Publication details
Photosynthesis of lichen symbiotic alga Trebouxia erici as affected by irradiance and osmotic stress
| Authors | |
|---|---|
| Year of publication | 2006 |
| Type | Article in Periodical |
| Magazine / Source | Biologia Plantarum |
| MU Faculty or unit | |
| Citation | |
| web | http://dx.doi.org/10.1007/s10535-006-0016-2 |
| Field | Microbiology, virology |
| Keywords | chlorophyll fluorescence; oxygen evolution; photobiont; photosynthesis; quantum yield |
| Description | The relation between oxygen evolution rate (OER) and quantum yield of photochemical reactions in photosystem 2 ("Fi"PS2) was examined in lichen symbiotic alga Trebouxia erici Ahmadjian (strain UTEX 911) exposed to different irradiances and osmotic stress (2 M sucrose for 60 h). Linear relationship was found between OER and "Fi"PS2 in control cell suspension within irradiance range of - 0 500 umol m-2 s-1. Under osmotic stress, OER and "Fi"PS2 were significantly reduced. Relation between OER and "Fi"PS2 was curvilinear due to strong osmotically-induced inhibition of OER at high irradiance. The highest used irradiance (500 umol m-2 s-1) was photoinhibitory for osmotically-stressed T. erici because non-photochemical quenching (NPQ) increased substantially. Energy-dependent quenching represented major part of NPQ increase. Osmotic stress led also to the reduction of capacity of photochemical processes in PS 2 (Fv/Fm) and increase in Fo/Fm. These changes indicated negative effects of osmoticum on structure and function of photosynthetic apparatus. |
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