Garstka Maciej, Venema Jan Henk, Rumak Izabela, Gieczewska Katarzyna, Rosiak Malgorzata, Koziol-Lipinska Joanna, Kierdaszuk Borys, Vredenberg Wim J, Mostowska Agnieszka
Department of Metabolic Regulation, Institute of Biochemistry, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland.
Planta. 2007 Oct;226(5):1165-81. doi: 10.1007/s00425-007-0562-7. Epub 2007 Jun 14.
The effect of dark-chilling and subsequent photoactivation on chloroplast structure and arrangements of chlorophyll-protein complexes in thylakoid membranes was studied in chilling-tolerant (CT) pea and in chilling-sensitive (CS) tomato. Dark-chilling did not influence chlorophyll content and Chl a/b ratio in thylakoids of both species. A decline of Chl a fluorescence intensity and an increase of the ratio of fluorescence intensities of PSI and PSII at 120 K was observed after dark-chilling in thylakoids isolated from tomato, but not from pea leaves. Chilling of pea leaves induced an increase of the relative contribution of LHCII and PSII fluorescence. A substantial decrease of the LHCII/PSII fluorescence accompanied by an increase of that from LHCI/PSI was observed in thylakoids from chilled tomato leaves; both were attenuated by photoactivation. Chlorophyll fluorescence of bright grana discs in chloroplasts from dark-chilled leaves, detected by confocal laser scanning microscopy, was more condensed in pea but significantly dispersed in tomato, compared with control samples. The chloroplast images from transmission-electron microscopy revealed that dark-chilling induced an increase of the degree of grana stacking only in pea chloroplasts. Analyses of O-J-D-I-P fluorescence induction curves in leaves of CS tomato before and after recovery from chilling indicate changes in electron transport rates at acceptor- and donor side of PS II and an increase in antenna size. In CT pea leaves these effects were absent, except for a small but irreversible effect on PSII activity and antenna size. Thus, the differences in chloroplast structure between CS and CT plants, induced by dark-chilling are a consequence of different thylakoid supercomplexes rearrangements.
在耐冷（CT）豌豆和冷敏（CS）番茄中研究了暗冷处理及随后的光激活对叶绿体结构和类囊体膜中叶绿素 - 蛋白质复合物排列的影响。暗冷处理对两种植物类囊体中的叶绿素含量和叶绿素a/b比值均无影响。从番茄而非豌豆叶片分离的类囊体经暗冷处理后，在120K时观察到叶绿素a荧光强度下降以及PSI和PSII荧光强度比值增加。豌豆叶片冷处理导致LHCII和PSII荧光的相对贡献增加。在冷处理番茄叶片的类囊体中观察到LHCII/PSII荧光大幅下降，同时LHCI/PSI荧光增加；两者均因光激活而减弱。与对照样品相比，通过共聚焦激光扫描显微镜检测，暗冷处理叶片叶绿体中明亮基粒片层的叶绿素荧光在豌豆中更聚集，而在番茄中显著分散。透射电子显微镜下的叶绿体图像显示，暗冷处理仅导致豌豆叶绿体中基粒堆叠程度增加。对冷敏番茄叶片在冷处理恢复前后的O - J - D - I - P荧光诱导曲线分析表明，PS II受体侧和供体侧的电子传递速率发生变化，且天线大小增加。在耐冷豌豆叶片中，除了对PSII活性和天线大小有微小但不可逆的影响外，这些效应均不存在。因此，暗冷处理诱导的冷敏和耐冷植物叶绿体结构差异是类囊体超复合物不同重排的结果。
