires growth and development a low temperature (cold acclimation) which predisposes the plant to photoinhibition. Thus, photosynthetic acclimation is essential for proper energy balancing during the cold acclimation process.
(
) is an extremophile, a close relative of
, but possessing much higher constitutive levels of tolerance to abiotic stress. This comparative study aimed to characterize the photosynthetic properties of
(Columbia accession) and two accessions of
(Yukon and Shandong) isolated from contrasting geographical locations at cold acclimating and non-acclimating conditions. In addition, three different growth regimes were utilized that varied in temperature, photoperiod and irradiance which resulted in different levels of PSII excitation pressure. This study has shown that these accessions interact differentially to instantaneous (measuring) and long-term (acclimation) changes in PSII excitation pressure with regard to their photosynthetic behaviour.
accessions contained a higher amount of photosynthetic pigments, showed higher oxidation of P700 and possessed more resilient photoprotective mechanisms than that of
, perhaps through the prevention of PSI acceptor-limitation. Upon comparison of the two
accessions, Shandong demonstrated the greatest PSII operating efficiency (Φ
) and P700 oxidizing capacity, while Yukon showed greater growth plasticity to irradiance. Both of these
accessions are able to photosynthetically acclimate but do so by different mechanisms. The Shandong accessions demonstrate a stable response, favouring energy partitioning to photochemistry while the Yukon accession shows a more rapid response with partitioning to other (non-photochemical) strategies. |
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| Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 These authors contributed equally to this work. Present Address: Agriculture and Agri-Food Canada, Lacombe Research and Development Centre, 1 Research Road, P.O. Box 29, Beaverlodge, AB T0H 0C0, Canada. Present Address: University of Saint Katherine, 1637 Capalina Road, San Marcos, CA 92069, USA. |
| ISSN: | 2223-7747 2223-7747 |
| DOI: | 10.3390/plants6030032 |