I'm a plant physiology researcher, but water potentials are not really my thing, so I don't have a great grasp on the literature. I'm dealing with water potential data right now though, and it seems questionable to me. Some of the measured water potential (solute + metric potentials, after lysing cells to break turgor) are as low as -48 bars (most in -10 to -35 range).
That would, if my math is correct, translate to a solute concentration in the 2000 mOsmol range, which seems extremely high to me. Consequently, I'm trying to determine if there is an analytic issue with the data collection. I've run through the equipment chain, checked calibrations, and everything seems ok. I've also been combing plant physiology lit. for comparable data, and I find some in that range, but I can't find any theoretical work that would help set a 'ceiling' for what constitutes a reasonable solute + metric potential.
So, my questions are these:
What is the theoretical maximum capacity for dissolved ion concentration in water, and what pressure potential would that represent, compared to pure water.
Is anyone aware of plant physiology research that has attempted to establish a minimum in vivo water potential in plants (either total potential, or S+M if it's broken out)?