Plant Diversity ›› 2015, Vol. 37 ›› Issue (03): 283-292.DOI: 10.7677/ynzwyj201514098

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Effect of Growth Temperature on the Activity of Cyclic Electron Flow in Tobacco Leaves

 HUANG  Wei, HU  Hong   

  1.  Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany,
    Chinese Academy of Sciences, Kunming 650201, China
  • Received:2014-07-01 Online:2015-05-25 Published:2014-07-25
  • Supported by:

    National Natural Science Foundation of China (grant 31300332) and the Following Scientific Foundations (110201101003 (TS03), 2011YN02, 2011YN03)


Cyclic electron flow (CEF) around photosystem I (PSI) is an important mechanism for photoprotection in higher plants under environmental stresses. However, the response of CEF activity to growth temperature has not been clarified. We here monitored gas exchange, chlorophyll fluorescence, and the P700 redox state over a range of light intensities in leaves of tobacco cultivar ‘k326’ grown at 24/18℃ and 32/26℃ (day/night). No significant difference was found in the capacity of photosynthetic CO2 assimilation between the plants grown at 24℃ and 32℃. In addition, the light response changes in the photochemical quenching of photosystem II (Y(II)) and nonphotochemical quenching (NPQ) did not differ significantly between those plants. Light response curves indicated that the plants grown at 24℃ and 32℃ displayed the same level of electron flow through PSII (ETR II) irrespective of light intensity. However, under intense light, plants grown at 24℃ showed significantly higher electron flow through PSI (ETR I). The ETR I/ETR II ratio was significantly higher in plants grown at 24℃ when exposed to intense light.  Furthermore, after shortterm treatment with strong light at 24℃, the maximum quantum yield of photosystem II (Fv/Fm) was significantly higher in plants grown at 24℃ than that grown at 32℃. Taken together, our results suggest that enhancement of CEF activity in plants grown at 24℃ alleviates PSII photoinhibition, which is an important strategy in tobacco for acclimating to a relatively low growth temperature.

Key words: Cyclic electron flow, Growth temperature, Photoinhibition, Photoprotection Photosystem II

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