Iron toxicity in Chlamydomonas in relation to P limitation

绿色鞭毛虫藻种Chlamydiumacidophila在多重胁迫环境中面临共限制条件。在该方案中，无机磷（Pi）和无机碳（CO2）的共同限制条件以及在高铁浓度湖泊中的生存（多重胁迫）是中心议题。嗜酸菌可能受到Pi和/或CO2的限制。在正在进行的实验室实验中，在收购的Pi或CO2的权衡被发现，这是更强烈的细胞磷配额（QP）比外部营养浓度。这种相关性增强了我们对自然浮游植物种群动态的理解，可能是Pi和CO2的共同限制。结果表明，铁胁迫对铁胁迫下的生长和光合产量具有较强的耐受性。嗜酸菌，但也有负面影响。例如，高的外部Fe浓度导致细胞的Pi限制。其他结果表明，增强细胞铁积累和叶绿素含量之间呈负相关。在项目GA 401/12的第三年，我想完成一个共同限制的实验工作，并研究生理反应（例如铁积累和位置，C，P和Fe细胞配额和光合作用）的嗜酸藻不同的环境P：Fe比，目的是解开铁耐受机制和铁积累对我们的模式藻类的生理生态的影响。

The green flagellate algal species Chlamydomonas acidophila faces co-limiting conditions in a multi-stress environment. In this proposal, co-limiting conditions for inorganic P (Pi) and inorganic carbon (CO2) as well as survival in lakes with high iron concentrations (multi-stress) are the central topics.In the very acidic lakes, growth of C. acidophila is potentially limited by Pi and/or CO2. In ongoing laboratory experiments, a trade-off in the acquisition of either Pi or CO2 was revealed, that was more strongly related to the cellular P quota (Qp) than to the external nutrient concentration. This correlation enhanced our understanding of the dynamics of natural phytoplankton populations possibly co-limited for Pi and CO2. First data show a high tolerance for high iron concentrations on the growth and photosynthetic yield of C. acidophila, but also negative effects. For example, high extemal Fe concentrations resulted in a cellular Pi-limitation. Other results showed a negative correlation between enhanced cellular Fe accumulations and the chlorophyll content. In a 3rd year of the project GA401/12, I want to finalise the experimental work on a co-limitation, and study the physiological response (e.g. Fe accumulation and location, C, P and Fe cell quotas and photosynthesis) of C acidophila to different ambient P:Fe ratios with the aim to unravel mechanisms of iron tolerance and the impact of Fe accumulation on the ecophysiology of our model algal species.