TY - JOUR
T1 - Xanthophyll cycle, light energy dissipation and photosystem II down-regulation in senescent leaves of wheat plants grown in the field
AU - Lu, C.
AU - Lu, Q.
AU - Zhang, Jianhua
AU - Zhang, Q.
AU - Kuang, T.
N1 - Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2001
Y1 - 2001
N2 - Photosynthesis, the xanthophyll cycle, light energy dissipation and down-regulation of photosystem II (PSII) in senescent leaves of wheat plants grown in the field were investigated. With the progress of senescence, maximal efficiency of PSII photochemistry decreased only slightly early in the morning but substantially at midday. Actual PSII efficiency, photochemical quenching, efficiency of excitation capture by open PSII centres, and the I-P phase of fluorescence induction curves decreased significantly and such decreases were much more evident at midday than in the morning. At the same time, non-photochemical quenching, thermal dissipation and de-epoxidation status of the xanthophyll cycle increased, with much greater increases at midday than in the morning. These results suggest that the xanthophyll cycle played a role in photoprotection of PSII in senescent leaves by dissipating excess excitation energy. Taking into account the substantial decrease in photosynthetic capacity in senescent leaves, our data seem to support the view that the decrease in actual PSII efficiency in senescent leaves may represent a mechanism to down-regulate photosynthetic electron transport to match the decreased CO2 assimilation capacity and avoid photodamage of PSII from excess excitation energy.
AB - Photosynthesis, the xanthophyll cycle, light energy dissipation and down-regulation of photosystem II (PSII) in senescent leaves of wheat plants grown in the field were investigated. With the progress of senescence, maximal efficiency of PSII photochemistry decreased only slightly early in the morning but substantially at midday. Actual PSII efficiency, photochemical quenching, efficiency of excitation capture by open PSII centres, and the I-P phase of fluorescence induction curves decreased significantly and such decreases were much more evident at midday than in the morning. At the same time, non-photochemical quenching, thermal dissipation and de-epoxidation status of the xanthophyll cycle increased, with much greater increases at midday than in the morning. These results suggest that the xanthophyll cycle played a role in photoprotection of PSII in senescent leaves by dissipating excess excitation energy. Taking into account the substantial decrease in photosynthetic capacity in senescent leaves, our data seem to support the view that the decrease in actual PSII efficiency in senescent leaves may represent a mechanism to down-regulate photosynthetic electron transport to match the decreased CO2 assimilation capacity and avoid photodamage of PSII from excess excitation energy.
KW - Chlorophyll fluorescence
KW - Leaf senescence
KW - Photosynthesis
KW - Photosystem II
KW - Thermal energy dissipation
KW - Xanthophyll cycle
UR - http://www.scopus.com/inward/record.url?scp=0034783608&partnerID=8YFLogxK
U2 - 10.1071/pp01109
DO - 10.1071/pp01109
M3 - Journal article
AN - SCOPUS:0034783608
SN - 0310-7841
VL - 28
SP - 1023
EP - 1030
JO - Australian Journal of Plant Physiology
JF - Australian Journal of Plant Physiology
IS - 10
ER -