|作者：||Rahma Goussi, Arafet Manaa, Walid Derbali, Simone Cantamessa, Chedly Abdelly, Roberto Barbato|
1Faculté des Sciences de Tunis, Université Tunis El Manar, 2092, Tunisia
2Laboratory of Extremophile Plants, Centre of Biotechnology of Borj Cedria, B.P. 901, Hammam-Lif 2050, Tunisia.
3Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale, viale Teresa Michel 11, 15121 Alessandria, Italy
|刊名：||Journal of Photochemistry & Photobiology, B: Biology, 2018, Vol.183 , pp.275-287|
|关键词：||Chloroplasts; Fluorescence; Halophyte; Photosynthesis; Salinity; Thellungiella;|
|英文摘要：||Abstract(#br)Salinity is one of the most important abiotic stress affecting plant growth and productivity worldwide. Photosynthesis, together with cell growth, is among the primary process affected by salinity. Here, we report the effects of salt stress on photosynthesis in the model halophyte Thellungiella salsuginea . Plants were grown in hydroponic system and then treated for 2 weeks with different NaCl concentrations (0, 100, 200 and 400 mM). Leaf analysis using both photonic and transmission electron microscopes showed some changes in mesophyll cell organization, including shape and dimension. Under high NaCl concentration (400 mM) a swelling of thylakoids and starch accumulation was also observed. The obtained results also showed a change in the photosynthetic efficiency of both... photosystems (PSI and PSII), depending on both NaCl concentrations and duration of the stress treatment. Under moderate salinity (100 and 200 mM NaCl) no significant variation was observed in PSI and PSII yield parameters. Chlorophyll a fluorescence transient showed some variations in OJ, JI and IP phases under salt stress depending also on NaCl levels and the duration of stress. Under high salinity PSII donor side was affected as well as quantum yield of PSI which also showed a donor side limitation. A significant decrease on quantum yields Y(I) and Y(II) under high salt treatment (400 mM NaCl) for prolonged period of time (15 days) was observed. The decrease of these parameters was quantitatively compensated by a corresponding increase of energy thermal dissipation Y(NPQ) in photosystem II and a increase in the Y(ND) in PSI. Analysis of derived parameters from the OJIP transient curve revealed that ABS/RC decreased under NaCl treatment by reason of the increase in size of antenna of active reaction centers. An increase in the performance index PI (ABS) , a slight decrease in the rate of DI O /RC, TR O /RC and the level of electron transport per PSII RC (ET O /RC) were observed during the first days of salt stress treatment reflecting a high PSII efficiency.|