Photosynthesis Research

, Volume 56, Issue 1, pp 95–102

Both spillover and light absorption cross-section changes are involved in the regulation of excitation energy distribution between the two photosystems during state transitions in wheat leaf

  • Xin-Xing Tan
  • Da-Quan Xu
  • Yun-Kang Shen
Article

DOI: 10.1023/A:1005953528191

Cite this article as:
Tan, XX., Xu, DQ. & Shen, YK. Photosynthesis Research (1998) 56: 95. doi:10.1023/A:1005953528191

Abstract

Weak red light-induced changes in chlorophyll fluorescence parameters and in the distribution of PS I and PS II in thylakoid membranes were measured in wheat leaves to investigate effective ways to alter the excitation energy distribution between the two photosystems during state transition in vivo. Both the chlorophyll fluorescence parameter Fm/Fo and F685/F735, the ratio of fluorescence yields of the two photosystems at low temperature (77 K), decreased when wheat leaves were illuminated by weak red light of 640 nm, however, Fm/Fo decreased to its minimum in a shorter time than F685/F735. When Photosystem (PS II) thylakoid (BBY) membranes from adequately dark-adapted leaves (control) and from red light-illuminated leaves were subjected to SDS-polyacrylamide gel electrophoresis under mildly denaturing conditions, PS I was almost absent in the control, but was present in the membranes from the leaves preilluminated with the weak red light. In consonance with this result, the content of Cu, measured by means of the energy dispersive X-ray microanalysis (EDX), increased in the central region, but decreased in the margin of the grana stacks from the leaves preilluminated by the red light as compared with the control. It is therefore suggested that: (i) both spillover and absorption cross-section changes are effective ways to alter the excitation energy distribution between the two photosystems during state transitions in vivo, and the change in spillover has a quicker response to the unbalanced light absorption of the two photosystems than the change in light absorption cross-section, and (ii) the migration of PS I towards the central region of grana stack during the transition to state 2 leads to the enhancement of excitation energy spillover from PS II to PS I.

chlorophyll fluorescence LHC II Photosystem I Photosystem II protein transfer state transition thylakoid membranes 

Copyright information

© Kluwer Academic Publishers 1998

Authors and Affiliations

  • Xin-Xing Tan
    • 1
  • Da-Quan Xu
    • 1
  • Yun-Kang Shen
    • 1
  1. 1.Shanghai Institute of Plant Physiologythe Chinese Academy of SciencesShanghaithe People's Republic of China

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