Lichens Assist the Drought-Induced Fluorescence Quenching of Their Photobiont Green Algae Through Arabitol
In order to clarify the role of symbiotic association in drought tolerance of photosynthetic partners in lichens, responses to air-drying treatments in a green-algal lichen (Ramalina yasudae Ras(a)nen) and its green algal photobiont (Trebouxia sp.) were studied. Responses to dehydration in the isolated Trebouxia sp. were different from those in the lichen. R. yasudae. Dehydration induced quenching of PS Ⅱ fluorescence (d-NPQ) was less in the isolated Trebouxia sp. compared with that in R. yasudae, suggesting that a substance(s) or a mechanism(s) to dissipate absorbed light energy to heat was lost by the isolation of the photobiont, and the air-dried isolated Trebouxia sp. showed a higher sensitivity to photoinhibition than R. yasudae. We assayed the effects of various substances extracted from R. yasudae thalli on the fluorescence of Trebouxia sp. And we found the d-NPQ-type fluorescence quenching in the Trebouxia sp. was accelerated if they were dried with arabitol which was the main component of the water extract of R. yasudae. These results support the idea that arbitol triggered the photoprotection mechanism under drought conditions of the photobiont symbiotic with the mycobionts.
Drought tolerance Photoinhibition Non-photochemical quenching Symbiosis Lichens
Makiko Kosugi Akihisa Miyake Yasuhiro Kasino Yutaka Shibata Kazuhiko Satoh Shigeru Itoh
Division of Biosciences, Graduate School of Natural Science and Technology, Okayama University, Okay Division of Material Science (Physics), Graduate School of Science, Nagoya University, Furocho, Chik Department of Life Science, School of Life Science, University of Hyogo, Harima Science Garden City,
国际会议
15th International Conference on Photosynthesis(第15届国际光合作用大会)
北京
英文
514-517
2010-08-22（万方平台首次上网日期，不代表论文的发表时间）