Dustin, this is a great question. I haven't used a PhotosynQ , but it should be good at making a few different measurements that provide a robust index of of how much photosynthesis a leaf is capable of. With some additional gear, it could also provide an index of how active soil microbes are. These types of biological activity vary for lots of reasons, so PhotosynQ measurements will be most useful when they are planned to control for many variables. For example, photosynthetic activity or efficiency varies with season, time of day, temperature, humidity, light level, soil moisture, soil fertility, plant species, plant phenology, and plant health. Ascribing differences in PhotosynQ measurements to plant health requires controlling all of those other variables. If this is done, and differences in plant health are suspected, ascribing those differences to contaminants requires other information about the contaminants (information which the PhotosynQ cannot provide).

Having a PhotosynQ MultispeQ is going to be like having a fancy stethoscope that in addition to heart sounds also records blood oxygen and sugar levels and the temperature and conductivity of skin. We could go around easily collecting data from lots of people. If I gave you the data from 20 people I ran into during a day, could you tell which ones had the flu? Which ones were old? Which ones smoked? Which were overweight? Which ones were alcoholics? Without other information about my data collection, probably not.

But if I told you that 10 of the people were high school soccer players and 10 were retired office workers, and the measurements were taken right after a five minute treadmill session, you might be able to figure out which was which. Or if the measurements were taken every six minutes of one person who was snowshoeing for an hour and another person who was watching television for an hour, you could probably tell which was the slacker. Or if I told you that the measurements were taken once per hour on two people, one of whom ate lunch and dinner and one of whom ate nothing, you could probably discern which was hungry. Or if the measurements were taken every 10 minutes on two people watching television, one who had a 32 ounce Coke after 30 minutes and one who drank water after 30 minutes, you could probably identify the Coke drinker.

However, if I didn't tell you anything about the people I measured, you could discern the differences between them, but you would be hard pressed to know what caused the differences. PhotosynQ measurements will differentiate plants with different photosynthetic characteristics, but they might not tell you much about why the plants are different. There are a whole lot of things that can cause photosynthetic measurements of two plants, or of the same plant at two times, to differ.

PhotosynQ measurements will be most useful if they are taken in a deliberate manner that isolates one variable and provides many replicate data points. Figuring out a good study design will require thinking about what environmental and physiological variables influence the measurements. There are some potential studies listed at this wiki, but it doesn't seem to be very up to date. I hope some good introductory materials are produced to help people design good observations.

Chris