120th General Meeting of the KCS

Type Symposium
Area Physical Chemistry of Bioimaging and Biospectroscopy
Room No. Room 208+209+210
Time FRI 10:05-:
Code PHYS2-4
Subject Monitoring state transitions in plants using in vivo spectromicroscopy
Authors Tae Kyu Ahn
Department of Energy Science, Sungkyunkwan University, Korea
Abstract In chloroplasts of plants and algae, state transition is an important regulatory mechanism to maintain the excitation balance between PSI and PSII in the thylakoid membrane. Light-harvesting complex II (LHCII) plays a key role as the regulated energy distributor between PSI and PSII. It is widely accepted that LHCII, which is bound to PSII localized mainly in the granal thylakoid, migrates to bind with PSI localized mainly in the stroma-exposed thylakoid under preferential excitation of PSII. The phenomena have been extensively characterized by many methods. However, the exchange of LHCII between PSII and PSI has not been directly observed in vivo at physiological temperatures. Herein we applied fluorescence spectromicroscopy to Arabidopsis mesophyll protoplasts in order to observe in vivo changes in fluorescence spectra of granal and stromal thylakoid regions during the state transition. The microscopic fluorescence spectra obtained from a few sections with different depths were decomposed into PSI and PSII spectra and self-absorption effects were removed. We were able to determine amplitude changes of PSI and PSII in fluorescence spectra solely due to state transition. Subdomain analysis of granal and stromal thylakoid regions clarified variant behaviors in the different regions. 1. E. Kim, T.K. Ahn, S. Kumazaki, Plant & Cell Physiology 2015, 56(4), 749-768
E-mail taeahn@skku.edu