Photoprotective mechanisms in photosystem II of Ephedra monosperma during development of frost tolerance

Photoprotective mechanisms in photosystem II of Ephedra monosperma during development of frost... Dissipation of light energy absorbed by photosystem II (PSII) in assimilating shoots of an evergreen shrub Ephedra monosperma was investigated during its transition from the vegetative to frost-tolerant state under natural conditions of Central Yakutia. The dynamics of modulated chlorophyll fluorescence and carotenoid content was analyzed during seasonal decrease in ambient temperature. The seasonal cooling was accompanied by a stepwise decrease in photochemical activity of PSII (F v/F m = (F m − F 0)/F m). The decrease in F v/F m occurred from the beginning of September to the end of October, when the temperature was lowered from 10 to −8°C. During winter period the residual activity of PSII was retained at about 30% of the summer values. The seasonal decrease in temperature was accompanied by a significant stimulation of pH-independent dissipative processes in reaction centers and antenna of PSII. The increase in energy losses was paralleled by a proportional increase in zeaxanthin content on the background of decreasing content of violaxanthin and β-carotene as possible zeaxanthin precursors. At the same time, inhibition of light-induced non-photochemical quenching in the PSII antenna was observed. The results suggest that principal photoprotective mechanisms during seasonal lowering of temperature are: (1) inactivation of PSII and dissipation of excitation energy in PSII reaction centers and (2) zeaxanthin-mediated energy dissipation in the antenna complexes. The first mechanism seems to prevail at early stages of seasonal cooling, whereas both mechanisms are recruited from the onset of sustained freezing temperatures. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Russian Journal of Plant Physiology Springer Journals

Photoprotective mechanisms in photosystem II of Ephedra monosperma during development of frost tolerance

Loading next page...
 
/lp/springer_journal/photoprotective-mechanisms-in-photosystem-ii-of-ephedra-monosperma-FxWAWrMXwz
Publisher
Pleiades Publishing
Copyright
Copyright © 2014 by Pleiades Publishing, Ltd.
Subject
Life Sciences; Plant Physiology; Plant Sciences
ISSN
1021-4437
eISSN
1608-3407
D.O.I.
10.1134/S1021443714060181
Publisher site
See Article on Publisher Site

Abstract

Dissipation of light energy absorbed by photosystem II (PSII) in assimilating shoots of an evergreen shrub Ephedra monosperma was investigated during its transition from the vegetative to frost-tolerant state under natural conditions of Central Yakutia. The dynamics of modulated chlorophyll fluorescence and carotenoid content was analyzed during seasonal decrease in ambient temperature. The seasonal cooling was accompanied by a stepwise decrease in photochemical activity of PSII (F v/F m = (F m − F 0)/F m). The decrease in F v/F m occurred from the beginning of September to the end of October, when the temperature was lowered from 10 to −8°C. During winter period the residual activity of PSII was retained at about 30% of the summer values. The seasonal decrease in temperature was accompanied by a significant stimulation of pH-independent dissipative processes in reaction centers and antenna of PSII. The increase in energy losses was paralleled by a proportional increase in zeaxanthin content on the background of decreasing content of violaxanthin and β-carotene as possible zeaxanthin precursors. At the same time, inhibition of light-induced non-photochemical quenching in the PSII antenna was observed. The results suggest that principal photoprotective mechanisms during seasonal lowering of temperature are: (1) inactivation of PSII and dissipation of excitation energy in PSII reaction centers and (2) zeaxanthin-mediated energy dissipation in the antenna complexes. The first mechanism seems to prevail at early stages of seasonal cooling, whereas both mechanisms are recruited from the onset of sustained freezing temperatures.

Journal

Russian Journal of Plant PhysiologySpringer Journals

Published: Oct 12, 2014

References

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 12 million articles from more than
10,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Unlimited reading

Read as many articles as you need. Full articles with original layout, charts and figures. Read online, from anywhere.

Stay up to date

Keep up with your field with Personalized Recommendations and Follow Journals to get automatic updates.

Organize your research

It’s easy to organize your research with our built-in tools.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

DeepDyve Freelancer

DeepDyve Pro

Price
FREE
$49/month

$360/year
Save searches from Google Scholar, PubMed
Create lists to organize your research
Export lists, citations
Access to DeepDyve database
Abstract access only
Unlimited access to over
18 million full-text articles
Print
20 pages/month
PDF Discount
20% off