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Relative contributions of photochemical and non‐photochemical routes to excitation energy dissipation in rice and barley illuminated at a chilling temperature
Author(s) -
Xu Chang Cheng,
Jeon Young Ah,
Lee ChoonHwan
Publication year - 1999
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1034/j.1399-3054.1999.100411.x
Subject(s) - photoinhibition , xanthophyll , non photochemical quenching , chlorophyll fluorescence , quenching (fluorescence) , oryza sativa , hordeum vulgare , photosystem ii , electron transport chain , photosynthesis , japonica , chemistry , photochemistry , photoprotection , violaxanthin , cultivar , chlorophyll , botany , biology , poaceae , fluorescence , carotenoid , lutein , zeaxanthin , biochemistry , physics , quantum mechanics , gene
The mechanistic basis for differential sensitivities to chilling‐induced photoinhibition among two rice ( Oryza sativa L.) cultivars (an Indica and a Japonica type) and one barley cultivar ( Hordeum vulgare L. cv. Albori) was examined. When leaf segments were exposed to moderate illumination at 4°C, a sustained decrease in the photochemical efficiency of photosystem (PS) II measured as the ratio of variable to maximal fluorescence (F v /F m ) was observed for several hours. An analysis of fluorescence quenching revealed a sudden drop in PSII‐driven electron transport rate (ETR) and a rapid rise in the reduction state of the primary electron acceptor Q A upon exposure to chilling in moderate light. There was no appreciable difference in the level of non‐photochemical quenching (NPQ) nor in the xanthophyll cycle activity between Japonica rice and barley. However, barley was capable of sustaining a higher ETR, thereby keeping a lower reduction state of Q A throughout the chilling for 6 h. The Indica rice was characterized by the lowest ability to develop the xanthophyll cycle‐associated NPQ, particularly the fast relaxing NPQ component (qf), accompanied by the highest reduction state of Q A and photoinhibitory quenching (qI). It is concluded that the lower susceptibility of barley to chilling‐induced photoinhibition than Japonica rice is attributable to its higher potential to dissipate excess light energy via a photochemical mechanism, whereas Indica rice is more sensitive to photoinhibition at a chilling temperature than Japonica rice, due primarily to its lower capacity to develop an efficient NPQ pathway.