Abstract
The extreme environment of the Great Salt Plains (GSP) results in low algal biomass, such that natural selection is likely driven by survival of multiple abiotic stresses rather than rapid growth and biotic interactions. The objective of this study was to determine the effect of combined salinity stress and iron limitation on growth and photosynthesis in the green alga, Picochlorum oklahomensis isolated from the GSP habitat. Algal cells were grown in batch cultures under iron sufficiency or iron limitation at salinities of 10, 50 and 100 ppt in artificial seawater (AS 100) medium. Cells were physiologically characterized by growth rates, cell density, photosynthetic light-response curves (oxygen evolution), pigment composition and the chlorophyll fluorescence parameters Fv/Fm, ФPSII, qP and NPQ. P. oklahomensis cultured in no added Fe exhibit smaller inhibition by 100 ppt salinity relative to 10 ppt. Thus, high salinity appears to be reduced under low nutrient conditions. Fe stress resulted in qualitative differences in physiological response. The interaction between salinity and low iron is consistent with a general stress response that concurrently protects against several abiotic stress factors. Key words: Iron limitation, salinity stress, Picochlorum sp.
Highlights
Origin, characteristics and classification of Picochlorum oklahomensisPicochlorum oklahomensis, a unicellular halotolerant green alga, was isolated from shallow evaporitic pools at the Salt Plains National Wildlife Refuge (SPNWR) in northwestern Oklahoma, USA
The objective of this study was to determine the effect of combined salinity stress and iron limitation on growth and photosynthesis in the green alga, P. oklahomensis
The organism used in this study is P. oklahomensis, a unicellular green alga, which was isolated from the Salt Plains National Wildlife Refuge, Oklahoma, USA
Summary
Picochlorum oklahomensis, a unicellular halotolerant green alga, was isolated from shallow evaporitic pools at the Salt Plains National Wildlife Refuge (SPNWR) in northwestern Oklahoma, USA. Is classified as belonging to the Domain Eukarya, Kingdom Protista, Division Chlorophyta and Class Trebouxiophyceae (Graham and Wilcox, 2000; Henley et al, 2002, 2004). The SPNWR is characterized as being a hypersaline environment with a warm-temperate, semiarid, continen-. Tal climate (Henley et al, 2002). Hypersaline environments, including the SPNWR usually have high salinity, exhibit fluctuations in their salt concentration over time because they are occasionally flooded by rain or seawater and are subject to evaporation. Organisms living in the SPNWR are exposed to these environmental variations and may have developed ways to cope with these changes
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
