Journal
PROTOPLASMA
Volume 254, Issue 4, Pages 1755-1767Publisher
SPRINGER WIEN
DOI: 10.1007/s00709-016-1068-6
Keywords
Chlorophyll fluorescence; Desiccation; Light; Photosynthesis; Temperature
Categories
Funding
- Austrian Science Foundation (FWF)
- FWF [P 24242-B16, I 1951-B16]
- DFG [KA899/16-1/4]
- USA NSF [DEB-1036448]
- Austrian Science Fund (FWF) [I1951] Funding Source: Austrian Science Fund (FWF)
- Direct For Biological Sciences
- Division Of Environmental Biology [1036448] Funding Source: National Science Foundation
Ask authors/readers for more resources
The phylogenetic placement of Prasiola calophylla, from an anthropogenic habitat previously shown to contain a novel UV sunscreen compound, was confirmed by analysis of its rbcL gene. This alga has the capacity to tolerate strong water-limiting conditions. The photosynthetic performance and ultrastructural changes under desiccation and osmotic stress were investigated. Freshly harvested thalli showed an effective quantum yield of PSII [Y(II)] of 0.52 +/- 0.06 that decreased to similar to 60% of the initial value at 3000 mM sorbitol, and 4000 mM sorbitol led to a complete loss of Y(II). The Y(II) of thalli exposed to controlled desiccating conditions at 60% relative humidity (RH) ceased within 240 min, whereas zero values were reached after 120 min at 20% RH. All investigated samples completely recovered Y(II) within similar to 100 min after rehydration. Relative electron transport rates (rETR) were temperature dependent, increasing from 5, 10, to 25 A degrees C but strongly declining at 45 A degrees C. Transmission electron microscopy of samples desiccated for 2.5 h showed an electron dense appearance of the entire cytoplasm when compared to control samples. Thylakoid membranes were still visible in desiccated cells, corroborating the ability to recover. Control and desiccated cells contained numerous storage lipids and starch grains, providing reserves. Overall, P. calophylla showed a high capacity to cope with water-limiting conditions on a physiological and structural basis. A lipophilic outer layer of the cell walls might contribute to reduce water evaporation in this poikilohydric organism.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available